U.S. patent application number 13/908695 was filed with the patent office on 2013-12-05 for economizer hvac and control system.
The applicant listed for this patent is David DAVIS. Invention is credited to David DAVIS.
Application Number | 20130324027 13/908695 |
Document ID | / |
Family ID | 49670794 |
Filed Date | 2013-12-05 |
United States Patent
Application |
20130324027 |
Kind Code |
A1 |
DAVIS; David |
December 5, 2013 |
ECONOMIZER HVAC AND CONTROL SYSTEM
Abstract
An HVAC and control system with an economizer mode and
continuous damper position verification. Three dampers are provided
with a control module that accepts inputs from multiple temperature
sensors and a user, and which monitors and reports the position and
off-normal operation of multiple dampers.
Inventors: |
DAVIS; David; (Boise,
ID) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DAVIS; David |
Boise |
ID |
US |
|
|
Family ID: |
49670794 |
Appl. No.: |
13/908695 |
Filed: |
June 3, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61654561 |
Jun 1, 2012 |
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Current U.S.
Class: |
454/258 |
Current CPC
Class: |
F24F 2011/0006 20130101;
F24F 11/32 20180101; F24F 11/0001 20130101; F24F 2110/00 20180101;
F24F 2110/12 20180101; F24F 11/65 20180101; F24F 2140/40 20180101;
F24F 2011/0002 20130101; F24F 11/30 20180101 |
Class at
Publication: |
454/258 |
International
Class: |
F24F 11/00 20060101
F24F011/00 |
Claims
1. An HVAC and control system for economizer operation, the HVAC
system having a power source, a circulation fan, a cooling unit,
and a network of air delivery ducts for cooling a conditioned
space, the HVAC and control system comprising: an outside air
intake duct and a first damper movable between an open and a closed
position, with said first damper comprising a damper open position
sensor and a damper closed position sensor, with said damper
position sensors sensing and signaling a closed or open damper
position; an outside air temperature sensor for sensing the
temperature of outside air; a control module mounted in said
conditioned space with a damper error indicator comprising at least
one visual indicator of damper position error, with said control
module operationally connected to said power source, said
circulation fan and cooling unit, to said first damper, and to said
outside air temperature sensor; an economizer mode in which said
first damper is opened to allow outside air to be pulled into said
HVAC system when said economizer mode is selected, with said
selection based on a preselected temperature of outside air or by
manual control selection; and a non-economizer mode in which said
first damper is closed to prevent outside air from entering said
HVAC system when said economizer mode is not selected, with said
non-economizer mode selected by outside air temperature being above
said preselected temperature or by manual selection.
2. The HVAC and control system of claim 1 which further comprises
an isolation damper positioned in a return air duct, with said
isolation damper coordinated with said first damper to operate in
an opposite manner as said first damper, with said isolation damper
closed when said first damper is open, and open when said first
damper is closed, thereby using exclusively outside air for cooling
when outside air is at temperature is at or below the user setting,
with said isolation damper comprising a damper open position sensor
and a damper closed position sensor, with said damper position
sensors sensing and continuously signaling a closed or open damper
position.
3. The control system of claim 2 which further comprises a relief
damper positioned in said return air duct between said conditioned
space and said isolation damper, with said relief damper
coordinated with said isolation damper to operate in an opposite
manner as said isolation damper, with said relief damper closed
when said isolation damper is open, and open said isolation damper
is closed, thereby routing air from said conditioned space out of
said duct system when said system is using outside air for cooling,
with said relief damper comprising a damper open position sensor
and a damper closed position sensor, with said damper position
sensors sensing and continuously signaling a closed or open damper
position.
4. The HVAC and control system for an economizer system of claim 1
in which said damper position sensors send a continuous feedback of
proper damper position to said control module, with said control
module displaying a continuous indicator of proper damper
position.
5. The HVAC and control system for an economizer system of claim 1
which further comprises an economizer failsafe signal which is
activated when an off normal damper position is detected,
preventing operation with improperly positioned dampers, and in one
embodiment configured to close said first damper.
6. The HVAC and control system for an economizer system of claim 1
in which said outside air temperature sensor is configured to
activate said economizer mode, by a comparison between said outside
air temperature and a user setting.
7. The HVAC and control system for an economizer system of claim 1
which further comprises a damper cable with a first end and a
second end, with said end of said damper cable comprising a
plurality of conductors with said damper cable terminated on both
ends with geometrically coded connectors, with said control module
comprising a corresponding geometrically coded connector for
engagement with said first end of said damper cable, and with said
second end of said damper cable configured to engage a
corresponding geometrically coded connection at said damper(s) with
said geometrically coded connectors shaped to prevent misalignments
and to allow for error free assembly.
8. The HVAC and control system for an economizer system of claim 1
which further comprises an isolation damper and a third damper, the
isolation damper positioned in a duct between said conditioned
space and said outside air intake duct, and said third damper
positioned between said conditioned space and said isolation
damper, to allow the release of air from the ducting system, with
said isolation damper closed and said third damper open in said
economizer mode, and with said isolation damper open and said third
damper closed in said non-economizer mode.
9. An HVAC and control system for an economizer system for use with
an HVAC system, the HVAC system having a power source, a
circulation fan, a cooling unit, and a network of air delivery
ducts for cooling a conditioned space, the control system
comprising: an outside air intake duct and a first damper movable
between an open and a closed position, with said first damper
comprising a damper open position sensor and a damper closed
position sensor, with said damper position sensors sensing and
signaling a closed or open damper position; an isolation damper
positioned between said conditioned space and said outside air
intake duct, with said isolation damper closed in said economizer
mode and with said isolation damper open in said non-economizer
mode, with said isolation damper comprising a damper open position
sensor and a damper closed position sensor, with said damper
position sensors sensing and signaling a closed or open damper
position; and a third damper positioned between said conditioned
space and said isolation damper, to allow the release of
pressurized air from the conditioned space said third damper
configured to release overpressure air in said economizer mode, and
with said third damper closed in said non-economizer mode, with
said third damper comprising a damper open position sensor and a
damper closed position sensor, with said damper position sensors
sensing and signaling a closed or open damper position; in which
each of said damper position sensors send a continuous feedback of
proper damper position to said control module, with two damper
position signals per damper; an outside air temperature sensor for
sensing the temperature of outside air; a control module mounted in
said conditioned space with a damper error indicator comprising at
least one visual indicator of damper position error, with said
control module operationally connected to said power source, said
circulation fan and cooling unit, to said first damper by a damper
cable, and to said outside air temperature sensor, and with said
control module displaying a continuous indicator of proper damper
position indicating all dampers are in proper position; said damper
cable with a first end and a second end, with said damper cable
comprising a plurality of conductors with said damper cable
terminated on both ends with geometrically coded connectors, with
said control module comprising a corresponding geometrically coded
connector for engagement with said first end of said damper cable,
and with said second end of said damper cable configured to engage
a corresponding geometrically coded connection at said first,
second, and third damper with said geometrically coded connectors
shaped to prevent misalignments and to allow for quick and error
free assembly; an economizer mode in which said first damper is
opened to allow outside air to be pulled into said HVAC system when
said economizer mode is selected, with said selection based on a
preselected temperature of outside air or by manual control
selection; and a non-economizer mode in which said first damper is
closed to prevent outside air from entering said HVAC system when
said economizer mode is not selected, with said non-economizer mode
selected by outside air temperature being above said preselected
temperature or by manual selection.
10. The HVAC and control system for an economizer system of claim 9
in which said two damper position signals from each of three
dampers are sent to a damper position verification unit, which
sends a single damper position signal to said control module.
11. The HVAC and control system for an economizer system of claim 9
which further comprises an economizer failsafe signal which is
activated when an off normal damper position is detected, with said
economizer failsafe signal configured to prevent improper
operation, and in one embodiment to close said first damper.
12. The HVAC and control system for an economizer system of claim 9
in which said outside air temperature sensor is configured to
activate said economizer mode, by a comparison between said outside
air temperature and a user setting.
13. The HVAC and control system of claim 9 which further comprises
a readiness status signal, which is calculated and displayed on
said control module, with said readiness status calculated based on
outside temperature being sufficient to provide space cooling, and
safety conditions determined and configured by system installer
being satisfied.
14. The HVAC and control system of claim 9 which further comprises
a sensor monitor for monitoring of temperature sensors and
reporting of temperature sensor malfunction, with errors displayed
on said control display.
15. The HVAC and control system of claim 9 which further comprises
a calculator of system statistics and a display of system usage and
economic benefit, comprising run time and percentage of cooling
accomplished by input of outside air.
16. An HVAC and control system for an economizer system for use
with an HVAC system, the HVAC system having a power source, a
circulation fan, a cooling unit, and a network of air delivery
ducts for cooling a conditioned space, the control system
comprising: an outside air intake duct and a first damper movable
between an open and a closed position, with said first damper
comprising a damper open position sensor and a damper closed
position sensor, with said damper position sensors sensing and
signaling a closed or open damper position; an isolation damper
positioned between said conditioned space and said outside air
intake duct, with said isolation damper closed in said economizer
mode and with said isolation damper open in said non-economizer
mode, with said isolation damper comprising a damper open position
sensor and a damper closed position sensor, with said damper
position sensors sensing and signaling a closed or open damper
position; and a third damper positioned between said conditioned
space and said isolation damper, to allow the release of
pressurized air from the conditioned space said third damper
configured to release overpressure air in said economizer mode, and
with said third damper closed in said non-economizer mode, with
said third damper comprising a damper open position sensor and a
damper closed position sensor, with said damper position sensors
sensing and signaling a closed or open damper position; in which
each of said damper position sensors send a continuous feedback of
proper damper position to said control module, with two damper
position signals per damper, with said two damper position signals
from each of three dampers are sent to a damper position
verification unit, which sends a single damper position signal to
said control module; an outside air temperature sensor for sensing
the temperature of outside air; a control module mounted in said
conditioned space with a damper error indicator comprising at least
one visual indicator of damper position error, with said control
module operationally connected to said power source, said
circulation fan and cooling unit, to said first damper by a damper
cable, and to said outside air temperature sensor, and with said
control module displaying a continuous indicator of proper damper
position indicating all dampers are in proper position; said damper
cable with a first end and a second end, with said damper cable
comprising a plurality of conductors with said damper cable
terminated on both ends with geometrically coded connectors, with
said control module comprising a corresponding geometrically coded
connector for engagement with said first end of said damper cable,
and with said second end of said damper cable configured to engage
a corresponding geometrically coded connection at said first,
second, and third damper with said geometrically coded connectors
shaped to prevent misalignments and to allow for quick and error
free assembly; an economizer mode in which said first damper is
opened to allow outside air to be pulled into said HVAC system when
said economizer mode is selected, with said selection based on a
preselected temperature of outside air or by manual control
selection; and a non-economizer mode in which said first damper is
closed to prevent outside air from entering said HVAC system when
said economizer mode is not selected, with said non-economizer mode
selected by outside air temperature being above said preselected
temperature or by manual selection.
Description
PRIORITY/CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/654,561, filed Jun. 1, 2012, the disclosure of
which is incorporated by this reference.
BACKGROUND
[0002] The disclosure generally relates to the field of heating,
ventilation, and air conditioning (HVAC) systems. In the world of
HVAC, cooling is provided when heat in the air within a conditioned
space (such as the interior of a building) is removed by
circulating the air through a cooling coil (i.e., an "air
conditioner") and then re-delivered to the conditioned space to
keep the space at the desired temperature. Some HVAC systems have
an economizer, which is a subsystem that introduces outside air
into the building when the outside air is cool enough that it can
be used to either supplement or replace mechanical cooling. An HVAC
system with an economizer typically has a set of three
actuator-driven dampers. Dampers are devices that function to
regulate airflow within an air duct by closing or opening in the
duct, to stop or allow air flow in the duct.
[0003] When an HVAC system operates in economizer mode, one damper
is closed to isolate the duct leading from the conditioned space to
the indoor blower, which circulates air in the HVAC system. This is
done to interrupt the flow of air from the conditioned space, or
return air, so that it is not circulated through the cooling coil
and resupplied to the conditioned space. At the same time, a
separate damper is opened in a connecting air duct, which allows
outside air to be pulled into the system. A third damper is also
often used to relieve air from the conditioned space so that new
air introduced from the outdoors does not overly pressurize the
conditioned space.
[0004] During economizer-supported cooling, the compressor of the
HVAC system may be stopped if outdoor air conditions are sufficient
to provide space cooling. This is generally called free cooling. If
the outdoor air is insufficient to provide cooling by itself the
compressor is allowed to run while dampers are configured for
economizing and in this way outside air can supplement compressor
operation. This is often called enhanced economizer operation or
economizer-supported mechanical cooling.
[0005] The theory behind economizer systems is that cool outside
air may be circulated throughout a building to provide cooling in a
conditioned space, with the goal of saving money by reducing the
need to run more energy-intensive mechanical (i.e.,
compressor-based) cooling. In practice, however, an estimated 64%
of economizer installations do not function properly. In fact, some
economizer systems function improperly from the day they are
installed. These problems can go unrecognized for years, and the
economizer may not be providing a benefit at all. Instead, the
economizer may be causing the HVAC system to use even more energy
than it otherwise would because the HVAC system operates to support
both cooling and heating of uncontrolled outside air.
[0006] Often, an economizer system functions improperly because of
malfunctioning dampers, which may be from improper installation,
mechanical problems, control issues, or normal wear. Damper
malfunctions include situations when a damper is disconnected from
system control, control cabling is cut or broken, seizes or
otherwise fails to move when directed to do so. While damper
malfunction is a large problem, it is the lack of detection of this
problem that causes energy to be wasted. If a damper is stuck open
or shut, the building owner is typically unaware of the error
condition. But the economizer system, and thus the HVAC system, is
functioning improperly, thereby contributing to higher costs of
HVAC system operation.
BRIEF SUMMARY
[0007] The disclosed technology is an HVAC system and control
module with an economizer function. The HVAC system and control
module utilizes dampers that have sensors that send signals
indicating when the damper is in either a closed or open position.
The system monitors the dampers and the economizer function and
displays system information to a user. The system verifies that the
dampers are in the correct positions required to support either
economizing or non-economizing operation. Certain systems could
operate with a partially open damper, and offer verification of
proper damper position.
[0008] The disclosed technology is an HVAC system and control
module which has a power source, a circulation fan, an air
conditioning compressor, a network of air delivery ducts for
delivering cool air to a conditioned space, such as interior space
in a building. The system includes an outside air intake duct and a
first damper, also called the outside air damper. The intake damper
is movable between an open and closed position and the damper
includes two sensors which detect if it is in the open or closed
position. No other split-system economizer provides two sensors of
damper position. (Definition--A split-system air conditioning
system is one in which air circulates in a closed loop.) The damper
position sensors send a signal to a control module in the
conditioned space, which indicates to the user by a visible
indicator if the intake damper is in the fully open or fully closed
position, or if the damper has failed to achieve the correct
position for the selected mode.
[0009] The disclosed technology includes an outside air sensor,
which can take the form of a thermostat. Economizer operation is
activated when the outside air temperature falls below the setting
chosen on an outdoor air thermostat.
In another version an outdoor temperature sensor is used; a
calculation performed by the controller generates a minimum outside
air temperature target, and if the outside air temperature reaches
the set minimum temperature, then an economizer mode is
activated.
[0010] In the economizer mode, the intake damper is opened and
outside air is drawn into the ducting of the system. Two position
sensors on the intake duct verify that the damper position is
correct for the economizer mode; if the damper is in an incorrect
position, a visual indicator is activated at the control
module.
[0011] The control module of the system is mounted in the
conditioned space. The control module has a damper error indicator
which is a visual indicator of some type such as a light or an
indicator on a display. Having a control module for the damper
located in the conditioned space, and having the control module
display a visual error indicator is a critical improvement of the
disclosed technology. Besides an error indicator, the control
module can display an indicator that the economizer mode is
activated and working properly, and other information to the
user.
[0012] The control module in the disclosed system also has a
non-economizer mode which is the normal mode for the HVAC system
when the economizer mode is not activated. In the non-economizer
mode, the first damper is closed to prevent outside air from
entering the HVAC system when the economizer mode is not selected.
The non-economizer mode is automatically selected when the outside
air temperature is sensed as being above the pre-selected
temperature or it may be activated based on pre-selected parameters
set by the user, or by manual selection of the non-economizer
mode.
[0013] The control system of the disclosed technology can also
include an economizer fail-safe signal, which is activated when an
off normal damper position is detected. The system then attempts to
allow the system to run in non-economizing mode. When the fail-safe
signal is generated, the economizer mode will be turned off and the
non-economizing mode activated. All embodiments prevent continued
use of an economizer mode when dampers are in a fault condition,
such as when the intake damper is in the wrong position for the
economizer mode. This would stop the incorrect running of the
economizer mode even if the operator of the system is not aware
that the error had occurred. All embodiments also prevent
non-economizing mode operation if dampers are not identified in the
proper position to support non-economizing operation.
[0014] Another version of the disclosed technology is one which
includes an inside air temperature sensor, which is used to
activate the economizer mode by a comparison of the inside
temperature and outside temperature, with the control module making
a calculation as to when the outside air is sufficiently cooler
than the inside air to be productive to introduce into the cooling
system.
[0015] The control module is operationally connected to the power
source, the circulation fan and the compressor relay of the HVAC
unit. It is also connected to the outside air temperature sensor,
and to the first damper.
[0016] Although the disclosed technology can operate with one
damper, other versions of the system operate with two or three
dampers. In versions in which two dampers are present, the
isolation damper is in the ducting between the conditioned space
and the circulation fan, and closes off the air from the
conditioned space from going back to the cooling unit. In place of
this re-circulated air, outside air is admitted through the first
damper and is delivered to the conditioned space through the HVAC
system fan. In installations in which a third damper is part of the
system, the third damper is provided to open to prevent an over
pressurization of the conditioned space. The third damper may not
be required in some installations because there may be sufficient
leakage of air to make over pressurization not possible. The
leakage of air would occur when cool air is blown into the
conditioned space and some of that cool air leaks around doors,
windows, spaces in walls and attic, and ducted exhaust such as
kitchen and bathroom exhaust vents.
[0017] An important improvement in the disclosed technology is in
the cabling between the control module and other parts of the
control system, particularly the dampers. The prior art
installation of such a system requires a technician to run wires
between a control module and the dampers, as well as the power
source and the circulation fan and cooling unit and the outside
temperature sensor. In prior installations, the control module is
often located at the blower unit in a mechanical space and is not
useful to the user, and must be serviced by a technician in tight
quarters. The damper cable installation can amount to as many as 26
wire segments needing to be properly terminated at different places
on the control module and to the dampers and damper status switches
in the system. As many as 21 of these terminations would need to be
made in the attic where temperatures may exceed 150 degrees
Fahrenheit. If any one of them is connected to the wrong place, the
system will not function. To avoid this complexity it is common
practice to minimize the number of conductors required. Damper
position sensors are typically not installed for this reason.
Complexity of installation of damper status has in the past been
prohibitive to its use.
[0018] The complexity problem is addressed in the disclosed
technology by a connection methodology that eliminates technician
effort and greatly simplifies the way the system is installed. Each
of the control cables have a first end and a second end, with the
first end connecting to the control module and the second end
connecting to one of the required system components, which are the
furnace control board, the dampers, and the external temperature
sensor. Each of the cables are terminated with a fitting which is
geometrically coded so that it only fits in one receptacle in the
control module, and it can only fit in the fitting in one
orientation. For this reason, each of the cables can only fit in
the control module in the proper interfitting connection and only
one orientation of the fitting is possible this reduces the
potential for termination errors by one half. This feature alone
makes the disclosed technology much more fool proof and
economically efficient to set up.
[0019] The damper cable is particularly prone to errors during
installation if it is left to a technician to make all the
connections for proper operation in a difficult environment. In
connecting the control module to each damper, for instance, there
are power connections to the damper motors, there are connections
to the position sensors of the damper, and connections in between
damper switches creating the circuit that provides status logic.
This typically results in the need to connect twenty six wires and
if any one of them is connected to the wrong attachment point the
system will be in error. This is one of the reasons why prior art
of economizer systems have such a high error rate. Not only does
the use of geometrically coded and pre-wired cables guarantee that
the system is set up correctly, but it also enables errors in the
damper positioning to be detected and reported to the user in the
conditioned space, and greatly reduces the amount of time a
technician spends in the hot environment of an attic. Each of these
are features which are not found in the prior art.
[0020] The system also comprises a means of shutting down the
economizer function when it is not functioning as intended. In one
such embodiment the HVAC system operates exclusively with
mechanical cooling. When an error condition of the intake damper is
detected, the unit will stop operation, or only allow
non-economizing operation if it can be done safely. For example if
a system outside air temperature low limit sensor is installed, the
outdoor air temperature would need to be above the limit setting in
order for the readiness status signal to indicate that conditions
are suitable, "ready" for outdoor air to be brought into the
conditioned space. (Typical safety conditions would include outdoor
air temperature high and low limits, outdoor humidity, outdoor
dewpoint, or outdoor CO level.
[0021] The disclosed system can also operate with other sensors
within the conditioned space, and intake of outside air can be
based on conditions other than temperature. Sensors can include
sensors for CO2, CO, formaldehyde, radon, particulates, VOCs, and
other hazardous air components. For instance if a high level of CO
was sensed, the system can activate the economizer mode regardless
of temperature, in order to dilute and flush out the air in the
conditioned space.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a schematic diagram of an HVAC system with the
disclosed economizer control system.
[0023] FIG. 2 is a view of a damper in the open position.
[0024] FIG. 3 is a view of a damper in the closed position.
[0025] FIG. 4 is a view of a geometrically coded connection and the
plug in on the control module.
[0026] FIG. 5 is a control diagram of the disclosed economizer
control system.
[0027] FIG. 6 is a diagram showing the control logic of the
disclosed economizer control system.
DETAILED DESCRIPTION
[0028] FIG. 1 shows the HVAC system of the disclosed technology,
which provides for economizer mode operation of the HVAC system 10.
The HVAC system 10 includes a circulation fan 12, cooling unit 14,
and a network of air delivery ducts 16. The HVAC system 10 provides
heating and cooling for a conditioned space 18. A user controls the
economizing portion of the HVAC system 10 with control module 20.
The HVAC system 10 includes an outside air intake duct 22 to
provide outside airflow 24 to the conditioned space 18. Also
included is a first, or intake, damper 26. The first damper 26 has
two positions: a first, or closed, position 28, and a second, or
open, position 30. The HVAC system 10 may have an isolation damper
32, operable between an open position 34 and a closed position 36,
and a third (relief) damper 38, operable between a closed position
42 and an open position 40. A preferred embodiment of the control
system and HVAC system uses three dampers. Both the second
(isolation) damper 32 and the third (relief) damper 38 are located
in a return air duct 44 between the conditioned space 18 and the
cooling unit 14.
[0029] The control module 20 has inputs from outside air
temperature sensor 46, from inside air temperature sensor 48
(optional), and includes a user input means and display screen
(optional). In one embodiment a user may set the HVAC system 10 to
automatically provide free cooling, economizer-supported mechanical
cooling, or both. In all instances, a user may completely override
any automatic control, providing for manual control of the
economizing system 10. The control module also can receive inputs
such as outside air temperature, outdoor humidity, outdoor dew
point, or outdoor CO level, and assess high and low limits on such
factors to generate a readiness signal which can disallow start of
the economizer mode.
[0030] The control module 20 is connected to the essential
components of the system by cables, with one end of the cables
terminated by connectors which are shaped to fit in only one place
in the system, and to fit in that one place in only one
orientation. These terminals are referred to as "geometrically
coded" because they can only fit in one place in the system, and in
only one orientation. Thus the control module is connected to the
dampers by a damper cable 50. The control module is connected to
the outside temperature sensor 46 by an outside sensor cable 52.
The control module is connected to a power source by a power cable
54. The control module is connected to the furnace control board by
a furnace cable 56. Control module 20 may be connected to an inside
temperature sensor 48 by an inside sensor cable 58.
[0031] The damper cable 50 preferably has four connectors, (3
damper connections and one for the control module,) and includes a
circuit that would be prohibitive to fabricate and terminate in the
field. The system feature of supporting damper position information
is only possible if a pre-assembled damper cable is provided with
geometrically coded terminations. The damper cable 50 eliminates 26
field terminations which would require over an hour to make, and
allows these same connections to be made by 3 snap connectors in
the attic, and one at the control module, which take less than a
minute to connect. Cables connecting the furnace, and power source
also replace a required 9 terminations in the field which would
take at least 20 minutes.
[0032] Makes possible a very fast and 100% correct installation of
all conductors needed to support damper operation and damper error
detection. Connecting the cable requires attaching four "Quick
Connect" connectors. One of the connectors being unique to the
board, the other three connectors being interchangeable. Making
these connections takes less than one minute, and is impossible to
do incorrectly.
[0033] The damper cable also reduces production cost in that it
allows the product to use two series circuits to determine proper
damper operation for three dampers. The typical way this would be
accomplished would be to use twelve wires; two for each damper
switch. The damper cable provides two series circuits with a single
common that work in unison with a single relay on the circuit
board. This vastly simplifies the task of determining if dampers
are operating properly. Damper verification is an extremely
important aspect of the disclosed technology and its marketing.
This feature has not been offered in the past because it is too
complex for field termination, and too expensive to provide with a
conventional configuration. We solved both problems.
[0034] Without the disclosed prefabricated damper cable, installers
would be required to make 38 field connections, (26 terminations
and 12 splices.) Just on this one cable. Without the quick connect
installation time would be increased by more than an hour and would
have a high probability of having been done incorrectly.
[0035] While other cables included in the disclosed system are
simpler, using them reduces a further 9 connections to two
additional "Quick Connects." In one embodiment two ends of one
quick connect cable reduce terminations by 23 connections. Each
termination being another opportunity for error, the "Quick
Connects" provides a distinct advantage in the disclosed
technology, and contributes to market acceptance of a new product
that might be otherwise considered too complicated and therefore
unworkable.
[0036] The damper cable is in itself is more akin to a circuit
board having multiple logic paths making up a circuit than it is a
bundle of straight-through conductors having a single connector at
each end. The damper cable contains both series and parallel
circuits, the series circuits being switched by sensing devices at
each damper. It also contains circuitry that enables the use of a
diagnostic tool that is not covered in this patent. In its absolute
simplest form, supporting only a single first damper, a technician
would need to make 12 terminations all needing to be performed
correctly in order for the system to operate properly.
[0037] In one embodiment the HVAC system 10 may provide outside
airflow 24 into the conditioned space 18 when the outside air
temperature is sufficiently lower than inside air temperature
thereby providing economizer-supported mechanical cooling. In the
economizer mode, the first damper 26 is in the second or open
position 28, and outside air 24 is drawn into the ducting network
16. In two or three damper systems, the isolation damper 32 is in
the closed position 36, and the third damper 38 is in the open
position 40. The HVAC system 10 then circulates outside air such
that the HVAC output flow 60 is comprised of outside air. The
isolation damper 32 operates with the first damper 26 in a
coordinated fashion such that when the first damper 26 is open, the
isolation damper 32 is closed, and when the first damper 26 is
closed, the isolation damper 32 is open. The third (relief) damper
38 is similarly coordinated such that it mirrors the operation of
the first damper 26. So, when the isolation damper 32 is open, the
relief damper 38 is closed, and when the isolation damper 32 is
closed, the relief damper 38 is open.
[0038] The outside temperature sensor 46 of the system is
preferably a thermostat, which differs from a sensor in that the
sensor transmits information, such as to a control logic board. A
thermostat is a mechanically actuated switch, with the mechanical
action based on the sensed temperature. A thermostat such as model
no 4LZ94A, made by Dayton Temperature Controls Inc. is an example
of a suitable thermostat.
[0039] The control system disclosed can interact with an existing
indoor thermostat, or can operate without connection to the indoor
temperature sensor or thermostat. If the outside temperature sensor
is a thermostat, the temperature to begin the economizer mode can
be set at the outdoor thermostat. It could also be set at the
control module in the conditioned space.
[0040] FIG. 2 shows a damper which is typical of a damper used in
the system herein disclosed. The damper can be cylindrical or
rectangular, and in this example it is cylindrical and has crinkled
end sections so that it can engage similar end caps of other ducts
in the system. This damper is designated as a first damper 26, but
each of the other dampers of the system could appear very similar.
The diameter of the ducting of this damper, as well as the ducts in
this system, would be tailored to a particular installation and
cooling and heating requirements. A typical diameter of a duct such
as this would be 16 to 20 inches, and it could be 18 to 22 inches
long. Inside the first damper 26, is a damper blade 64 which is
shown in FIG. 2 in the open position 28. The damper blade 64 has a
damper shaft 66, to which the damper blade 64 is attached. Both
ends of the damper shaft 66 pivot on bearings connected to the side
walls of the damper duct 26. A damper actuator 68 is shown in both
FIGS. 2 and 3. The damper actuator 68 receives a signal from the
control module to open or close the damper blade 64. An open
position damper position sensor 70 is shown in FIG. 2. When the
damper blade 64 is in the open position, electrical contact is made
at the open damper position sensor 70, and a signal indicating that
the damper blade is in the open position is sent to the control
module.
[0041] In FIG. 3 a closed damper position 30 sensor is shown. When
the damper blade 64 is in the closed position 30, electrical
contact is made through the closed damper position sensor 72, and a
signal is sent to the control module. The open or closed damper
position sensors are verified against the operating mode of the
HVAC system, whether in economizer mode or non-economizer mode, and
a determination is made if the dampers are in the correct position
for the selected mode of operation. If they are in the correct
position, a signal is shown at the control module, such as a green
light. If the dampers are not in the correct position, another
visual indicator is activated which indicates an error in damper
blade position, such as a red light. A particular installation can
have one indicator to indicate all dampers are operating correctly,
or it could have individual lights for each damper.
[0042] FIG. 4 shows a view of the backside of the control module
20, showing a geometrically coded connector unit 74 which is on the
end of a damper cable 50. The coded connector fits in a receptacle
76 which is shaped to receive the electrical connections of the
connector, with the receptacle 76 including an orienting structure
78 which engages a similar orienting structure 78 on the connector
74, so that only one orientation of connection is possible. The
damper cable 50 connects to the dampers in parallel to deliver the
open/close control signal, and in series to provide the circuit
used to determine proper damper position. (See Damper Cable diagram
X.) This allows any damper to be plugged into any of the connectors
at the end of the damper cable 50 while maintaining the path
required to support damper status on one input.
[0043] FIG. 5 shows a control diagram for the control of the
economizing system 10. The control module 20 accepts a user input
80, or override control, which allows a user to direct the HVAC
system 10 to allow outside airflow 24 to the conditioned space 18.
The control module 20 accomplishes this by providing an outside air
activation signal 82 to the first damper 26. The outside air
activation 82 signals the first damper 26 to operate in an open
damper position 28. The control module 20 not sending an outside
air signal 82 to the first damper 26 permits the first damper 26 to
operate in a closed damper position 30. The first damper 26
communicates its position either with an open damper signal 84 from
the open damper position sensor 70, or a closed damper signal 86
from the closed damper position sensor 72 to a damper position
verification module 88. The third (relief) damper 38 is not needed
in many older homes. Leakage provides enough pressure relief that
the system would work adequately. The second (return) damper could
also be excluded in certain installations.
[0044] The damper position verification module 88 communicates with
the control module 20 the position of the first damper 26, the
isolation damper 32, and the relief damper 38 with a single damper
position verification signal 90. The control module 20 may be
equipped with at least one warning indicator 92, which indicates
when any damper is in an erroneous position, i.e., in an off normal
position causing malfunctioning. A damper is in an off normal
position if it is not operating as directed, which could include,
for example: (1) the damper is in neither an open nor a closed
damper position; (2) the damper is in a closed position despite
receiving a signal to open; or (3) the damper is in a closed
position despite receiving a signal to open.
[0045] Alternate embodiments can include warning indicators for
each damper, to facilitate efficient repair of a malfunctioning
damper.
[0046] In one such embodiment, if any damper is in an erroneous
position, the damper position verification signal 90 indicates as
much, and the control module 20 activates a failsafe signal 94,
which causes the first damper 26 to switch to a closed position 30.
The failsafe signal 94 also causes the isolation damper 32 to open
and the relief damper 38 to close. The isolation damper 32
communicates its position to the damper position verification
module 88 via a closed damper position signal 96 and an open damper
position signal 98. Likewise, the relief damper 38 communicates its
position to the damper position verification module 88 via an open
damper position signal 100 and a closed damper position signal 102.
Correct damper position is reported in series. Any damper not
detected in the proper position is detected through the circuit
consisting of the switches, damper cable, and control board. The
components described above provide continuous feedback of proper
damper position. The feature is unique in the HVAC industry in that
it provides assurance of proper operation without having to
periodically test and inspect the dampers.
[0047] FIG. 6 shows a more focused view of a control logic diagram
of the disclosed technology. The number references in FIG. 6 have
been previously described in the description of FIG. 5, and include
a control module 20, an outside air activation signal 82, a first
damper 26, open damper position sensors 70, closed damper position
sensors 72, a damper position verification module 88, a third
(relief) damper 38, an isolation damper 32, a relief damper 38, a
damper position verification signal 90.
[0048] The disclosed technology thus uses a unique configuration of
end switches and wiring harness that provides continuous damper
status that is reported by indicator within the conditioned space.
Normally 6 digital inputs would be used to verify proper damper
position of all 6 operating positions in the three dampers. In the
disclosed technology, two series circuits that are further
supported by a circuit board which verifies the proper signal is
received to match the mode of operation. The disclosed technology
uses a single input (from the damper position verification module)
to support what would normally require 6 inputs. This reduces the
cost of the product. Because this configuration requires a large
number of terminations, it could not be easily accomplished in the
field by a technician of average skill level. The quick connects
and a harness (cables) that provides a portion of the circuit that
would be required to configure in the field further allows this
system to work given the skills possessed by the average
technician. Using hand terminated wiring as in prior art, the
damper control and verification circuit without the disclosed
technology system would require a minimum of an hour to terminate
and would likely be terminated with errors. Using the disclosed
system the damper control and verification circuit can be
completely and correctly installed in about 1 minute, using four
quick connects.
[0049] The control module 20 accepts an input 104 from an outside
air temperature sensor 46. Based on this input, and a user input
80, the control module 20 directs the operation of the first damper
26, the isolation damper 32, and the relief damper 38. In one
embodiment, the control module 20 may also signal and report a
temperature sensor error or malfunction 106 if any temperature
sensor operates improperly.
[0050] In addition, the control module 20 is equipped with a mode
display 110 to indicate that the system is operating in the
economizer mode 10, that is with the cooling benefit of outside
air, or in the non-economizer mode 112. The HVAC system 10 may also
provide feedback through a separate display by calculating and
displaying the economic benefits of the system, including the
run-time, in number of hours, and percentage of total space
conditioning that has been provided through free cooling and
economizer-supported mechanical cooling.
[0051] Further, the HVAC system 10 may provide user further control
options as follows. The control module 20 provides the user with a
target temperature. The target temperature is the outdoor air
temperature at which the system can operate in the economizer mode
and provide an economic benefit through economizer-supported
mechanical cooling or free cooling. This information enables users,
if desired, to activate operation earlier than an automatic system
operation might provide. The user simply uses an override control
114 to instruct the control module 20 to send an outside air input
82. The system ON/OFF allows the user to prevent the HVAC system 10
from using any economizing function, relying exclusively on
mechanical cooling.
[0052] Some embodiments of the disclosed HVAC system include a
Logic Box, shown in FIG. 5. The primary purpose of the Logic Box to
provide a termination point for all component cabling, and to
interpret incoming damper status signals providing a hardwired
circuit to prevent operation of the economizer if improper damper
position is detected. In addition to this function, in one
embodiment the Logic Box also provides circuitry to control the
economizer, an LED display output, and a means of enabling and
overriding the system. In another embodiment the Logic Box is
connected to a separate display/controller providing a more
sophisticated user interface to the system. It contains a circuit
board and cable specific connectors supporting required
terminations. It is connected to the power supply, furnace control
board, damper(s), outdoor temperature sensor, and in one embodiment
to the separate display/controller.
[0053] The functions of the logic box can be combined in one unit,
the control module, or can be mounted as a separate unit apart from
the control module in the conditioned space. The advantage of
splitting the controls into a logic box and a control module is
that it allows us to manufacture the product at a much lower price,
reduces the number of inputs and outputs required to connect to
system devices, (6 inputs are fed into one input to determine
damper status,) and allows us the option of utilizing various
manufacturers controllers to support future modifications of the
product.
[0054] While certain exemplary embodiments are shown in the Figures
and described in this disclosure, it is to be distinctly understood
that the presently disclosed inventive concept(s) is not limited
thereto but may be variously embodied to practice within the scope
of the following claims. From the foregoing description, it will be
apparent that various changes may be made without departing from
the spirit and scope of the disclosure as defined by the following
claims.
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