U.S. patent application number 13/940432 was filed with the patent office on 2014-01-02 for automatically balancing register for hvac systems.
This patent application is currently assigned to Zoner LLC. The applicant listed for this patent is Zoner LLC. Invention is credited to Jon Barrett, Ronald Lingemann.
Application Number | 20140000861 13/940432 |
Document ID | / |
Family ID | 42046330 |
Filed Date | 2014-01-02 |
United States Patent
Application |
20140000861 |
Kind Code |
A1 |
Barrett; Jon ; et
al. |
January 2, 2014 |
Automatically Balancing Register for HVAC Systems
Abstract
Distributed nodes, such as intelligent register controllers, of
a heating, ventilating and/or air conditioning (HVAC) system
wirelessly communicate with each other on a peer-to-peer basis,
forming a network, and collectively control the HVAC system,
without a central controller. The intelligent register controllers
collectively control the amount of conditioned air introduced into
each region. Each node may base its operation at least in part on
information about one or more (ideally all) of the other nodes.
Each intelligent register controller automatically determines how
much conditioned air to allow into its region, or how much return
air to allow to be withdrawn from its region. Each register
controller automatically determines when and to what extent to
operate its respective controllable damper.
Inventors: |
Barrett; Jon; (Boulder,
CO) ; Lingemann; Ronald; (Boulder, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Zoner LLC |
Boulder |
CO |
US |
|
|
Assignee: |
Zoner LLC
Boulder
CO
|
Family ID: |
42046330 |
Appl. No.: |
13/940432 |
Filed: |
July 12, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12650320 |
Dec 30, 2009 |
8550370 |
|
|
13940432 |
|
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61203911 |
Dec 30, 2008 |
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Current U.S.
Class: |
165/208 ;
165/211; 236/49.3; 236/51 |
Current CPC
Class: |
F24F 11/56 20180101;
F24F 11/76 20180101; F24F 13/082 20130101; F24F 11/755 20180101;
G05D 23/1934 20130101; F24F 3/044 20130101; F24F 11/62 20180101;
G05D 23/1932 20130101; F24F 11/30 20180101; F24H 9/2064 20130101;
G05D 23/1928 20130101 |
Class at
Publication: |
165/208 ;
236/49.3; 236/51; 165/211 |
International
Class: |
G05D 23/19 20060101
G05D023/19; F24F 11/053 20060101 F24F011/053; F24H 9/20 20060101
F24H009/20; F24F 3/044 20060101 F24F003/044 |
Claims
1. A system for controlling an HVAC system having a plurality of
HVAC vents, each vent of the plurality of HVAC vents disposed in a
corresponding location in a building, the system comprising: a
plurality of intelligent controlled registers, wherein each
register of the plurality of intelligent controlled registers: is
in airflow communication with a corresponding vent of the plurality
of HVAC vents; is in data communication with at least one other
register of the plurality of intelligent controlled registers; and
includes a controller configured to execute an autonomous local
control program, such that the controller processes data provided
by each other register of the plurality of intelligent controlled
registers so as to: collectively control the plurality of HVAC
vents on a peer-to-peer basis, such that, if a location in the
building corresponding to another register of the plurality of
intelligent controlled registers fails to reach a first desired
temperature despite the another register being fully open, and a
location in the building corresponding to the intelligent
controlled register has reached a second temperature, the
intelligent controlled register decreases airflow therethrough.
2. A system for controlling an HVAC system according to claim 1,
wherein the controller is configured to decreases the airflow by an
amount based at least in part on a difference between a temperature
of the location in the building corresponding to the another
register and the first desired temperature.
3. A system for controlling an HVAC system according to claim 2,
wherein the controller is configured to decreases the airflow by an
amount based at least in part on an amount of time during which the
location in the building corresponding to the another register has
failed to reach the first desired temperature.
4. A system for controlling an HVAC system according to claim 1
wherein, if the location in the building corresponding to the
another register fails to reach the first desired temperature
despite the another register being fully open, and the location in
the building corresponding to the intelligent controlled register
has reached a second temperature, the controller is configured to
expand a range of desired temperature.
5. A system for controlling an HVAC system according to claim 1,
wherein at least one register of the plurality of intelligent
controlled registers is in wireless communication with at least one
other register of the plurality of intelligent controlled
registers.
6. A system for controlling an HVAC system according to claim 1,
wherein at least one register of the plurality of intelligent
controlled registers is in wired communication with at least one
other register of the plurality of intelligent controlled
registers.
7. A system for controlling an HVAC system according to claim 1,
wherein each register of the plurality of intelligent controlled
registers is configured to: automatically determine presence of an
intelligent controlled register that is not part of the system for
controlling the HVAC system; automatically ascertain if the
determined intelligent controlled register should be added to the
system for controlling the HVAC; and if the determined intelligent
controlled register should be added to the system for controlling
the HVAC system, automatically add the determined intelligent
controlled register to the system for controlling the HVAC
system.
8. A system for controlling an HVAC system according to claim 7,
wherein each register of the plurality of intelligent controlled
registers is further configured to automatically ascertain if the
determined intelligent controlled register should be added to the
system for controlling the HVAC system according to timing of air
flow through the register and timing of air flow through the
determined intelligent controlled register.
9. A system for controlling an HVAC system according to claim 1,
wherein each register of the plurality of intelligent controlled
registers is configured to: automatically determine presence of at
least one other register of the plurality of intelligent controlled
registers; automatically ascertain if the at least one other
register should be added to the system for controlling the HVAC;
and if the at least one other register should be added to the
system for controlling the HVAC system, automatically add the at
least one other register to the system for controlling the HVAC
system.
10. A system for controlling an HVAC system according to claim 9,
wherein each register of the plurality of intelligent controlled
registers is further configured to automatically ascertain if the
at least one other register should be added to the system for
controlling the HVAC system according to timing of air flow through
the register and timing of air flow through the at least one other
register.
11. A system for controlling an HVAC system according to claim 1,
wherein each register of the plurality of intelligent controlled
registers is configured to: wirelessly automatically determine
presence of a thermostat that is not part of the system for
controlling the HVAC system; automatically ascertain if the
determined thermostat should be added to the system for controlling
the HVAC; if the determined thermostat should be added to the
system for controlling the HVAC system, automatically add the
determined thermostat to the system for controlling the HVAC system
and wirelessly receive from the thermostat the second
temperature.
12. A system for controlling an HVAC system according to claim 11,
wherein each register of the plurality of intelligent controlled
registers is further configured to automatically ascertain if the
determined thermostat should be added to the system for controlling
the HVAC system according to timing of light detected by the
thermostat and timing of light detected by the register.
13. A system for controlling an HVAC system according to claim 11,
wherein each register of the plurality of intelligent controlled
registers is further configured to automatically ascertain if the
determined thermostat should be added to the system for controlling
the HVAC system according to timing of temperature changes detected
by the thermostat and timing of temperature changes detected by the
register.
14. A system for controlling an HVAC system according to claim 1,
wherein each register of the plurality of intelligent controlled
registers includes a controllable damper, and each register is
configured such that, when air flows through the controllable
damper, at least one of the dampers of the plurality of intelligent
controlled registers is fully open.
15. A system for controlling an HVAC system according to claim 1,
wherein each register of the plurality of intelligent controlled
register is configured to: wirelessly receive data from at least
one other register of the plurality of intelligent controlled
registers; and forward at least some of the received data to
another at least one register of the plurality of intelligent
controlled registers.
16. A system for controlling an HVAC system according to claim 1,
wherein each register of the plurality of intelligent controlled
registers is configured, absent an external input specifying a
setpoint temperature for the corresponding location, so as to
equalize temperatures of the locations in the building.
17. A system for controlling an HVAC system according to claim 1,
wherein each register of the plurality of intelligent controlled
registers is configured so as to maximize flow through at least one
register of the plurality of intelligent controlled registers.
18. A system for controlling an HVAC system according to claim 1,
wherein: the HVAC system comprises a blower and a heating or
cooling unit; at least one of the plurality of HVAC vents comprises
a return vent; and at least one of the plurality of HVAC vents
comprises a supply vent; the system further comprising a thermostat
coupled to the HVAC system so as to control the blower and coupled
to at least one of the plurality of intelligent controlled
registers; and wherein each register of the plurality of
intelligent controlled registers is configured to operate so as to
permit air to be drawn in by an automatically selected at least one
of the return vent, moved by the blower, and exhausted through an
automatically selected at least one of the supply vent, without
operating the heating or cooling unit, so as to transfer air from
at least one automatically selected location in the building to
another at least one automatically selected location in the
building.
19. A system for controlling an HVAC system having a plurality of
HVAC vents, each vent of the plurality of HVAC vents disposed in a
corresponding location in a building, the system comprising: a
plurality of intelligent controlled registers, wherein each
register of the plurality of intelligent controlled registers: is
in airflow communication with a corresponding vent of the plurality
of HVAC vents; is in data communication with at least one other
register of the plurality of intelligent controlled registers; and
includes a controller configured to execute an autonomous local
control program, such that the controller processes data provided
by each other register of the plurality of intelligent controlled
registers so as to: collectively control the plurality of HVAC
vents on a peer-to-peer basis, so as to, absent an external input
specifying a setpoint temperature for the register, equalize
temperatures of the locations in the building.
20. A method for controlling an HVAC system having a plurality of
HVAC vents, each vent of the plurality of HVAC vents disposed in a
corresponding location in a building, the HVAC system including a
plurality of intelligent controlled registers, wherein each
register of the plurality of intelligent controlled registers: (a)
is in airflow communication with a corresponding vent of the
plurality of HVAC vents, (b) is in data communication with at least
one other register of the plurality of intelligent controlled
registers and (c) includes a controller, the method comprising:
executing an autonomous local control program by the controller of
one register of the plurality of intelligently controlled
registers; processing, by the controller, data provided by each
other register of the plurality of intelligent controlled registers
so as to: collectively control the plurality of HVAC vents on a
peer-to-peer basis, such that, if a location in the building
corresponding to another register of the plurality of intelligent
controlled registers fails to reach a first desired temperature
despite the another register being fully open, and a location in
the building corresponding to the intelligent controlled register
has reached a second temperature, the intelligent controlled
register decreases airflow therethrough.
21. A method for controlling an HVAC system having a plurality of
HVAC vents, each vent of the plurality of HVAC vents disposed in a
corresponding location in a building, the HVAC system including a
plurality of intelligent controlled registers, wherein each
register of the plurality of intelligent controlled registers: (a)
is in airflow communication with a corresponding vent of the
plurality of HVAC vents, (b) is in data communication with at least
one other register of the plurality of intelligent controlled
registers and (c) includes a controller, the method comprising:
executing an autonomous local control program by the controller of
one register of the plurality of intelligently controlled
registers; processing, by the controller, data provided by each
other register of the plurality of intelligent controlled registers
so as to: collectively control the plurality of HVAC vents on a
peer-to-peer basis, so as to, absent an external input specifying a
setpoint temperature for the register, equalize temperatures of the
locations in the building.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 61/203,911, filed Dec. 30, 2008 by Jon
Barrett and Ronald Lingemann, titled "Automatically Balancing
Register for HVAC Systems," and U.S. patent application Ser. No.
12/650,320, filed Dec. 30, 2009 by Jon Barrett and Ronald
Lingemenn, titled "Automatically Balancing Register for HVAC
System, the entire contents of all of which are hereby incorporated
by reference herein, for all purposes. This application is a
continuation of U.S. patent application Ser. No. 12/650,320.
TECHNICAL FIELD
[0002] The present invention relates to control systems for
heating, ventilating and air conditioning (HVAC) system and, more
particularly, to systems that distribute control of an HVAC system
among a plurality of components, such as air supply registers,
remote control units and thermostats, which communicate with each
other.
BACKGROUND ART
[0003] Conventional forced air heating, ventilating and/or air
conditioning (HVAC) systems have manually adjustable air register
vents (air volume control dampers) to control the amount of
conditioned air introduced into a room or other portion (for
simplicity, collectively hereinafter referred to as a "region") of
a building. In theory, the vents may be manually adjusted upon
installing the HVAC system or thereafter, so as to provide a
correct amount of heated, cooled, filtered, etc. (collectively
referred to herein as "conditioned") air to each region. However,
in practice, this seldom works properly. Usually, the registers are
not adjusted at all, unless a region is intolerably cold or hot. In
addition, it may be impossible to get enough conditioned air to a
region without adjusting the registers in every other region. Thus,
manually adjusted registers rarely achieve a uniform comfort level
throughout a building.
[0004] Manually adjusted registers can also waste energy. For
example, introducing more conditioned air into a region than is
necessary to achieve a comfortable temperature causes a heating or
cooling plant to operate longer or at a higher level than would
otherwise be necessary. Even if registers have been adjusted to
achieve a desired temperature in all regions, the registers may all
be closed more than necessary, thus constricting the air flow and
increasing pressure in the ducts. This causes the blower that moves
the air to do more work than necessary, thereby wasting energy. In
addition, the high air pressure in the ducts exacerbates any leaks
in the ducts. Such duct leaks frequently allow conditioned air to
enter an attic, crawl space or other region that does not need
heating or cooling, thereby wasting energy.
[0005] Most homes with forced air HVAC systems have only one
thermostat. Not only does this mean that only one region actually
maintains a desired temperature, it also makes it impractical to
adjust the temperature in different rooms to suit the needs of
occupants in those rooms. Consequently, room temperatures cannot be
personalized.
[0006] To overcome some of these problems, some buildings are
zoned. Each zone has an associated thermostat to adjust the
temperature in that zone. In private homes, this is often
implemented by installing a separate HVAC system for each zone.
Each zone has its own thermostat, fan, heat exchange, furnace or
heat pump, cooling compressor, ducts, etc. This is not only
expensive; it can also be extremely wasteful of energy. For
example, there is usually nothing to prevent one HVAC zone from
heating a portion of a building while another HVAC zone cools
another, possibly overlapping, region of the building.
[0007] Attempts to solve the multi-zone HVAC problem often include
installing a centralized control system coupled to various
thermostats and, in some cases, to electrically or pneumatically
operated dampers in the ducts. However, such centralized systems
require installing wiring to the thermostats, dampers, etc.,
thereby increasing the difficulty of retrofitting existing
buildings. These systems are, therefore, more suitable for new
construction than for renovating existing buildings. Furthermore,
once such a system is installed, it is difficult to subdivide it
into additional zones or to incrementally expand the system.
[0008] Prior art electronically controlled register vents for zone
heating and cooling are described in U.S. Pat. No. 7,168,627 to
Lawrence Kates, et al. A design for a multi-zone HVAC control
system from an existing single-zone system using wireless sensor
networks is described by Andrew Redfern, et al., in Smart
Structures, Devices and Systems III, edited by Said F. Al-Sarawi,
Proc. of SPIE, Vol. 6414 (2007). The contents of both these
documents are incorporated herein by reference.
SUMMARY OF THE INVENTION
[0009] An embodiment of the present invention provides a system for
controlling an HVAC system of a type having a plurality of HVAC
vents. Each HVAC vent may be disposed in a corresponding location
in a building, such as to provide heat or air conditioning to a
region of the building. The system for controlling the HVAC system
may include a corresponding plurality of intelligent controlled
registers. Each intelligent controlled register is associated with
a distinct one of the HVAC vents. Each one of the intelligent
controlled registers is in communication with at least one other of
the plurality of intelligent controlled registers. Each intelligent
controlled registers executes an autonomous local control program.
The control program processes data provided by each of the other
intelligent controlled registers. Consequently, the plurality of
intelligent controlled registers collectively control the plurality
of HVAC vents on a peer-to-peer basis.
[0010] At least one of the plurality of intelligent controlled
registers may be in wired or wireless communication with at least
one other of the plurality of intelligent controlled registers.
[0011] Each one of the plurality of intelligent controlled
registers may be configured to automatically determine presence of
an intelligent controlled register that is not part of the system
for controlling the HVAC system. If such an (uninstalled)
intelligent controlled register is detected, each intelligent
controlled register of the HVAC control system may automatically
ascertain if the determined (uninstalled) intelligent controlled
register should be added to the system for controlling the HVAC
system. If so, the determined (uninstalled) intelligent controlled
register is automatically added to the system for controlling the
HVAC system. In other words, the network of intelligent controlled
registers may automatically detect newly-installed intelligent
controlled registers and automatically add them to the network.
[0012] In another embodiment, a newly-installed intelligent
controlled register automatically discovers a network of
intelligent controlled registers and automatically installs itself.
In this case, each one of the plurality of intelligent controlled
registers is configured to automatically determine presence of at
least one other of the plurality of intelligent controlled
registers and automatically ascertain if the intelligent controlled
register should be added to the system for controlling the HVAC
system. If so, the intelligent controlled register is automatically
added to the system for controlling the HVAC system.
[0013] Each intelligent controlled register may be further
configured to automatically ascertain if the determined intelligent
controlled register should be added to the system for controlling
the HVAC system according to timing of air flow through the
intelligent controlled register and timing of air flow through the
determined intelligent controlled register. Optionally or
alternatively, the determination may be made according to timing of
light detected by the intelligent controlled register and timing of
light detected by the determined intelligent controlled
register.
[0014] Each intelligent controlled register may be configured to
detect other newly-installed components of the network. For
example, the intelligent controlled register may be configured to
detect wirelessly automatically determine presence of a thermostat
that is not part of the system for controlling the HVAC system and
automatically ascertain if the determined thermostat should be
added to the system for controlling the HVAC. If so, the determined
thermostat may be automatically added to the system for controlling
the HVAC system.
[0015] The intelligent controlled register may be further
configured to automatically ascertain if the determined thermostat
should be added to the system for controlling the HVAC system
according to timing of light detected by the thermostat and timing
of light detected by the intelligent controlled register or
according to timing of temperature changes detected by the
thermostat and timing of temperature changes detected by the
intelligent controlled register.
[0016] Each intelligent controlled register may include a
controllable damper. The intelligent controlled register may be
configured such that, when air flows through the controllable
damper, at least one of the dampers of the plurality of intelligent
controlled registers is fully open.
[0017] Each intelligent controlled register may be configured to
wirelessly receive data from at least one other of the plurality of
intelligent controlled registers and to forward at least some of
the received data to a different at least one other of the
plurality of intelligent controlled registers.
[0018] The HVAC system may include a ducted air handling system, a
hydronic system and/or an electric resistance heating system. At
least one of the plurality of intelligent controlled registers may
be configured to control a valve and/or to control an electrical
switch of a proportional control device.
[0019] Each intelligent controlled register may include a motor
coupled to a controllable damper, a temperature sensor and a
wireless transceiver for communicating with at least one other of
the plurality of intelligent controlled registers. A controller may
be coupled to the motor, to the temperature sensor and to the
transceiver. A power source may be coupled to the motor, to the
transceiver and to the controller. The controller may be configured
to carry out processes, such as obtaining data from the temperature
sensor and, via the wireless transceiver, data from at least one
other of the plurality of intelligent controlled registers. Using
the obtained data, the controller may automatically determine a
desired operation of the damper and drive the motor to cause the
desired operation of the damper.
[0020] The power source may include an array of photovoltaic cells
and/or a fan-powered generator. The controllable damper of at least
one of the plurality of intelligent controlled registers may
include a valve. Each of at least one of the plurality of
intelligent controlled registers may be mounted in an air
register.
[0021] The motor may include a coil, and each intelligent
controlled register may further include a circuit board on which
are mounted electronic circuits implementing at least a portion of
the controller. The coil of the motor may be mounted directly to
the printed circuit board.
[0022] The circuit board may further include a plurality of
electrically conductive elements, and the motor may further include
a conductive element spaced apart from the plurality of
electrically conductive elements to form a capacitor between the
conductive element in the motor and one or more of the plurality of
electrically conductive elements on the printed circuit board.
Capacitance of the capacitor depends on a rotational position of
the motor. The controller may be configured to ascertain the
rotational position of the motor based on the capacitance of the
capacitor.
[0023] The motor may include two sets of rotors and two sets of
stators. One of the rotors and one of the stators may form a first
"submotor" and the other one of the rotors and the other one of the
stators may form a second "submotor." The two submotors may be
disposed beside each other and geared together.
[0024] The system for controlling an HVAC may further include a
portable remote control unit that includes a wireless transmitter
and at least one user-actuateable control. The intelligent
controlled register may be configured to receive a wireless signal
from the portable remote control unit. The controller may be
configured to automatically determine the desired operation of the
damper based, at least in part, on the received wireless signal
from the portable remote control unit.
[0025] The wireless transmitter of the portable remote control may
include a line-of-sight wireless transmitter and/or a wireless
line-of-sight detector.
[0026] Each of the plurality of intelligent controlled registers
may include a volume control damper configured to adjustably
control an amount of heat delivered through the intelligent
controlled register. A motor may be under control of the autonomous
control program and mechanically coupled to operate the volume
control damper. A printed circuit board may include electronic
circuits and windings of the motor. The motor may be a stepper
motor.
[0027] The system for controlling an HVAC system may also include a
volume control damper position indicator that includes at least two
electrically conductive elements spaced apart by a dielectric, such
as air, thereby forming a capacitor. At least one of the at least
two electrically conductive elements may be configured to move,
with respect to the other of the at least two electrically
conductive elements. The movement may be in relation to the
operation of the volume control damper, so as to vary capacitance
of the capacitor in relation to the operation of the volume control
damper.
[0028] Each of the plurality of intelligent controlled registers
may be configured, absent an external input specifying a setpoint
temperature for the corresponding location, so as to equalize
temperatures of the locations in the building.
[0029] Each of the plurality of intelligent controlled registers
may be configured so as to maximize flow through at least one of
the plurality of intelligent controlled registers.
[0030] The HVAC system may include a blower and a heating or
cooling unit. At least one of the plurality of HVAC vents may
include a return vent, and at least one of the plurality of HVAC
vents may include a supply vent. The system may further include a
thermostat coupled to the HVAC system so as to control the blower
and coupled to at least one of the plurality of intelligent
controlled registers. Each of the plurality of intelligent
controlled registers may be configured to operate so as to permit
air to be drawn in by an automatically selected at least one of the
return vent. The air may be moved by the blower, and the air may be
exhausted through an automatically selected at least one of the
supply vent, all without operating the heating or cooling unit.
Thus, air may be transferred from at least one automatically
selected location in the building (such as a room where the air is
too hot) to another at least one automatically selected location in
the building (such as a room where the air is too cold).
[0031] The HVAC system may include a blower controlled by blower
control leads and a heating or cooling unit controlled by heating
or cooling unit control leads. The HVAC control system may further
include a thermostat coupled to the HVAC system so as to control
the blower and the heating or cooling unit. The thermostat may be
further coupled to at least one of the plurality of intelligent
controlled registers. The thermostat may be configured to
automatically identify: power leads connected to the thermostat,
the blower control leads connected to the thermostat and the
heating or cooling unit control leads connected to the
thermostat.
[0032] An embodiment of the present invention provides a system for
controlling an HVAC system of a type having a plurality of HVAC
vents. Each HVAC vent may be disposed in a corresponding location
in a building, such as to provide heat or air conditioning to a
region of the building. The HVAC control system may include a
corresponding plurality of intelligent controlled registers. Each
intelligent controlled register may be associated with a distinct
one of the HVAC vents. Each intelligent controlled register may
include a motor coupled to a controllable damper, a a temperature
sensor and a a wireless transceiver for communicating with at least
one other of the plurality of intelligent controlled registers. A
controller may be coupled to the motor, to the temperature sensor
and to the transceiver. A power source may be coupled to the motor,
to the transceiver and to the controller. The controller may be
configured to carry out processes, such as obtaining data from the
temperature sensor and, via the wireless transceiver, data from at
least one other of the plurality of intelligent controlled
registers. Using the obtained data, the controller may
automatically determine a desired operation of the damper; and
drive the motor to cause the desired operation of the damper.
[0033] Yet another embodiment of the present invention provides a
method for controlling an HVAC system of a type having a plurality
of HVAC vents, in which each HVAC vent is disposed in a
corresponding location in a building. The HVAC control system may
include a corresponding plurality of intelligent controlled
registers. Each intelligent controlled register may be associated
with a distinct one of the HVAC vents. Data is obtained from a
temperature sensor. In addition, data is wirelessly obtained from
at least one other of the plurality of intelligent controlled
registers. The obtained data is used to automatically determine a
desired operation of a damper. A motor is driven to cause the
desired operation of the damper.
[0034] Presence of an intelligent controlled register that is not
part of the system for controlling the HVAC system may be
wirelessly automatically determined. The determined intelligent
controlled register may be automatically added to the system for
controlling the HVAC system.
[0035] Data may be wirelessly received from at least one other of
the plurality of intelligent controlled registers. At least some of
the received data may be forwarded to a different at least one
other of the plurality of intelligent controlled registers.
[0036] Electrical power may be generated with an array of
photovoltaic cells and/or with a fan-powered generator at at least
one of the plurality of HVAC vents. The motor may be powered at
least partially by the generated electrical power.
[0037] The motor may adjust vanes of an air volume control damper,
adjust a valve, adjust an electrically controlled switch and/or
adjust an electrically controlled proportional control device.
[0038] A wireless signal may be received from a portable remote
control unit. The received wireless signal may be used to obtain
the data to automatically determine a desired operation of a
damper.
[0039] Another embodiment of the present invention provides an
intelligent controlled register for use in an HVAC system of a type
having a plurality of HVAC vents. Each HVAC vent may be disposed in
a corresponding location in a building. The intelligent controlled
register includes a motor coupled to a controllable damper, a
temperature sensor, and a wireless transceiver for communicating
with at least one other intelligent controlled register, A
controller may be coupled to the motor, to the temperature sensor
and to the transceiver. A power source may be coupled to the motor,
to the transceiver and to the controller. The controller may be
configured to carry out processes, such as obtaining data from the
temperature sensor and, via the wireless transceiver, data from at
least one of the at least one other intelligent controlled
register. The controller may use the obtained data to automatically
determine a desired operation of the damper and drive the motor to
cause the desired operation of the damper.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] The invention will be more fully understood by referring to
the following Detailed Description of Specific Embodiments in
conjunction with the Drawings, of which:
[0041] FIG. 1 is a schematic diagram of an HVAC system in which
embodiments of the present invention may be practiced;
[0042] FIG. 2 is a perspective view of the front of an intelligent
controlled register, according to an embodiment of the present
invention;
[0043] FIG. 3 is a perspective view, from the right, of the rear of
the intelligent controlled register of FIG. 2;
[0044] FIG. 4 is a perspective view, from the left, of the rear of
the intelligent controlled register of FIG. 2;
[0045] FIG. 5 is an exploded perspective view of the intelligent
controlled register of FIG. 2;
[0046] FIG. 6 is a schematic block diagram of the intelligent
controlled register of FIG. 2;
[0047] FIG. 7 is a schematic circuit diagram of a power supply for
the controlled register of FIG. 2, according to an embodiment of
the present invention;
[0048] FIG. 8 is a schematic block diagram of an HVAC remote
control unit of FIG. 1, according to an embodiment of the present
invention;
[0049] FIG. 9 is a flowchart illustrating a temperature control
process, according to an embodiment of the present invention;
[0050] FIG. 10 is a flowchart illustrating another temperature
control process, according to an embodiment of the present
invention;
[0051] FIG. 11 is a flowchart illustrating operation of the
controlled register of FIG. 2, according to an embodiment of the
present invention
[0052] FIG. 12 is a schematic timing diagram of a communication
protocol among the controlled registers of FIG. 1, according to an
embodiment of the present invention;
[0053] FIGS. 13A and 13B collective contain a flowchart
illustrating operations performed by the controlled register of
FIG. 2 upon first being installed or upon recovering from a
power-down condition, according to an embodiment of the present
invention;
[0054] FIG. 14 is a flowchart illustrating operations performed by
the intelligent controlled register of FIG. 2 for forming a network
with other intelligent controlled registers, according to an
embodiment of the present invention;
[0055] FIG. 15 is a flowchart illustrating operations performed by
the intelligent controlled register of FIG. 2 for joining an
existing network of other intelligent controlled registers,
according to an embodiment of the present invention;
[0056] FIG. 16 is a perspective view of an integrated motor and
sensor assembly, according to an embodiment of the present
invention;
[0057] FIG. 17 is an exploded perspective view of the integrated
motor and sensor assembly of FIG. 16;
[0058] FIG. 18 is another exploded perspective view of the
integrated motor and sensor assembly of FIG. 16, showing sensor
pads, according to an embodiment of the present invention;
[0059] FIG. 19 is an exploded perspective view of the integrated
motor and sensor assembly of FIG. 16, showing the sensor pads as
the motor is rotated to a different position;
[0060] FIG. 20 is a schematic diagram of another HVAC system in
which embodiments of the present invention may be practiced;
[0061] FIG. 21 is a schematic block diagram of an exemplary data
packet, according to an embodiment of the present invention;
[0062] FIG. 22 is a schematic block diagram of an exemplary a
device settings data packet, according to an embodiment of the
present invention;
[0063] FIG. 23 is a schematic block diagram of an exemplary a
remote command packet, according to an embodiment of the present
invention;
[0064] FIG. 24 is a schematic block diagram of an exemplary remote
standard update packet, according to an embodiment of the present
invention;
[0065] FIG. 25 is a schematic block diagram of an exemplary remote
settings update packet, according to an embodiment of the present
invention; and
[0066] FIG. 26 is a schematic block diagram of an exemplary device
information table, according to an embodiment of the present
invention.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0067] Definitions.
[0068] As used in this description and the accompanying claims, the
following terms shall have the meanings indicated, unless the
context otherwise requires:
[0069] "HVAC system" means a system that provides heat, ventilation
and/or air conditioning to a building or a portion of a building.
An HVAC system may provide one or more such functions.
[0070] "Array of photovoltaic cells" means one or more cells that
convert light into electricity by the photovoltaic effect.
[0071] "Hydronic" means the use of water as a heat-transfer medium
in a HVAC heating or cooling system. Examples of heating systems
include steam and hot-water radiators. In large-scale commercial
buildings, such as high-rise and campus facilities, a hydronic
system may include a chilled water loop and a heated water loop to
provide for both heating and air conditioning. Chillers and cooling
towers may be used separately or together to provide water cooling,
while boilers may be used to heat water.
[0072] A "controllable damper" is a device that controls heat
transfer into or out of a region associated with a location in a
building. In an air-based HVAC system, a controllable damper may be
implemented by an adjustable register in a vent, such as by an
adjustable vane. The register may be binary, i.e., the register may
have exactly two possible states (such as partially or fully closed
and partially or fully open), or the register may be step-wise or
continuously variable between two extreme states, i.e., the
register may have more than two possible states. In a hydronic HVAC
system or in an electric resistance heating system, a controllable
damper may be implemented by an adjustable regulator, similar to
that used in an air-based HVAC system, to control air flow through
or near a heat exchanger, such as a radiator. Optionally or
alternatively, a hydronic controllable damper may be implemented by
a valve to control flow of water, steam or another fluid.
[0073] Embodiments of the present invention provide methods and
systems for controlling HVAC systems in a distributed manner. In
various embodiments, such control is achieved by providing
intelligent register controllers that operate in a peer-to-peer
manner. FIG. 1 is a schematic diagram of an air-based HVAC control
system 100 (enclosed within a dashed line) that includes
components, and that performs processes, in accordance with an
embodiment of the invention. Each intelligent register controller
automatically determines how much conditioned air to allow into its
region, or how much return air to allow to be withdrawn from its
region, based on information collected by the register controller,
such as: current temperature of the region; desired temperature of
the region; calculated amount of conditioned air required to change
the region's temperature to the desired temperature; temperature of
conditioned air begin supplied by a duct to the register; current
time, day of week, vacation or other schedule data; temperatures of
other regions and their respective desired temperatures; calculated
amounts of air required to be supplied or withdrawn by the other
controlled registers to change their respective regions'
temperatures to their desired temperatures; or combinations
thereof. However, as will be described below, other embodiments of
the present invention employ similar components and similar
principles to control other types of HVAC systems, such as hydronic
or electric resistance heating systems.
[0074] As shown in FIG. 1, a furnace, heat pump, cooler and/or
other device or combination of devices 103 heats or cools air that
is then moved through the HVAC system by a blower 106. (The blower
106 may be coupled to the input, rather than to the output, of the
heating/cooling device 103.) A conventional thermostat 108 and a
conventional HVAC control unit 109 control operation of the
heating/cooling device 103 and the blower 106. Optionally or
alternatively, the air may be filtered and/or exchanged for outside
air, etc. (not shown). For simplicity of explanation, the air is
referred to herein as being "conditioned," regardless of how the
air is treated, i.e., heated, cooled, etc.
[0075] The conditioned air is carried by a series of ducts 110 to a
plurality of HVAC vents, such as supply registers 113, 116, 120 and
128. Of course, there may be more or fewer supply registers and
more or less complex duct work than are shown in FIG. 1. The supply
registers 113-120 and 128 may be disposed in various locations of a
building, such as in walls of rooms of a house, in walls or
ceilings of corridors or in ceilings of an office building. One or
more of the supply registers 113-120 and 128 may be in a given
room. Each supply register 113-120 and 128 may introduce
conditioned air into its respective region. Return registers 123,
126 and 129 and an associated return duct 130 return air to the
heating/cooling device 103. Of course, there may be other numbers
of return registers and more or less complex return duct work.
[0076] One or more of the supply registers 113-120 and 128 may
include a respective intelligent register controller 133, 136 and
140. Each register controller 133-140 operates a controllable
damper to control the amount of conditioned air the corresponding
supply register 113-120 allows into its respective region. In
addition, each register controller 133-140 measures the temperature
of its respective region.
[0077] Optionally, one or more of the return registers 123-129 also
includes a register controller 143 and 146 that controls the
relative amount of air allowed to be drawn from its respective
region back into the HVAC system. A register 113-120 and 123-126
that is equipped with a register controller may be referred to
herein as an "intelligent controlled register" or simply a
"controlled register."
[0078] The amount of air permitted to flow through a register
113-126 may be controlled by any suitable structure, such as a
motorized adjustable vane or a set of vanes in the register. Each
controlled register's controller 133-146 operates its respective
vane(s).
[0079] The controlled registers 113-126 and the register
controllers 133-146 are not, however, centrally controlled.
Furthermore, the register controllers 133-146 need not necessarily
be connected to the heating/cooling system thermostat 108, the
blower 106, the HVAC control unit 109 or the heating/cooling device
103. The register controllers 133-146 form a wireless communication
network, by which the register controllers 133-146 (and optionally
other components of the HVAC control system 100, collectively
referred to as "nodes" of the network) can provide information to
other register controllers 133-146 in the network.
[0080] Each register controller 133-146 automatically determines
how much conditioned air to allow into its region, or how much
return air to allow to be withdrawn from its region, based on
information collected by the register controller 133-146. This
information may include: the current temperature of the region; a
desired temperature of the region; a calculated amount of
conditioned air required to change the region's temperature to the
desired temperature; temperature of conditioned air begin supplied
by a duct to the register; current time, day of week, vacation or
other schedule data; temperatures of other regions and their
respective desired temperatures; calculated amounts of air required
to be supplied or withdrawn by the other controlled registers to
change their respective regions' temperatures to their desired
temperatures; charge state of a battery powering the register
controller 133-146 or a combination thereof. Based on the
determination of the amount of conditioned air required, each
register controller 133-146 automatically determines when to
operate its respective controllable damper and an extent to which
the controllable damper should be opened or closed, and the
register controller 133-146 operates the controllable damper. It
should be noted that a register's controllable damper may be opened
for only a portion of the amount of time the blower 106 is
operating.
[0081] Each node of the network may base its operation at least in
part on information about one or more (ideally all) of the other
nodes in the network. Thus, the intelligent register controllers
133-146 (and optionally other nodes) of the network collectively
control the amount of conditioned air introduced into each region.
This control function is distributed across the network of
intelligent controlled registers. Significantly, this control
function does not use a central controller. That is, no central
controller instructs each register controller how and when to
operate its controllable damper. None of the register controllers
133-146 is a "master" that controls the other register controllers.
A remote control unit 150-153 (described in more detail below) or a
central node, such as a computer 156, may provide information about
desired temperatures, set-back times, etc. However, by sending this
information, the remote control unit 150-153 or the computer 156
does not command a register controller 133-146 to open or close its
controllable damper. Instead, the register controllers 133-146 use
this information as part of their calculations to determine when
and to how to operate their respective controllable dampers.
[0082] Each register's controller 133-146 includes a wireless
transceiver that enables the register controller 133-146 to
wirelessly communicate with other register controllers 133-146 in
nearby registers 113-126. The ducts 110 and 130 may act as
waveguides to carry wireless signals or otherwise facilitate the
wireless communication among the register controllers 133-146.
Nevertheless, all the register controllers 133-146 may not be able
to directly wirelessly communicate with all the other register
controllers 133-146, due to limitations on transmitter power,
distances involved, electromagnetic interference (EMI), battery
charge level, etc. Therefore, each register controller 133-146
relays data it receives from other register controllers 133-146 to
yet other register controllers 133-146. Thus, each register
controller 133-146 may ultimately receive information about every
other register controller 133-146 in the HVAC control system 100,
albeit not necessarily directly from the register controller about
which the information is provided.
[0083] Any number of (including zero) hand-held remote control
units, exemplified by remote control units 150 and 153, may be
used. These remote control units wirelessly communicate with
register controllers 133-146 in nearby registers 113-126, although
the communication between a remote control unit 150-153 and a
register controller 133-146 may involve a different medium (such as
infrared light-based communication or radio frequency (RF)-based
communication) or a different frequency than the communication
among the register controllers 133-146. Each remote control unit
150-153 includes a keyboard and a display, by which a user may
instruct the HVAC control system 100 or a component thereof to
change a parameter, such as a desired temperature in the region
where the user is located. Optionally, one or more of the remote
control units 150-153 may be attached to fixed locations, such as
on walls, in the building.
[0084] Optionally, one or more network thermostats, exemplified by
network thermostat 160, may be included in the HVAC control system
100. The network thermostat 160 may be installed in a region, such
as mounted on a wall of a room, to allow the user to directly set a
desired temperature or temperature program for the near-by area.
Like the registers, the thermostats automatically detect and
connect to an existing network, but unlike the registers, never
create a new network. The primary function of the network
thermostat is to inform the registers of the desires of the system
user, and to provide sufficient information on its environment so
that each register may determine if it is to use the set point
information. For example the network thermostat may record and
report to the network the times of sudden increase or decrease in
light level, presumably caused by someone turning on a light or
opening a door or a window shade. Any register observing the same
environmental changes would then assume that it is near that
thermostat, and should use that thermostats temperature set point
as its temperature goal. The network thermostat 160 may be powered
by a photovoltaic cell and/or a conventional user-replaceable
battery.
[0085] Optionally, one or more of the network thermostats,
exemplified by network thermostat 163, may be connected to (or
replace) the thermostat 108. Optionally or alternatively, the
network thermostat 163 may be connected to the HVAC control 109, or
the network thermostat 163 may be otherwise connected to the HVAC
system. In either case, the network thermostat 163 may control
operation of the heating/cooling device 103 and/or the blower 106.
For example, if one region is warmer than it needs to be, while
another region is cooler than it needs to be, the HVAC control
system 100 may move some air from the warm region to the cool
region by opening controllable dampers in the respective regions,
closing other controllable dampers, and causing the blower 106 (but
not the heating/cooling device 103) to operate. One or more
controllable return registers 123-126 proximate the region from
which air is to be move may be opened while controllable return
registers proximate other regions may be closed, and one or more
controllable supply registers 113-120 proximate the region to which
the air is to be moved may be opened while controllable supply
registers proximate other regions may be closed. A network
thermostat that is electrically connected to the thermostat 108,
etc. may be powered by the HVAC system and need not, therefore,
necessarily include a photovoltaic cell.
[0086] As noted, the register controllers 133-146 receive
information about the other register controllers 133-146. Using
this information, as well as information about a desired
temperature in the region serviced by a given register controller
133-146, the register controller 133-146 determines a desired
operation of an controllable damper in its corresponding controlled
register, and the register controller 133-146 drives a servo, such
as a stepper motor and position sensor, to cause the desired
operation of the damper. Thus, the register controller 133-146
controls the amount of conditioned air introduced into its region
or withdrawn from its region, in order to meet (as well as
possible, given the capacity of the heating/cooling device 103 and
the blower 106, ambient conditions, etc.) the desired temperature.
Absent information from any remote control unit 150-153, computer
156 or network thermostat 160-163 about a desired temperature, the
register controllers 133-146 may operate so as to equalize the
temperatures of all the regions. Thus, in an installation with a
single conventional HVAC thermostat 108, which is not connected to
the network of registers, and the addition of only the controlled
registers 113-126 may operate to equalize the temperature in all
the rooms of a house. This feature, alone, provides a significant
improvement in comfort level and energy savings (by avoiding
over-heating one or more of the rooms to satisfy the thermostat
108) over prior art HVAC control systems.
Installation
[0087] One or more components of the HVAC control system 100 may be
installed in a new HVAC system, or one or more components of the
HVAC control system 100 may be retrofitted into an existing
structure. In either case, later, addition components of the HVAC
control system 100 may also be installed.
[0088] Upon being installed, each new component attempts to
communicate with other components of the HVAC control system 100
that are within range of the newly installed component's wireless
transceiver. The newly installed component then identifies which,
if any, of these other components are part of the same HVAC system
as the newly installed component. (It should be noted that there
may be components installed in unrelated HVAC systems that are
within wireless communication range, such as HVAC systems in nearby
homes or on other floors of a multi-story building, and the newly
installed component should ignore these unrelated components.) A
process of discovering other components is described in the context
of installing a register controller; however, a similar process may
be used by other types of components.
[0089] A newly installed register controller 133-146 monitors the
communications of other register controllers that are within range
of the newly installed register controller's wireless transceiver.
By comparing environmental data received from the discovered
network, such as the time that air flow starts and stops, with its
own measurements, the register determines if it should, or should
not join that network. Components with photovoltaic cells may
optionally or alternatively note times at which light intensities
(presumably due to the apparent movement of the sun or artificial
lighting) are high or low and correlate the detected lighting level
patters with other light-sensitive components, as described in more
detail below. If the discovered network is in the same environment
as the new register, it joins that network. Register controllers
133-146 may routinely send information about their respective air
flow times, light level patterns, etc., or the register controllers
133-146 may be queried by the newly installed register controller
for this information.
[0090] Similarly, the network thermostats 160-163 should experience
environmental changes that correlate well with nearby
registers.
[0091] Although in some embodiments components use timings of air
flows or temperature changes to facilitate automatically
discovering other components, this automatic discovery may be based
on timings of other environmental changes, such as humidity or
light. For example, as noted below, the controlled registers may
include photovoltaic cells to power the register controllers
133-146. Using timings and strengths of signals from these
photovoltaic cells, the register controllers 133-146 may correlate
times at which relatively strong light, such as sunlight, shines on
the photovoltaic cells, or times at which relative weak light, such
as artificial light from interior lamps, or no light shines on the
photovoltaic cells.
[0092] If the newly installed register controller 133-146 fails to
find a network using the same HVAC system, the newly installed
register controller 133-146 forms a new network and operates alone,
until another register controller 133-146 or network thermostat
160-163 that is part of the same HVAC system comes within range and
joins its network. The network thermostats 160-163 perform similar
operations upon their installation.
[0093] Thus, each register controller 133-146 and network
thermostat 160-163 is essentially self-installing, in that no user
involvement is required to interconnect the register controllers
133-146 or the network thermostats 160-163 to each other. The user
only needs to put the registers and thermostats where he wants
them. The HVAC system 100 facilitates incremental growth;
components may be added at any time, and not all register need to
be equipped with register controllers. Consequently, a building
owner may install register controllers in a few selected locations,
such as rooms that are chronically too hot or too cold, so as to
enhance comfort in these regions. In another scenario, the building
owner may install register controllers 133-146 in locations that
are frequently unoccupied, so as to save energy by minimizing the
amount of conditioned air supplied to these regions. While
installation of register controllers 133-146 in less than all the
registers of an HVAC system may not be optimum, such an
installation may provide the greatest saving or comfort improvement
for the corresponding investment, i.e., the cost of the controlled
registers.
Intelligent Register Controller
[0094] The main functions of the intelligent register controller
133-146 are: dynamically control the amount of air allowed to pass
through an associated register 113-126; measure air temperature in
the associated region (room); measure temperature of air in the
associated duct; identify, communicate with and coordinate with
other network components; maintain a clock/calendar; generate
electrical power to operate the register controller; and
communicate with one or more remote control units 150-156.
[0095] FIG. 2 is a perspective view of the front of an exemplary
register 200. Much of the face 203 of the register 200 may be
covered by, or constructed of, photovoltaic cells, exemplified by
photovoltaic cells 206. An indicator, such as a light-emitting
diode (LED) 210, may be included to display status information. A
circuit board 213 may be attached to the rear, or another
convenient portion, of the register 200. The circuit board 213
includes a processor, power control circuits, etc., as described
herein.
[0096] FIG. 3 is a perspective view of the rear of the register
200. A controllable damper, here exemplified by two
counter-rotating vanes 300 and 303, is attached to the register 200
to control air flow through the register 200. The controllable
damper may be operated by a servo, such as a stepper motor and
position sensor (not visible). The controllable damper may be
constructed so as to hold its position, such as by friction,
without use of power between times the positions of the vanes 300
and 303 are changed by the servo motor 306. A high pole count
motor, such as a stepper motor, may be used. Natural magnetic
detents provided by the poles may be used to hold the controllable
damper in place. The position of the controllable damper may be
manually adjusted by a user, such as by a thumb wheel (not shown),
in case the register controller fails. Return registers 123-126
should be equipped with controllable dampers that fail in an open
state, so that if such a register fails, air may still return via
the register.
[0097] FIG. 4 is another perspective view of the rear of the
register 200, in which the circuit board 213 may be more clearly
seen. FIG. 5 is an exploded view of the register 200. In the
embodiment shown in FIG. 5, a transparent front plate 500 covers
the photovoltaic cells 206. A perforated grill 503 disperses air
flowing through the grill 200. The servo motor 506 is visible in
FIG. 5.
[0098] FIG. 6 is a schematic block diagram of one of the
intelligent register controllers 133-146. The register controller
may be implemented by electronic components on, or connected to,
the circuit board 213. The photovoltaic cells 206 are connected to
a power supply 600, which is described in more detail below. The
power supply 600 may include a rechargeable battery, a super
capacitor or another suitable energy storage device for powering
the remaining circuits when the photovoltaic cells 206 are
insufficiently illuminated to directly power the circuits. The
register controller may communicate with other network nodes via a
wireless transceiver 603, such as an RF transceiver. Among other
information, the intelligent register controller may inform other
nodes of the amount of energy in its energy storage device, so that
network tasks may be allocated to nodes having the greatest power
reserves.
[0099] An infrared (IR) transceiver (or, in some cases, only a
receiver or transmitter) 606 facilitates wireless communication
between the register controller and a remote control unit 150-153.
One or more temperature sensors 610, such as one or more
thermistors, silicon diodes or any other suitable
temperature-sensitive components, are located so as to be exposed
to air flowing through the register 200. A controller 613 controls
operation of the remaining components of the register controller.
The controller 613 may be implemented with a processor 620
executing instructions stored in a memory 622. A clock 626 enables
the controller 613 to keep track of time and date although, as
noted below, the clock may keep track of time according to an
arbitrary time zone, such as a time zone based on 12 o'clock
corresponding to high noon or high moon, as detected by bright
light illuminating the photovoltaic cells.
[0100] To minimize power consumption, the baffle should maintain
its position without power use. In addition, a user should be able
to manually adjust the position of the baffle, in case of a failure
of the register. In one embodiment, a high pole count motor, such
as a stepper motor, drives the baffle without gearing. The natural
magnetic detent properties of such a motor may be used to hold the
baffle in place. The baffle, motor, and manual adjustment wheel may
be on a common shaft. In the case of multiple baffle blades, which
may be used to reduce the depth of the register, one blade may be
on the common shaft, and the other blades may be driven by gears or
a linkage.
[0101] To reduce the parts count, wiring and cost of the stepper
motor baffle drive, part of the motor and position sensing device
may be mounted on the main printed circuit board. Windings of the
motor may be mounted on the circuit board, and permanent magnet
pole pieces may be attached to the shaft. A (plated through) hole
in the circuit board may provide a shaft bearing to keep the motor
parts aligned. A position sensor may also be a part of the board. A
capacitance sensor may be formed by pads on the board and rotating
segmented plates attached to the shaft. The moving permanent magnet
pole piece may be either in the shape of a cup that surrounds a
puck-shaped coil assembly attached to the circuit board, or the
rotating permanent magnet poles may be in the center of a
stationary ring of a coil assembly. In either case, the moving
capacitor plates may be attached to the pole piece assembly. The
capacitor plates, or the entire baffle-shaft assembly, may be
spring mounted to force them into contact with the board, and one
of the plates (stationary or moving) may be covered with a thin
insulator. The moving plates may be activated by a stationary plate
segment on the circuit board, so that no wires to the moving parts
may be required.
[0102] The manual adjustment of the baffle may be made using a
wheel on the baffle shaft that has a large enough diameter so that
a chord of the wheel protrudes through a slot in the face of the
register. The shaft from the baffle to the wheel may be made
slightly flexible, so that pushing the wheel into the face of the
register (caused, for example, by someone stepping on the register)
does not cause damage.
Clock
[0103] Each register controller 113-146 maintains several clock
times and several states related to these times. The most
fundamental time in each register controller 113-146 is a unit time
(UT) clock. This is a count that is initialized to zero when the
register controller 113-146 is manufactured and is incremented at a
fixed rate as long as the register controller's processor 620 is
powered up. This time has enough resolution to record the time of
events as accurately as needed, such as within 1/256 second. The
accumulator for this time has enough bits, such as 40 bits, that it
will not overflow during the expected lifetime of the register
controller. If the processor 620 detects that it will soon run out
of power, this clock is saved in nonvolatile memory.
[0104] As part of the state for this clock, there are three other
saved values. One value is the current status of the UT: Resetting
or Valid. This status bit is set to "Resetting" from the time that
the component saves the UT in preparation for a complete shutdown,
due to low power, until power is restored and accumulation resumes.
When the UT is again running, its state is changed to "Valid." The
second status datum is the value of the UT at the previous power
failure, or Last Crash Unit Time (LCUT). This value is initialized
at the time of manufacture to zero and is set to the value of the
saved UT value when the UT is restarted, and may in fact be the
value in nonvolatile memory saved at the time of a power failure.
The time since the last power failure may be calculated by
subtracting LCUT from the current UT. The processor can ascertain
if a stored UT value is valid as a time span measurement by
checking that this value is greater than the LCUT. The third value
is a count of the number of times that the LCUT has been changed,
i.e. the number of processor power failure crashes. This last value
is used to determine if a register controller is having frequent
power failures and should perhaps be up graded from a light powered
register controller to a light and wind or externally powered
register controller.
[0105] The second "time" each register controller maintains is
network time (NT). This is in fact a correction from UT to a time
consistent among the members of a network. It is set to the UT of
the oldest member of a network. Each network component maintains a
signed value which, when added to its UT, gives NT and a status
value which is set to Valid after a register joins a network and is
given or gives the NT. To prevent disagreements in NT when a new
component joins a network, there is a process that first has all
components in the network set NT as not valid. The process then
distributes the new NT, from which each component computes its
correction value, and then the process sets NT as valid.
[0106] The last time the register controller maintains is real
time. This is also kept as an offset from UT, and a status. The
offset is the number of that must be added to UT to produce the
local real time in seconds since a predetermined time, such as the
beginning of the year 2000. This value has at least two possible
statuses: valid and not valid. The status is initialized to not
valid and reset to not valid on any crash. The status is set to
valid when the register controller is informed of the local time by
a remote control unit 150-153 or from another node of the
network.
[0107] Using the temperature sensor 610, the register controller
may ascertain the temperature of conditioned air being delivered to
the region. In addition, the register controller may ascertain the
speed of the air being delivered, such as by forcing a known
electric current through the thermistor for a short time, thereby
heating the thermistor above the temperature of the conditioned
air, and then measuring the amount of time required for the
temperature of the thermistor to drop a predetermined amount, such
as to one-half the difference between the heated temperature and
the flowing air temperature.
[0108] A relationship between air flow speed and temperature drop,
as a function of time, may be determined experimentally or
algorithmically using known characteristics of the thermistor. Data
representing this relationship or representative air
speed-temperature drop time value pairs may be stored in a table,
such as in the memory 622 of the controller 613. Optionally or
alternatively, this relationship may be stored as a mathematical
function in the memory 622. The table or function may be used to
calculate the air flow speed from the temperature drop time.
[0109] After the blower 106 has stopped operating and a suitable
amount of time has passed for temperatures within the register to
stabilize with the region, the temperature sensor 610 may be used
to measure the temperature of the region, thus obviating or
reducing the need for a thermometer in the region.
[0110] Optionally or alternatively, the conditioned air flow rate
may be measured by another sensor (not shown), such as two
electrically conductive pads. One of the pads may be fixed on the
circuit board 213, and the other pad may be attached to a flexible
vane within the path of the conditioned air flow. When the
conditioned air flows, it deflects the flexible vane an amount
proportional to the air flow rate. The controller 613 measures
capacitance between the two pads when the conditioned air flows and
when it does not flow. The difference in the two capacitance
measurements indicates the amount of vane deflection and,
therefore, the air flow rate.
[0111] Thus, the controller 613 may ascertain three pieces of
information: region temperature, conditioned air temperature and
conditioned air flow rate.
[0112] By testing for air flow at frequent intervals, the
controller 613 may measure the amount of time that the
heating/cooling device 103 and/or the blower 106 operate, i.e., an
HVAC system "run-time." However, all the controlled registers
112-126 experience air flows at nearly the same time. Therefore,
all the register controllers 133-146 need not simultaneously
perform their own HVAC system run-time measurements. Instead, only
one or a small number of the register controllers 133-146 may need
to perform the HVAC system run-time measurement at any point in
time, and the run-time information may then be provided to the
other register controllers 133-146 in the network. Register
controllers 133-146 not performing the HVAC system run-time
measurement may be able to enter a low power state, thereby
conserving energy. The task of measuring HVAC system run-time may
be allocated in a round-robin fashion among the register
controllers 133-146. Optionally or alternatively, this allocation
may be modified so as to exclusively or more heavily use register
controllers 133-146 having the greatest power reserves (i.e., the
highest levels of charge in their batteries.
[0113] The HVAC system run-time and information about differences
between temperatures of conditioned air supplied to regions and the
regions' temperatures may be used by one or more nodes of the
network to calculate the amount of energy delivered through the
registers 112-126. If the energy used by the HVAC system is also
known, the efficiency of the HVAC system can be calculated. The
energy used by the HVAC system may be input by a user, such as by
entering data from energy bills. Alternatively, if the power rating
(ex., the kilowatt rating of an air conditioning unit) of the HVAC
system components, i.e., the heating/cooling device 103 and the
blower 106, are known, the amount of energy used by the HVAC system
may be calculated by multiplying the power rating by the amount of
time the HVAC system components operate.
[0114] Even if the amount of energy used by the HVAC system is not
known, relative efficiencies of providing conditioned air to
various regions, i.e., through particular controlled registers
113-120, may be calculated by nodes of the network. If one or more
of these regions or registers 112-120 operates less efficiently
than the others, a node may notify a user, such as by sending a
message to a remote control unit 150-153 or to the computer 156 or
by illuminating the indicator 210 on the registers 200. This may
alert the user to improve thermal insulation of the region and/or
decrease infiltration of outside air into the region. Optionally or
alternatively, the user may be able to make informed decisions
regarding continued heating or cooling of the region, in light of
the amount of use the region receives, relative to the amount of
energy used to heat or cool the region. Similarly, a sudden
decrease in the efficiency of a region may be caused by a window
having been left open, and the user may be similarly alerted.
[0115] Optionally, each controlled register 113-126 may be equipped
with a thermal infrared sensor 212 (FIGS. 2, 5 and 6), positioned
and oriented so as to have a view into the region serviced by the
controlled register 113-126. This sensor measures black body
radiation from the nearest solid object in front of it. The
infrared sensor 212 accepts radiation through a window on the face
500 of the register 200, so if the register 200 is mounted in a
floor, the infrared sensor 212 may measure the temperature of a
ceiling. This measurement can be correlated with the region air
temperature measurement made using the temperature sensor 610.
Using this correlation, the infrared temperature may be used to
compute the region's room air temperature, even when air is passing
through the register 200.
[0116] Region occupancy information may be advantageously used by
the controller 613 to save energy by providing less than the usual
amount of conditioned air into a region that has not been occupied
for some time. The controller 613 may employ one or more of several
methods to ascertain region occupancy. For example, the infrared
sensor 212 may be used to detect when a person or animal briefly
passes in front of the register 200. Optionally or alternatively,
the photovoltaic cells 206 may be used to detect that room lights
are on, which may indicate that the room is occupied. A shadow, for
example a shadow cast by a passing occupant, briefly passed over
the photovoltaic cells 206 may also indicate the region is
occupied. In some cases, opening or closing a door to a region
alters airflow into or out of the region. Thus, a change in the air
flow through the controlled register 113-126, without the
controller 613 having caused a change in the air control vanes
300-303, may indicate an occupant entered or exited the region.
[0117] Optionally or alternatively, a remote control unit 150-153
may be used by an occupant to indicate that the region is occupied.
For example, the remote control unit 150-153 may include a button
that, when pressed, indicates the region is occupied. Furthermore,
receiving any command, such as setting a desired temperature or a
set-back time, issued within a region may be used to infer that the
region is occupied. Absence of any indication of occupancy for
several minutes may indicate a region is not occupied.
[0118] Artificial light can be differentiated from sunlight by the
relatively low level of illumination provided by artificial lights
and by the rapid increase or decrease in light level when a lamp is
switched on or off, compared to the gradual increase or decrease in
light level during sunrise or sunset, moon rise or moon set. Thus,
daytime versus nighttime may be automatically distinguished, even
if the clock 626 is not set. Even without the clock 626 being set,
the register controllers 133-146 may share their information about
the detection of bright light and, thus, measure the number of
daylight hours.
[0119] If the system clock 626 has been set, the controller 613 can
determine the times of sunrise and sunset by noting times when
strong light begins to shine on the photovoltaic cells 206 and when
this strong light ceases to shine on the photovoltaic cells 206.
Thus, an arbitrary time zone may be created, in which noon is made
to correspond to the brightest average light level detected, or
alternatively half way between sunrise and sunset, during a series
of 24-hour periods.
[0120] The thermal infrared sensor 212 may also be used to measure
an amount of ambient thermal infrared radiation in the region.
Ambient thermal infrared level is an important component of comfort
level. By measuring both air temperature and thermal infrared
level, the network can maintain a better comfort level. For
example, the controlled registers 113-120 may provide less heated
air in areas with significant amounts of thermal infrared
radiation, such as from windows, thus achieving energy savings.
Power Supply
[0121] As noted, the photovoltaic cells 206 provide electric power
for the register controller. Optionally or alternatively, a fan
(not shown) located in the air flow stream may be used to drive a
generator (not shown). The fan should be positioned so it is never
occluded by the adjustable damper or such that it is occluded only
near the extreme closed state of the damper. Optionally, a primary
battery (not shown) and/or an external power supply (not shown) may
be used.
[0122] FIG. 7 is a schematic circuit diagram of an exemplary power
supply 600. Energy is supplied by photovoltaic cells V1-Vn 206
and/or a fan-powered generator. An optional DC power input may also
be provided, so that an external source may also be used. Diodes D1
and D2 combine the power from the external source and the
photovoltaic cells (and/or the fan-powered generator) into
capacitor C1. Resistors R1 and R2 divide the voltage from the
external source to a level tolerable to a microprocessor U4 to
allow the two sources to be distinguished. The voltage on C1 is
applied to a switching power converter U1. This converter supplies
a current output, which is supplied to rechargeable batteries
B1-Bn. The current supplied to the rechargeable batteries B1-Bn is
controlled, via a switching converter U1, by the microprocessor U4.
The microprocessor U4 can also monitor the current in or out of the
rechargeable batteries B1-Bn via R3 and amplifier U2. The
microprocessor U4 can thus maximize the current into the batteries,
thus optimizing utilization of the power out of the solar cells for
any light level.
[0123] Resistors R4 and R5 divide the voltage from the rechargeable
batteries B1-Bn to a level tolerated by the microprocessor U4. The
microprocessor U4 is thus able to measure both voltage and current
levels in the rechargeable batteries B1-Bn to optimize battery
charging.
[0124] Power from the rechargeable batteries B1-Bn is supplied
directly to the servo motor and also to a switching power converter
U3, which provides regulated voltage to the microprocessor U4 and
other circuitry in the register controller. Since the
microprocessor U4 can ascertain the rechargeable battery B1-Bn
voltage, the microprocessor U4 can compensate motor drive signals
accordingly. The power converter U3 output is connected to a large
capacitor C2 that allows the microprocessor U4 to shut the
converter U3 down much of the time, reducing energy used by the
converter U3. Other shutdown circuitry (not shown) allows the
microprocessor U4 to save additional power by turning devices on
only when they are needed. The circuitry is also designed so that
rechargeable battery B1-Bn charging occurs automatically, even if
the rechargeable battery B1-Bn voltage is too low for
microprocessor U4 operation.
Network
[0125] The goals of the network include conserving energy and
enhancing comfort. The network accomplishes these goals in a number
of ways, some of which are summarized in Table 1.
TABLE-US-00001 TABLE 1 Network Goals Maintains desired temperature
in all areas (by controlling the amount of conditioned air supplied
to each region) Measures temperature more accurately and accounts
for IR background Eliminates or reduces the overheating or cooling
of any area of the home Simplifies owner initiated temperature
setback of selected areas Simplifies reducing heating/cooling of
entire house at selected times Enables setback when a room is
unoccupied Reduces waste from over-pressure in the ducts Prompts
for or causes the circulation of air from overheated (over-cooled)
areas to under heated (under-cooled) areas with HVAC system blower
alone Alarms for energy waste from open doors or windows Identifies
areas that need improved insulation or reduced infiltration
Measures overall system efficiency thereby improving upgrade
decisions
[0126] Although the register controllers 113-146 have been
described as having an RF transceiver for communicating with other
nodes of the network, other forms of wireless communication, such
as ultrasonic or infrared, may be used. Each network node has a
unique communications address assigned during manufacture and used
for point-to-point communication. This address may also be used as
the node's serial number. All nodes also have a common (broadcast)
address that all components respond to.
[0127] One use for the common address is to allow the handheld
remote units 150-153 to discover the unique address of any network
node. This is done by pointing the handheld remote unit 150-153 at
a node and transmitting a command from the remote control unit
150-153 via the RF transceiver in the remote control unit to all
nodes, where the command causes the nodes to transmit their unique
addresses via their infrared transceivers 606 (FIG. 6). The remote
control unit has an infrared transceiver 816 (FIG. 8) that is
directional and only receives this optical signal from the node
that the remote control unit 150-153 is pointed at. Once the remote
control unit has received a node's unique address, it can
communicate with that node explicitly over the normal RF wireless
network. The optical path can be used to determine that the user of
the remote control unit is still pointing at the same component for
all subsequent communications, but in this case a single flash of
light from only the node addressed by the remote control unit is
sufficient to confirm that the correct node has been addressed. If
the remote control unit fails to detect this flash, it will
reinitiate the address discovery procedure.
[0128] The remote control unit allows the user to select a network
component by pointing the remote at it like a gun, but avoids the
expense of a separate full duplex high speed optical communications
system for each controlled register. The proposed system requires
the addition of only a single LED, which can be used for other
functions, such as to indicate to the owner that the controlled
register is working properly. While the remote control unit must
have a light detector, it needs to support only low speed
communications that can be run by the microprocessor, without the
need for other dedicated hardware.
[0129] In some embodiments, a node returns its unique address over
the light path. In other embodiments, other systems may be used.
For example, because the remote control unit 150-153 normally has a
list of all addresses in the system 100, it may sequentially
command each of them to flash its (visible or IR) LED until the
remote control unit detects a flash. At installation, if the remote
control unit has not already acquired the list of unique component
addresses, it may use the broadcast address to discover all nodes
in range, not all of which may be in the local system 100.
Nevertheless, use of optical feedback from the node allows a "point
to select" mode to be used.
[0130] Each network node has several states, and among these are:
New (never installed); Discovery (installed in an HVAC system, but
still discovering other components); and Installed. When a
controlled register 113-126 is installed on a duct, the controlled
register 113-126 eventually detects air flow that is either hotter
or colder than the ambient temperature in the region. The register
controller notes the (relative) time (UT) that air flow starts and
stops. The existence of hot or cold air passing through the
register indicates that the controlled register has been installed
in an HVAC system. At that time, the controlled register switches
to discovery mode. The register controller sends out a request to
the common address for all units within communication range to
respond with their unique addresses. This request is accompanied by
the newly installed register controller's own unique address.
Alternatively the new unit may monitor all of the frequencies used
by networks of registers, and if appropriate, attach a request to
join at the end of the normal network transmission. In either case
the unit only joins networks that appear to be on the same HVAC
system. As noted, this may be accomplished by comparing the times
that both nodes observed recent starts and stops of air flow. If
these times are approximately equal, such as within about three
seconds, the newly installed node joins the communications network
of the discovered node, and the newly installed node changes its
mode to "installed."
[0131] The network includes all the nodes that have set their
states to indicate they are in the same network. The network may
have an Identification Number that is arbitrary but unique. One way
to guarantee uniqueness of the network ID is to use the unique
address of any unit in the network, for example the first register
controller in the network. This node is elsewhere called the
"oldest" component and is the basis for network time, in that NT is
identical to this node's UT.
[0132] A node may be removed from the network's list of nodes for
any of several reasons. For example, if a node has not communicated
with any node of the network for a substantial period of time, such
as about a day, the network may mark the uncommunicative node as no
longer a member of the network. This might happen if a register has
been removed from the HVAC system. If any node of the network
identifies itself as a member of another network, it is removed as
a member of this network. If a register controller records the HVAC
system's on and off times as substantially different from the
consensus on-off times, the register controller is removed from the
network.
[0133] If for any reason the "oldest" node is no longer a component
of the network, it is possible that it will become the "oldest"
component of a different network. To maintain uniqueness, the
network changes its ID to the unique address of a different
component, such as the numerically smallest ID among the remaining
nodes. The offset for NT need not be changed, so that time may
remain consistent within the network.
[0134] A controlled register 113-126 may also assume it has been
installed when it detects a threshold level of air flow. Requiring
detection of hot or cold air and an air flow may reduce false
attempts to install. However, because false attempts to install do
little harm, it is possible to attempt to install on air flow only.
A controlled register 113-126 should not attempt to install itself
until it has received a fairly full power supply charge and has
detected a full system blower cycle of minimum duration (for
example greater than one minute), so it can determine if it is in
the same system as other units it discovers.
[0135] There are several methods of determining if two nodes are in
the same system 100, but they all amount to discovering
similarities in their respective environments. "Turn on" and "turn
off" times for the air flow are good indicators for controlled
registers 113-126. To identify a network thermostat 160-163,
temperature fluctuations over time may be correlated, which should
correlate best with a nearby controlled register 113-126. Once that
register controller is identified, all other system nodes may be
revealed by that register controller. In the case of a network
thermostat 160-163, there may be a minimum correlation of
temperature over time and a minimum signal strength for the
communication link before the network thermostat is incorporated
into the system 100. This acceptance threshold may be reduced over
time, so the network thermostat 160-163 is eventually accepted,
even if the correlation and the signal are weak. It may be assumed
that the network thermostat 160-163 should be a part of some system
and that a user would not put a network thermostat in a region with
no controlled registers.
[0136] As an additional protection against installation mistakes,
in one embodiment, register controllers 133-146 accept set point
changes only from one network thermostat 160-163, and that network
thermostat must be the one with the highest correlation of
temperature fluctuations with the register controller. In addition,
every change of set point may then be used to conduct an experiment
to ensure that all register controllers are responding to the
correct network thermostat, not a network thermostat in a nearby
region.
[0137] For example, if the system is heating, and the local set
point is reduced below the current region temperature (such as by a
human adjusting the thermostat), all associated controlled
registers may close their baffles to reduce air flow. This should
result in a reduction in temperature, primarily in the region in
which the network thermostat and its associated controlled
register(s) are located. If there is a greater correlation with a
different network thermostat or with a controlled register that is
not associated with this network thermostat, the association may be
incorrect and should be changed.
[0138] The "experiment" described above was initiated as a result
of an action by a human. It is also possible for any node to
initiate a similar experiment, absent action by a human. For
example, if the temperature over time correlation is below a
threshold, and there is a comparable correlation with other
non-associated nodes, the node may automatically initiate the
experiment.
[0139] Just as an automatically configuring network should be
prepared to add new nodes, the network should also remove
components that appear to have left the network. It is possible
that a node has been removed by the owner to use on a different
HVAC control system 100 that is within communication range. For
example, the node may have been moved to another zone in the same
building. Continuing to treat this component as a member of the old
network could cause malfunction or suboptimal performance of the
network. The HVAC control system 100 should periodically or
occasionally compare HVAC on and off times and check other
criteria, such as correlated temperature over time, to ensure that
moved components are removed from the network.
[0140] A controlled register 113-126 can determine if it is sharing
a region with another controlled register 113-126 by closing its
damper and then monitoring the network to see if any other
controlled register has had to open its damper to compensate. The
experiment may also be run by opening the damper and seeing which
controlled registers had to close its damper to compensate.
Normally, the most effective technique (opening or closing) is the
one that causes the greatest change in total air flow into or out
of the region. In addition, duct pressure at the controlled
register that initiated the experiment and all other registers can
be measured and compared. Closing a supply register should increase
the duct pressure at nearby supply registers, and opening a supply
register should decrease the nearby supply register pressures. The
results of these experiments can be combined with correlations of
temperature and duct pressure.
Return Register
[0141] In conventional HVAC systems, the air flow is controlled
only by air supply registers. The air return registers have no
control baffle. In a conventional system, any attempt to control
the air return registers would make balancing the system
difficult.
[0142] In some embodiments of the present invention, a controllable
air return register is used improve the system's ability to move
air from areas that are too hot to where it is needed (or in the
case of air conditioning, to move too cool air to where it is
needed). With no control of the air returns, return air would come
from all areas and tends to be the average air temperature in the
building. This would limit the utility of simply moving air,
without operating the heating/cooling device 103, to achieve
comfort. In fact, if the system attempts to move the air from all
over a building to a specific region, a greater portion of the
returned air comes from that region, because the region with the
open supply register tends to have a higher air pressure than other
regions with closed supply registers. Consequently, little or no
net change is made, and energy is wasted operating the blower
106.
[0143] In the case of heating, having controlled baffles on all of
the returns allows the system to selectively move air from the
hottest area to the coldest area. A secondary use for the
controlled air return is to limit air movement from the rest of the
building to regions that have been set back or turned off.
[0144] Although the controlled return registers 123-126 have
hardware similar to the controlled supply registers 113-120, the
control algorithm may be different. In some embodiments, the
controlled return registers 123-126 have only two damper positions:
open and closed.
[0145] The highest priority for a return register is to ensure it
never fails in the closed state. Because most of the time the
network controls temperature by adjusting the air supply registers,
it is important that an inoperative controlled return register does
not interfere with this process. To this end, the hardware should
include a "default to open."
Remote Control Unit
[0146] The main function of the remote control units 150-153 is to
allow a user to communicate with the network, such as to set a
desired temperature within in specific region or to turn on or to
turn off the supply of conditioned air to the region. However, the
remote control units 150-153 do not act as central controls for the
HVAC system. As noted, control of the HVAC system is distributed
among at least the register controllers 133-146.
[0147] Each remote control unit 150-153 enables the user to: set a
desired temperature within a specific region; program a temperature
set-back schedule for each region; program set-backs based on other
conditions, such as room occupancy; set the time and date in the
network; turn the HVAC system on or off, in toto or in a selected
region; override automatic installation parameters; display status
information; display system performance data; display suggestions
from the network for energy conservation or comfort improvement;
and display error messages, such as messages related to
dysfunctional components or inefficiencies.
[0148] FIG. 8 is a schematic block diagram of an exemplary remote
control unit. A processor 800 executes instructions stored in a
memory 803. According to the instructions, the processor accepts
user inputs via a set of user interface buttons 806 and/or a
touchscreen 819 and displays information on a display 810 or the
touchscreen 819. The processor 800 communicates with a controller
613 (FIG. 6) in a nearby controlled register 113-120 via an
infrared transceiver 813 and/or an RF transceiver 816. Thus, the
user may use any remote control unit 150-153 to communicate with
any controlled register 113-120 by aiming the infrared transceiver
813 at the infrared transceiver 606 (FIG. 6) of the controlled
register 113-120.
Thermostat
[0149] Returning to FIG. 1, up to three types of thermostats may be
used. The original HVAC system thermostat 108 may be retained to
control the heating/cooling device 103 and blower 106. A network
thermostat 163 that is connected to control the heating/cooling
device 103 and the blower 106 may be connected to the original HVAC
system thermostat 108, or the network thermostat 163 may replace
the HVAC system thermostat 108. In either case, the network
thermostat 163 includes a wireless transceiver, so it can
communicate with other nodes of the network. A user may set a
desired temperature, such as with conventional user interface
buttons and a display on the network thermostat 163. The network
thermostat 163 sends information about the user inputs, such as a
desired temperature or set-back time, to the nodes of the
network.
[0150] The third type of thermostat is a network thermostat 160
that is not connected to control the HVAC system. In other
respects, the network thermostat 160 is similar to the network
thermostat 163.
[0151] Network thermostats 160-163 may be added to any region. To
ease installation, in some embodiments, network thermostats need no
power connections. Each network thermostat 160-163 may have a
photovoltaic cell on its front surface. The network thermostat may
also have provision for a primary battery. While the network
thermostat may have the same temperature measuring devices
(thermistor and/or IR) as the register controllers, this is used
primarily to determine which controlled registers are in the same
region as the thermostat. Once installed in the network, the
network thermostat may be completely turned off until the user
pushes a button. In this case, the power to transmit the new
setting to the network may be generated as the button is pressed,
such as in a manner similar to that used for remote lighting
controls. The thermostat may be thin enough to look like an
electrical switch plate when it is glued to a wall.
[0152] As noted, a network thermostat 163 can replace the HVAC
thermostat 108. To make the replacement of an existing thermostat
simple, the network thermostat 163 allows for the connection to the
wiring to be done arbitrarily. One embodiment of the network
thermostat 163 has 7 input terminals, which provide a connector for
every possible lead from the HVAC control 109. Once connected to
the HVAC control 109, the network thermostat 163 measures voltage,
resistance and/or impedances between pairs of connections. These
pairs are either power supplies or windings on relays that control
heating, cooling, and the blower. There are, at most,
6+5+4+3+2+1=21 such pairs. The power inputs should be obvious from
the voltage across a pair. Pairs with a fairly low resistance are
likely the windings of control relays in the HVAC control 109. The
network thermostat may then determine which relays control the
heating, cooling and blower by applying the HVAC supplied power to
one or more of the relay leads and determining what happens, i.e.,
whether air flow begins, whether the flowing air is heated or
cooled, etc. This mechanism not only makes the installation of the
network thermostat easy, it also prevents user installation
errors.
[0153] The network thermostat 160 is primarily a user interface
allowing the user to observe the real temperature and the set point
temperature, to adjust the set point temperature and to turn off
the heating (cooling) to a region. As noted, the network thermostat
160 has local temperature measuring capability, but that is just
reported to the network and does not directly adjust any register.
For this reason, the network thermostat 160 only needs to be
powered up for installation or after a button is pushed. A
combination of a primary battery and power generated from pushing
the button should allow a thermostat to install itself in a network
and continue to perform its most important functions after the
battery dies.
Temperature Control Algorithm
[0154] Each intelligent register controller 133-140 in a controlled
supply register 113-120, and optionally each intelligent register
controller 143-146 in a controlled return register 123-126,
executes an algorithm that determines how and when the respective
register's adjustable damper should be operated. In a system with
generous power reserves available, the control algorithm can be
quite simple, as illustrated by the flowchart of FIG. 9 For
example, in heating mode, at 920, each register controller 133-146
opens its vanes when heat is supplied by the heating/cooling device
103 and blower 106, and at 923, the register controllers 133-146
close the vanes when their respective regions reach the desired
temperatures. By closing the vanes most of the way in conventional,
i.e., uncontrolled, registers 128 in the region containing the HVAC
thermostat 108, the region serviced by the uncontrolled registers
128 heat more slowly than the regions supplied by the controlled
registers 112-120. The heating device 103 shuts off when the HVAC
thermostat 108 is satisfied. By that time, the regions supplied by
the controlled registers 113-120 should have reached their
respective target temperatures, and their respective register
controllers 133-128 should have closed their adjustable
dampers.
[0155] At 900, if air flow is detected, control passes to 903,
where the room temperature is measured. If the HVAC system is
operating in a heating mode, at 906 control passes to 910,
otherwise control passes to 913. At 910, if the room is hotter than
the target temperature for the room, control passes to 923, at
which the vanes of the register are closed an incremental amount,
such as a predetermined number of steps of a stepping motor. On the
other hand, if at 910 the room is not hot enough, control passes to
920, where the register is opened an incremental amount. After a
delay 926 to allow the room temperature to change in response to
the increased or decreased airflow resulting from the incremental
opening 920 or incremental closing 923 of the register, control
returns to 900. Thus, as long as air is flowing through the
register, the control loop repeated compares the room temperature
to the desired room temperature and incrementally opens or closes
the register, as needed. Optionally (not shown), if the room
temperature is within a predetermined range of the desired
temperature (i.e., within a "dead band"), the register opening may
be left as it was in a previous iteration of the loop. Optionally
(not shown), if the level of charge in the battery is below a
predetermined threshold, the register opening may be left as it was
in a previous iteration of the loop to conserve battery power that
would otherwise be consumed operating the servo.
[0156] Similarly, if the HVAC system is operating in a cooling
mode, at 913 the comparison between the current room temperature
and the desired room temperature causes the register to be
incrementally opened 930 or incrementally closed 933.
[0157] In another embodiment, the algorithm is more complex, as
illustrated in the flowchart of FIG. 10 The vanes do not
necessarily move continuously in reaction to real-time conditions.
Instead, the vanes move only a step or two at a time in accordance
with an algorithm that monitors system behavior over time and
predicts the minimum needed adjustments, based on the energy
requirements and physical characteristics of each region making up
the entire system. In other words, the network collects data
related to how much of a temperature change is caused by a certain
change in openness of a register. For example, it may be
experimentally determined that, for a given register, during a
particular season of the year, a 10% change in the amount the
register is open typically causes a 0.3.degree. F. change in room
temperature. Once this data has been collected, at 1026, the amount
by which a register should be incrementally opened or closed may be
calculated, based on the difference between the current room
temperature and the desired room temperature. Then, at 1043, 1046,
1050 or 1053, the register may be opened or closed by the
calculated incremental amount. Other aspects of the flowchart of
FIG. 10 are similar to the flow chart of FIG. 9.
[0158] Each node of the network, or at least each register
controller 133-140 in a controlled register, maintains a table (a
Device Information Table (DIT)) of data for each other node in the
network, or at least each register controller 133-140. Data in this
table is used to maintain the communications network and to support
the control algorithm. Most of this data is periodically or
occasionally updated, such as every two minutes. A description of
DIT entries and other data relevant to the control calculation is
now provided.
[0159] Current Measured Temperature (Tpresent)--A best estimate of
region temperature at the device. For a controlled register
113-126, the floor temperature is measured by a thermistor and the
ceiling temperature is measured by a thermal IR detector, as
previously discussed. The reported temperature is a weighted
average from the two devices. Remote control units 150-153 and
network thermostats 160-163 measure temperature with internal
thermistors.
[0160] Target Temperature (Ttarget)--A temperature the controlled
register 112-126 is attempting to achieve, if the device is in a
constant temperature mode. On the other hand, if a schedule is
active for the device, this value is ignored, and the target
temperature set by the schedule is used.
[0161] Vent Position (controlled registers 112-126)--A percentage
that the vents are currently open.
[0162] Heating Vent Gain (Fventgainh)--A factor used to determine
the effectiveness of opening a vent a given amount. For example,
this may be calculated as a rate of change in temperature a region
might experience for a 25.degree. C. outside temperature with the
heating device 103 operating and all vents in the building open
50%.
[0163] Cooling Vent Gain (Fventgainc)--A factor used to determine
the effectiveness of opening a vent a given amount. For example,
this may be calculated as the rate of change in temperature a
region might experience for a 25.degree. C. outside temperature
with the cooler 103 operating and all vents in the building open
50%.
[0164] Heating and Cooling Temperature Position Factor (Fposh and
Fposc)--Regions near the outside of a building generally require
energy inputs that are different than the inputs required by inside
regions. These factors account for that difference.
[0165] Outside/Inside Air Temperature Factor (Foutin)--A factor
based on the percentage of time that the heating/cooling device 103
has operated over the last 24-hour period, which is proportional to
the difference in inside and outside temperatures. Blower 106
operation and temperature are both monitored to rule out
"blower-only" time.
[0166] Daily Temperature Pattern (Fpattern)--A temperature profile
over the course of a day typically follows pattern similar to
previous days, and the maximum temperature typically occurs at
about the same time from day to day. The algorithm may include a
factor based on this pattern. For example, the algorithm may
anticipate a need to provide more or less heating or cooling in the
immediate or near future, based on this historical data. For
example, the historical data may show that additional heating will
likely be required beginning at about 5:00 PM, at least in certain
rooms, such as because the sun ceases to shine at about that time
on the part of the building where the rooms are located. Thus, the
HVAC control system 100 may begin heating those rooms, beginning a
little before 5:00 PM. Such anticipatory heating or cooling may
even out the load on the heating/cooling device 103 (FIG. 1), thus
reducing the capacity of the heating cooling device 103 required to
meet instantaneous needs.
[0167] Power Available--A variable that gives an indication of the
power available to a device. This may be an indication of the level
to which the battery is charged. Any suitable range, such as
integers from 0 to 10, may be used. For example, 0 and 1 may
indicate the device does not have adequate power available to
adjust its vents.
[0168] Dawn and Dusk Times--Each device utilizes its sensors to
establish an estimate of dawn and dust times using two techniques.
The first records the output of the photovoltaic cells to ascertain
a pattern of sunrise and sunset, as described above. The second
monitors the airflow pattern to determine when the peak heating or
cooling times occur. (It may be assumed that the peak heating
occurs at midnight, and the peak cooling occurs at noon.) Since
each device has the data from all other devices, these numbers can
be combined to make the best estimate of dawn and dusk. Because all
devices execute the same algorithm and use the same data, all the
devices arrive at the same values. Dawn and dusk time are used to
time-calibrate a standard temperature pattern, described above.
[0169] As noted, the HVAC control system 100 includes no central
controller. Each register controller 133-146 accumulates data from
all other register controllers 133-146 in the system 100, and then
each register controller 133-146 calculates its next action, taking
into account the calculated actions of all of the other register
controllers 133-146. These calculations occur periodically or
occasionally, such as every two minutes during active airflow
periods. The calculation results in a decision to open or close the
vanes one or more steps or leave the vanes unchanged. The objective
is to heat or cool all regions at the same rate of temperature
change so, when the airflow ceases, each room will have achieved
its target temperature. The algorithm proceeds as follows, as
illustrated by the flowchart in FIG. 10. Heating or cooling
versions of the factors are chosen to match the current mode of the
system.
[0170] At 1020, for each controlled register 113-126, determine a
target change in temperature to be achieved over the current
airflow cycle. If a set-back, vacation or other schedule is active
for the register, the target temperature is used from that
source.
[0171] At 1023, for each controlled register 113-126, calculate a
value proportional to the energy flow, such as according to
equation (1).
Energy flow contribution
(n)=(Ttarget-Tpresent)*Fventgain*Fpos*Foutin*Fpattern (1)
[0172] At 1026, sum and normalize the values just calculated to
determine the target vent openings required throughout the system
100. Compensate for any registers that may be stuck in position due
to inadequate power reserves. Preferably, adjust the values so that
at least one controlled supply register 113-120 will have it vents
fully opened. This maximizes air flow and minimizes air
leakage.
[0173] At 1030, from these results, determine the direction and
rates the register vanes should be moved. Examine the time at which
a movement last occurred to assess if a new movement is due. If so,
execute that movement. As noted, if the current room temperature is
within the dead band, or if the register's battery charge level is
low, the register vanes may be left unchanged, at least for the
current iteration through the control loop.
[0174] When air flow ceases, update the calculated values for each
of the factors listed above, based on data from the air flow
cycle.
Air Movement
[0175] Moving air from one region to another region, without
operating the heating/cooling device 103, can save energy while
increasing comfort, if several criteria are met. First, there
should be a temperature difference between the two regions. Second,
there should be at least two regions that are within their "dead
bands," i.e., temperatures that are within a predetermined range,
such as about three degrees, of their set points. However, at least
one of the regions should be above its target temperature, and at
least one of the regions should be below its target temperature. In
addition, the region above its target temperature should be hotter
than the region that is below its target temperature.
[0176] Each register controller 113-146 may have several goals,
including: maintaining a desired temperature, minimizing energy
consumption by the HVAC system and maintaining a minimum energy
level in its power supply. If a minimum charge is maintained in its
power supply, a register controller attempts to maintain the
desired temperature range, and then to minimize energy consumption
by the HVAC system.
[0177] If a register controller 113-146 is low on power, it reduces
its power consumption by first increasing its dead band. If the
power reserve continues to decline, at a predetermined point the
register controller notifies the network of the problem and turns
itself off. The register controller does not turn on again until a
minimum power level (higher than the turn-off level) has been
restored.
[0178] The main way an owner can help the system minimize HVAC
energy consumption is to expand the dead band. If the system is
heating, and a controlled register is in a region that is below the
dead band temperature range, the controlled register normally opens
its damper until the region reaches minimum desired temperature. If
the controlled register receives information over the network
indicating that other regions failed to reach their desired
temperatures, the controlled register temporarily expands its dead
band, thereby permitting the temperature of its region to be lower
or higher (depending on whether the HVAC system is heating or
cooling) than the original set point. For example, if the HVAC
system is heating, and the coolest controlled register is fully
open but has failed to reach its minimum desired temperature,
warmer controlled registers decrease their respective airflows,
thereby making more air pressure and air flow available for the
coolest controlled register. The goal of minimizing HVAC energy
consumption causes the controlled register to close its damper by
an amount that is a function of how far from the comfortable
temperature the room air is, and how long it has been that way. If
all of the registers in a system are in the same network, these
register adjustments result in all regions coming to the same
temperature, a temperature set by the HVAC system thermostat 108.
This forms a basis for automatic network self-installation, without
a need to connect to the HVAC system or replace and existing HVAC
system thermostat. Attempting to balance the temperatures by first
opening the coolest region's register (if the HVAC system is
heating, or opening the warmest region's register if the HVAC
system is cooling) ensures that all registers are as open as
possible and still achieves a balance. This, in turn, ensures that
the HVAC system has the least pressure in its ducts, thus
minimizing energy waste in the HVAC blower and from duct
leakage.
[0179] FIG. 11 is a flowchart illustrating operation of an
intelligent controlled register 113-120. At 1100, air temperature
of a region is measured. At 1103, optionally, a signal is received
from a remote control unit. The signal may convey information about
a desired set point temperature, set-back time, or the like. At
1106, signals are received from one or more first other intelligent
controlled registers 113-120. The signals may convey information
about measured air temperatures, desired set point temperatures,
battery charge levels, air flow rates, damper states, and the like
for the respective intelligent controlled register(s). At 1110, the
information received from the other intelligent controlled
register(s), along with corresponding information about this
intelligent controlled register, is sent ("forwarded"), so that
other intelligent controlled registers that are not within wireless
communication range of the first other intelligent controlled
registers may receive the information. That is, the information is
distributed to other nodes of the network. At 1113, a desired
damper operation is calculated, based at least in part on the
available information about this and the other intelligent
controlled registers of the network. The calculation may also
involve information received from the remote control unit and/or a
wireless thermostat. At 1116, a servo is driven to operate a
damper, according to the calculated desired damper operation.
Control then returns to 1100.
Network Communication
[0180] In normal operation, the devices in the HVAC control system
100 may be asleep between messages, and the amount of time that
receivers are on is minimized. This is done to conserve the small
amount of power (typically supplied by solar cells) that is
available to each device. All of the devices in the network wake up
in synchronization very briefly, such as at regular intervals, such
as every two seconds, to see if a remote control is attempting to
communicate. During one of these wake-up periods, at another
interval, such as every two minutes, each of the devices in the
system 100 passes a standard data messages in succession to all of
the other devices. The standard data message may include current
status and critical data for the device and additional information
that is designed to optimize and maintain the integrity of the
network. Each message contains an embedded device ID and a CRC
message integrity check.
[0181] Each device maintains a Device Information Table (DIT). This
table contains detailed information about all of the devices in the
network. The DIT may be updated over the course of several message
bursts. The data includes power stability and availability
information for each device, as well as data on the reliability of
reception of each device by the other devices. This allows a device
to request forwarding channels to be set up, so that it may acquire
data from devices it cannot directly receive from reliably.
[0182] Since all devices have data available from all other
devices, and all devices run the same software, each individual
device is able to compute the control decisions for the entire
network and then locally apply the decisions that are applicable to
itself. This is the key design element that allows the system 100
to operate without a central controller.
[0183] Exemplary numbers are given for the various timings of the
system. Many of these values are defined by system settings in the
software and are subject to change. The values given here are only
exemplary; other values may be used, based on needs of the system,
user preferences and other design considerations.
[0184] Typically, after the system 100 has formed a working
network, periodic or occasional communication burst are used. In
one embodiment, every two minutes, all of the devices in the system
100 pass data between themselves in a burst of successive messages,
as illustrated in FIG. 12. Portions of the message burst of FIG. 12
are now described.
[0185] IDQ--During this 10 mSec. time slot, each device calibrates
an internal synthesizer, enables its receiver, and listens for an
ID query command from the remote. The IDQ search occurs every 2
seconds. The remainder of the burst occurs only at the two-minute
interval.
[0186] Dev 0-Dev n--This is the normal succession of transmissions
by each member of the network. They start at predetermined times in
2 mSec. increments. If a device fails to transmit, the next device
will still transmit at its allotted time. The first device
transmits its data twice as part of the collision avoidance system,
which is described below.
[0187] FWD--One or more packets may appear in this position for
forwarded data. A forwarded data packet is identical to that
originally sent by the device being forwarded. Forwarding is
explained later in this document.
[0188] JOIN--New devices requesting membership in the network
transmit a packet during this time. Joining the network follows a
protocol described later in this document.
[0189] UPDT--A long block with software update data may be appended
to the message stream at this position. Devices will only look for
this block if the software update bit in the status byte of the
previously received packet is set.
[0190] IRID--If the remote queried to identify a device during the
IDQ period, all devices will respond with an ID message using the
infrared (IR) link. If the remote query occurs at the time a
message burst is scheduled, the IR response occurs at the end of
the message burst as shown. Otherwise, the IR response occurs
immediately after the query.
[0191] Devices in the system have very limited power available to
them. When a new device is installed, it may have some power stored
in rechargeable battery, or the battery might need to be charged
before the newly-installed device can become a reliable member of
the system 100. When a device "wakes up" for the first time, it
assesses the power reserves available to it. It will not attempt to
join or start a communications network until it determines that it
has adequate power reserves to support reliable communication for
twenty-four hours. Operations performed by a device upon waking,
such as searching for a network to join, are illustrated in a
flowchart in FIGS. 13A and 13B.
[0192] A device can stop functioning if it suffers a loss of power
for a long extended period. As a result, it would have stopped
communicating in a network it was previously part of. While the
device was out of commission, a number of events might have
occurred. In most cases, the network would have resumed normal
operation without the dropped member. RF interference may have
caused the network to shift to an alternate frequency. Discovery of
another network operating at the same frequency may have caused the
network to change to another frequency. The device may have been
taken out of the network and placed into another. All devices in
the network may have dropped out. The device may be new and never
have been part of a network before.
[0193] Once reliable power has been established, the device checks
non-volatile memory to see if it was previously part of a network.
If it was part of a network, it will look in non-volatile memory
for the position it held in the message burst sequence and for the
selected communication frequency and network ID.
[0194] In all cases, the device will then wait until its internal
airflow sensor indicates that the HVAC fan has been activated. Once
it sees airflow, it records the time at which the airflow started
and enables its receiver. If it was previously part of a network,
it will listen first at the memorized frequency. Otherwise, it will
listen at the default frequency. It will listen at the starting
frequency for 2.5 minutes. If a network is not found, it will shift
to the next alternative frequency and make the same search. It will
step through all of the frequencies twice in this manner. As it
steps through the frequencies, the device will make a record of
those frequencies that were clear of interference or other
networks.
[0195] The receiver consumes significant power and, in most cases,
cannot be run continuously. If the search for a network is
unsuccessful, the receiver will be shut down and the search will be
tried again at a later time determined by the available power.
[0196] If a network is found with the same airflow time, the search
ends. A former member that has not lost its time slot merely
resumes transmission. A new device or a former network member that
has lost its time slot will enter the network joining process
described below. A device that was part of a network previously but
finds a different network ID may have been removed from one network
and placed in another, but there is a small chance that it has
discovered another network and that the furnaces came on at the
same time. This case is handled by actions of the self-repair
process described later in this document.
[0197] If a network is found with a different airflow start time,
that network will be ignored and the search will resume when the
channel is again clear.
[0198] If no network is found, a new device will attempt to
establish one. To do this, it will restart its receiver at the
lowest frequency that it has found to be clear of interference or
other network traffic. It will then search at this frequency for a
pseudo-random amount of time ranging form zero to 2.5 minutes. If
no other device is found in that time, it will attempt to form a
new network, as described in the following section.
[0199] The above discussion assumes that device has access to an
airflow sensor, as do registers, main thermostats, and remotes
docked to a thermostat back. Room thermostats and freestanding
remotes do not have direct access to airflow sensors. These devices
monitor temperatures over a length of time to correlate with
changes in room temperature and thus calculate an equivalent
airflow start time. If a remote is used to access a device that is
connected to a network, it will obtain the network information from
the device and join at that time.
[0200] The process of network formation is illustrated by a
flowchart in FIG. 14. The process is typically initiated by a
register. All practical systems contain at least one register, and
registers will also have the necessary access to airflow
sensors.
[0201] To form the network, the device transmits the MSGOa, MSGOb
sequence described above, looking for the presence of a carrier
after each message. If no carrier is found, it assumes it is the
first messenger on the network, and continues to transmit
accordingly. Other devices will form around it according to the
network joining process described below. If a carrier is found
immediately after either MSGOa or MSGOb, it is assumed that another
device is trying to send in the MSGO position, and the device
restarts the process of looking for an established network. The
chances of such a collision are extremely small. The transmitter
will only start if it sees a clear channel. The chance of two
transmitters starting at the same time is about 5 .mu.Sec./2
minutes or one in 4.17E-8. The device established as the first
messenger drops off the network and restarts the process if no
other devices attempt to join within 24 hours.
[0202] A device that desires to join the network typically first
finds an existing network using the procedure detailed above and
illustrated by a flowchart in FIG. 15.
[0203] It then sends a standard data message twice. The first is
during the "join" time slot interval described above. The second is
at time within the span of time that would be required for a
message burst for a maximum sized system. The time slot at which
the device sends its message is determined by a pseudo-random
number.
[0204] When the device that is the first messenger sees a message
in the "join" time slot, it keeps its listening open for the
remainder of the maximum sized message burst. If it sees one or
more valid messages during that time it will, on the next burst,
send Ids for the new devices seen in the cyclic data areas of MSG0a
and MSG0b. It will also tell these devices their position in the
message burst. After that point the new devices will begin to
transmit in their allotted time slots. This process continues until
all requesting devices have joined the network. Some collisions may
occur during this time, but the devices will all be joined over a
few cycles.
[0205] Each network member collects data from all of the other
members. There may be physical problems, such as excessive distance
or path obstructions, that prevent direct reception of a message
from one member to another. To overcome this difficulty, a message
forwarding system is implemented that operates as follows:
[0206] 1--The data packet transmitted by each member contains three
values that assist in the establishment of a forwarding link. These
are the ID of the previous member and a rotating triplet consisting
of the ID, receive signal strength, and power reliability index of
each of the other members in the network.
[0207] 2--Each member builds a Device Information Table (DIT) that
contains a data block for each other network member consisting of
ID, power reliability index, and receive signal strengths for all
other members in the network.
[0208] 3--The member that lacks data from another member analyzes
the table to determine the best member to select as a forwarder for
the missing data. Selection is based on the reliability of power
and received signal quality from both the missing member and the
requesting member. The requesting device then sends a request to
the selected forwarder to regularly forward the missing data. This
request is contained in the cyclic data section of the requesting
member's standard data message.
[0209] The remote control 150-153 can be used in a variety of
modes. In most systems, it is used to enter user preferences, such
as temperature targets and schedules, into the system. To do this,
the remote may be pointed at a device to send an RF query message
to it and receives an IR response from it. This is called
point-to-connect mode. The remote can also interact with devices
remotely via RF, serving as an "armchair console" for the system.
It can also be docked with a thermostat to act as the central
furnace-controlling thermostat for the system.
[0210] When docked with a thermostat, the remote usually can
receive power from the thermostat circuit. In this case, it
connects to the system like other devices and communicates at the
regular two-minute interval.
[0211] If not docked, the remote can operate in the same regular
communication mode or, to conserve power and extend battery life,
it can communicate at much longer intervals, dropping off the
network and rejoining it as needed.
[0212] When operated in point-to-connect mode, the remote can
access the device quickly in the following manner:
[0213] Point to Connect Device Acquisition--When the remote is
commanded to connect to a device using the infrared (IR) link, the
process is as follows:
[0214] 1--If the remote has been actively communicating with the
network, it will time the sending of the query message so as not to
interfere. If not, it checks to see if RF traffic is present. If
so, the remote will wait until the traffic stops, monitoring the
message burst so that it will be synchronized to further traffic.
It then sends an RF ID query message.
[0215] 2--The remote waits for an immediate IR response if no RF
traffic was present, or for a response at the end of the traffic.
If a response is received, the remote proceeds with processing. If
not, the remote repeats the enquiry until a response is received,
or 2.5 seconds has elapsed. After each enquiry, the remote checks
for RF traffic. If traffic is found, the remote records the time of
the traffic and predicts the time of the next loop so that it can
avoid future interference with the network. The IR message returned
also includes the time of the next RF loop for the same purpose.
The message also includes the device ID and, if established,
network ID.
[0216] 3--The responding device will now have "awakened" so that it
continuously looks for additional addressed RF enquiries from the
remote. These include requests to send data or settings information
and downloads from the remote of updated information.
[0217] 4--Once the remote has received the settings information
from the device, it will use the variables table and main display
screen corresponding to that device.
[0218] 5--If a timeout period of no activity occurs, the device
will return to normal operation.
[0219] Whenever the remote is on, it monitors the network, updating
information from all other devices. A future remote screen will
allow examination of the general health of the network.
[0220] The network is designed to be self-healing. Changes to the
structure of the network follow the same general model as the
method of establishing forwarding paths. Each device in the network
is expected to act as a conscientious member. It is responsible for
its own welfare, being sure it has adequate power before attempting
transmissions or other actions. If it cannot hear one of the other
members, it will ask another member to relay messages, but only
after being sure the other member has adequate power reserves to
handle such requests, and that the other member is also able to
clearly hear the distant device. If a device determines that it
will soon drop off the network due to a loss of power or other
problem, it will inform the other members of the time when the
drop-out will occur.
[0221] Interference and Changing Frequency--It is possible that two
networks can be operating at the same frequency but not see each
other because they have different start times. Eventually, as they
drift due to slight differences in their crystal frequencies, they
will collide. When this occurs, one or both networks will shift
frequency.
[0222] Dropping a Device--A device will drop out if airflow times
do not match (checked at time of second burst after airflow
starts). Loss of power may cause a device to drop out. If so, it
will notify the network in advance that it is about to leave.
[0223] Reassignment of Burst Position--Transmissions on the network
are synchronized to the first device to send a message during each
burst. The device performing that task is effectively the first
device to ask for it when the network is formed. That device will
continue to perform the task unless it develops a reliability
problem that causes it to drop from the network. In that case, it
will inform the network that it is dropping out. Another device
will assume the "first messenger" role automatically based on the
data in the DIT.
[0224] When devices receive an information update message, if
devices in the system are discovered not to contain the most
current code revision, the lowest ID numbered device with the most
current code revision will broadcast a copy of the code. Those
devices that are not current will update themselves,
[0225] Normally, message bursts occur every two minutes, as
described above. A demonstration mode can be entered via the
remote. In this mode, the message burst occurs every two seconds.
Demonstration mode may cause other operation changes within devices
that vary according to the device type.
[0226] The standard device data packet is 48 bytes long, and takes
1536 .mu.Sec. to transmit at 250 Kbps. The remainder of the 2 mSec.
time slot allows for RX/TX turnaround. An exemplary data packet is
illustrated in FIG. 21.
[0227] Cyclic Data--Some data elements only need infrequent update.
By not transmitting these every cycle, the average packet length
can be reduced, reducing reception time, and thus, power
requirements. The largest of these is a firmware update, which is
sent and accumulated in small parcels that are stored in serial
EEPROM by the receiving device for program update when the entire
file is complete. Includes the following:
[0228] Network ID
[0229] Reception quality from all other devices
[0230] Power stability indicator
[0231] Time of last airflow
[0232] Software rev
[0233] Time clocks--UT,
[0234] Device ID--Each product contains a unique 32-bit device ID
or serial number that is programmed in at manufacture. The three
MSBs of the ID also indicates the type of device--0=register,
1=thermostat, 7=remote.
[0235] Error Checking--A 16-bit CRC is appended to all packets.
Reception of a message that fails its CRC check causes that message
to be discarded. The data update frequency is great enough that an
occasional discarded packet causes no problems.
[0236] On query from the remote, the device sends settings
information via a device settings data packet, an example of which
is shown schematically in FIG. 22.
[0237] Short packets are sent by the remote to cause all devices to
send their IDs via IR or other information via RF. These packets
total 26 bytes in length, requiring 704 .mu.Sec. to transmit. An
example of such a remote command packet is shown schematically in
FIG. 23.
[0238] The remote standard update packet is 48 bytes long and is
used to update standard information in a device after it has been
edited by the remote. An example of such a remote standard update
packet is shown schematically in FIG. 24.
[0239] The remote settings update packets is 48 bytes long and is
used to update settings information in a device after it has been
edited by the remote. An example of such a remote settings update
packet is shown schematically in FIG. 25.
[0240] Each device maintains a table that records the most recent
data transmitted by all devices in the system as well as some
historical data. An example of such a device information table is
shown schematically in FIG. 26.
[0241] Remote--The remote looks for the loop like any other device.
An ID query RF message is queued for transmission. If a no-carrier
space is found, the remote will send repeated queries, waiting each
time for an IR response. If an RF carrier is found, a response will
be looked for after the end of the loop.
[0242] Device--If an IR ID message request is received during the
first interval, the response will be deferred until after the end
of the chain. If a response is received when there is no following
chain, the response will be sent immediately.
[0243] Remote--the remote looks for the loop like any other device.
Once it finds the loop, it avoids direct communications during
scheduled loop times. Otherwise, it will send messages anytime
there is no carrier. If the remote transmits at the same time as
the beginning of the loop, it will cause interference for that one
time, but the system is designed to recover. Successive loops will
not be interfered with.
[0244] The MSP processors used in the system may contain twice the
memory needed to support their programs. Code updates write into
alternate halves of the memory so that, if an update should fail,
the device can continue to operate with the previous version of the
code.
[0245] A unique motor may be implemented as part of the design of
an HVAC register, according to an embodiment of the present
invention. The construction of one embodiment of such a motor is
illustrated in FIGS. 16 and 17. This motor meets the following
objectives:
[0246] Low Cost--in both components and labor
[0247] Integrated Detent--to maintain position when power is
removed
[0248] High Power Efficiency--to allow it to be driven from a
source of minimal power, such as an array of low-cost solar
cells
[0249] According to one embodiment, the motor is a 4-phase stepper
motor. In this implementation, two stator stacks are formed as
illustrated in FIG. 17, where the components of the left half of
the motor have been shown in an exploded view. The first component
to the right of the printed circuit board (PCB) 1700 is the bottom
pole ring 1703. This is followed by a coil of wire 1706 wound on an
insulating bobbin and then the top pole ring 1710. These components
form one of the stators. The next component to the right is a rotor
ring magnet 1713, which has been magnetized with alternating poles
around its circumference at the same pitch as the two pole rings
1703 and 1710. The final component is the rotor housing 1716, to
which the rotor magnet is permanently mounted. A similar second
assembly 1720 mounts to the right to form a second stator and
rotor. The two rotor housings include integrated gear features 1723
and 1726 that cause symmetrical counter-rotation of the two rotors
with an offset of one pole position between the rotors. This causes
the motor to act as a 4-phase stepper as the coils are energized in
the conventional manner.
[0250] The cost savings of this motor over other forms that might
be utilized are based on the following:
[0251] Stamped Pole Construction--The pole rings 1703 and 1710 are
stamped form sheet metal material. This is an efficient and
inexpensive manufacturing process.
[0252] Simple Coil--The coil 1706 design is the simplest of forms,
reducing construction costs. Because the coil 1706 is mounted
directly to the PCB 1700, no cost is incurred in the attachment of
the lead wires needed with conventional motors.
[0253] Integration with PCB--The PCB 1700 is the mounting for the
motor. The back of the bobbin has integrated clips which eliminate
assembly screws, and plated holes in the PCB form the outer half of
the bearings for the rotors.
[0254] Multiple use of Rotor Housings--The rotor housings are not
only part of the motor, but form part of the position sensor
described below, include the arm for manual adjustment of the
register, and mount directly to the register vanes.
[0255] The pole segments of the motor are designed to cause
deliberate detents. These are designed to hold the position of the
vanes under airflow conditions even when power is removed from the
motor.
[0256] High power efficiency is achieved partially through the
absence of mechanical loss components such as gears and couplers.
The motor is designed to have a large diameter to achieve high
toque without the requirement of reduction gearing. The high ratio
the motor diameter to the gap between the rotor and stator
contributes to higher efficiency. The external rotor design allows
for a relatively large coil size, reducing electrical resistance
losses. A sensor, illustrated in FIGS. 18 and 19, according to one
embodiment of the present invention, is employed that is based on
changes in electrical capacitance. The design is very low in cost,
making use of the PCB 1700 and the rotor housing 1716 of one on the
sections of the motor described above. The sensor operates in the
following manner. Radial electrically conductive pads 1800 are
disposed on the PCB 1700 around the center of a rotor hole 1803.
Each of the radial pads 1800 around the circumference of the center
of the rotor hole 1803 is sequentially electronically connected to
a circuit that measures capacitance to ground or some other
reference node. This capacitance is affected by the position of the
rotor 1716, which is made of a metallic of metallically coated
material. The body of the rotor is grounded through motor
components. As the rotor rotates, one or more of the radial pads
becomes partially or fully uncovered, changing capacitance to
ground. The position of the rotor can thus be calculated from the
measures capacitance values.
Application to Electrical Heating Systems
[0257] The HVAC control system 100 can be applied to heating
systems incorporating an electric boiler or electric resistance
baseboard heaters. A system using an electric boiler is really a
hydronic system, as described above.
[0258] FIG. 20 shows a typical home heating system using baseboard
electrical resistance heaters. Multiple heating circuits are routed
from a central breaker box through a load controller. Each circuit
is then routed via one or more electrical high-voltage thermostats
to one or more baseboard heaters. Toroidal current transformers
surround each of the main power wires entering the breaker box, and
sensing wires from these transformers enter the load controller
box. An electronic assembly in the load controller switches the
heating circuits on and off to limit the maximum instantaneous load
current drawn. This is done to minimize energy expense.
[0259] An HVAC control system for an electric heating system has
the same features and advantages as an HVAC control system for a
forced-air system, except for the redistribution of air. Combined
systems can be implemented utilizing forced-air, hydronic and/or
electric elements as needed.
[0260] An electric baseboard heating system using an HVAC control
system as described herein may replace the standard electric
thermostats with an electric thermostat. This device may utilize
the control capabilities of a controllable register (as described
above), but may control a relay(s) or triac(s) to control electric
current to the heating element. Since the electric thermostat may
be wall mounted, it may also contain the display and buttons of the
standard wireless thermostat 160, described above with respect to
FIG. 1. All elements of this system may communicate wirelessly (or
optionally through wired connections) with other components, such
as wall thermostats and remote controls in the same manner as in a
forced-air system. One other component, a whole-house current
sensor transceiver, may be added in an electric heating control
system. This device utilizes the current sensors already connected
to the load controller and taps into the signals inside the load
controller box. Installation of this system is not a "drop-in," as
described above for a forced-air system. It requires the low-level
electrical work of replacing the electrical thermostats and adding
the whole-house current sensor transceiver.
[0261] In accordance with an exemplary embodiment, systems and
methods for controlling HVAC systems are provided. While specific
values chosen for these embodiments are recited, it is to be
understood that, within the scope of the invention, the values of
all of parameters may vary over wide ranges to suit different
applications.
[0262] An intelligent register controller has been described as
including a processor controlled by instructions stored in a
memory. The memory may be random access memory (RAM), read-only
memory (ROM), flash memory or any other memory, or combination
thereof, suitable for storing control software or other
instructions and data. Some of the functions performed by the
intelligent register controller have been described with reference
to flowcharts and/or block diagrams. Those skilled in the art
should readily appreciate that functions, operations, decisions,
etc. of all or a portion of each block, or a combination of blocks,
of the flowcharts or block diagrams may be implemented as computer
program instructions, software, hardware, firmware or combinations
thereof. Those skilled in the art should also readily appreciate
that instructions or programs defining the functions of the present
invention may be delivered to a processor in many forms, including,
but not limited to, information permanently stored on non-writable
storage media (e.g. read-only memory devices within a computer,
such as ROM, or devices readable by a computer I/O attachment, such
as CD-ROM or DVD disks), information alterably stored on writable
storage media (e.g. floppy disks, removable flash memory and hard
drives) or information conveyed to a computer through communication
media, including wired or wireless computer networks. In addition,
while the invention may be embodied in software, the functions
necessary to implement the invention may optionally or
alternatively be embodied in part or in whole using firmware and/or
hardware components, such as combinatorial logic, Application
Specific Integrated Circuits (ASICs), Field-Programmable Gate
Arrays (FPGAs) or other hardware or some combination of hardware,
software and/or firmware components.
[0263] While the invention is described through the above-described
exemplary embodiments, it will be understood by those of ordinary
skill in the art that modifications to, and variations of, the
illustrated embodiments may be made without departing from the
inventive concepts disclosed herein. For example, although some
aspects of a system for controlling an HVAC system have been
described with reference to a flowchart, those skilled in the art
should readily appreciate that functions, operations, decisions,
etc. of all or a portion of each block, or a combination of blocks,
of the flowchart may be combined, separated into separate
operations or performed in other orders. Moreover, while the
embodiments are described in connection with various illustrative
data structures, one skilled in the art will recognize that the
system may be embodied using a variety of data structures.
Furthermore, disclosed aspects, or portions of these aspects, may
be combined in ways not listed above. Accordingly, the invention
should not be viewed as being limited to the disclosed
embodiment(s).
* * * * *