Electric Heat Defrost Alogrithm
A method of operating an HVAC system is provided. The method comprises, when a defrost mode of the HVAC system ends and a defrost recovery mode of the HVAC system begins, continuing to operate a supplemental heat generator that was in operation in the defrost mode. The method further comprises, after a period of time in the defrost recovery mode has passed, deactivating at least a first portion of the total heating capacity of the supplemental heat generator.
The present application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application No. 61/943,828 filed on Feb. 24, 2014 by Leslie Lynn Zinger and entitled “Electric Heat Defrost Algorithm,” the disclosure of which is hereby incorporated by reference in its entirety.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENTNot Applicable.
REFERENCE TO A MICROFICHE APPENDIXNot applicable.
BACKGROUNDHeating, ventilation, and/or air conditioning systems (HVAC systems) may be used to heat and/or cool comfort zones to comfortable temperatures. Comfort zones are often the occupiable portions of residential and/or commercial areas and may be subject to variable zone conditions, such as temperature and humidity. A portion of an HVAC system may be installed outdoors or in some other location remote from the comfort zone for the purpose of performing heat exchange. Such a location may be referred to as an ambient zone and may also have variable temperature and humidity conditions.
Some HVAC systems are heat pump systems. Heat pump systems are generally capable of operating in a cooling mode in which a comfort zone is cooled by transferring heat from the comfort zone to an ambient zone using a refrigeration cycle (e.g., the Rankine cycle). Heat pump systems are also generally capable of operating in a heating mode in which the direction of refrigerant flow through the components of the HVAC system is reversed so that heat is transferred from the ambient zone to the comfort zone, thereby heating the comfort zone. Heat pump systems generally use a reversing valve for rerouting the direction of refrigerant flow between the compressor and the heat exchangers associated with the comfort zone and the ambient zone.
If moisture is present in an ambient zone, the moisture may condense on the ambient zone components of an HVAC system. Accordingly, when the temperature in the ambient zone is below a freezing point, frost and/or ice may accumulate on the outdoor portions of the HVAC system, sometimes necessitating a defrosting of the components of the HVAC system on which frost and/or ice have accumulated. In a heat pump system, the defrosting may be achieved by reversing the direction of refrigerant flow from the direction of flow used in the heating mode. Specifically, the refrigerant flow is such that heat is transferred from the comfort zone to the ambient zone during the defrosting of the HVAC system components.
SUMMARYIn an embodiment, a method for operating an HVAC system is provided. The method comprises, when a defrost mode of the HVAC system ends and a defrost recovery mode of the HVAC system begins, continuing to operate a supplemental heat generator that was in operation in the defrost mode. The method further comprises, after a period of time in the defrost recovery mode has passed, deactivating at least a first portion of the total heating capacity of the supplemental heat generator.
In another embodiment, an HVAC system is provided. The HVAC system comprises a supplemental heat generator configured such that, when a defrost mode of the HVAC system ends and a defrost recovery mode of the HVAC system begins, the supplemental heat generator continues operation that began in the defrost mode. The supplemental heat generator is further configured such that, after a period of time in the defrost recovery mode has passed, at least a first portion of the total heating capacity of the supplemental heat generator is deactivated.
In another embodiment, a method for operating an HVAC system is provided. The method comprises, when a supplemental heat generator in the HVAC system is activated in a defrost mode of the HVAC system, activating less than the total heating capacity of the supplemental heat generator. The method further comprises, when the defrost mode of the HVAC system ends and a defrost recovery mode of the HVAC system begins, continuing to operate the supplemental heat generator.
The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments of the disclosure, and by referring to the accompanying drawings.
For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.
The comfort zone blower 118 forces air from the comfort zone 102 into contact with the comfort zone heat exchanger 116 and subsequently back into the comfort zone 102 through air ducts 122. Similarly, the ambient zone fan 112 forces air from an ambient zone 124 into contact with the ambient zone heat exchanger 110 and subsequently back into the ambient zone 124 along an ambient air flow path 126. The HVAC system 100 is generally controlled by interactions between a controller 128 and a communicating thermostat 130. The controller 128 comprises a controller processor 132 and a controller memory 134, while the communicating thermostat 130 comprises a thermostat processor 136 and a thermostat memory 138.
Further, the controller 128 communicates with an ambient zone temperature sensor 140, while the communicating thermostat 130 communicates with a comfort zone temperature sensor 142. In this embodiment, communications between the controller 128 and the communicating thermostat 130, the controller 128 and the ambient zone temperature sensor 140, and the communicating thermostat 130 and the comfort zone temperature sensor 142 are bidirectional. Further, communications between the controller processor 132 and the controller memory 134 and between the thermostat processor 136 and the thermostat memory 138 are bidirectional. However, in alternative embodiments, the communication between some components may be unidirectional rather than bidirectional.
The HVAC system 100 is called a “split system” because the compressor 108, ambient zone heat exchanger 110, and ambient zone fan 112 are co-located in the ambient zone unit 104 while the restriction device 114, comfort zone heat exchanger 116, and comfort zone blower 118 are co-located in the comfort zone unit 106 separate from the ambient zone unit 104. However, in alternative embodiments of an HVAC system, substantially all of the components of the ambient zone unit 104 and the comfort zone unit 106 may be co-located in a single housing in a system called a “package system.” Further, in some embodiments, an HVAC system may include heat generators, such as electrically resistive heating elements and/or gas furnace elements, located in a comfort zone blower airflow path shared with a comfort zone heat exchanger.
While the comfort zone 102 may commonly be associated with a living space of a house or an area of a commercial building occupied by people, the comfort zone 102 may be also be associated with any other area in which it is desirable to control the temperature, humidity, and/or other air quality factors, such as computer equipment rooms, animal housings, or chemical storage facilities. Further, while the comfort zone unit 106 is shown as being located outside the comfort zone 102 (e.g., within an unoccupied attic or crawlspace), the comfort zone unit may alternatively be located within or partially within the comfort zone 102 (e.g., in an interior closet of a building).
Each of the ambient zone heat exchanger 110 and the comfort zone heat exchanger 116 may be constructed as air coils, shell and tube heat exchangers, plate heat exchangers, regenerative heat exchangers, adiabatic wheel heat exchangers, dynamic scraped surface heat exchangers, or any other suitable form of heat exchanger. The compressor 108 may be constructed as any suitable compressor, for example, a centrifugal compressor, a diagonal or mixed-flow compressor, an axial-flow compressor, a reciprocating compressor, a rotary screw compressor, a rotary vane compressor, a scroll compressor, or a diaphragm compressor. In some cases, the compressor 108 may be capable of operating in multiple stages (e.g., stage A and stage B). For example, the compressor 108 may be operated at a low speed (stage A) or a high speed (stage B). Alternative embodiments of an HVAC system may comprise one or more compressors that are operable at more than one speed or at a range of speeds (i.e., a variable speed compressor).
Further, while the HVAC system 100 is shown as operated in a cooling mode to remove heat from the comfort zone 102, the HVAC system 100 is configured as a “heat pump” system that selectively allows flow of refrigerant in the direction shown in
In the cooling mode, the compressor 108 operates to compress low pressure gas refrigerant into a hot and high pressure gas that is passed through the ambient zone heat exchanger 110. As the refrigerant is passed through the ambient zone heat exchanger 110, the ambient zone fan 112 operates to force air from the ambient zone 124 into contact with the ambient zone heat exchanger 110, thereby removing heat from the refrigerant and condensing the refrigerant into high pressure liquid form. The liquid refrigerant is then delivered to the restriction device 114. Forcing the refrigerant through the restriction device 114 causes the refrigerant to transform into a cold and low pressure gas. The cold gas is passed from the restriction device 114 into the comfort zone heat exchanger 116. While the cold gas is passed through the comfort zone heat exchanger 116, the comfort zone blower 118 operates to force air from the comfort zone 102 into contact with the comfort zone heat exchanger 116, heating the refrigerant and thereby providing a cooling and dehumidifying effect to the air, which is then returned to the comfort zone 102. In this embodiment, the HVAC system is using a vapor compression cycle, namely the Rankine cycle. In the heating mode, generally, the direction of the flow of the refrigerant is reversed compared to that shown in
Generally, the controller 128 communicates with the ambient zone temperature sensor 140 that is located in the ambient zone 124 (e.g., outdoors, outdoors within the ambient zone unit in an embodiment where the ambient zone unit is located in the ambient zone, adjacent to the ambient zone unit in an embodiment where the ambient zone unit is located in the ambient zone, or any other suitable location for providing an ambient zone temperature or a temperature associated with the ambient zone). While the controller 128 is illustrated as positioned within the ambient zone unit 104, in alternative embodiments, the controller 128 may be positioned adjacent to but outside an ambient zone unit, outside a comfort zone, within a comfort zone unit, within a comfort zone, or at any other suitable location. It will be appreciated that, in alternative embodiments, an HVAC system may comprise a second controller substantially similar to controller 128 and that the second controller may be incorporated into a comfort zone unit substantially similar to comfort zone unit 106. In the embodiment shown in
If the temperature in the ambient zone 124 is low, ice or frost may form on portions of the HVAC system 100 that are located in the ambient zone 124, such as the coils in the ambient zone heat exchanger 110. To prevent or mitigate the formation of ice or frost on the ambient zone portions of the HVAC system 100, the HVAC system 100 may enter a defrost mode. Entry into the defrost mode may be triggered when frost is detected on a portion of the ambient zone unit 104, or the defrost mode may be entered at regular intervals when ambient conditions are conducive for frost formation, or the defrost mode may be entered based on some other parameter.
In defrost mode, the HVAC system 100 heats the ambient zone portions of the system by entering the cooling mode. That is, refrigerant flow is directed such that heat is removed from the comfort zone 102 and is added to the portions of the ambient zone unit 104 that may be subject to frosting. If supplemental heat is not added to the air supplied to the comfort zone 102 while defrost mode is active, the supplied air may be uncomfortably cool at a time when comfort zone occupants are expecting warm air to be supplied. The term “discharge air” will be used herein to refer to the air that is provided to a comfort zone.
A situation where no supplemental heat is provided during defrost mode is illustrated in
Such a large drop in discharge air temperature during defrost mode may cause discomfort among comfort zone occupants. Warmer discharge air may be provided during defrost mode by adding supplemental heat to the air supplied to the comfort zone. For example, an HVAC system may include supplemental heat generators such as electrically resistive heating elements and/or gas furnace heating elements located in the airflow path of the comfort zone blower. Any such supplemental heat generators may be referred to hereinafter as electric heaters or electric heat, but it should be understood that the supplemental heat generators may take other forms. When defrost mode is entered, the electric heaters may be activated in order to warm the air being supplied to the comfort zone.
The use of electric heat during defrost mode is illustrated in
It can thus be seen that the use of electric heat may prevent the drastic drop in discharge air temperature from approximately 95° F. to approximately 43° F. that may occur in defrost mode without electric heat. However, in the example of
In addition, the electric heat is typically completely shut off when defrost mode ends and heating mode resumes. The system had been in cooling mode during defrost mode, and the cooling coils may remain cold for some time as heating resumes. This can result in a period in the first few minutes after the end of defrost mode in which discharge air with a lower than desired temperature is provided to the comfort zone. Such a “cold blow” condition can be seen in
In an embodiment, electric heat is activated in stages near the beginning of defrost mode and deactivated in stages after defrost mode ends. Such staged activation and deactivation of electric heat may prevent air that is excessively warm from being provided to a comfort zone as the result of the activation of a defrost mode and may prevent air that is excessively cool from being provided to a comfort zone as the result of the deactivation of a defrost mode.
More specifically, when defrost mode is activated, electric heat may be brought on only in a first stage to offset the cooling provided by the cooling mode. This first stage may provide less heat than is provided by the entire electric heating system, thus preventing excessively warm air from being supplied to the comfort zone. As cooling of the discharge air continues during defrost mode, a second stage of electric heat may be brought on to provide additional heat and offset the additional cooling. Such activation of electric heat may continue in stages up to the number of heating stages available in the HVAC system. Alternatively, activation of electric heat may continue in stages until a desired discharge air temperature is reached. As used herein, the terms “stage” or “heating stage” may refer to a portion of the full capacity of a heating system, such as one bank of electric heating elements in a plurality of banks of electric heating elements or one set of gas furnace heating elements among a plurality of gas furnace heating elements.
The period of time from the time defrost mode ends to the time the discharge air temperature with no electric heat returns to its typical heating mode operating level may be referred to as defrost recovery. In an embodiment, when defrost mode ends and defrost recovery begins, electric heat may be turned off in stages rather than being completely shut off all at once. That is, at some period of time after defrost mode has ended and heating mode has resumed, one of the stages of electric heat that was turned on during defrost mode is turned off. As defrost recovery progresses, additional stages of electric heat may be turned off in succession until all of the stages are deactivated. In this way, uncomfortably cool air is not supplied during defrost recovery, and the temperature of the air provided to a comfort zone during defrost recovery may be kept near a desired level.
The upper curve of
The slight delay in the activation of electric heat and the activation of electric heat in stages may prevent excessively warm air from being supplied when defrost mode is entered. For example, in
It can also be seen from
The continuation of electric heat in such a manner during defrost recovery may prevent the “cold blow” situation described above in which uncomfortably cool air is provided to a comfort zone for a period of time after the end of defrost mode. For example, in
The staging of the deactivation of the electric heat may allow a desired discharge air temperature range to be maintained during defrost recovery. In the example of
The example of
The examples of
The examples of
In an embodiment, an HVAC system may provide a plurality of options related to staging electric heat during defrost mode and defrost recovery. Each of the options may offer a different tradeoff between energy savings and comfort by offering a different combination of the number of heating stages, the heating capacities of the stages, the timing of the activation and deactivation of the stages, the desired discharge air temperature during defrost mode and defrost recovery, and other parameters. In some embodiments, only two operating methods, such as the high comfort method and the net capacity method, are provided. In other embodiments, two or more operating methods may be provided that are similar to the high comfort method and the net capacity method but have different levels of tradeoff between energy savings and comfort. In other embodiments, the traditional method of using electric heat without staging, as depicted in
In an embodiment, an HVAC system may provide users of the system with an opportunity to choose a desired operating method for electric heat. For example, the HVAC system may offer a choice between the high comfort method and the net capacity method; between the high comfort method, the net capacity method, and the normal operation method; between the high comfort method, the net capacity method, the normal operation method, and the high efficiency method; between two or more operating methods similar to the high comfort method and the net capacity method but with different levels of tradeoff between energy savings and comfort; or between some other combination of operating methods.
The choice may be provided as an option on a thermostat, a comfort control, or some other type of control mechanism, such as the communicating thermostat 130 of
Examples of procedures that may be followed in activating electric heat in stages in defrost mode and deactivating electric heat in stages in defrost recovery are provided below for the high comfort and net capacity methods. It should be understood that these are only examples and that other procedures and other values for variables could be used.
TDD=Demand Discharge Temperature for defrost and defrost recovery
TSA=Supply Air Temperature (measured) between indoor coil and electric heat
TDA=Discharge Air Temperature (calculated) after electric heat
ΔTEH=Temperature rise across the electric heater at given airflow
ΔHADJ=Heat rise adjustment factor for electric heater coils
ΔDEH=% Demand adjustment for Electric Heat
L=15 seconds (interval between updates to discharge temperature)
NOTE: ΔHADJ is 1.08 for Nikrothal® N60 wire planned for electric heater elements; 3412.142 is factor for conversion from BTU/hr to kW.
Defrost
% Demand=MIN{% Demand+ΔDEH, INT(CC demand stages/CC configured stages)*100%)}
Defrost Recovery
% Demand=MAX{% Demand−ΔDEH, 0%}
NOTE: % Demand≦INT(CC demand stages/CC configured stages)*100%)
Defrost (Maintain TDD±5° F.)
% Demand=0
ΔDEH=10%
Initial EH demand starts at 0; will add EH capacity to maintain discharge air temperature while Defrost state=TRUE
Defrost Recovery (Maintain TDD±5° F.)
Previous state was Defrost; if Heat/Cool Demand changes, exit recovery while Defrost Recovery state=TRUE
It can be seen that measurements and calculations are made to determine a percentage related to the amount of electric heat that needs to be provided to achieve a desired discharge air temperature. This percentage of electric heat demand may be related to the number of stages of electric heat to be activated. For example, if two stages of electric heat are available and the demand for electric heat is less than 50%, only one stage of electric heat may be activated. If the demand for electric heat is 50% or more, both stages of electric heat may be activated. If three stages of electric heat are available and the demand for electric heat is less than 33%, only one stage of electric heat may be activated. If the demand for electric heat is 33% to 66%, two stages of electric heat may be activated. If the demand for electric heat is greater than 66%, all three stages of electric heat may be activated. In other examples, the percentage of electric heat demand may be related in other ways to the number of stages of electric heat that are activated. Similar concepts may apply to greater numbers of stages.
The HVAC system 100 described above may comprise a processing component (such as controller processor 132 and/or the thermostat processor 136 shown in
The processor 1310 executes instructions, codes, computer programs, or scripts that it might access from the network connectivity devices 1320, RAM 1330, ROM 1340, or secondary storage 1350 (which might include various disk-based systems such as hard disk, floppy disk, or optical disk). While only one processor 1310 is shown, multiple processors may be present. Thus, while instructions may be discussed as being executed by a processor, the instructions may be executed simultaneously, serially, or otherwise by one or multiple processors. The processor 1310 may be implemented as one or more CPU chips.
The network connectivity devices 1320 may take the form of modems, modem banks, Ethernet devices, universal serial bus (USB) interface devices, serial interfaces, token ring devices, fiber distributed data interface (FDDI) devices, wireless local area network (WLAN) devices, radio transceiver devices such as code division multiple access (CDMA) devices, global system for mobile communications (GSM) radio transceiver devices, worldwide interoperability for microwave access (WiMAX) devices, and/or other well-known devices for connecting to networks. These network connectivity devices 1320 may enable the processor 1310 to communicate with the Internet or one or more telecommunications networks or other networks from which the processor 1310 might receive information or to which the processor 1310 might output information.
The network connectivity devices 1320 might also include one or more transceiver components 1325 capable of transmitting and/or receiving data wirelessly in the form of electromagnetic waves, such as radio frequency signals or microwave frequency signals. Alternatively, the data may propagate in or on the surface of electrical conductors, in coaxial cables, in waveguides, in optical media such as optical fiber, or in other media. The transceiver component 1325 might include separate receiving and transmitting units or a single transceiver. Information transmitted or received by the transceiver 1325 may include data that has been processed by the processor 1310 or instructions that are to be executed by processor 1310. Such information may be received from and outputted to a network in the form, for example, of a computer data baseband signal or signal embodied in a carrier wave. The data may be ordered according to different sequences as may be desirable for either processing or generating the data or transmitting or receiving the data. The baseband signal, the signal embedded in the carrier wave, or other types of signals currently used or hereafter developed may be referred to as the transmission medium and may be generated according to several methods well known to one skilled in the art.
The RAM 1330 might be used to store volatile data and perhaps to store instructions that are executed by the processor 1310. The ROM 1340 is a non-volatile memory device that typically has a smaller memory capacity than the memory capacity of the secondary storage 1350. ROM 1340 might be used to store instructions and perhaps data that are read during execution of the instructions. Access to both RAM 1330 and ROM 1340 is typically faster than to secondary storage 1350. The secondary storage 1350 is typically comprised of one or more disk drives or tape drives and might be used for non-volatile storage of data or as an over-flow data storage device if RAM 1330 is not large enough to hold all working data. Secondary storage 1350 may be used to store programs that are loaded into RAM 1330 when such programs are selected for execution.
The I/O devices 1360 may include liquid crystal displays (LCDs), touch screen displays, keyboards, keypads, switches, dials, mice, track balls, voice recognizers, card readers, paper tape readers, printers, video monitors, or other well-known input or output devices. Also, the transceiver 1325 might be considered to be a component of the I/O devices 1360 instead of or in addition to being a component of the network connectivity devices 1320.
At least one embodiment is disclosed and variations, combinations, and/or modifications of the embodiment(s) and/or features of the embodiment(s) made by a person having ordinary skill in the art are within the scope of the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, Rl, and an upper limit, Ru, is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=Rl+k*(Ru−Rl), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . 50 percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 97 percent, 98 percent, 99 percent, or 100 percent. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed. Use of the term “optionally” with respect to any element of a claim means that the element is required, or alternatively, the element is not required, both alternatives being within the scope of the claim. Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Accordingly, the scope of protection is not limited by the description set out above but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present invention.
Claims
1. A method of operating an HVAC system, comprising:
- when a defrost mode of the HVAC system ends and a defrost recovery mode of the HVAC system begins, continuing to operate a supplemental heat generator that was in operation in the defrost mode; and
- after a period of time in the defrost recovery mode has passed, deactivating at least a first portion of the total heating capacity of the supplemental heat generator.
2. The method of claim 1, further comprising, when the supplemental heat generator has a plurality of portions of total heating capacity, after an additional period of time in the defrost recovery mode has passed, deactivating at least one additional portion of the total heating capacity of the supplemental heat generator, the deactivations of the portions continuing until the total heating capacity of the supplemental heat generator is deactivated.
3. The method of claim 1, wherein the HVAC system provides a plurality of options for operation of the supplemental heat generator, the plurality of options including:
- at least a first option that provides relatively warmer discharge air in the defrost mode and the defrost recovery mode and uses a relatively greater amount of energy; and
- at least a second option that provides relatively cooler discharge air in the defrost mode and the defrost recovery mode and uses a relatively smaller amount of energy,
- wherein the discharge air temperature and the energy usage are at least partially controlled by activation and deactivation of the supplemental heat generator.
4. The method of claim 3, wherein the plurality of options for operation of the supplemental heat generator further includes an option wherein operation of the supplemental heat generator ceases when the defrost mode ends.
5. The method of claim 4, wherein the plurality of options for operation of the supplemental heat generator further includes an option wherein the supplemental heat generator is not operated.
6. The method of claim 3, wherein the HVAC system includes a control mechanism that displays the plurality of options for operation of the supplemental heat generator and allows one of the plurality of options to be selected.
7. The method of claim 1, wherein, when the supplemental heat generator is activated in the defrost mode, less than the total heating capacity of the supplemental heat generator is activated, and wherein at least one additional portion of the total heating capacity of the supplemental heat generator is activated at a later time, the activations of the portions continuing until the total heating capacity of the supplemental heat generator is activated or until a desired discharge air temperature is reached.
8. An HVAC system, comprising:
- a supplemental heat generator configured such that, when a defrost mode of the HVAC system ends and a defrost recovery mode of the HVAC system begins, the supplemental heat generator continues operation that began in the defrost mode, and further configured such that, after a period of time in the defrost recovery mode has passed, at least a first portion of the total heating capacity of the supplemental heat generator is deactivated.
9. The HVAC system of claim 8, wherein the supplemental heat generator is further configured such that, when the supplemental heat generator has a plurality of portions of total heating capacity, after an additional period of time in the defrost recovery mode has passed, at least one additional portion of the total heating capacity of the supplemental heat generator is deactivated, the deactivations of the portions continuing until the total heating capacity of the supplemental heat generator is deactivated.
10. The HVAC system of claim 8, wherein the HVAC system provides a plurality of options for operation of the supplemental heat generator, the plurality of options including:
- at least a first option that provides relatively warmer discharge air in the defrost mode and the defrost recovery mode and uses a relatively greater amount of energy; and
- at least a second option that provides relatively cooler discharge air in the defrost mode and the defrost recovery mode and uses a relatively smaller amount of energy,
- wherein the discharge air temperature and the energy usage are at least partially controlled by activation and deactivation of the supplemental heat generator.
11. The HVAC system of claim 10, wherein the plurality of options for operation of the supplemental heat generator further includes an option wherein operation of the supplemental heat generator ceases when the defrost mode ends.
12. The HVAC system of claim 11, wherein the plurality of options for operation of the supplemental heat generator further includes an option wherein the supplemental heat generator is not operated.
13. The HVAC system of claim 10, wherein the HVAC system includes a control mechanism that displays the plurality of options for operation of the supplemental heat generator and allows one of the plurality of options to be selected.
14. The HVAC system of claim 8, wherein, when the supplemental heat generator is activated in the defrost mode, less than the total heating capacity of the supplemental heat generator is activated, and wherein at least one additional portion of the total heating capacity of the supplemental heat generator is activated at a later time, the activations of the portions continuing until the total heating capacity of the supplemental heat generator is activated or until a desired discharge air temperature is reached.
15. A method of operating an HVAC system, comprising:
- when a supplemental heat generator in the HVAC system is activated in a defrost mode of the HVAC system, activating less than the total heating capacity of the supplemental heat generator; and
- when the defrost mode of the HVAC system ends and a defrost recovery mode of the HVAC system begins, continuing to operate the supplemental heat generator.
16. The method of claim 15, wherein at least one additional portion of the total heating capacity of the supplemental heat generator is activated at a later time in the defrost mode, the activations of the portions continuing until the total heating capacity of the supplemental heat generator is activated or until a desired discharge air temperature is reached.
17. The method of claim 15, wherein, after a period of time in the defrost recovery mode has passed, a first portion of the total heating capacity of the supplemental heat generator is deactivated, and wherein, after an additional period of time in the defrost recovery mode has passed, at least one additional portion of the total heating capacity of the supplemental heat generator is deactivated, the deactivations of the portions continuing until the total heating capacity of the supplemental heat generator is deactivated.
18. The method of claim 15, wherein the HVAC system provides a plurality of options for operation of the supplemental heat generator, the plurality of options including:
- at least a first option that provides relatively warmer discharge air in the defrost mode and the defrost recovery mode and uses a relatively greater amount of energy; and
- at least a second option that provides relatively cooler discharge air in the defrost mode and the defrost recovery mode and uses a relatively smaller amount of energy,
- wherein the discharge air temperature and the energy usage are at least partially controlled by activation and deactivation of the supplemental heat generator.
19. The method of claim 18, wherein the plurality of options for operation of the supplemental heat generator further includes an option wherein operation of the supplemental heat generator ceases when the defrost mode ends and an option wherein the supplemental heat generator is not operated.
20. The method of claim 18, wherein the HVAC system includes a control mechanism that displays the plurality of options for operation of the supplemental heat generator and allows one of the plurality of options to be selected.
Type: Application
Filed: Dec 19, 2014
Publication Date: Aug 27, 2015
Inventor: Leslie Lynn Zinger (Bullard, TX)
Application Number: 14/577,886