U.S. patent application number 11/743821 was filed with the patent office on 2007-11-08 for humidity control algorithm.
This patent application is currently assigned to MAPLE CHASE COMPANY. Invention is credited to George N. Catlin, John G. Chapman.
Application Number | 20070257121 11/743821 |
Document ID | / |
Family ID | 38660345 |
Filed Date | 2007-11-08 |
United States Patent
Application |
20070257121 |
Kind Code |
A1 |
Chapman; John G. ; et
al. |
November 8, 2007 |
HUMIDITY CONTROL ALGORITHM
Abstract
A system and method is provided to control the operation of an
HVAC system to remove humidity from an indoor air environment
without cooling the indoor air environment. The system includes a
thermostat that operates the HVAC system to remove humidity when
the sensed humidity falls below a humidity set point. After
operation of the HVAC system, the thermostat monitors whether the
temperature within the indoor air environment falls due to the
operation of the HVAC system. If the temperature within the indoor
air environment falls consistently, the humidity control algorithm
determines that the HVAC system cannot operate without cooling and
prevents future operation of the HVAC system to provide only
dehumidification. If, however, the humidity control algorithm
determines that the HVAC system can operate to dehumidify without
cooling, the humidity control algorithm operates the HVAC system
accordingly.
Inventors: |
Chapman; John G.; (Delaware,
OH) ; Catlin; George N.; (Grove City, OH) |
Correspondence
Address: |
ANDRUS, SCEALES, STARKE & SAWALL, LLP
100 EAST WISCONSIN AVENUE, SUITE 1100
MILWAUKEE
WI
53202
US
|
Assignee: |
MAPLE CHASE COMPANY
Downers Grove
IL
|
Family ID: |
38660345 |
Appl. No.: |
11/743821 |
Filed: |
May 3, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60797633 |
May 4, 2006 |
|
|
|
Current U.S.
Class: |
236/44C |
Current CPC
Class: |
F24F 11/0008 20130101;
F24F 2110/20 20180101; F24F 11/30 20180101; F24F 3/14 20130101;
F24F 2110/10 20180101 |
Class at
Publication: |
236/44.C |
International
Class: |
F24F 3/14 20060101
F24F003/14 |
Claims
1. A method of operating an HVAC system capable of dehumidifying
and cooling an indoor air environment comprising the steps of:
sensing the humidity in a location having the indoor air
environment controlled by the HVAC system; comparing the sensed
humidity to a humidity set point; activating the HVAC system when
the sensed humidity exceeds the humidity set point; sensing a
starting temperature in the location having the indoor air
environment controlled by the HVAC system upon activation of the
HVAC system; monitoring a current temperature in the location
having the indoor air temperature controlled by the HVAC system;
comparing the starting temperature to the current temperature; and
deactivating the HVAC system when the current temperature falls
below the starting temperature by more than a temperature
limit.
2. The method of claim 1 wherein the HVAC system is deactivated
even when the sensed humidity exceeds the humidity set point when
the change in temperature exceeds the temperature limit.
3. The method of claim 1 wherein the HVAC system is activated when
the sensed humidity exceeds the humidity threshold and the current
temperature is below a temperature set point.
4. The method of claim 3 wherein the temperature set point and the
humidity set point are user selectable.
5. The method of claim 1 wherein the step of activating the HVAC
system includes at least activating a dehumidifier and activating a
blower to operate in concert with the dehumidifier.
6. The method of claim 1 wherein the HVAC system is deactivated
when the current temperature falls below the start temperature by
more than the temperature limit and the current temperature is
below the temperature set point.
7. A method of operating an HVAC system capable of dehumidifying
and cooling an indoor air environment comprising the steps of:
sensing the humidity in a location having the indoor air
environment controlled by the HVAC system; comparing the sensed
humidity to a humidity set point; activating the HVAC system when
the sensed humidity exceeds the humidity set point; sensing a
starting temperature of the air flow from the HVAC system upon
activation of the HVAC system; monitoring a current temperature of
the air flow from the HVAC system after activation of the HVAC
system; comparing the current temperature of the air flow to the
starting temperature; and deactivating the HVAC system when the
current temperature of the air flow falls below the starting
temperature by more than a temperature limit.
8. The method of claim 7 wherein the HVAC system is deactivated
even when the sensed humidity exceeds the humidity set point when
the current air flow temperature falls below the starting
temperature by more than the temperature limit.
9. The method of claim 7 wherein the HVAC system is activated when
the sensed humidity exceeds the humidity threshold and a current
temperature of the indoor air environment controlled by the HVAC
system is below a temperature set point.
10. The method of claim 9 wherein the temperature set point and the
humidity set point are user selectable.
11. The method of claim 7 wherein the step of activating the HVAC
system includes at least activating a dehumidifier and activating a
blower to operate in concert with the dehumidifier.
12. The method of claim 7 wherein the HVAC system is deactivated
when the air flow temperature falls below the starting temperature
by more than the temperature limit and the current temperature is
below the temperature set point.
13. A method of operating a thermostat to control the activation of
an HVAC system, the method comprising the steps of: sensing the
humidity of an indoor air environment controlled by the HVAC
system; comparing the sensed humidity to a humidity set point
entered into the thermostat; activating the HVAC system when the
sensed humidity exceeds the humidity set point; sensing a starting
temperature related to the indoor air environment upon activation
of the HVAC system; monitoring a current temperature related to the
indoor air environment after activation of the HVAC system;
comparing the current temperature to the starting temperature; and
deactivating the HVAC system when the current temperature falls
below the starting temperature by more than a temperature
limit.
14. The method of claim 13 wherein the current temperature is the
temperature of the indoor air environment controlled by the HVAC
system.
15. The method of claim 14 wherein the current temperature is
sensed by a temperature sensor within the thermostat.
16. The method of claim 14 wherein the HVAC system is deactivated
even when the sensed humidity exceeds the humidity set point when
the current temperature falls below the starting temperature by
more than the temperature limit.
17. The method of claim 13 wherein the temperature set point and
the humidity set point are user settable in the thermostat.
18. The method of claim 13 wherein the current temperature is the
temperature of the air flow from the blower of the HVAC system.
19. The method of claim 18 further comprising the steps of:
positioning an air flow temperature probe to detect the temperature
of the air flow from the HVAC system; and communicating the air
flow temperature from the air flow temperature probe to the
thermostat.
20. A system for controlling the operation of an HVAC system
capable of dehumidifying and cooling an indoor air environment, the
system comprising: a thermostat positionable within the indoor air
environment to be controlled by the HVAC system, the thermostat
having operational output in communication with the HVAC system; a
temperature sensor coupled to the thermostat and operable to
determine the air temperature of the indoor air environment; a
humidity sensor coupled to the thermostat and operable to determine
the humidity of the indoor air environment; and an air flow probe
positionable downstream from the dehumidifier to sense the
temperature of the air flow from the HVAC system.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application is based on and claims priority from
U.S. Provisional Patent Application Ser. No. 60/797,633 filed on
May 4, 2006.
BACKGROUND OF THE INVENTION
[0002] Recently, there have been many advancements in the operation
of HVAC systems regarding humidity control. In particular, there
currently exist HVAC systems that are capable of removing humidity
from the air without cooling the air. In many of these systems,
humidity is removed from the air and, once the humidity has been
removed, the dehumidified air is heated enough such that the air
returned to the enclosed environment has not been cooled.
[0003] As with many technological advances, the controls and
control algorithms for HVAC systems have lagged the advances in the
physical equipment. Presently, thermostats or HVAC controls only
call for dehumidification when there is also a call for cooling or
when the current temperature of the indoor air environment is close
to the cooling temperature set point such that a small amount of
over-cooling may be allowed. However, currently available
thermostats and HVAC controllers are not capable of operating the
HVAC system as a dehumidifier independently when the temperature
within the building is below the cooling temperature set point such
that a demand for cooling is not indicated.
[0004] In addition, in many applications, a thermostat or HVAC
controller may be installed after the HVAC system or the thermostat
may be an upgrade to the original thermostat installed with the
HVAC system. In these situations, the thermostat will not know the
operational characteristics of the HVAC system or appreciate the
HVAC system's ability to dehumidify the air without additional
cooling. Thus, the thermostat may not utilize the ability of the
HVAC system to dehumidify the air within the indoor air environment
being controlled.
[0005] Therefore, a need exists for an improved thermostat and HVAC
controller that takes advantage of the advancements in HVAC systems
to remove humidity from the air while monitoring for a decrease in
temperature.
SUMMARY OF THE INVENTION
[0006] The present invention generally relates to a system and
method for controlling the operation of an HVAC system that is
capable of dehumidifying and cooling an indoor air environment. The
method and system generally includes a thermostat positioned within
the building or room in which the HVAC system operates to control
the temperature and humidity of the indoor air environment. The
thermostat is in communication with the HVAC system such that
control signals from the thermostat can be used to control the
operation of the HVAC system.
[0007] In one embodiment, the thermostat senses the humidity in a
location that has the indoor air environment controlled by the HVAC
system. If the humidity in the location is greater than a humidity
set point, the thermostat activates the HVAC system to begin
removing humidity from the indoor air environment. At the time the
HVAC system is initially activated, the thermostat senses the
temperature in the location having the indoor air environment
controlled by the HVAC system.
[0008] Following activation of the HVAC system, the thermostat
continues to monitor the temperature in the location having the
indoor air temperature controlled by the HVAC system and compares
the starting temperature to the current temperature. If the HVAC
system is not capable of dehumidifying the indoor air environment
without also cooling the indoor air environment, the current
temperature will fall below the starting temperature. The
thermostat continues to monitor the difference between the current
temperature and the starting temperature and deactivates the HVAC
system when the current temperature falls below the starting
temperature by more than a temperature limit.
[0009] In this manner, the thermostat operates the HVAC system
without knowing whether the HVAC system is capable of dehumidifying
without cooling. If the thermostat learns that the HVAC system is
not capable of dehumidifying without cooling, the thermostat will
discontinue activating the HVAC system for dehumidification
purposes only in the future. In this manner, the thermostat can
learn the operational characteristics of the HVAC system and
utilize performance characteristics of the HVAC system to provide
for improved cooling and dehumidification functions.
[0010] In one embodiment, the thermostat senses the starting
temperature in the location near the thermostat and within a
building or room having the indoor air environment controlled by
the HVAC system. In this embodiment, both the starting temperature
and the current temperature are temperatures measured near the
thermostat. In an alternate embodiment, the system includes a
temperature probe positioned to sense the temperature of the air
flow leaving the HVAC system. In this alternate embodiment, the
temperature probe relays the current temperature of the air flow
from the HVAC system to the thermostat such that the thermostat can
compare the temperature of the air flow leaving the HVAC system to
a starting temperature that is related to the temperature of the
indoor air environment being controlled by the HVAC system. The use
of a temperature probe to sense the air flow from the HVAC system
provides a more immediate indication of whether the HVAC system is
capable of operation to remove humidity without cooling the indoor
air environment.
[0011] As described above, current improvements in dehumidifiers
are generally centered around the equipment's ability to remove
humidity from the air without cooling the air. This is accomplished
by different manufacturers in different ways, such as reheating the
air after the dehumidification process. Because the dehumidifier is
not cooling the air, it is possible to run the dehumidification
equipment when there is a call for dehumidification but not a call
for cooling. One implementation of this would be to observe the
room temperature at the start of the call for dehumidification and
monitor that temperature as the call continues. If the temperature
begins to fall during the call for dehumidification by a pre-set
temperature differential, the call for dehumidification will be
terminated. Otherwise, the call will continue until the
dehumidifier has satisfied the demand for dehumidification.
[0012] Alternatively, the method could be further enhanced by
providing a temperature probe at an outlet vent for the HVAC
system. By observing the temperature at the outlet vent, rather
than at the thermostat or control itself, the thermostat could
respond faster to equipment that does cool and prevent
undercooling, and thus not leave the homeowner uncomfortable. The
thermostat could also, after several cycles, "remember" that the
equipment is capable of dehumidification without cooling.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The drawings illustrate the best mode presently contemplated
of carrying out the invention. In the drawings:
[0014] FIG. 1 is a schematic illustration of the thermostat control
as used with an HVAC system;
[0015] FIG. 2 is a schematic illustration of a second, alternate
embodiment of the thermostat control used with an HVAC system;
[0016] FIG. 3 is a state diagram showing the specific transitions
that apply to a dehumidification-controlling algorithm implemented
by the thermostat shown in FIGS. 1 and 2; and
[0017] FIG. 4 is a flowchart illustrating the operational decision
made by the dehumidification-controlling algorithm implemented by
the thermostat shown in FIGS. 1 and 2.
DETAILED DESCRIPTION OF THE INVENTION
[0018] Referring now to FIG. 1, thereshown is a thermostat 10
connected to an HVAC system 12 that includes both a dehumidifier 14
and an air conditioner 16. The HVAC system includes a blower 18
that draws a supply of air through an inlet duct 20 from the indoor
air environment being conditioned through the HVAC system 12 and
out of an outlet duct 22 for return to the home.
[0019] The thermostat 10 includes a user input 24 that allows the
home occupant to enter the desired set point temperature for
heating and cooling. Further, the user input 24 allows the home
occupant to enter a desired set point for the relative humidity
within the home. The thermostat 10 receives a temperature signal
from the temperature sensor 26 and a humidity signal from the
humidity sensor 28. Typically, the temperature sensor 26 and
humidity sensor 28 are incorporated directly into the thermostat
10. However, the temperature sensor 26 and humidity sensor 28 can
be located remotely from the thermostat and communicate to the
thermostat using either a wired or wireless connection while
operating within the scope of the present invention.
[0020] During normal operation, the thermostat 10 monitors the
temperature from the temperature sensor 26 and compares the current
temperature to the cooling temperature set point. If the room
temperature exceeds the cooling set point, the thermostat 10 sends
a signal to the air conditioner 16 and the blower 18 to begin
operation. Once the air conditioner 16 has begun operation, the
thermostat 10 monitors the current room temperature from the signal
received from the temperature sensor 26 and continues to operate
the air conditioner 16 until the room temperature falls below the
cooling temperature set point minus an offset value. As an example,
if the cooling set point is selected to be 70.degree., the
thermostat 10 will continue to operate the air conditioner until
the temperature sensor 26 returns a sensed temperature of
68.degree., which is a 2.degree. offset below the cooling set
point.
[0021] In presently available HVAC systems, the thermostat 10 will
turn on the dehumidifier 14 when both the relative humidity of the
indoor air environment exceeds the humidity set point and the
temperature of the indoor air environment calls for cooling. Some
systems will also activate the dehumidifier 14 when the temperature
within the home is very near the cooling set point. In prior HVAC
systems, the operation of the dehumidifier 14 resulted in cooling
of the air being drawn from the house such that operation of the
dehumidifier 14 would result in cooling of the air within the home.
For this reason, the thermostat 10 allowed for operation of the
dehumidifier 14 only when there was a call for cooling or when the
current temperature was very close to the cooling set point to
prevent overcooling of the home. However, currently available HVAC
systems 12, such as shown in FIG. 1, include dehumidifiers 14 that
can be operated without cooling the air within a home.
[0022] In addition to the HVAC system shown in FIG. 1, currently
available HVAC systems 50, such as shown in FIG. 2, are available
that include an additional heater 52 that is positioned downstream
from the dehumidifier 14. Since the operation of the dehumidifier
14 results in a reduction in the temperature of the air flow, the
heater 52 can be operated to reheat the air flow after the
dehumidification process. The net result of the operation of the
dehumidifier 14 and the heater 52 is that the output air flow has
the same temperature as the input but with a significant reduction
in the humidity of the air flow. The operation of the HVAC system
50 to remove humidity without cooling the indoor air environment
requires operation of both the dehumidifier 14 and the heater 52 to
prevent a reduction in the temperature of the air within the indoor
air environment. As with the embodiment shown in FIG. 1, the
thermostat 10 controls the operation of the entire HVAC system 50,
including the blower 18.
[0023] In accordance with the present invention, upon a
dehumidification demand without a request for cooling, the
thermostat 10 will send a signal to the dehumidifier 14 and the
blower 18 to begin operation when the relative humidity within the
home exceeds the humidity set point. During operation of the
dehumidifier 14 and the blower 18, the thermostat 10 will monitor
the temperature within the home through the use of the temperature
sensor 26. If the temperature within the home begins to fall during
the operation of the dehumidifier 14 and the blower 18, the call
for dehumidification will be terminated to prevent overcooling of
the home. Since the thermostat 10 may be connected to an HVAC
system that does not include a dehumidifier 14 that can operate
without cooling the air, the thermostat 10 must monitor the
temperature within the home during operation of the dehumidifier to
prevent overcooling.
[0024] If the thermostat 10 determines that the dehumidifier 14
cannot be operated without cooling the air, the thermostat 10 will
"remember" that the dehumidifier 14 is not capable of
dehumidification without cooling and will no longer operate the
dehumidifier 14 when the temperature within the home is below the
cooling set point. However, if the thermostat 10 determines that
the operation of the dehumidifier 14 and the blower 18 does not
result in cooling within the home, the thermostat 10 will continue
to operate the dehumidifier 14 until the relative humidity within
the home falls below the humidity set point. In this manner, the
thermostat 10 is able to "learn" the type of equipment contained
within the HVAC system 12 and operate the dehumidifier 14
accordingly.
[0025] In a most preferred embodiment of the invention, the HVAC
systems 12, 50 include a temperature probe 29 positioned within the
outlet duct 22 leaving the HVAC system 12 or within an outlet vent.
The temperature probe 29 is directly connected to the thermostat 10
and provides a direct measurement of the temperature of the air
leaving the HVAC system 12. The thermostat 10 can observe the
temperature at the outlet duct 22 to immediately determine if the
dehumidifier 14 is cooling the air along with the dehumidification
process. If the thermostat 10 determines that the air is being
cooled and dehumidified, the thermostat 10 will "remember" that the
dehumidifier 14 is not capable of dehumidification without cooling
and will only operate the dehumidifier 14 when cooling is also
required. However, if the temperature probe 29 indicates that the
air is not being cooled, the thermostat 10 will continue to operate
the dehumidifier 14 when the relative humidity exceeds the humidity
set point. In this manner, the thermostat 10 can "learn" the type
of HVAC system 12 it is connected to and operate the dehumidifier
14 accordingly.
[0026] Referring now to FIG. 3, thereshown is a state diagram
showing the specific transitions that apply to the
dehumidification-controlling algorithm implemented in a thermostat
with internal, or external, realization of relative humidity levels
and desired limits. As indicated in FIG. 3, when the thermostat 10
is in the NO MODE ON state 30, the thermostat will transition to
the DEHUMIDIFY MODE ON state 32 upon a dehumidification demand, as
shown in box 34. Upon receiving a demand for dehumidification, the
control algorithm will set the start temperature equal to the
current temperature within the home, as also indicated in box 34.
Alternatively, in an HVAC system that includes a temperature probe
positioned within the outlet duct, the start temperature can be set
equal to the current temperature received from the temperature
probe.
[0027] As the dehumidification continues in state 32, the control
algorithm determines whether the start temperature minus the
current temperature is greater than a preselected temperature
limit. If the difference between the current temperature and the
start temperature exceeds the temperature limit, indicating that
the dehumidifier cools the air while removing the humidity, or if
there is no longer a demand for dehumidification, as shown in box
36, the control algorithm returns to the NO MODE ON state 30. As an
example, if the temperature limit is set at 4.degree., the
algorithm will turn off the dehumidifier once the difference
between the start temperature and the current temperature exceed
the 4.degree. temperature limit, thereby indicating that the
dehumidifier 14 is cooling the air returned to the home.
[0028] When the control algorithm is in the dehumidification mode
32, the algorithm will move to the COOL MODE ON 38 upon a call for
cooling, as indicated by box 40. The algorithm will return back to
the DEHUMIDIFY MODE ON 32 when the call for cooling has been
satisfied but the dehumidification demand remains, as indicated by
box 42. Alternatively, if the cooling and dehumidification demands
are both satisfied, the algorithm will return to the NO MODE ON
state 30, as indicated by box 44.
[0029] In an HVAC system including the temperature probe 29, the
thermostat will set the start temperature to equal the temperature
of the air flowing over the temperature probe 29 when the HVAC is
first activated. The control algorithm will monitor for a change in
the temperature at the temperature probe 29 and will turn off the
dehumidifier if the temperature changes more than a selected
limit.
[0030] FIG. 4 illustrates a flowchart setting forth the operational
sequence performed by the humidity control algorithm that is
present within the thermostat or HVAC controller 10. FIG. 4 simply
illustrates the humidity control algorithm and does not describe
the entire operation of the thermostat 12 for controlling the
operation of the HVAC system.
[0031] As illustrated in FIG. 4, the humidity control algorithm
initially determines at step 54 whether the humidity sensed by the
humidity sensor 28 is greater than a humidity set point. In such a
case, the indoor air environment being controlled by the HVAC
system has a humidity level higher than the humidity set point
entered by the user.
[0032] If the sensed humidity is greater than the humidity set
point, the humidity control algorithm sets the start temperature
equal to the current temperature, as indicated in step 56. As
described previously, the start temperature can be either the
temperature received from the temperature sensor 26 or from the
temperature probe 29 positioned within the outlet duct leading from
the HVAC system. In either case, the thermostat sets the start
temperature to be equal to the current temperature prior to
activation of the HVAC system.
[0033] Once the start temperature has been set equal to the current
temperature, the thermostat activates the HVAC system, as shown in
step 58. As described previously, the activation of the HVAC system
may include only the activation of the dehumidifier 14 and the
blower 18. Alternatively, in the embodiment shown in FIG. 2, the
activation of the HVAC system to remove humidity from the indoor
air environment may also result in the activation of the heater 52.
In accordance with the humidity control algorithm presented by the
present invention, the thermostat initially activates the HVAC
system without the thermostat knowing the type of HVAC system to
which it is connected.
[0034] After the HVAC system has been activated to remove humidity
from the indoor air environment, the thermostat monitors the
current temperature in step 60. In one embodiment described
previously, the current temperature is measured by the temperature
sensor 26 while in another embodiment, the current temperature is
measured by the temperature probe 29. In either embodiment, the
current temperature is continuously monitored after activation of
the HVAC system 58.
[0035] As indicated in step 62, the humidity control algorithm
subtracts the current temperature from the start temperature and
determines whether the difference between the start temperature and
the current temperature is greater than a temperature limit. As an
example, if the HVAC system is not capable of removing humidity
from the indoor air environment without cooling, the current
temperature will begin to drop after activation of the HVAC system,
thus increasing the difference between the current temperature and
the start temperature. Preferably, the temperature limit will be
selected as a value that allows for a small variation between the
current temperature and the start temperature, such as for an
illustrative example only, 3.degree..
[0036] If the current temperature remains close enough to the start
temperature such that the difference does not exceed the
temperature limit, the humidity control algorithm then determines
if the sensed humidity is less than the humidity set point in step
64. If the sensed humidity is not yet below the humidity set point,
the algorithm returns to step 58 and continues to activate the HVAC
system to remove humidity.
[0037] However, if the sensed humidity is now below the humidity
set point, the HVAC system is deactivated in step 66 and the system
returns to the starting point for the algorithm.
[0038] Returning now to step 62, if the humidity control algorithm
determines that the temperature difference between the current
temperature and the start temperature is greater than the
temperature limit, the humidity control algorithm deactivates the
HVAC system in step 68. If the HVAC system is incapable of removing
humidity without cooling, the difference between the starting
temperature and the current temperature will most likely be due to
this inability of the HVAC system. However, it is possible that the
difference between the start temperature and the current
temperature may be due to other changes within the indoor air
environment and not based solely upon the inability of the HVAC
system to dehumidify without cooling. Thus, in step 70, the
humidity control algorithm determines whether the cooling of the
indoor air environment upon activation of the dehumidifier is
habitual. It is contemplated that the determination of whether the
cooling is habitual in step 70 can be carried out using many
different techniques. These techniques may count the number of
times the start temperature and current temperature vary greater
than the temperature limit as compared to the number of times the
dehumidification function has been carried out by the humidity
control algorithm.
[0039] If the humidity control algorithm determines that the HVAC
system is incapable of providing dehumidification without cooling,
the algorithm is deactivated in step 72. This prevents the
thermostat from activating the HVAC system to provide only
dehumidification when the HVAC system is incapable of operating in
such a manner.
[0040] If in step 70 the humidity control algorithm determines that
the cooling after activation of the HVAC system is not habitual,
the algorithm creates a delay in step 74 and then returns to the
start, as indicated in step 76. The reason for the delay and the
return to the start is so that the temperature within the indoor
air environment can return to a steady state prior to the humidity
control algorithm operating in step 54.
[0041] As can be understood by the above description, a thermostat
or HVAC controller that operates utilizing the humidity control
algorithm described includes internal operating methods that allow
the thermostat to identify whether the HVAC system that it is
controlling includes the ability to dehumidify air without
providing additional cooling. Thus, a thermostat operating under
the humidity control algorithm is capable of being installed in a
system and determining whether the system can be operated to simply
remove humidity, since the system is capable of learning as it
operates.
* * * * *