US20140352340A1

US20140352340A1 - Heat pump system having an enhanced comfort mode

Info

Publication number: US20140352340A1
Application number: US13/908,910
Authority: US
Inventors: Eric Berg; Rakesh Goel; Jon Douglas
Original assignee: Lennox Industries Inc
Current assignee: Lennox Industries Inc
Priority date: 2013-06-03
Filing date: 2013-06-03
Publication date: 2014-12-04
Also published as: CA2845433A1

Abstract

One aspect presents an enhanced comfort controller that 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 an enhanced airflow rate of the ID system in response to an outdoor ambient temperature data.

Description

TECHNICAL FIELD

This application is directed to heat ventilation air conditioning (HVAC) heat pump systems.

BACKGROUND

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.

SUMMARY

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.
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 an enhanced airflow rate of the ID system in response to an outdoor ambient temperature data.
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

Reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a block diagram of an example HP system in which the enhanced controller of the disclosure may be implemented;

FIG. 2 shows a schematic of a layout diagram of an embodiment of the enhanced controller circuit board;

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;

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;

FIG. 5 presents a flow diagram of an example operation of a HP unit having the enhanced comfort controller associated therewith.

DETAILED DESCRIPTION

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.
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 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.
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.
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.
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, 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.
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.
The HP system 100 further includes a thermostat 160, which, in certain embodiments may be the primary controller of 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 Ser. 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.
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 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.
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 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.
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:
Enhanced Comfort Airflow Rate=A+{B*((ODT+C)/(70+D))̂N}×Comfort Airflow Rate,
wherein:
ODT is the outdoor ambient temperature in degrees Fahrenheit,
Comfort Airflow Rate=Airflow Rate at 100% demand*(% heating demand/100),
and
where A, B, C, D, and N are real numbers adjusted to match the high pressure limit of a given system. The values of 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.
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.
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 determine the above-referenced Comfort Airflow Rate in real-time as follows:
Comfort Airflow Rate=Airflow Rate at 100% demand*(% heating demand/100).
In another embodiment, 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.
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 indoor airflow, which would feel more comfortable to a user, without exceeding the high pressure limit.
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.
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 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.
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.

Claims

What is claimed is:

1. A heat pump system, comprising:

an indoor blower/heat exchanger system (ID) system;

an outdoor fan/heat exchanger and compressor (OD) system;

said ID system and said OD system being fluidly coupled together by refrigerant tubing;

an outdoor temperature data source coupled to said heat pump system and configured to provide outdoor ambient temperature data to said heat pump system;

an enhanced comfort controller coupled to said outdoor temperature data source, and being configured to cause said ID system to deliver an enhanced airflow rate in response to said outdoor ambient temperature data.

2. The system of claim 1, wherein said enhanced comfort controller is coupled to a primary controller coupled to said ID system, said primary controller configured to control an operation of said heat pump system according to a temperature set-point.

3. The system of claim 2, wherein said primary controller is a thermostat and said thermostat includes said enhanced comfort controller.

4. The system of claim 1, wherein said indoor blower includes a variable speed motor.

5. The system of claim 1, wherein said enhanced comfort controller determines said enhanced airflow rate as follows:

Enhanced Comfort Airflow Rate=A+{B*((ODT+C)/(70+D))̂N}×Comfort Airflow Rate,

wherein:

ODT is the outdoor ambient temperature in degrees Fahrenheit,

Comfort Airflow Rate=Airflow Rate at 100% demand*(% heating demand/100),

and where

A, B, C, D, and N are real numbers that correspond to a predetermined high pressure limit of a given system.

6. The system of claim 5, wherein said enhanced comfort controller is further configured to determine said Comfort Airflow Rate.

7. The system of claim 1, further including an outdoor controller, wherein said outdoor controller is coupled to said enhanced comfort controller.

8. The system of claim 1, further including an indoor controller, wherein said indoor controller is coupled to said enhanced comfort controller.

9. The system of claim 1, wherein said outdoor temperature data source is an outdoor temperature sensor coupled to said OD system.

10. The system of claim 1, wherein said outdoor temperature data source is an internet based source wirelessly connected to said enhanced comfort controller.

11. An enhanced comfort controller, comprising:

a control board;

a microprocessor located on and electrically coupled to said control board; and

a memory coupled to said microprocessor and located on and electrically coupled to said control board and having an enhanced comfort program stored thereon, said enhanced comfort program configured to cause an indoor blower/heat exchange (ID) system of a heat pump to output an enhanced airflow rate of said ID system in response to an outdoor ambient temperature data.

12. The controller of claim 11, wherein said enhanced comfort controller is coupleable to a primary controller of a heat pump system, said primary controller configured to control an operation of said heat pump system according to a temperature set-point.

13. The system of claim 12, wherein said primary controller is a thermostat and said thermostat includes said enhanced comfort controller.

14. The system of claim 11, wherein said enhanced comfort controller is configured to send commands to a variable speed motor of said ID system.

15. The controller of claim 11, wherein said program determines said enhanced CFM demand as follows:

wherein:

ODT is the outdoor ambient temperature in degrees Fahrenheit,

Comfort Airflow Rate=Airflow Rate at 100% demand*(% heating demand/100),

and where

16. The controller of claim 15, wherein said enhanced comfort controller is further configured to determine said Comfort Airflow Rate.

17. The controller of claim 11, wherein said microprocessor includes said memory.

18. The controller of claim 11 being configured to communicate with one or more of a compressor controller, an indoor system controller, or a primary indoor controller of a heat pump system.

19. The controller of claim 11, further including communication circuitry capable of communicating with an outdoor temperature sensor.

20. The controller of claim 19, wherein said communication circuitry is configured to wirelessly communicate with an internet based outdoor temperature data source.

21. 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 indoor airflow rate of a heat pump system, said method comprising:

causing an indoor blower/heat exchange (ID) system of a heat pump to output an enhanced airflow rate of said ID system in response to an outdoor ambient temperature data.