Note: Descriptions are shown in the official language in which they were submitted.
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A HEAT PUMP SYSTEM
HAVING AN ENHANCED COMFORT MODE
TECHNICAL FIELD
[0001] This
application is directed to heat ventilation air
conditioning (HVAC) heat pump systems.
BACKGROUND
[0002] Heat
pump (HP) systems have gained wide commercial use
since their first introduction into the HVAC market because of
their operational efficiency and energy savings, and it is this
efficiency and energy savings that appeals to consumers and is
most often the deciding fact that causes them to choose HPs over
conventional HVAC furnace systems.
During the winter, a HP
system transfers heat from the outdoor air heat exchanger to an
indoor heat exchanger where the heat is used to heat the
interior of the residence or building. The
consumer uses a
thermostat to select a temperature set-point for the interior.
The HP then operates, using heat transferred from the outside,
to warm the indoor air to achieve the set-point. As a result,
the consumer enjoys a heating capability, while saving energy.
Though auxiliary heating systems, such as electric or gas
furnaces can be used in conjunction with the HP, this is
typically done only for a brief period of time in order to
achieve the set-point in extremely cold conditions.
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SUMMARY
[0003] One
embodiment of the present disclosure is a HP
system that comprises an indoor blower/heat exchanger system
(ID) system coupled to an indoor controller, an outdoor fan/heat
exchanger and compressor (OD) system coupled to an outdoor
controller, where the ID system and the OD system are fluidly
coupled together by refrigerant tubing. In this embodiment, the
HP unit further comprises an outdoor temperature data source
coupled to the HP system, and it is configured to provide
outdoor ambient temperature data to the HP system, and an
enhanced comfort controller coupled to the outdoor temperature
data source. The
enhanced comfort controller is configured to
cause the ID system to deliver an enhanced airflow rate in
response to the outdoor ambient temperature data.
[0004]
Another embodiment of the present disclosure is an
enhanced comfort controller. This
embodiment comprises a
control board, a microprocessor located on and electrically
coupled to the control board, and a memory coupled to the
microprocessor and located on and electrically coupled to the
control board. The enhanced comfort controller has an enhanced
comfort program stored thereon that is configured to cause an
indoor blower/heat exchange (ID) system of a heat pump to output
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an enhanced airflow rate of the ID system in response to an
outdoor ambient temperature data.
[0005] Another embodiment presents a computer program
product, comprising a non-transitory computer usable medium
having a computer readable program code embodied therein, said
computer readable program code adapted to be executed to
implement a method of measuring and managing an indoor airflow
rate of a heat pump system. The method comprises causing an
indoor blower/heat exchange (ID) system of a heat pump to output
an enhanced airflow rate of the ID system in response to an
outdoor ambient temperature data.
BRIEF DESCRIPTION
[0006]
Reference is now made to the following descriptions
taken in conjunction with the accompanying drawings, in which:
[0007] FIG.
1 illustrates a block diagram of an example HP
system in which the enhanced controller of the disclosure may be
implemented;
[0008] FIG.
2 shows a schematic of a layout diagram of an
embodiment of the enhanced controller circuit board;
[0009] FIG.
3 is a graph showing the relationship between
enhanced airflow rate and outdoor ambient temperature, generated
by changing constants of an equation implemented on the enhanced
comfort controller, as discussed herein;
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[0010] FIG.
4 is a graph showing the relationship between
discharge pressure and indoor airflow rate at various outdoor
ambient temperatures, where at low airflow rates, discharge
pressure exceeds system high pressure limit;
[0011] FIG.
5 presents a flow diagram of an example operation
of a HP unit having the enhanced comfort controller associated
therewith.
DETAILED DESCRIPTION
[0012] As
noted above, HP units have gained wide use and are
popular with consumers because they can reduce energy costs by
using the heat in outdoor air to heat the space of an indoor
structure, such as a residence or business.
Though these HP
units are typically very efficient in operation and energy
savings, there is a drawback. The drawback is that, in heating
mode, the airflow from the blower of the indoor unit may feel
cooler to the user than an airflow from a HVAC furnace system
that uses a gas or electric furnace to heat the air. The cooler
register air from the HP system can make the user feel
uncomfortably cool during the heating cycle.
[0013] In
such instances, the user can activate an enhanced
comfort function by activating an enhanced comfort controller of
the HP unit, as described herein, during the cycle time that the
heat pump system is attempting to reach the indoor temperature
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set-point of a thermostat that controls the HP unit. The
embodiments of the enhanced comfort controller of the present
disclosure provides a controller that can be coupled to an
outdoor temperature data source and is configured to cause an
indoor system of a HP system to deliver an enhanced airflow rate
based on the outdoor temperature data source. As
used herein
and in the claims, an enhanced airflow rate is one that causes a
temperature change in the air leaving the register in response
to the outdoor ambient temperature data. For
example, the
enhanced comfort controller may respond by causing an airflow
rate of the indoor blower to decrease, based on an outdoor
ambient temperature, which causes the temperature of the air
leaving the register to increase, thereby feeling warmer to the
user. Thus, in this embodiment, the user's comfort is enhanced
or improved by an increase in the airflow temperature when the
enhanced comfort controller is activated.
[0014] The
operation of the enhanced comfort controller, as
provided by the embodiments herein, is counter intuitive to a
conventional HP system in that its activation causes the HP's
efficiency to decrease and use more energy. Thus,
the user is
able to temporarily choose to trade energy savings and
operational efficiency for feeling more comfortable due to the
warmer airflow.
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[0015] One
embodiment of the enhanced comfort controller as
implemented in a HP system 100 is illustrated in FIG. 1. FIG. 1
illustrates a block diagram of an example of the HP system 100
in which an enhanced comfort controller 105, as provided by
embodiments described herein, may be used. Various embodiments
of the enhanced comfort controller 105 are discussed below. The
HP system 100 comprises an outdoor (OD) system 110 that includes
a heat exchanger 115, equipped with an outdoor fan 120, which in
certain embodiments may be a conventional variable speed fan, a
compressor 125, and an optional outdoor controller 130, coupled
to the OD system 110. When present, the outdoor controller 130
may be coupled to the OD system 110 either wirelessly or by
wire. For example, the outdoor controller 130 may be coupled to
either the compressor 125 or the fan 120, or both. In
the
illustrated embodiment, the outdoor controller 130 is attached
directly to the compressor 125 and is coupled to the compressor
125 by wire. If the outdoor controller is not present, it may be
controlled by an indoor thermostat.
[0016] The
HP system 100 further includes an indoor (ID)
system 135 that comprises an indoor heat exchanger 140, equipped
with an indoor blower 145, which in certain embodiments, may be
a conventional, variable speed blower, and an indoor system
controller 150. The indoor system controller 150 may be coupled
to the ID system 135 either wirelessly or by wire. For example,
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the indoor system controller 150 may be located on a housing
(not shown) in which the blower 145 is contained and hard wired
to the blower 145. Alternatively, the indoor system controller
150 may be remotely located from the blower 145 and be
wirelessly connected to the blower 145. The
indoor system
controller 150 may also be optional to the system, and when it
is not present, the indoor system 135 may be controlled by an
indoor thermostat.
[0017] The HP system 100 further includes an outdoor
temperature data source 155 that is coupled to the enhanced
comfort controller 105. In
one embodiment, the outdoor
temperature data source 155 may be a temperature sensor located
adjacent or within the OD system 110 and coupled to enhanced
comfort controller 105 either wirelessly or by wire. For
example, the temperature sensor may be located on the same board
as the outdoor controller 130. In an
alternative embodiment,
the temperature data source 155 may be an internet data source
that is designed to provide outdoor temperatures. In
such
instances, the enhanced comfort controller 105 would include a
communication circuit that would allow it to connect to the
internet through either an Ethernet cable or wirelessly through,
for example a Wi-Fi network.
[0018] The
HP system 100 further includes a thermostat 160,
which, in certain embodiments may be the primary controller of
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the HP system 100. The
thermostat 160 is preferably an
intelligent thermostat that includes a microprocessor and memory
with wireless communication capability and is of the type
described in U.S. Patent Publication, No. 2010/0106925,
Application, Serial No. 12/603,512, which is incorporated herein
by reference. The
thermostat 160 is coupled to the outdoor
controller 130 and the indoor controller 150 to form, in one
embodiment, a fully communicating HP system, such that all of
the controllers or sensors 105, 130, 150, 155, and 160 of the HP
system 100 are able to communicate with each other, either by
being connected by wire or wirelessly. In
one embodiment, the
thermostat 160 includes the enhanced comfort controller 105 and
further includes a program menu that allows a user to activate
an enhanced comfort mode program by selecting the appropriate
button or screen image displayed on the thermostat 160. In
other embodiments, the enhanced comfort controller 105 may be on
the same board as the outdoor controller 130 or the indoor
controller 150. Thus,
the enhanced comfort controller 105 may
be located in various locations.
[0019] In
general, the compressor 125 is configured to
compress a refrigerant, to transfer the refrigerant to a
discharge line 165, and, to receive the refrigerant from a
suction line 170. The
discharge line 165 fluidly connects the
compressor 125 to the outdoor heat exchanger 115, and the
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suction line 170 fluidly connects the indoor heat exchanger 140
to the compressor 125 through a reversing valve 175. The
reversing valve 175 has an input port 180 coupled to the
discharge line 165, an output port 182 coupled to the suction
line 170, a first reversing port 184 coupled to a transfer line
186 connected to the outdoor heat exchanger 115, and a second
reversing port 190 coupled to a second transfer line 192
connected the indoor heat exchanger 140. As understood by those
skilled in the art, the transfer lines 186, 192 allow for the
reversal of the flow direction of the refrigerant by actuating
the revering valve 175 to put the HP system 100 in a cooling
mode or a heating mode. One
skilled in the art would also
appreciate that the HP system 100 could further include
additional components, such as a connection line 194,
distributors 196 and delivery tubes 198 or other components as
needed to facilitate the functioning of the system.
[0020] FIG.
2 illustrates a schematic view of one embodiment
of the enhanced comfort controller 105. In
this particular
embodiment, the enhanced comfort controller 105 includes a
circuit wiring board 200 on which is located a microprocessor
205 that is electrically coupled to memory 210 and communication
circuitry 215. The memory 210 may be a separate memory block on
the circuit wiring board 200, as illustrated, or it may be
contained within the microprocessor 205. The
communication
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circuitry 215 is configured to allow the enhanced comfort
controller 105 to electronically communicate with other
components of the HP system 100, either by a wireless connection
or by a wired connection. The
enhanced comfort controller 105
may be a standalone component or it may be included within one
of the other controllers previously discussed above. In
one
particular embodiment, the enhanced comfort controller 105 will
be included within the thermostat 160. In
those embodiments
where the enhanced comfort controller 105 is a standalone unit,
it will have the appropriate housing and user interface
components associated with it.
[0021] The
enhanced comfort controller 105 is configured or
programmed with an enhanced comfort algorithm that changes the
indoor airflow rate of a HP system based on an outdoor ambient
temperature. In one embodiment, the enhanced comfort controller
algorithm determines the enhanced airflow rate as follows:
[0022]
Enhanced Comfort Airflow Rate = A +02, * ((CDT + 0)/(70
+ D))^111 x Comfort Airflow Rate, wherein:
[0023] CDT
is the outdoor ambient temperature in degrees
Fahrenheit,
[0024]
Comfort Airflow Rate = Airflow Rate at 100% demand *
(% heating demand/100), and
[0025] where
A, B, C, D, and N are real numbers adjusted to
match the high pressure limit of a given system. The values of
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the variables A, B, C, and D may vary, depending on the tonnage
of the particular HP system in which the enhanced comfort
controller will operate. For
example, there are different
tonnage capacities (e.g., 2 ton, 3 ton, 4 ton, 5 ton) of HP
units.
Potentially, for each matchup of outdoor and indoor
unit, tests are conducted for various OD ambient temperatures,
e.g., 17 F to 70 F, to determine at what enhanced comfort flow
rate, in cubit feet/minute (CFM), the high pressure limit for
the HP unit being tested will be reached.
[0026] The
high pressure limit is the limit beyond which the
unit should not be operated. Thus, in many instances, HP units
will have high pressure switches that will shut down the HP unit
once that predetermined high pressure is reached. The
high
pressure limit can vary from one type of HP unit to the other.
For example, the high pressure limit of a particular HP 4 ton
unit may be 590 psig. Using known software, a curve fit is then
developed for an enhanced comfort airflow Rate versus OD Temp
for that HP unit by changing the values of the constants A, B,C,
D, and N. This
provides a unique curve for each possible
combination.
[0027] An
example of one curve fit for a 4 ton HP unit is
shown in FIG. 3. In
another embodiment, the algorithm of the
enhanced comfort controller 105 is further configured to
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determine the above-referenced Comfort Airflow Rate in real-time
as follows:
[0028]
Comfort Airflow Rate = Airflow Rate at 100% demand *
(% heating demand/100).
[0029] In
another embodimentõ the controller 105 may be
embodied as a series of operation instructions that direct the
operation of the microprocessor 205 when initiated thereby. In
one embodiment, the controller 105 is implemented in at least a
portion of a memory 210 of the controller 105, such as a non-
transitory computer readable medium of the controller 105. In
such embodiments, the medium is a computer readable program code
that is adapted to be executed to implement a method of
measuring and managing an indoor airflow rate of the HP system
100. The
method comprises causing the indoor blower/heat
exchange (ID) system 135 of the HP system 100 to output an
enhanced airflow rate of the ID system 135 in response to an
outdoor ambient temperature data.
[0030] FIG.
4 is a graph that relates the indoor airflow rate
with the discharge high pressure and outdoor ambient
temperature. As seen in FIG. 4, as airflow rate decreases, the
discharge pressure increases. Thus,
in one embodiment, the
enhanced comfort controller 105, when activated will decrease
the airflow rate in order to increase the temperature of the
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indoor airflow, which would feel more comfortable to a user,
without exceeding the high pressure limit.
[0031] Fig.
4 also shows discharge pressure being lower at
low outdoor ambient temperatures, when compared with relative
medium to high outdoor ambient temperatures that occur during
times at which the HP unit would function in the heating mode.
Also, as the outdoor ambient temperature decreases, the
temperature of indoor airflow decreases. Thus,
the indoor
airflow rate can be further lowered at lower outdoor ambient
temperatures without exceeding the high pressure limit. Because
the enhanced mode causes a lower CFM rate at lower temperatures,
the temperature of the indoor airflow will increase, thereby
causing the user to feel warmer or more comfortable. The
enhanced comfort controller provides advantages over the
conventional controllers because conventional controllers run
from a fix data table programmed into the conventional
controller. Thus,
as the outdoor temperature drops, the unit
cannot adjust, but can only run in the pre-programmed fixed
mode, which results in higher indoor CFM, and which results in
cooler indoor airflow temperatures.
[0032] FIG.
5, illustrates a flow chart of the operation of a
HP implementing one embodiment of an enhanced comfort controller
as provided herein. At
start, controller will queries the HP
unit to determine if the HP is on and attempting to achieve the
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temperature set-point in the heating mode. If
the unit is on
the unit checks to see if the enhanced comfort function is
engaged. If
yes, using the enhanced comfort heating airflow
rate algorithm, the controller calculates and changes the indoor
airflow rate to an enhanced comfort heating airflow rate based
on the outdoor temperature, pursuant to the above-discussed
equation. The %heating demand may be supplied by a fixed table
programmed into another controller, such as the thermostat,
associated with the unit or into the enhanced comfort controller
itself, or it may be calculated in real-time by the enhanced
comfort controller, as discussed above. If
the enhanced
controller is not on, then the HP unit runs until temperature
set-point is achieved. Once engaged, the enhanced comfort mode
will continue running until either the user disengages the
enhanced comfort mode or the HP unit achieves the temperature
set-point as required by the thermostat setting.
[0033] Those
skilled in the art to which this application
relates will appreciate that other and further additions,
deletions, substitutions and modifications may be made to the
described embodiments.
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