U.S. patent application number 12/947417 was filed with the patent office on 2011-06-23 for residential integrated ventilation energy controller.
This patent application is currently assigned to The Regents of the University of California. Invention is credited to Darryl Dickerhoff, Max Sherman, Iain Walker.
Application Number | 20110151766 12/947417 |
Document ID | / |
Family ID | 44151749 |
Filed Date | 2011-06-23 |
United States Patent
Application |
20110151766 |
Kind Code |
A1 |
Sherman; Max ; et
al. |
June 23, 2011 |
RESIDENTIAL INTEGRATED VENTILATION ENERGY CONTROLLER
Abstract
A residential controller is described which is used to manage
the mechanical ventilation systems of a home, installed to meet
whole-house ventilation requirements, at the same time reducing
energy costs. This is achieved in part by shifting the ventilation
load of the whole-house system to off peak hours and by taking into
account exogenous mechanical ventilation induced by other systems.
The controller is linked by wire or wirelessly to other house
ventilation systems using any one of a number of communication
protocols, sensing the on-off status of such exogenous systems. An
operational algorithm preloaded and/or modified at the point of use
is used to control the on-off status or fan speed of a whole-house
ventilation fan which forms a part of the home ventilation system,
the operating status of the whole-house fan in part responsive to
the status of other home ventilation systems, and in part based on
time of day.
Inventors: |
Sherman; Max; (Moraga,
CA) ; Walker; Iain; (Alameda, CA) ;
Dickerhoff; Darryl; (Berkeley, CA) |
Assignee: |
The Regents of the University of
California
Oakland
CA
|
Family ID: |
44151749 |
Appl. No.: |
12/947417 |
Filed: |
November 16, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61287356 |
Dec 17, 2009 |
|
|
|
Current U.S.
Class: |
454/239 |
Current CPC
Class: |
F24F 11/46 20180101;
F24F 11/52 20180101; F24F 11/56 20180101; F24F 7/007 20130101; F24F
11/0001 20130101 |
Class at
Publication: |
454/239 |
International
Class: |
F24F 11/00 20060101
F24F011/00 |
Goverment Interests
STATEMENT OF GOVERNMENTAL SUPPORT
[0002] The invention described and claimed herein was made in part
utilizing funds supplied by the U.S. Department of Energy under
Contract No. DE-AC02-05CH11231 between the U.S. Department of
Energy and the Regents of the University of California for the
management and operation of the Lawrence Berkeley National
Laboratory. The government has certain rights in this invention.
Claims
1. A system for controlling the ventilation of a house, said system
including: a) a whole-house fan b) one or more other home supply or
exhaust fans c) a controller for regulating the on-off time of the
whole-house fan, said controller including a central processing
unit, a bios, a clock, and memory, said memory including
programmable software for both calculating the relative exposure
and relative dose within the building, and instructions based on
the calculated relative exposure and relative dose to either turn
the whole-house fan on or off; and, d) communication links with the
one or more other home exhaust or supply fans, such that a signal
is sent from each of the one or more other home exhaust or supply
fans to the controller, indicating the operating status of the fan,
such as whether or not it is on or off, or operating an some
intermediate speed, and a set of instructions within the controller
which either turns the whole-house fan on or off, or set it to some
intermediate speed, in response to the signals from the other home
exhaust or supply fans.
2. The system of claim 1, in which the set of instructions within
the controller which either turn the whole-house fan on or off, or
sets it to some intermediate speed, in response to the signals from
the other home exhaust or supply fans is programmed to turn the
whole-house fan off, or set it to some intermediate speed, when any
one of the other home exhaust or supply fans is operating.
3. The system of claim 2 further including an economizer.
4. The system of claim 2 further including a heat recovery
ventilation system.
5. The system of claim 1 further including a control algorithm
implemented in software residing within the controller, which
algorithm includes a programmed schedule during at least one
segment of which, the whole-house fan is in an "always off"
condition.
6. The system of claim 5 wherein said algorithm is programmed such
that the "always off" condition occurs during the peak energy
demand period is summer months for cooling, or in winter months for
heating.
7. The system of claim 5 further including means for programming
the controller algorithm from a separate electronic device, which
device can be accessed by a user to set programmable variables,
including when the whole-house fan will be in the "always off"
condition.
8. A system for controlling ventilation within a structure
including: a) a main whole-house ventilation control fan, including
an on-off switch or variable fan speed controller, said fan located
within said structure; b) one or more supply or exhaust fans
located within said structure, each of said fans having an on-off
switch, or variable fan speed controller; c) a central controller
in communication with the said switches or speed controller of said
main whole-house ventilation fan and said one or more supply or
exhaust fans; and, d) a software program associated with said
central controller, which software program includes a set of
electronic instructions which provides among other things for the
monitoring of the status of the one or more supply or exhaust fan
switches or speed controllers, such that if said one or more of
said supply or exhaust fans are operating, an electronic
instruction is sent to the on-off switch or variable fan speed
controller of the main whole-house ventilation control fan to turn
it off or to some reduced speed.
9. The system of claim 8 wherein the main ventilation control fan,
one or more exhaust or supply fans, and the central controller are
in wired communication with each other.
10. The system of claim 8 wherein said wired communication is
achieved employing an X10 protocol, or equivalent.
11. The system of claim 8 wherein the main ventilation control fan,
one or more exhaust or supply fans and the central controller are
in wireless communication with each other.
12. The system of claim 8 wherein additional instructions control
the operating status of the main whole-house ventilation fan based
on the time of day.
13. The system of claim 8 wherein instructions contained within the
said software program are used to calculate a relative dose and a
relative exposure function at set intervals during the day, the
calculated relative dose and relative exposure for that time of day
then compared with a preset value for these same variables at that
same time of day, whereby based on said comparison an instruction
is issued to the on-off switch or variable fan speed controller of
the main whole-house ventilation fan to be on, off or set to an
intermediate speed.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This Non Provisional US patent application claims priority
to U.S. Provisional Patent Application No. 61/287,356, filed Dec.
17, 2009, entitled Residential Integrated Ventilation Energy
Controller, the contents of said application incorporated in its
entirety, as if fully set forth herein.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] This invention relates generally to ventilation systems for
residential homes, designed to meet new and emerging air quality
standards, and more specifically to a programmed/programmable
device, the Residential Integrated Ventilation Energy Controller
(RIVEC) which provides for dynamic control of the operation of a
whole-house ventilation fan which forms part a residence
ventilation system in a way that minimizes energy usage.
[0005] 2. Description of the Related Art
[0006] Ventilation, and thus the transport of contaminants and
clean air, is becoming an ever more important issue as energy
efficiency of buildings and indoor air quality within buildings is
being sought to be improved.
[0007] Indoor air quality is a complex result of occupant
activities, human responses, source emission, and contaminant
removal. The key variables that requirements can be set for are
usually ventilation and source control. Virtually every building
code contains requirements related to ventilation and indoor air
quality, but an integrated approach to looking at residential
indoor air quality is usually lacking. The nation's first consensus
standard on residential ventilation and indoor air quality was
recently published by the American Society of Heating,
Refrigeration and Air-conditioning Engineers (ASHRAE Standard
62.2-2003, last updated 2007).
[0008] The ASHRAE standard in its simplest form requires continuous
whole-house mechanical ventilation at a rate which is based on the
size and occupancy load of the house. While it does not specify
specific performance conditions for the mechanical ventilation, it
does allow the use of dual purpose fans (e.g. a bath exhaust, or
kitchen exhaust) to meet whole-house requirements. The basic
requirement of the standard is that there be mechanical ventilation
operating at a rate equal to 1 cubic foot per minute (cfm) per
hundred square feet of floor area plus 7.5 cfm per person, where
the number of people is presumed to be equal to one more than the
number of bedrooms. In more general terms, the present standard
calls for about 1/3 of the home air volume to be change per hour
(0.33 ACH) using combined mechanical and natural ventilation, or
about 8 air changes per day, in order to maintain reasonable air
quality conditions within a house
[0009] Many newer homes are now required to be well insulated in
order to improve energy efficiency by, on the one hand, reducing
heating and cooling requirements. However, as a consequence of air
tightness requirements needed to meet such mandated energy
efficiencies, without provision for ventilation, contaminant build
up within the house can quickly become unacceptable. Thus, new
homes in some jurisdictions are also required to include a
whole-house ventilation system in order to maintain acceptable
indoor air quality. The most common method for meeting this
ventilation requirement is to have a ventilation fan than operates
continuously, every hour of the day, 24 hours a day.
[0010] Currently, in older homes, ventilation is typically achieved
via operable windows or envelope leakage (i.e. infiltration)
combined with a mixture of low-efficiency ventilation fans.
However, these simple solutions cannot be relied upon for adequate
ventilation as most new insulative dual pane windows are kept shut
most of the time to keep heat in during the winter months, heat out
during the summer months, or for reasons relating to noise or
security. With retrofit sealing of older homes, the problem is
exacerbated by the fact the contribution of infiltration to home
ventilation is reduced such that infiltration alone can no longer
be relied upon as a means for achieving adequate air exchange.
[0011] Accordingly there is a need for the providing of ventilation
systems to supplement open windows and envelope leakage/natural
infiltration. However, there remains a concern that such
ventilation systems with their own energy requirements can add
significantly to the costs of operating a home. Thus there remains
a need for a whole-house ventilation system with minimal energy
requirements.
BRIEF SUMMARY OF THE INVENTION
[0012] By way of this invention, a smart fan controller is provided
that can substantially reduce the energy and peak power required to
provide mechanical ventilation to a home in a way that effectively
maintains home air quality. The smart fan controller achieves this
by communicating with other exhaust or supply air systems in the
home, such as those commonly found in bathrooms, kitchens, dryers,
and the like, and controlling the operation of the whole-house
ventilation fan which comprises a vital component of the mechanical
ventilation system, turning it off (or down in the case where the
fan can operate at variable speeds) in response to the status of
other exhaust and supply fans in the home. In one embodiment, the
smart fan controller is used detect whether or not such other,
exogenous home exhaust or supply fans are on, and if so, it directs
the whole-house fan to turn off. In another embodiment, where the
whole-house fan can operate at variable speeds, the smart fan
controller can also be used to detect the speed at which exogenous,
variable speed supply or exhaust fans are operating, and adjust the
speed of a variable speed whole-house fan in response. In yet
another embodiment, using an on-off control algorithm, the
ventilation load of the whole-house ventilation system can be
shifted to off peak hours. In one embodiment, this is achieved by
dividing the day into several segments, during one of which the
ventilation fan is programmed to be completely shut off.
[0013] In yet a further exemplary refinement, the on-off algorithm
can divide the day into four parts, a base line, peak, pre-peak and
post peak periods. In one mode of operation, during peak times of
the day, the whole-house fan is turned completely off. During both
the pre and post peak periods, the fan is turned on, with the fan
being turned off or down, as the case may be in the case where the
whole-house fan can operate at variable speeds, when other supply
or exhaust fans are running in the house.
[0014] In another embodiment, a computer program is provided which
can be web accessible and can be programmed using a browser. A
graphic user interface (GUI) allows a technician or the homeowner
to program or reprogram the smart fan controller, taking into
account variables such as the number of rooms in the house, the
square footage and volume of the house, the number of occupants,
and the number and air flow at single or variable speeds of the
other supply and exhaust fans within the house. Based on a control
algorithm that computes the exposure to pollutants relative to the
exposure based on continuous fan operation, the controller
according to its embedded logic decides if the whole-house
ventilation fan needs to be on or off, or at a intermediate speed
in the case where the fan can operate at variable speeds to insure
relative dose and exposure levels are maintained within acceptable
limits. The parameters used in the control algorithm are: Relative
Exposure (R), defined as the occupant exposure to pollutants
relative to the exposure resulting from use of continuous
ventilation at the target air change rate (A) (e.g., as set by
ASHRAE 62.2), and Relative Dose (d), defined as average value of
relative exposure over representative exposure time (e.g., 24
hours). In one embodiment, the control algorithm can be preloaded.
In another embodiment, the GUI allows an installer or homeowner to
modify the program at the point of use.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The foregoing aspects and others will be readily appreciated
by the skilled artisan from the following description of
illustrative embodiments when read in conjunction with the
accompanying drawings.
[0016] FIG. 1 is a schematic depiction of a typical home showing
how a whole-house ventilation system might be set up.
[0017] FIG. 2 is a schematic depiction illustrating the
interconnectivity of the whole-house ventilation fan with the other
components of the home ventilation system.
[0018] FIG. 3 is a screen shot of the Input/Output interface
allowing for user input for the set up of the operational control
algorithms of the smart fan controller.
[0019] FIG. 4 is a flowchart of the software logic used to control
the on-off periods of operation of the whole-house fan.
[0020] FIG. 5 is a plot of relative exposure vs. relative dose over
a period of time, plotted against the on-off cycles for various
home exhaust and supply fans and the whole-house fan.
DETAILED DESCRIPTION
[0021] New homes in some jurisdictions are required to meet the
ASHRAE Standard on residential ventilation (62.2-2007). This
standard specifies minimum continuous mechanical ventilation rates.
While it does not specifically address the issues of source control
or ventilation load shifting, it does allow alternative approaches
to be used if they can be shown to provide equivalent
performance.
[0022] Existing building stock is substantially leakier than
typical new construction. Despite the natural and increasingly
legal incentives to control energy costs, a key barrier to improved
envelope air tightness is the real concern that indoor air quality
will be compromised. Unlike new construction, existing homes have
no mandate to meet any ventilation or indoor air quality standard.
Thus, if air tightness is to be improved, provision at the same
time needs to be made for maintenance of indoor air quality.
[0023] To address this indoor air quality issue, a low cost, energy
efficient home ventilation system has been developed which utilizes
existing home ventilation systems in combination with a whole-house
ventilation fan. To maximize indoor air quality, while reducing
costs of operation, an electronic controller, a residential
integrated ventilation energy controller (RIVEC), is employed to
control the on-off operations of the whole-house fan. This control
is achieved in part by monitoring the use of other supply or
exhaust systems in the house. If they are on during a time when the
whole-house fan would otherwise be programmed to be on, the
controller directs the whole-house fan to turn off, or in the case
of a variable speed whole-house fan, to reduce fan speed.
[0024] With reference now to FIG. 1, a residential home is
illustrated, showing several existing ventilation systems,
including a bath exhaust fan 102 connected to an exhaust duct 103,
a cooking range ventilation fan 104 connected to an exhaust duct
105 and a dryer 106 having its own, internal exhaust (not shown)
connected to a dryer exhaust duct 107. A controlled whole-house
exhaust fan 114 is shown connected to its own exhaust dust 115. The
placement of the fan 114 is not critical, being on a first or
second floor, or even in an attic, so long as it is in
communication with the rest of the house. RIVEC controller 120 is
the brains of the system and is used to control the on-off status
of fan 114.
[0025] Communication between fans 102, 104 and 106 to the RIVEC
controller is shown by dotted lines. In a new house, internal
wiring can be provided to connect these units to the controller,
providing a pathway for signals that alert the controller as to
their operational status, be it full on, or off, or at some
intermediate speed. In existing homes, other wireless methods of
communication may be used. One such system, but by no means the
only one, utilizes a protocol known as X10, which system includes
associated hardware devices and a defined X10 communications
language. There are many X10 compatible devices on the market.
Common uses include control of house lighting and home security
functions. The communications protocol, limited to simple, low
speed communications, allows compatible devices to talk to one
another using the existing home electrical wiring. Because it uses
the home's existing electrical wires, installation is quite simple.
Other higher bandwidth alternative can be used including KNX,
INSTEON, BACnet, and ONWorks.
[0026] According to ASHRAE Standard 62.2-2007, a mechanical exhaust
system, or supply system or combination thereof should be capable
of providing whole building ventilation with outdoor air each hour
at a specified rate, according to the equation:
Q.sub.fan=0.01A.sub.floor+7.5(n.sub.br+1)
Where
[0027] Q.sub.fan=fan flow rate in cubic feet per minute (cfm)
A.sub.floor=floor area in square feet (ft.sup.2) N.sub.br=number of
bedrooms; not to be less than one
[0028] In one embodiment of the invention, the RIVEC can be used in
conjunction with a Heat Recovery Ventilator (HRV) system as an
adjunct to the whole-house fan. Such HRV systems make mechanical
ventilation more cost effective by reclaiming energy from exhaust
airflows. They do so by heat exchange, to heat cool incoming fresh
air, or cool hot incoming fresh air, in this way recapturing 60 to
80 percent of the conditioned air temperatures that would otherwise
be lost upon venting. When used with a whole-house fan, the HRV
system can be included as an additional exogenous system to be
monitored by the RIVEC controller, and according to the embedded
logic of the controller, cause a shut down, or slow down of the
whole-house fan when the HRV system is running. In another
embodiment the HRV itself can serve as the whole-house fan.
[0029] It is to be appreciated that the controller of this
invention can also be used in conjunction with existing
"economizer" units as well, such economizers typically used at
night during the summer months to bring in cool outside air to help
maintain cooler indoor temperatures during the day. It can also be
programmed to operate with Central Fan Integrated Supply (CFIS)
systems which uses the existing central forced air system fan (even
when there is no demand for heating or cooling) to pull air in from
the outside (often through a separate ventilation air intake duct)
and circulate it within the house. In such a typical set up, a
motorized ventilation damper is used, the damper open only during
ventilation-only mode, to limit the potential for over-ventilation
during heating and/or cooling, in order to save the energy of
unnecessarily conditioning extra outside air. All of these
auxiliary approaches to home ventilation are well known in the art,
and do not constitute a separate part of this invention. However,
if used in place of a whole-house fan, such as in the case of a
CFIS system, operation can be controlled by the controller of this
invention in a manner similar to that of the whole-house fan.
[0030] FIG. 2 depicts the electronic set up of the whole-house
ventilation system 200. At the heart of the system is the RIVEC
controller 220. The RIVEC controller 220, which comprises a CPU,
including control algorithms 221 (which will be discussed later in
more detail), along with its supporting electronic elements, is
electronically connected to fan sensors 202, 204, and 206, and 207
(which may for example be for an economizer) which sensors detect
whether or not fans 102, 104 and 106 (etc.) are on, off, or running
at some intermediate speed. This information is sent to controller
220, via any of the previously mentioned protocols, in one
embodiment being the X10 protocol, wherein signals are sent through
the existing home electrical wiring. Controller 220 is also
provided with its own clock timer 208, and independent power supply
209. The on-off status of whole-house ventilation fan 214 is
controlled by whole-house fan switch 212, which in turn is
activated to the on or off state depending upon signals received
from controller 220. The whole-house ventilation van may also be
equipped with a variable fan speed controller, in the case where
the fan is capable of operation at various speeds. During a period
of time during which the whole-house fan 214 is programmed to be
on, if any of the fan operation sensors detect that their
associated ventilation fan is turned on, then a signal is sent to
the RIVEC controller 220 through I/O port 217, and a command issued
via I/O 217 to whole-house fan switch 212 to shut off or reduce the
speed of whole-house fan 214.
[0031] Home specific operational variables to be inputted into the
control program of the RIVEC is accomplished via I/O interface 218,
which in one embodiment can be linked either by wire or wirelessly
to a personal computer. While the RIVEC unit can be installed with
a preprogrammed algorithm, given the many variables that can affect
ventilation requirements for a given house incorporating a RIVEC
system, the capability through I/O 218 is provided to change to the
default settings in the field or at the point of use (which can be
one in the same).
[0032] An exemplary screen shot of a GUI which can be used to
program the RIVEC is depicted in FIG. 3. Therein, as shown in the
screen shot, one can (among other things) select the default
program. Customizing data to be entered include the floor area of
the house, the volume of the home, the number of bedrooms, the
target ACH flow, along with the listing of ventilation locations,
including supply and exhaust flows, if known. Entry of other
information such as the presence of an economizer is shown in the
I/O along with an entry window for recording its air flow capacity.
Other entry windows allow for additional adjustments to the
operational algorithm, which will now be described in connection
with FIG. 4.
[0033] Embedded logic in the controller allows it to make the
decision to turn the whole-house mechanical ventilation fan on or
off, or to an intermediate speed, the decision made at each
discrete time interval, which in one embodiment can be set to every
five minutes. The following set of actions is performed at each
time interval, be it at every five minutes, ten minutes, or longer
interval such as every hour.
[0034] Determine current mechanical ventilation rate: the
controller monitors the status of the whole-house mechanical system
and all exogenous mechanical ventilation systems.
[0035] Estimate current Indoor Air Quality: the relative exposure,
R, and relative dose d are calculated. These values are then used
in the decision making process of the control algorithm.
[0036] Modify whole-house mechanical ventilation: Based on the
imbedded and programmed logic of the control algorithm, the
whole-house mechanical ventilation is turned on or off for the next
time interval.
[0037] The control algorithms of control program 221 (which may be
implemented in software, firmware or a combination of both) are
programmed to keep the dose d at or below 1, but allow the
whole-house mechanical ventilation system to be turned off during a
defined peak period. To do this each day in the embodiment of the
invention illustrated in the figure, the day is broken up into four
periods (box 303). There is a (4 hour) peak period where the
whole-house system is "off" (box 312). There is a pre-peak and a
post-peak shoulder period (4 hours each), and then a 12 hour base
period. Each period has its own control logic including allowable
levels of relative dose and relative exposure. These levels are set
through a combination of engineering judgment and results of
simulations and field testing.
[0038] For the base period: the Minimum Total Mechanical
Ventilation is set at A (the target ACH--air change per hour), the
Maximum Total Mechanical Ventilation is set to: unlimited. The
algorithm turns on the whole-house ventilation fan (box 310) if d
is greater than 1 or R is greater than 0.8 (box 304)]. The
algorithm turns off the whole-house ventilation (312) if d is less
than 1 and R is less than 0.8.
[0039] For the pre-peak shoulder period: The minimum whole-house
mechanical ventilation is set to zero. If the ventilation system
has variable capacity, the maximum whole-house mechanical
ventilation is set at: 1.25 A. The algorithm is set to turn on
whole-house ventilation (box 310) if R is greater than 1 (box 305),
but not if the then current mechanical ventilation rate total is at
least 1.25 A (box 308). The algorithm will turn off whole-house
ventilation fan (box 312) if R is less than 1 (box 305) and d is
less than 1 (box 306).
[0040] For the Peak Period: Minimum whole-house mechanical
ventilation is set to zero, maximum whole-house mechanical
ventilation set to zero. The algorithm is programmed to always turn
off the whole-house ventilation fan (box 312).
[0041] For the Post-Peak Shoulder Period: The minimum whole-house
mechanical ventilation is set to zero. If the ventilation system
has variable capacity, maximum whole-house mechanical ventilation
is set to 1.25 A. The algorithm is set to turn on whole-house
ventilation fan (box 310): if d is greater than 1, or R is greater
than 1 (box 307), but not if the then current mechanical
ventilation total is already at least 1.25 A (box 309). The program
algorithm is set to turn off whole-house ventilation fan: if d is
less than 1, and R is less than 1 (box 307) or current mechanical
ventilation total is at least 1.25 A (box 309).
[0042] To program the controller, step 218 of FIG. 2, the user will
usually start by clicking the "Select Defaults" button (see FIG.
3). This will fill in the windows which define winter and summer
months and peak hours. It also assigns three bedrooms to the house
with a default area of 3,500 ft.sup.2 and a volume of 30,800
ft.sup.3. From this it calculates the ASHRAE 62.2 constant
ventilation requirement, in this case 0.15ACH (also shown in units
of CFM). The user can then modify the number of bedrooms, floor
area, and house volume and then click the "Cal. ACH" button to
calculate the ASHRAE 62.2 ventilation rate for their house. The
user can replace this target ventilation rate to a value of their
own choosing if they so desire.
[0043] The pull down menu "RIVEC Device Type" defaults to RIVEC
control of the whole-house fan. Other active selections are "Always
ON" and "Always OFF". The other ventilation control types listed
have the same control logic as the "Exhaust Fan" but are names of
other common ventilation devices.
[0044] The names of the various ventilation devices, their X10
address, and flow rates can now be set. These can also be changed
during RIVEC operation and will take effect when the device is next
used. A sensor is used (usually a clamp-on current sensor) to
detect when other ventilating fans are on. The summer and winter
seasons and peak and shoulder times can be changed. Controller step
time and serial communications port to the X10 controller can also
be adjusted as well. After the user has completed filing in the
information, then click the "init" button. This will start up
communications with the X10 interface, start logging data, and
start the RIVEC control.
[0045] With reference now to FIG. 5, a plot of relative exposure
(R) vs. relative dose (d) is shown over a two day period, the plot
exemplary as to the operation of the ventilation system employing a
RIVEC fan. As can be seen from this plot, when the fan is off, the
relative exposure increased above 1, and then began to decrease as
soon as the RIVEC whole-house fan was turned on. When other house
exhaust or supply fans were turned on, such as in the bathroom or
the kitchen, the RIVEC whole-house fan turned off, and then cycled
back on again staying on for extended periods of time. All the
while, the relative dose remained near 1. To be noted in this
exemplary test of the RIVEC system illustrated in FIG. 5, the
controller was programmed to perform calculations of R and d every
10 minutes to determine if the fan should be on or off in order to
maintain the relative dose as near to 1 as possible.
[0046] By way of summary, in using the RIVEC controller it is
possible to successfully control ventilation while still
maintaining acceptable indoor air quality. Due to the "smart"
nature of the device, implementation of the RIVEC approach can lead
to run times of but 30-70% of normal full time operation.
Substantially higher savings may further be realized if home
occupants use equipment like dryers, exhaust or supply fans, or
economizers to a degree higher than is assumed in standard
calculations. Existing homes may be retrofitted with the RIVEC
technology and can show improved Indoor Air Quality (IAQ) and/or
ventilation energy savings.
[0047] From time to time in describing the operation of the
whole-house fan, reference has been made to periods where the
whole-house fan is either on or off. It is to be appreciated that
for whole-house fans capable of being operated at various speeds,
when reference has been made to the "on" state, such contemplates
an "on" state which can be full on, or at some intermediate speed.
Whether or not the whole-house fan is to be operated at an
intermediate speed will depend upon what other home exhaust or
supply fans are on at the time, and at what speed those fans might
be running, where they too may be capable of operating at more than
one speed. Other variations in the operation of the whole-house fan
are possible, and any such variations are considered to be within
the scope of this invention.
[0048] This invention has been described herein in considerable
detail to provide those skilled in the art with information
relevant to apply the novel principles and to construct and use
such specialized components as are required. It is to be understood
that the invention can be carried out by different equipment,
materials and devices, and that various modifications, both as to
the equipment and operating procedures, can be accomplished without
departing from the scope of the invention itself.
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