U.S. patent application number 13/432870 was filed with the patent office on 2012-10-04 for ventilation systems and methods.
This patent application is currently assigned to Tuckernuck Technologies LLC. Invention is credited to Jason Wolfson.
Application Number | 20120252345 13/432870 |
Document ID | / |
Family ID | 46927866 |
Filed Date | 2012-10-04 |
United States Patent
Application |
20120252345 |
Kind Code |
A1 |
Wolfson; Jason |
October 4, 2012 |
Ventilation Systems and Methods
Abstract
This application describes methods and systems for ventilating a
building. A method for ventilating a building includes drawing in
air, using a central fan, for heating or cooling at least a portion
of the building and exhausting air from the building using at least
one exhaust fan. The exhaust fan can be automatically operated
during time periods when the central fan is not switched on. The
method further includes automatically opening a damper, during at
least a portion of the time periods, such that fresh air enters the
building through the damper
Inventors: |
Wolfson; Jason; (Marshfield,
MA) |
Assignee: |
Tuckernuck Technologies LLC
Duxbury
MA
|
Family ID: |
46927866 |
Appl. No.: |
13/432870 |
Filed: |
March 28, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61470801 |
Apr 1, 2011 |
|
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Current U.S.
Class: |
454/239 ;
454/252; 454/256 |
Current CPC
Class: |
F24F 2007/001 20130101;
F24F 7/08 20130101; F24F 11/77 20180101; F24F 2011/0002
20130101 |
Class at
Publication: |
454/239 ;
454/252; 454/256 |
International
Class: |
F24F 11/00 20060101
F24F011/00; F24F 13/08 20060101 F24F013/08; F24F 7/06 20060101
F24F007/06 |
Claims
1. A method for ventilating a building, the method comprising:
drawing in air, using a central fan, for heating or cooling at
least a portion of the building; exhausting air from the building
using at least one exhaust fan, wherein the exhaust fan is
automatically operated during time periods when the central fan is
not switched on; and during at least a portion of the time periods,
automatically opening a damper, such that fresh air enters the
building through the damper.
2. The method of claim 1, further comprising: receiving control
signals from a controller at the central fan, the at least one
exhaust fan and the damper; and operating the central fan, the at
least one exhaust fan, and the damper in accordance with the
control signals.
3. The method of claim 2, further comprising switching on the
central fan in accordance with one of the control signals when a
heating or cooling system is operating to heat or cool the portion
of the building.
4. The method of claim 2, further comprising switching on the
exhaust fan in accordance with one of the control signals
responsive to a manual input.
5. The method of claim 4, further comprising switching off the
exhaust fan after a predetermined time period.
6. The method of claim 1, further comprising automatically opening
the damper during a time period when the central fan is switched
on.
7. The method of claim 1, wherein the exhaust fan is a bathroom
exhaust fan.
8. The method of claim 1, wherein the exhaust fan is a kitchen
exhaust fan.
9. A controller for controlling the ventilation of a building in
which there is a central fan configured to draw in air for heating
or cooling at least a portion of the building, at least one exhaust
fan adapted to exhaust air from the building, and a damper that,
when opened, permits fresh air to enter the building, the
controller comprising: a control logic adapted to generate signals
to automatically operate the exhaust fan to exhaust air from the
building during time periods when the central fan is not switched
on and to open the damper during at least a portion of the time
periods, such that fresh air enters the building through the
damper.
10. The controller of claim 9, wherein the controller is further
adapted to generate signals to switch on the central fan in
accordance with an operation of a heating or cooling system.
11. The controller of claim 9, wherein the controller is adapted to
generate signals to switch on the exhaust fan responsive to a
manual input.
12. The controller of claim 11, wherein the controller is adapted
to generate signals to switch off the exhaust fan after a
pre-determined time period.
13. The controller of claim 9, wherein the controller is adapted to
generate signals to open the damper during a time period when the
central fan is switched on.
14. The controller of claim 9, wherein the exhaust fan is a
bathroom exhaust fan.
15. The controller of claim 9, wherein the exhaust fan is a kitchen
exhaust fan.
16. A method for ventilating a building, the method comprising:
drawing in air, using a central fan, for heating or cooling at
least a portion of the building, wherein the central fan is
automatically switched on during periods when a heating or cooling
system is supplying hot or cold air to the building; and expelling
air from the building using at least one exhaust fan, wherein the
exhaust fan is configured to be operated during periods in which
the central fan is not operational, such that the total amount of
ventilation of the building resulting from the operation of the
central fan and the exhaust fan is controlled to approximate a
predetermined amount.
17. The method of claim 16, wherein the at least one exhaust fan is
configured to be operated for a first time period responsive to a
manual input and automatically for a second additional time period
on determining that the exhaust fan is to be operated for the
second additional time period to achieve the approximate
predetermined amount of ventilation.
18. The method of claim 17, wherein automatically operating the
exhaust fan comprises operating the exhaust fan during periods when
the central fan is not switched on.
19. The method of claim 17, further comprising automatically
opening a damper that permits the inflow of fresh air into the
building during the first time period or the second additional time
period.
20. The method of claim 16, wherein the exhaust fan is part of a
heat recovery ventilator (HRV) or an energy recovery ventilator
(ERV).
21. A controller for controlling the ventilation of a building
having a central fan for distributing air in a heating or cooling
system and at least one exhaust fan, the controller comprising: a
control logic adapted to generate signals to operate the at least
one exhaust fan during periods when the central fan is not
operational, so that the total amount of ventilation of the
building resulting from the operation of the central fan and the
exhaust fan is controlled to approximate a predetermined
amount.
22. The controller of claim 21, wherein the controller is further
adapted to automatically open a damper during at least a portion of
time periods when the exhaust fan is switched on, such that fresh
air enters the building through the damper.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional
Application No. 61/470,801, filed on Apr. 1, 2011, the entire
content of which is incorporated herein by reference.
BACKGROUND
[0002] New energy efficient homes are being constructed almost air
tight. So tight they now need mechanical ventilation added to bring
in just enough fresh air to keep the occupants healthy.
[0003] ASHRAE (American Society of Heating and Refrigeration and
Air-conditioning Engineers) provides a formula for the amount of
ventilation: 7.5 cfm (N+1)+(A.times.0.01) where N=number of
bedrooms, A=square footage of the home. So for example a 4 bedroom,
2,000 sq ft home would require: 7.5.times.5+(2,000.times.0.01)=57.5
CFM continuously of fresh air. The homes are measured for air
leakage that can be subtracted from the calculated requirement. For
this example assume we measured 27.5 CFM of leakage. That leaves 30
CFM we need to bring in continuously to meet the ventilation
standards. Coming standards are going to penalize builders for over
ventilating so the more precise the method of control the
better.
[0004] An inexpensive and effective method to bring in fresh air is
to use the central fan and existing duct work from the heating and
air-conditioning system to bleed in an amount of fresh air from an
outside known source and distribute it throughout the home using a
controller such as the AirCycler.TM. available from Lipidex
Corporation of Marshfield, Mass. Techniques for accomplishing this
are described in U.S. Pat. Nos. 5,547,017 & 5,881,806 &
6,431,268, which are incorporated herein by reference.
[0005] With this known system you could bring in 90 cfm 1/3 of the
time to meet the 30 cfm continuous ventilation requirement. The
AirCycler.TM. control monitors the thermostat and if it hasn't run
1/3 of the time from heating or cooling, it will bring on the
central fan to bring in the remaining requirement of fresh air.
[0006] One issue with using the central fan to provide needed
ventilation is that a central fan will typically draw a lot of
power (e.g. 400 W) to move a relatively small amount of air. By
contrast, a typical bathroom exhaust fan only uses 30 W.
[0007] U.S. Pat. No. 7,798,418, which is incorporated herein by
reference, discloses three alternative methods for ventilating a
space having a central fan (for heating/cooling) and a bathroom
exhaust fan.
[0008] Method 1:
[0009] the exhaust fan comes on whenever the central fan comes on.
This provides "balanced" ventilation. The central fan is used to
bring air into the building, and a bathroom exhaust ventilation fan
is used to exhaust the same volume of air out of the building.
[0010] Some jurisdictions require "balanced" ventilation. They are
concerned with where the fresh air comes from when you exhaust
stale air. In hot humid climates you don't want to depressurize a
building because that could pull outside moisture into the
walls.
[0011] In other jurisdictions, the balanced approach is not
required, and ventilation may be achieved by either only supplying
fresh air (which will force out stale air by leakage out of the
building), or by only exhausting stale air (which will be replaced
by leakage into the building).
[0012] Method 2:
[0013] the exhaust fan is turned on whenever the Central fan is
off. The idea is you make up the required ventilation you're not
getting when the central fan is off by turning on the ventilation
fan. With this technique, you do not have to run the large
expensive central fan for ventilation, only heating and cooling.
However this method could cause over-ventilation as a result of
excess exhaust fan run time.
[0014] Method 3
[0015] the exhaust fan runs independently. A controller determines
how many minutes per hour to run the exhaust fan and it monitors
fan run time when a person is in the bathroom manually operating
the fan, including the "delay" time that the fan runs to continue
after the person leaves, then subtracting that from the required
time and making up the difference.
[0016] One potential problem with home ventilation systems is the
possibility that unhealthy air may be drawn into the building. For
example, when an exhaust fan is operating, air may leak into the
building from the garage, and such air may include volatile organic
hydrocarbons (VOCs), which are known to be carcinogenic.
[0017] Another potential problem with home ventilation systems is
over ventilation, whereby more fresh air than is desired or needed
is brought into the building.
SUMMARY
[0018] In one aspect, the application describes a method for
ventilating a building. The method includes drawing in air, using a
central fan, for heating or cooling at least a portion of the
building and exhausting air from the building using at least one
exhaust fan. The exhaust fan can be automatically operated during
time periods when the central fan is not switched on. The method
further includes automatically opening a damper, during at least a
portion of the time periods, such that fresh air enters the
building through the damper.
[0019] In another aspect, the application describes a controller
for controlling the ventilation of a building. In the building
there are a central fan configured to draw in air for heating or
cooling at least a portion of the building, at least one exhaust
fan adapted to exhaust air from the building, and a damper that,
when opened, permits fresh air to enter the building. The
controller includes control logic adapted to generate signals to
automatically operate the exhaust fan to exhaust air from the
building during time periods when the central fan is not switched
on and to open the damper during at least a portion of the time
periods, such that fresh air enters the building through the
damper.
[0020] In another aspect, the application describes a method for
ventilating a building. The method includes drawing in air, using a
central fan, for heating or cooling at least a portion of the
building. The central fan is automatically switched on during
periods when a heating or cooling system is supplying hot or cold
air to the building. The method also includes expelling air from
the building using at least one exhaust fan such that the total
amount of ventilation of the building resulting from the operation
of the central fan and the exhaust fan is controlled to approximate
a predetermined amount. The exhaust fan is configured to be
operated during periods in which the central fan is not
operational.
[0021] In another aspect, the application describes a controller
for controlling the ventilation of a building having a central fan
for distributing air in a heating or cooling system and at least
one exhaust fan. The controller includes a control logic adapted to
generate signals to operate the at least one exhaust fan during
periods when the central fan is not operational, so that the total
amount of ventilation of the building resulting from the operation
of the central fan and the exhaust fan is controlled to approximate
a predetermined amount.
[0022] Implementations can include one or more of the
following.
[0023] Control signals can be received from the controller at the
central fan, the at least one exhaust fan and the damper and these
can be operated in accordance with the control signals. The central
fan can be switched on in accordance with one of the control
signals when a heating or cooling system is operating to heat or
cool a portion of the building. The exhaust fan can be switched on
in accordance with one of the control signals responsive to a
manual input. The exhaust fan can be switched off after a
predetermined time period. The damper can be automatically opened
during a time period when the central fan is switched on. The
exhaust fan can be a bathroom exhaust fan. The exhaust fan can be a
kitchen exhaust fan.
[0024] The controller can be further adapted to generate signals to
switch on the central fan in accordance with an operation of a
heating or cooling system. The controller can be adapted to
generate signals to switch on the exhaust fan responsive to a
manual input. The controller can be adapted to generate signals to
switch off the exhaust fan after a pre-determined time period. The
controller can be adapted to generate signals to open the damper
during a time period when the central fan is switched on.
[0025] The at least one exhaust fan can be configured to be
operated for a first time period responsive to a manual input and
automatically for a second additional time period on determining
that the exhaust fan is to be operated for the second additional
time period to achieve the approximate predetermined amount of
ventilation. Automatically operating the exhaust fan can include
operating the exhaust fan during periods when the central fan is
not switched on. A damper can be automatically opened to permit the
inflow of fresh air into the building during the first time period
or the second additional time period.
[0026] The exhaust fan can be part of a heat recovery ventilator
(HRV) or an energy recovery ventilator (ERV). The controller can be
further adapted to automatically open a damper during at least a
portion of time periods when the exhaust fan is switched on, such
that fresh air enters the building through the damper.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a diagram illustrating an example of a ventilation
system.
[0028] FIG. 2 is a flowchart of an example process for operating a
ventilation system.
[0029] FIG. 3 is a flowchart of an example process for operating a
ventilation system.
[0030] FIG. 4 is a block diagram of a computing system.
DETAILED DESCRIPTION
[0031] The present application describes methods and systems for
ventilating a building. Referring to FIG. 1, a ventilation system
100 of a building includes a main or central fan 105 that is used
for heating and/or cooling at least a portion of the building in
connection with a heating or air conditioning system, at least one
exhaust fan 110 (such as a bathroom or kitchen exhaust fan), and a
damper 115 in communication with the central fan, for example
through a controller 120. The central fan 105 can be disposed
within the building or in a unit external to the building. Fresh
air is drawn in by the central fan 105 and circulated in the
building via one or more fresh air ducts 106. In some
implementations, air from within the building can be expelled or
exhausted from the building through one or more exhaust ducts 108.
The controller 120 is usually disposed inside the building, for
example on a wall. The controller 120 may include an electronic
controller such as a microcontroller, microprocessor or a digital
signal processor (DSP). In some implementations, the exhaust fan
110 is switched on during time periods when the central fan 105 is
not operating, in order to exhaust stale air from the building. In
some implementations, during at least a portion of those time
periods, the damper 115 is automatically opened, so that fresh air
enters the building through the damper, rather than other,
potentially less desirable, routes (e.g. via a leakage from the
garage). Even though the example of FIG. 1 illustrates that the
damper 115 is disposed in an intake duct 113 connected to the
central fan 105, the damper 115 can also be disposed elsewhere in
the building. For example, the damper can be disposed on an
external wall of the building or in another duct or pipe that
facilitates a flow of fresh air. The controller 120 can be
configured to send control signals to one or more of the central
fan 105, the exhaust fan 110, and the damper 115 to facilitate the
automatic operations (e.g. switching on or off). For example, the
exhaust fan 110 may be automatically operated by the controller for
certain time periods in addition to periods when the exhaust fan
110 is manually operated, for example, using a switch 113. In
another example, the controller 120 may send one or more control
signals to operate the central fan 105 when the heating or cooling
system is operating. The controller 120 may also operate the
exhaust fan 110 when a person is using the bathroom (e.g., based on
determining if the bathroom light is turned on), and potentially
for a period afterwards. The controller 120 may further operate the
exhaust fan 110 to perform any additional ventilation needed to
achieve a desired amount of ventilation in the building over a
predetermined time period (e.g. an hour, a day, or during normal
work hours). In some implementations, the exhaust fan may be part
of an energy recovery ventilator or a heat recovery ventilator.
[0032] The controller 120 can also be configured to send control
signals to the damper 115 to automatically open or close the damper
115. In some implementations, the controller 120 can be configured
to open the damper 115 during periods when the central fan 105 is
operating. In some implementations, the controller 120 can also be
configured to open the damper 115 during periods when the exhaust
fan 110 is operating.
[0033] In some implementations, a user of the ventilation system
100 may enter the desired continuous ventilation requirement, for
example 30 CFM, into the controller 120. The controller 120 may
also be provided with a measured exhaust fan ventilation flow rate
and the central fan supply flow rate in CFM. The controller 120 may
then monitor the central fan 105, tracking the amount of fresh air
supplied to the home as a result of heating and/or cooling
operations. The controller 120 may also track the amount of fresh
air supplied as a result of manual operation of the exhaust fan 110
(e.g., when a user is using the bathroom). If the desired amount of
ventilation in a given time period (e.g., one hour) was not reached
from heating and cooling and the manual exhaust fan operation, the
controller 120 may calculate, based on for example, the provided
flow rates for the central and exhaust fans, an amount of
additional ventilation still required to be made up by the exhaust
fan 110. The controller 120 then operates the exhaust fan 110 for
an additional period of time to achieve the additional amount of
ventilation.
[0034] In one example, the central fan 105 brings in or circulates
120 CFM of fresh air and the bathroom ventilation fan 110 exhausts
or expels 90 CFM of air. If the desired ventilation rate is 30 CFM,
the controller 120 may calculate the additional ventilation needed
as follows. In this example, the hourly requirements are 30
CFM.times.60 Minutes/hr=1,800 Cubic Feet/hr. If the central fan
runs for 10 minutes in a given hour, 120 CFM.times.10 Min=1,200 CF
of fresh air is brought in therefore leaving an additional 600 CF
to bring in. In this example, 600 CF/90 CFM=6.7 minutes of
additional ventilation operation of the exhaust fan 110 is needed
either at the end of the hour or within the hour to meet the 1,800
CF/hr requirement.
[0035] During long heating and cooling runs, the controller 120 may
close the damper 115 to restrict the amount of fresh air to a
predetermined amount, thus preventing over ventilation. In some
implementations, during periods of little or no heating or cooling,
the controller 120 provides the required ventilation by operating
the exhaust fan 110, while also opening the motorized damper 115 in
the fresh air duct to the air handler to provide pressure
relief.
[0036] In a case where the central fan 105 comes on at the end of
the hour (or another predetermined period) while the exhaust fan
110 is running, the controller 120 may track the additional flow
and subtract the additional amount from the following hour or
period, thus preventing over-ventilation. In another example, if
the ventilation fan is operated for an excess amount of time (e.g.,
because of a long occupancy of the bathroom), the resulting excess
ventilation amount may be subtracted from the desired ventilation
in a following time period.
[0037] FIG. 2 is a flowchart 200 of an example process for
operating a ventilation system. In some implementations, the
process represented by the flowchart 200 can be implemented in the
ventilation system 100 described with reference to FIG. 1.
Operations of the process can include circulating air, using a
central fan, for heating or cooling at least a portion of a
building (202). Operations of the process also include exhausting
air from the building using at least one exhaust fan that is
automatically operated during time periods when the central fan is
not switched on (204). The automatic operation of the exhaust
fan(s) with respect to the central fan can be controlled by a
controller such as the controller 120 described with reference to
FIG. 1. Operations of the process further include automatically
opening a damper during at least a portion of the time periods
(206). The damper is opened such that fresh air enters the building
through the damper.
[0038] FIG. 3 is a flowchart 300 of an example process for
operating a ventilation system. In some implementations, the
process represented by the flowchart 300 can be implemented in the
ventilation system 100 described with reference to FIG. 1.
Operations of the process include drawing in air, using a central
fan, for heating or cooling at least a portion of a building (302).
The central fan can be switched on during periods when a heating or
cooling system is supplying hot or cold air to the building.
Operations of the process also include expelling air from the
building using at least one exhaust fan such that a predetermined
amount of ventilation is achieved (304).
[0039] FIG. 4 is a schematic diagram of a computer system 400 that
can be used to implement the controller described in association
with any of the computer-implemented methods described herein,
according to one embodiment. The system 400 includes a processor
410, a memory 420, a storage device 430, and an input/output device
440. Each of the components 410, 420, 430, and 440 are
interconnected using a system bus 450. The processor 410 is capable
of processing instructions for execution within the system 400. In
one embodiment, the processor 410 is a single-threaded
processor.
[0040] In another embodiment, the processor 410 is a multi-threaded
processor. The processor 410 is capable of processing instructions
stored in the memory 420 or on the storage device 430 to display
graphical information for a user interface on the input/output
device 440. In some implementations, the processor 410 can be
substantially similar to the controller 125 described above with
reference to FIG. 10.
[0041] The memory 420 stores information within the system 400. In
some embodiments, the memory 420 is a computer-readable storage
medium. The memory 420 can include volatile memory and/or
non-volatile memory.
[0042] The storage device 430 is capable of providing mass storage
for the system 400. In general, the storage device 430 can include
any non-transitory tangible media configured to store computer
readable instructions. In one embodiment, the storage device 430 is
a computer-readable medium. In various different embodiments, the
storage device 430 may be a floppy disk device, a hard disk device,
an optical disk device, or a tape device.
[0043] The input/output device 440 provides input/output operations
for the system 400. In some embodiments, the input/output device
440 includes a keyboard and/or pointing device. In some
embodiments, the input/output device 440 includes a display unit
for displaying graphical user interfaces.
[0044] The features described in this application can be
implemented in digital electronic circuitry, or in computer
hardware, firmware, or in combinations of them. The features can be
implemented in a computer program product tangibly embodied in an
information carrier, e.g., in a machine-readable storage device,
for execution by a programmable processor; and features can be
performed by a programmable processor executing a program of
instructions to perform functions of the described embodiments by
operating on input data and generating output. The described
features can be implemented in one or more computer programs that
are executable on a programmable system including at least one
programmable processor coupled to receive data and instructions
from, and to transmit data and instructions to, a data storage
system, at least one input device, and at least one output device.
A computer program includes a set of instructions that can be used,
directly or indirectly, in a computer to perform a certain activity
or bring about a certain result. A computer program can be written
in any form of programming language, including compiled or
interpreted languages, and it can be deployed in any form,
including as a stand-alone program or as a module, component,
subroutine, or other unit suitable for use in a computing
environment.
[0045] Generally, a computer will also include, or be operatively
coupled to communicate with, one or more mass storage devices for
storing data files; such devices include magnetic disks, such as
internal hard disks and removable disks; magneto-optical disks; and
optical disks. Storage devices suitable for tangibly embodying
computer program instructions and data include all forms of
non-volatile memory, including by way of example semiconductor
memory devices, such as EPROM, EEPROM, and flash memory devices;
magnetic disks such as internal hard disks and removable disks;
magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor
and the memory can be supplemented by, or incorporated in, ASICs
(application-specific integrated circuits).
[0046] To provide for interaction with a user, the features can be
implemented on a computer having a display device such as a CRT
(cathode ray tube) or LCD (liquid crystal display) monitor for
displaying information to the user and a keyboard and a pointing
device such as a mouse or a trackball by which the user can provide
input to the computer. Alternatively, the computer can have no
keyboard, mouse, or monitor attached and can be controlled remotely
by another computer.
[0047] The features can be implemented in a computer system that
includes a back-end component, such as a data server, or that
includes a middleware component, such as an application server or
an Internet server, or that includes a front-end component, such as
a client computer having a graphical user interface or an Internet
browser, or any combination of them. The components of the system
can be connected by any form or medium of digital data
communication such as a communication network. Examples of
communication networks include, e.g., a LAN, a WAN, and the
computers and networks forming the Internet.
[0048] The computer system can include clients and servers. A
client and server are generally remote from each other and
typically interact through a network. The relationship of client
and server arises by virtue of computer programs running on the
respective computers and having a client-server relationship to
each other.
[0049] The processor 410 carries out instructions related to a
computer program. The processor 410 can include hardware such as
logic gates, adders, multipliers and counters. The processor 410
can further include a separate arithmetic logic unit (ALU) that
performs arithmetic and logical operations.
[0050] Other embodiments not explicitly described herein are also
within the spirit of the invention and the scope of the claims. It
will be understood by those skilled in the art that various changes
in form and details may be made to the disclosed embodiments
without departing from the spirit and scope of the invention as
defined by the claims. Those skilled in the art will recognize or
be able to ascertain using no more than routine experimentation,
many equivalents to the specific embodiments of the invention
described specifically herein.
* * * * *