US20140216078A1

US20140216078A1 - Reduced energy heat pump defrost for unoccupied space

Info

Publication number: US20140216078A1
Application number: US14/093,668
Authority: US
Inventors: Mark J. Ladd
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 2013-02-04
Filing date: 2013-12-02
Publication date: 2014-08-07

Abstract

Embodiments are directed to determining, by a controller comprising a processor, that a coil associated with a heat pump is subjected to a defrost cycle, determining, by the controller, that at least one of: a conditioned space is occupied, and a thermostat associated with the conditioned space indicates that an energy saving mode is not in use, and enabling, by the controller, an auxiliary heat source based on the determination that the coil is subject to the defrost cycle and the determination that the conditioned space is occupied or the thermostat indicates that the energy saving mode is not in use.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional patent application Ser. No. 61/760,398, filed Feb. 4, 2013, the entire contents of which are incorporated herein by reference.

BACKGROUND

A heat pump may be used to generate heat for an indoor space even when it is relatively cold outside. Typical air source heat pump outdoor coils will build up frost when operating at some ambient conditions, such as when it is cold outside. The frost may reduce or degrade the performance of the heat pump. To overcome the performance degradation, the heat pump may be configured to reverse refrigerant direction and transfer heat from the indoor space to the outdoor coil during a defrost cycle. Operation of the heat pump during the defrost cycle may cause the heat pump to effectively operate as an air conditioner, such that the indoor space or environment is cooled.
It is typical for heat pump controls to call for or engage auxiliary heat to counteract the cooling effect of the heat pump during the defrost cycle in order to maintain comfort for occupants in the indoor space in contact with the conditioned air. Electric resistance heaters, which often serve as the source of the auxiliary heat, are less desirable than the heat pump as a source of heat for a variety of reasons, such as operating cost. By using electric resistance heaters instead of the heat pump the overall cost to operate a climate control system is increased.

BRIEF SUMMARY

An embodiment of the disclosure is directed to a method comprising: determining, by a controller comprising a processor, that a coil associated with a heat pump is subjected to a defrost cycle, determining, by the controller, that at least one of: a conditioned space is occupied, and a thermostat associated with the conditioned space indicates that an energy saving mode is not in use, and enabling, by the controller, an auxiliary heat source based on the determination that the coil is subject to the defrost cycle and the determination that the conditioned space is occupied or the thermostat indicates that the energy saving mode is not in use.
An embodiment is directed to an apparatus comprising: at least one processor, and memory having instructions stored thereon that, when executed by the at least one processor, cause the apparatus to: determine that a coil associated with a heat pump is subjected to a defrost cycle, determine that at least one of: a conditioned space is occupied based on a detected motion, and an energy saving mode is not in use in association with the conditioned space, and enable an auxiliary heat source based on the determination that the coil is subject to the defrost cycle and the determination that the conditioned space is occupied or that the energy saving mode is not in use.
An embodiment is directed to a system comprising: a sensor configured to provide an indication of whether a motion in an amount greater than a first threshold is detected within a second threshold amount of time, and a processor configured to: determine whether a coil associated with a heat pump is subjected to a defrost cycle, determine whether a conditioned space is occupied based on the indication provided by the sensor, and enable an auxiliary heat source that is located within the conditioned space when the coil is subject to the defrost cycle and when the conditioned space is occupied.
Additional embodiments are described below.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements.

FIG. 1 is a schematic block diagram illustrating an exemplary computing system in accordance with one or more embodiments of this disclosure;

FIG. 2 illustrates a block diagram of an exemplary environment including a heat pump in accordance with one or more embodiments of this disclosure;

FIG. 3 is a flow chart of an exemplary method in accordance with one or more embodiments of this disclosure;

FIG. 4 is a wiring diagram in accordance with the prior art; and

FIG. 5 is an exemplary wiring diagram in accordance with one or more embodiments of this disclosure;

DETAILED DESCRIPTION

It is noted that various connections are set forth between elements in the following description and in the drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections in general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. In this respect, a coupling between entities may refer to either a direct or an indirect connection.
Exemplary embodiments of apparatuses, systems, and methods are described for defrosting an outdoor coil associated with a heat pump. In some embodiments, a determination may be made whether an indoor space is unoccupied. If the indoor space is unoccupied, then auxiliary heat might not be used. If the indoor space is occupied, then auxiliary heat may be used.
Referring to FIG. 1, an exemplary computing system 100 is shown. The system 100 is shown as including a memory 102. The memory 102 may store executable instructions. The executable instructions may be stored or organized in any manner and at any level of abstraction, such as in connection with one or more processes, routines, methods, etc. As an example, at least a portion of the instructions are shown in FIG. 1 as being associated with a first program 104 a and a second program 104 b.
The instructions stored in the memory 102 may be executed by one or more processors, such as a processor 106. The processor 106 may be coupled to one or more input/output (I/O) devices 108. In some embodiments, the I/O device(s) 108 may include one or more of a keyboard or keypad, a touchscreen or touch panel, a display device, a microphone, a speaker, a mouse, a button, a remote control, a joystick, a printer, a sensor, etc. The I/O device(s) 108 may be configured to provide an interface to allow a user to interact with the system 100.
The system 100 is illustrative. In some embodiments, one or more of the entities may be optional. In some embodiments, additional entities not shown may be included. For example, in some embodiments the system 100 may be associated with one or more networks. In some embodiments, the entities may be arranged or organized in a manner different from what is shown in FIG. 1.
One or more of the entities shown in FIG. 1 may be associated with one or more of the devices or entities described herein. For example, one or more of the entities shown in FIG. 1 may be associated with a heat pump or a controller as described below.
Turning to FIG. 2, a system environment 200 is shown in accordance with one or more embodiments. The environment 200 may include a structure or a wall 202 that may define or separate an outdoor space 204 and an indoor space 206. The wall 202 may be associated with a building (e.g., an office building, a residential building, etc.), a room, or the like.
In some embodiments, the environment 200 may be indicative of a single packaged system. A single packaged system may be located indoors or outdoors. Typically, air may be ducted to a single package system from another environment. Thus, wall 202 may represent a divider within equipment to separate a first air stream from a second air stream.
The environment 200 may include a heat pump 210. The heat pump may include a first coil 214 located in the outdoor space 204 and a second coil 216 located in the indoor space 206. The coils 214 and 216 may be communicatively or fluidly coupled to one another 218. For example, the coils 214 and 216 may be coupled to one another 218 via the use of refrigerant, which may be used to facilitate a heat-exchange relationship.
The heat pump 210 may operate in a number of modes. For example, when the heat pump 210 is operating in a first mode, the coil 214 may function as a condenser and the coil 216 may function as an evaporator. Operation in the first mode may be indicative of a cooling or air conditioning mode, such that the indoor space 206 may tend to be cooled. When the heat pump 210 is operating in a second mode, the coil 214 may function as an evaporator and the coil 216 may function as a condenser. Operation in the second mode may be indicative of a heating mode, such that the indoor space 206 may tend to be heated.
In some instances, the coil 214 may build up frost, which may degrade the performance of the heat pump 210. The heat pump 210 may be operated in connection with a “defrost cycle” in order to reduce or eliminate the amount of frost present on the coil 214. The defrost cycle may be indicative of the cooling or air conditioning mode described above.
Cooling the temperature in the indoor space 206 may be undesirable in some instances. For example, if people are occupying the indoor space 206 during, e.g., winter, then cooling the indoor space 206 may run counter to a goal of providing a comfortable indoor climate. To counteract or compensate for the cooling effect during a defrost cycle, the heat pump 210 may include, or be coupled to, an auxiliary heat source 230 that may supply heat to the indoor space 206. The auxiliary heat source 230 may include electric resistance heaters or strip heaters in some embodiments.
In some embodiments, the heat pump 210 and/or the auxiliary heat source 230 may include, or be coupled to, a controller 250. In some embodiments, the controller 250 may include a control board (not shown). The controller 250 may be configured to provide control signals or commands to the heat pump 210 and the auxiliary heat source 230. The controller 250 may be configured to receive status signals from the heat pump 210 and the auxiliary heat source 230. In some embodiments, the controller 250 may include a thermostat 252, which may be a programmable thermostat. In some embodiments, the thermostat 252 may be configured to communicate with one or more entities. For example, the thermostat 252 may be configured to communicate over one or more networks, such as a data or telephone network. A temperature set point may be received as an input by the thermostat 252 from a device, e.g., a mobile phone.
As described further below, the controller 250 may be configured to determine whether a defrost cycle of the heat pump 210/coil 214 should be initiated by turning on or engaging the auxiliary heat source 230. In some embodiments, such a determination may be based on input provided to the thermostat 252 or whether the indoor space 206 is occupied. Occupancy may be determined by one or more sensors 254. For example, occupancy may be detected by one or more sensor types, such a motion sensor.
In some embodiments, occupancy may be determined by use of a mobile device, such as a mobile phone. For example, a tracking (e.g., a GPS tracking) associated with the mobile device may be used to determine a location or position of the mobile device, and hence, a user associated with the mobile device. In some embodiments, occupancy may be determined when the mobile device connects to a network, such as a local network (e.g., Wi-Fi or Bluetooth).
The environment 200 is illustrative. In some embodiments, one or more of the entities may be optional. In some embodiments, additional entities not shown may be included. In some embodiments, the entities may be arranged or organized in a manner different from what is shown in FIG. 2.
Turning now to FIG. 3, a flow chart of a method 300 is shown. The method 300 may be operative in connection with one or more environments, systems, devices, or components, such as those described herein. The method 300 may be operative in connection with the system 100 of FIG. 1 and/or the environment 200 of FIG. 2. For example, the method 300 may be used to control the temperature of the indoor space 206 during a defrost cycle of the heat pump 210/coil 214.
In block 302, a defrost cycle may be initiated. The defrost cycle may be initiated based on a number of factors or conditions. For example, in some embodiments when a switch (e.g., a bimetallic switch) associated with an outdoor coil (e.g., the coil 214 of FIG. 2) detects a threshold temperature, a signal may be provided to a controller (e.g., controller 250 of FIG. 2) to indicate that the outdoor coil requests a defrost cycle. The controller may examine timing information or scheduling information to determine whether the requested defrost cycle should be granted, and in response to determining that the defrost cycle should be granted, may signal the heat pump (e.g., heat pump 210 of FIG. 2), the outdoor coil (e.g., coil 214 of FIG. 2), or a circuit associated therewith to engage in a defrost cycle. In some embodiments, one or more sensors on the outdoor coil and/or in the outdoor air may be used to initiate and control the defrost cycle. Other techniques may be used for initiating a defrost cycle.
In block 304, a determination may be made whether a thermostat (e.g., the thermostat 252 of FIG. 2) is configured for low energy, unoccupied space defrosts. If not (e.g., the ‘no’ path is taken out of block 304), then flow may proceed to block 306 to initiate or perform a defrost on an outdoor coil (e.g., coil 214 of FIG. 2) while turning on auxiliary heat (e.g., auxiliary heat source 230 of FIG. 2). Otherwise (e.g., the ‘yes’ path is taken out of block 304), flow may proceed to block 308.
In block 308, a determination may be made whether a heat pump control (e.g., controller 250 of FIG. 2) includes an occupancy detection sensor (e.g., sensor 254 of FIG. 2). If so (e.g., the ‘yes’ path is taken out of block 308), flow may proceed to block 310. Otherwise (e.g., the ‘no’ path is taken out of block 308), flow may proceed to block 312.
In block 310, a determination may be made whether an indoor space (e.g., indoor space 206 of FIG. 2) is considered unoccupied by sensor logic (e.g., sensor 254 of FIG. 2). For example, the indoor or conditioned space may be considered unoccupied if motion is not detected by the sensor logic above a threshold amount, optionally as a function of time. The conditioned space may be considered to be occupied when, e.g., a motion in an amount greater than a (first) threshold occurs or is detected within a (second) threshold amount of time. If the conditioned space is considered unoccupied by the sensor logic (e.g., the ‘yes’ path is taken out of block 310), flow may proceed to block 314 to initiate or perform a defrost on the outdoor coil (e.g., coil 214 of FIG. 2) without turning on auxiliary heat (e.g., auxiliary heat source 230 of FIG. 2). Otherwise, if the conditioned space is considered occupied by the sensor logic (e.g., the ‘no’ path is taken out of block 310), flow may proceed to the block 306 to initiate or perform a defrost on the outdoor coil (e.g., coil 214 of FIG. 2) while turning on the auxiliary heat (e.g., auxiliary heat source 230 of FIG. 2).
In block 312, a determination may be made whether a thermostat (e.g., thermostat 252 of FIG. 2) has received an input indicating that a heat pump (e.g., heat pump 210 of FIG. 2) and/or an auxiliary heat source (e.g., auxiliary heat source 230 of FIG. 2) should operate in an “energy saving mode.” The “energy saving mode” may be expressed using one or more terms, such as being “setback,” “away,” “on vacation,” “sleep,” etc. The thermostat may include one or more interfaces (e.g., one or more keys, buttons, switches, menus, slider bars, voice recognition devices, etc.) to facilitate user entry of “energy saving mode” inputs, selections, or parameters.
In some embodiments, the “energy saving mode” may be established or entered into as a function of time or a schedule. For example, at a time of day when people are not expected to be proximate to the heat pump or auxiliary heat source, the “energy saving mode” may be entered or enabled, and at a time of day when people are expected to be proximate to the heat pump or the auxiliary heat source the “energy saving mode” may be disabled. The schedule may be entered at a thermostat (e.g., thermostat 252 of FIG. 2).
It is understood that specification of the “energy saving mode”, which may indicate that auxiliary heat should be disabled or turned off, could be expressed as a counterpart “comfort mode” to indicate when auxiliary heat should be enabled or turned on. For example, when a “comfort mode” is turned on or enabled, auxiliary heat may be enabled/turned on during a defrost cycle, and otherwise the auxiliary heat may be disabled.
In some embodiments, specification of the “energy saving mode” may be based on a setting or a setting with multiple levels. For example, energy saving mode could be implemented as a slider bar between comfort and efficiency. When the slider bar is pushed all the way to “comfort”, auxiliary heat may run with every defrost. When the slider bar is pushed all the way to “efficiency”, auxiliary heat would never run with defrost. Slider bar settings in between would bring in more modes as you pushed the slider closer to efficiency. Alternately, controls may be established to allow a user to select the modes they wanted to disable the auxiliary heat with on an individual basis.
If the determination of block 312 indicates that the thermostat is in an energy saving mode (e.g., the ‘yes’ path is taken out of block 312), then flow may proceed to block 314 to initiate or perform a defrost on the outdoor coil (e.g., coil 214 of FIG. 2) without turning on auxiliary heat (e.g., auxiliary heat source 230 of FIG. 2). Otherwise, if the determination of block 312 indicates that the thermostat is not in an energy saving mode (e.g., the ‘no’ path is taken out of block 312), flow may proceed to block 306 to initiate or perform a defrost on the outdoor coil (e.g., coil 214 of FIG. 2) while turning on auxiliary heat (e.g., auxiliary heat source 230 of FIG. 2).
In some embodiments, one or more of the blocks or operations (or a portion thereof) of the method 300 may be optional. In some embodiments, the blocks may execute in an order or sequence different from what is shown in FIG. 3. In some embodiments, one or more additional blocks or operations not shown may be included. For example, if auxiliary heat is turned on or is utilized during a defrost cycle, once the defrost cycle is complete (or at some time thereafter), the auxiliary heat may be turned off.
Turning now to FIG. 4, a wiring diagram 400 in accordance with the prior art is shown. In FIG. 4, a heat pump 402, a fan coil 404, and a thermostat 406 are shown. Each of the signals denoted by the alphanumeric characters ‘R’, ‘C’, W2′, ‘Y’, ‘G’, and ‘O’ may be conveyed between the heat pump 402, the fan coil 404, and the thermostat 406 on a dedicated, separate, or individual wire. Signaling may be performed at a particular level or value. For example, 24-Volt signaling may be used. The heat stage 2 or ‘W2’ signal may be indicative of a request for auxiliary heat. For example, the heat pump 402 may signal the thermostat 406 (via the fan coil 404) that auxiliary heat should be enabled or turned on via the ‘W2’ signal.
Turning now to FIG. 5, a wiring diagram 500 in accordance with one or more embodiments is shown. In FIG. 5, a heat pump 502, a fan coil 504, and a thermostat 506 are shown. The ‘W2’, ‘W2_HP’, and ‘W2_FC’ signals in FIG. 5 may be associated with the control or enablement of auxiliary heat. The heat pump 502 may generate a request for auxiliary heat via the connection ‘W2’-‘W2_HP’ between the heat pump 502 and the thermostat 506. The thermostat 506 may include a relay or other switching device (not shown) that may conditionally pass or forward the request for auxiliary heat via the connection ‘W2_FC’-‘W2_HP’ between the thermostat 506 and the fan coil 504. The relay may be opened when the premises are unoccupied or when operating in an energy saving mode in order to block the request for auxiliary heat originating from the heat pump 502. The relay may otherwise be closed so as to enable the request for auxiliary heat to be forwarded. Thus, the wiring diagram 500 of FIG. 5 provides an ability to selectively forward or block a request for auxiliary heat by providing for a wiring change relative to the wiring diagram 400 of FIG. 4.
In some embodiments, a selective forwarding or blocking of a request for auxiliary heat may be performed in software. The use or modification of software may occur in embodiments where each signal is not allocated or present on a dedicated wire. For example, in some embodiments, signals (e.g., control signals or values) may be conveyed using serial or two-wire (e.g., clock and data) communications.
As described above, auxiliary heat may be turned on or enabled when an indoor space is considered to be occupied in order to maintain a comfortable temperature during a defrost cycle. The indoor space may be considered to be occupied based on a sensory function or parameter (e.g., detected motion), or based on input received at a thermostat or controller. When the indoor space is not considered to be occupied, the auxiliary heat may be turned off or disabled during the defrost cycle in order to conserve or save energy and reduce operating cost. Efficiency may be improved by avoiding the use of auxiliary heat when the auxiliary heat does not provide a comfort benefit because a conditioned space (e.g., an indoor space) is unoccupied.
Embodiments of this disclosure may be tied to one or more particular machines. For example, a controller may be configured to determine whether an auxiliary heat source should be turned on or enabled during a defrost cycle based on a determination of whether a conditioned space is occupied or based on a determination of whether an energy saving mode is entered. The controller may include a processor, a thermostat, and/or a sensor to provide for such a determination.
Illustrative examples described herein related aspects of this disclosure to a thermostat and sensors. The thermostat and sensors may be used in a variety of applications, such as refrigeration, ovens, heating, ventilation, and air-conditioning (HVAC) appliances (e.g., furnaces, boilers, heat pumps, air handlers, package units), and ranges. Aspects of the disclosure may be incorporated in controls (e.g., electronic controls) that run these types of units.
As described herein, in some embodiments various functions or acts may take place at a given location and/or in connection with the operation of one or more apparatuses, systems, or devices. For example, in some embodiments, a portion of a given function or act may be performed at a first device or location, and the remainder of the function or act may be performed at one or more additional devices or locations.
Embodiments may be implemented using one or more technologies. In some embodiments, an apparatus or system may include one or more processors, and memory storing instructions that, when executed by the one or more processors, cause the apparatus or system to perform one or more methodological acts as described herein. Various mechanical components known to those of skill in the art may be used in some embodiments.
Embodiments may be implemented as one or more apparatuses, systems, and/or methods. In some embodiments, instructions may be stored on one or more computer-readable media, such as a transitory and/or non-transitory computer-readable medium. The instructions, when executed, may cause an entity (e.g., an apparatus or system) to perform one or more methodological acts as described herein.
Aspects of the disclosure have been described in terms of illustrative embodiments thereof. Numerous other embodiments, modifications and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure. For example, one of ordinary skill in the art will appreciate that the steps described in conjunction with the illustrative figures may be performed in other than the recited order, and that one or more steps illustrated may be optional.

Claims

What is claimed is:

1. A method comprising:

determining, by a controller comprising a processor, that a coil associated with a heat pump is subjected to a defrost cycle;

determining, by the controller, that at least one of:

a conditioned space is occupied, and

a thermostat associated with the conditioned space indicates that an energy saving mode is not in use; and

enabling, by the controller, an auxiliary heat source based on the determination that the coil is subject to the defrost cycle and the determination that the conditioned space is occupied or the thermostat indicates that the energy saving mode is not in use.

2. The method of claim 1, wherein an indication that the energy saving mode is in use is expressed as being at least one of: setback, away, on vacation, and sleep.

3. The method of claim 1, wherein the indication that the energy saving mode is not in use is based on a schedule entered at the thermostat.

4. The method of claim 1, wherein the conditioned space is determined to be occupied when a motion in an amount greater than a first threshold is detected by a sensor within a second threshold amount of time.

5. The method of claim 1, wherein the coil is located outside of a building.

6. The method of claim 1, wherein the thermostat comprises a device configured to selectively pass a request for auxiliary heat based on the determination that the conditioned space is occupied or the thermostat indicates that the energy saving mode is not in use.

7. The method of claim 6, wherein the thermostat receives the request for auxiliary heat from the heat pump.

8. The method of claim 6, wherein the device comprises a relay or a switching device.

9. The method of claim 6, wherein the thermostat receives the request for auxiliary heat in accordance with serial communications.

10. The method of claim 1, further comprising:

disabling, by the controller, the auxiliary heat source following the completion of the defrost cycle.

11. An apparatus comprising:

at least one processor; and

memory having instructions stored thereon that, when executed by the at least one processor, cause the apparatus to:

determine that a coil associated with a heat pump is subjected to a defrost cycle,

determine that at least one of:

a conditioned space is occupied, and

an energy saving mode is not in use in association with the conditioned space, and

enable an auxiliary heat source based on the determination that the coil is subject to the defrost cycle and the determination that the conditioned space is occupied or that the energy saving mode is not in use.

12. The apparatus of claim 11, wherein a determination that the energy saving mode is not in use is based on at least one input received at a thermostat.

13. The apparatus of claim 11, wherein the conditioned space is determined to be occupied when a motion in an amount greater than a first threshold is detected by a sensor within a second threshold amount of time.

14. The apparatus of claim 11, wherein the auxiliary heat source is enabled using a control signal on a dedicated wire.

15. The apparatus of claim 14, wherein the instructions, when executed by the at least one processor, cause the apparatus to:

receive a request for auxiliary heat from the heat pump on a second dedicated wire,

wherein the enabling of the auxiliary heat source is based on the received request.

16. The apparatus of claim 11, wherein the auxiliary heat source is enabled based on a control value included as part of a two-wire serial communication.

17. A system comprising:

a sensor configured to provide an indication of whether a motion in an amount greater than a first threshold is detected within a second threshold amount of time; and

a processor configured to:

determine whether a coil associated with a heat pump is subjected to a defrost cycle,

determine whether a conditioned space is occupied based on the indication provided by the sensor, and

enable an auxiliary heat source that is located within the conditioned space when the coil is subject to the defrost cycle and when the conditioned space is occupied.

18. The system of claim 17, further comprising:

a thermostat configured to receive an input that indicates whether an energy saving mode is entered,

wherein the processor is configured to enable the auxiliary heat source when the coil is subject to the defrost cycle and when the input indicates that the energy saving mode is not entered.

19. The system of claim 18, wherein the thermostat is configured to receive the input via at least one of: a key, a button, a switch, a menu, a slider bar, and a voice recognition device.

20. The system of claim 18, wherein the thermostat is configured to receive the input via a slider bar, and wherein the energy saving mode comprises a plurality of levels corresponding to positions of the slider bar, and wherein when the slider bar is pushed to a comfort level the auxiliary heat source is enabled with every defrost, and wherein when the slider bar is pushed to an efficiency level the auxiliary heat source is disabled during defrost.