HEATING, VENTILATION AND AIR CONDITIONING SYSTEM WITH A THERMAL ENERGY STORAGE DEVICE

Abstract

The invention relates to a heating, ventilation, and air conditioning ("HVAC") system for use with a refrigerant. The HVAC system includes a compressor, a condenser, an evaporator expansion device, and an evaporator. The HVAC system also includes a thermal energy storage device ("TESD") comprising in-line thermal energy storage means between the condenser and the evaporator. A control system is programmed to operate the compressor and the evaporator expansion device to control the flow of refrigerant through the HVAC system. The control system is also programmed to control the flow of refrigerant through the TESD to charge the TESD with thermal energy.The control system is also programmed to control the flow of refrigerant through the evaporator expansion device and evaporator and discharge thermal energy from the charged TESD to improve the performance of the HVAC system.

Description

HEATING, VENTILATION AND AIR CONDITIONING SYSTEM WITH A THERMAL ENERGY STORAGE DEVICE BACKGROUND OF THE INVENTION This section is intended to introduce the reader to various technical aspects that may be related to several aspects of the modalities currently described, in order to facilitate a better understanding of these modalities. Consequently, these statements should be understood in light of this context, and not as admissions of prior art. In general, heating, ventilation, and air conditioning (HVAC) systems circulate indoor air through low-temperature (for cooling) or high-temperature (for heating) sources, thereby adjusting the ambient air temperature. HVAC systems generate these low- and high-temperature sources, among other techniques, by taking advantage of a well-known physical principle: a fluid changing from a gas to a liquid releases heat, while a fluid changing from a liquid to a gas absorbs heat. Within a typical HVAC system, a refrigerant circulates through a closed-loop piping system that uses a compressor and flow control devices to manipulate the refrigerant's flow and pressure, causing it to change between liquid and gaseous phases. These phase transitions generally occur within the HVAC system's heat exchangers, which are part of the closed loop and are designed to transfer heat between the circulating refrigerant and the surrounding ambient air. As expected, the heat exchanger that provides heating or cooling to the climate-controlled space or structure is described as "indoor," and the heat exchanger that transfers heat to the surrounding outdoor environment is described as "outdoor." The refrigerant circulating between the indoor and outdoor heat exchangers, transitioning between phases along the way, absorbs heat from one place and releases it to the other. Those in the HVAC industry describe this cycle of heat absorption and release as “pumping.” To cool a climate-controlled indoor space, heat is “pumped” from the inside to the outside, and the indoor space is heated by doing the opposite, pumping heat from the outside to the inside. Another type of HVAC system is the thermal energy storage (TES) system. TES systems shift cooling energy use to off-peak hours, thus changing the load on the HVAC system. They cool storage media such as water, ice, or a phase-change material during periods of low cooling demand for later use to meet air conditioning loads and reduce strain on the electrical grid. Operating strategies are generally classified as full storage or partial storage, referring to the amount of cooling load transferred from peak to off-peak. In a TES system, a storage medium is cooled during periods of low temperature. The cooling demand and stored cooling is later used to meet air conditioning or process cooling loads. The system consists of a storage medium in a tank, a compact chiller or built-in refrigeration system, and interconnecting piping, pumps, and controls. The storage medium is usually water, ice, or a phase-change material (sometimes called a eutectic salt); it is typically cooled to lower temperatures than would be required for direct cooling to keep the storage tank size within economic limits. BRIEF DESCRIPTION OF THE INVENTION Certain aspects of some embodiments described herein are set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief overview of some forms the invention could take and are not intended to limit the scope of the invention. In fact, the invention may encompass a variety of aspects that may not be set forth below. This description may relate to a compact air conditioning system, a heat pump, a chiller, or a close-coupled split system. It may also relate to district cooling, supermarket cooling, or other distributed systems. The system includes a thermal energy storage device (TESD) comprising in-line thermal energy storage media between a condenser and an evaporator. A control system is programmed to operate the compressor and an evaporator expansion device to control the refrigerant flow through the HVAC system. The control system is also programmed to charge the TESD with thermal energy, control the refrigerant flow through the evaporator expansion device and the evaporator, and discharge the thermal energy from the charged TESD to enhance the HVAC system's performance.Performance can be considered the heating or cooling capacity provided by the HVAC system per unit of energy consumption. Examples include EER (Energy Efficiency Ratio) for cooling and COP (Coefficient of Performance) for heating. Advantageously, certain modalities described can provide improvements in system performance, lower operating costs, reduced unit size, and flexibility to meet the thermal load demands of the conditioned space. There may be various refinements of the features described above in relation to different aspects of the present embodiments. Additional features may also be incorporated into these various aspects. These refinements and additional features may exist individually or in any combination. For example, several features discussed below in relation to one or more of the illustrated embodiments may be incorporated into any of the aspects described above in this description, either alone or in any combination. Again, the brief summary presented above is intended only to familiarize the reader with certain aspects and contexts of some embodiments, without limitation to the claimed object. PLQfrLn / ZZnZ / B / YIAI BRIEF DESCRIPTION OF THE FIGURES These and other features, aspects, and advantages of certain modalities will be better understood when the following detailed description is read with reference to the accompanying drawings, in which the same characters represent equal parts throughout the drawings, where: PLQfrLn / ZZnZ / B / YIAI Figure 1 is a block diagram of an HVAC system, according to one or more modes; Figure 2 is a block diagram of an HVAC system, according to one or more modes; Figures 3A and 3B are pressure enthalpy graphs illustrating the cycles of HVAC system cooling shown in FIGURE 2; Figure 4 is a block diagram of an HVAC system, according to one or more modes; Figure 5 is a block diagram of an HVAC system, according to one or more modes; Figure 6 is a pressure enthalpy graph illustrating a refrigeration cycle; and Figure 7 is a block diagram of a control system, according to one or more modes. DETAILED DESCRIPTION OF THE INVENTION The following will describe one or more specific modalities of this description. In an effort to provide a concise description of these modalities, it is possible that not all features of an actual implementation will be described. It should be borne in mind that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific objectives, such as meeting system and business constraints, which may vary from one implementation to another. Furthermore, it should be appreciated that such a development effort may be complex and time-consuming, but it would nevertheless be a routine design, fabrication, and manufacturing task for those with ordinary knowledge who benefit from this description. When introducing elements of various types, the articles “a,” “one,” “the,” and “such” mean that there is one or more of the elements. The terms “comprises,” “includes,” and “has” are intended to be inclusive and mean that there may be additional elements besides those listed. Returning now to the figures, FIGURE 1 illustrates a schematic of an HVAC system 100. As shown, the HVAC system 100 heats and cools a residential structure 102. However, the concepts described here are applicable to numerous heating and cooling situations, including industrial and commercial environments. The HVAC system 100 is divided into two main parts: the outdoor unit 104, which comprises components for transferring heat with the environment outside the structure 102; and the indoor unit 106, which comprises components for transferring heat with the air inside the structure 102. To heat or cool the illustrated structure 102, the indoor unit 106 draws in indoor air through the returns 110, passes that air through one or more heating / cooling systems (i.e., heat or cooling sources), and then directs that conditioned air, whether heated or cooled, back to the various climate-controlled spaces 112 through ducts or conduits 114, which are relatively large pipes that can be rigid or flexible. A blower 116 provides the driving force for circulating the ambient air through the returns 110 and the ducts 114.Furthermore, although FIGURE 1 shows a split system, the described modalities can be applied equally to packaged or other system configurations. As shown, the HVAC system 100 is a dual-fuel system with multiple heating elements, such as an electric heating element or a gas furnace 118. The gas furnace 118, located downstream (relative to the airflow) of the blower 116, burns natural gas to produce heat in the furnace tubes (not shown) that are wound through the gas furnace 118. These furnace tubes act as a heating element for the indoor air that is exhausted from the blower 116, over the furnace tubes, and into the ducts 114. However, the gas furnace 118 is generally operated only when strong heating is desired. During conventional heating and cooling operations, the air from the blower 116 passes through an indoor heat exchanger 120 and into the duct 114.The blower 116, gas furnace 118, and indoor heat exchanger 120 can be packaged as an integrated air handling unit, or these components can be modular. In other configurations, the positions of the gas furnace 118, indoor heat exchanger 120, and blower 116 can be reversed or rearranged. In at least one embodiment, the indoor heat exchanger 120 acts as a heating or cooling medium, adding or removing heat from the building, respectively, by manipulating the pressure and flow of refrigerant circulating within and between the indoor and outdoor units through the refrigerant lines 122. In another embodiment, the refrigerant may circulate only to cool (i.e., remove heat from) the building, with heating provided independently by another source, such as, but not limited to, the gas furnace 118. In other embodiments, there may be no heating of any kind. HVAC systems 100 that use refrigerant for both heating and cooling the building 102 are often described as heat pumps, while HVAC systems 100 that use refrigerant only for cooling are commonly described as air conditioners. Whatever the state of the indoor heat exchanger 120 (i.e., absorbing or releasing heat), the outdoor heat exchanger 124 is in the opposite state. More specifically, if heating is desired, the indoor heat exchanger 120 acts as a condenser, facilitating the transition of the refrigerant from a high-pressure gas to a high-pressure liquid and releasing heat in the process. The outdoor heat exchanger 124 acts as an evaporator, facilitating the transition of the refrigerant from a low-pressure liquid to a low-pressure gas, thereby absorbing heat from the outside environment. If cooling is desired, the outdoor unit 104 has flow control devices 126 that reverse the refrigerant flow, allowing the outdoor heat exchanger 124 to act as a condenser and the indoor heat exchanger 120 to act as an evaporator.The flow control devices 126 can also act as an expander to reduce the pressure of the refrigerant flowing through them. In other embodiments, the expander may be a separate device located in the outdoor unit 104 or the indoor unit 106. To facilitate heat exchange between the indoor ambient air and the outdoor environment in the described HVAC system 100, the respective heat exchangers 120, 124 have tubes that are coiled or wound through heat exchange surfaces to increase the surface area of ​​contact between the tubes and the surrounding air or environment. The outdoor unit 104 may also include an accumulator 128 that helps prevent liquid refrigerant from reaching the inlet of a compressor 130. The outdoor unit 104 may include a receiver 132 that helps maintain sufficient refrigerant charge distribution in the HVAC system 100. The size of these components is often defined by the amount of refrigerant used by the HVAC system 100. Compressor 130 receives low-pressure refrigerant gas from the indoor heat exchanger 120 if cooling is required, or from the outdoor heat exchanger 124 if heating is required. Compressor 130 then compresses the refrigerant gas to a higher pressure based on a compressor volume ratio, that is, the ratio between the discharge volume (the volume of gas leaving compressor 130 after compression) and the suction volume (the volume of gas entering compressor 130 before compression), and ambient conditions. In the illustrated configuration, the compressor 130 is a multi-stage compressor that can switch between at least two volume ratios depending on whether heating or cooling is required. In other configurations, the HVAC system 100 may be set up for cooling only or heating only, and the compressor 130 may be a single-stage compressor with only one volume ratio.Alternatively, the compressor could be a variable volume ratio compressor. With reference now to FIGURES 2, 3A, and 3B, FIGURE 2 is a simplified block diagram of an HVAC system 200. The HVAC system 200 includes a compressor 230, an outdoor heat exchanger or condenser 224, a first control valve 202, a first expansion device (“TESD”) 209, a second control valve 204, a thermal energy storage device (“TESD”) 240, a third control valve 206, a fourth control valve 208, a second expansion device (evaporator) 210, an indoor heat exchanger or evaporator 222, and a control system 212. The control system 212 (described below) is in electronic communication (wired or wireless) with the compressor 230, the control valves 202, 204, 206, 208, and the expansion devices 209. 210 and is programmed to select between multiple operating modes based on the load on the HVAC 200 system and / or user input PLQfrLn / ZZnZ / B / YIAI as described below. The HVAC 200 system may also include the equipment shown in FIGURE 1 and they operate as discussed above with reference to FIGURE 1. Accordingly, the function of the condenser 224, expansion devices 209, 210, evaporator 222, and compressor 230 will not be discussed in detail except when necessary to understand the HVAC 200 system shown in FIGURE 2. In full-load mode, typically used during off-peak hours, control system 212 is programmed to operate compressor 230 to compress the refrigerant into a vapor that flows through condenser 224, where it condenses into high-pressure liquid refrigerant. As shown schematically, an optional fan can be used to direct airflow, indicated by arrows, over condenser 224 to make the refrigerant condensation process more efficient. Control system 212 is programmed to regulate refrigerant flow by controlling the operation of compressor 230 and other components based on the HVAC system load 200 and ambient conditions. Control system 212 is also programmed to operate the first control valve 202 to allow high-pressure liquid refrigerant to enter the TESD 209 expansion device, which may be a variable expansion device and is adjusted by control system 212 to expand and decrease the refrigerant pressure. The refrigerant then flows through the TESD 240, which includes a flow path through a thermal energy storage medium within the TESD 240. The thermal storage medium can be any medium suitable for storing and discharging thermal energy over a period of time, such as water, glycol, or eutectic material. The flow of refrigerant through the TESD 240 charges the TESD 240 with thermal energy by the refrigerant absorbing heat from the TESD 240 through a heat exchange process.The heat exchange process results in a reduction of the medium temperature in the TESD 240 and evaporation of the refrigerant. The amount of thermal energy absorbed by the TESD 240 can also be controlled by adjusting the expansion device 209. Furthermore, depending on the storage medium used, the medium may undergo a phase change (e.g., from gas to liquid or from liquid to solid) as it cools. The amount of media charged in the TESD 240 depends on the total capacity of the HVAC system 200 and the anticipated cooling loads in the system. The control system 212 is also programmed to operate the second control valve 204 so that at least some of the refrigerant flows through a bypass flow path 216, diverting it from and not flowing through the TESD 240. This allows refrigerant to flow through system 200 in case the TESD 240 is fully charged, or does not need to be charged much more at that time, or if some of the refrigerant is needed to meet the cooling requirements of the conditioned space. The control system 212 is also programmed to operate the third control valve 206 so that the low-pressure refrigerant flows through a bypass flow path 218, thereby diverting it from flowing through the evaporator 222. The low-pressure refrigerant then re-enters the compressor 230 where it is recompressed into high-pressure refrigerant, and the cycle is repeated. Alternatively, the third control valve 206 can be operated to allow some or all of the low-pressure refrigerant to flow through the evaporator 222. Doing so may involve the control system 212 operating the fourth control valve 208 so that the refrigerant flows through a bypass flow path 220 to bypass the second expansion device 210 before entering the evaporator 222.Alternatively, the expansion device 210 can be activated if the TESD 240 charge occurs at a higher temperature level and the evaporator 222 operation is processed at a different, lower temperature level. In a full discharge mode, as shown in FIGURE 2 and illustrated in FIGURES 3A and 3B, and typically used during peak load or maximum load times, the control system 212 is programmed to operate the compressor 230 to compress the refrigerant into a vapor refrigerant that flows through the condenser 224, where the refrigerant condenses into a high-pressure liquid refrigerant. The control system 212 is also programmed to operate the first control valve 202 so that the high-pressure liquid refrigerant flows through a bypass flow path 214, thereby bypassing the TESD expansion device 209 and remaining as a high-pressure liquid.The bypass flow path 214 only needs to be used when the TESD expansion device cannot be fully opened to minimize refrigerant flow restriction, although normally during higher thermal loads in system 200, the TESD expansion device 209 is fully open and the bypass flow path 214 does not need to be used. The refrigerant then flows through the TESD 240 with the thermal energy storage media charged. The thermally charged storage media absorbs heat from the refrigerant, thus subcooling it, as shown in the shaded portion of FIGURE 3A.As shown in FIGURE 3A, the shaded portion represents an additional cooling effect provided by the TESD 240 and resulted from a refrigeration cycle in which the thermal storage medium was precooled to a temperature above or approximately at the evaporation temperature of the refrigerant in evaporator 222. This ensures that the refrigerant is in liquid form upon entering the expansion leading to point 5 of the cycle. Alternatively, as shown in FIGURE 3B, the shaded portion represents a refrigeration cycle in which the storage medium was precooled to a temperature below the evaporation temperature of the refrigerant in evaporator 222. This allows for a lower enthalpy before entering evaporator 222 and thus improves the process and evaporation performance of the HVAC system 200. In such a situation, the TESD 209 expansion device can be used in the process.Regardless of whether the TESD 240 was cooled below or above the evaporation temperature, subcooling the refrigerant increases the cooling capacity of the HVAC 200 system compared to not using the TESD 240 by allowing a higher ratio of. PLQfrLn / ZZnZ / B / YILI heat absorption in the later stages of the cycle is discussed below. The amount of refrigerant flowing through the TESD 240, and therefore the amount of subcooling, depends on the overall load demands of the HVAC 200 system and the ambient conditions. Furthermore, as mentioned earlier, performance is the heating or cooling capacity provided by the HVAC 200 system per unit of energy consumption. Examples include EER (Energy Efficiency Ratio) for cooling and COP (Coefficient of Performance) for heating. Control system 212 is also programmed to operate the second control valve 204 in such a way that the refrigerant flows through a bypass flow path 216, thereby avoiding TESD 240. Alternatively, control system 212 can control the second control valve 204 to allow some refrigerant to flow through TESD 240 and some refrigerant to be bypassed from TESD 240. In this way, the amount of refrigerant subcooling can be controlled during discharge by controlling the amount of refrigerant flowing through TESD 240. Control system 212 is also programmed to operate the third and fourth control valves 206 and 208 to allow all of the subcooled refrigerant to enter the second expansion device 210, where it expands into low-pressure liquid refrigerant. As noted earlier, the subcooling of the refrigerant allows the second expansion device 210 to operate more efficiently because all of the refrigerant is in liquid form. The low-pressure liquid refrigerant then enters evaporator 222, where it evaporates into low-pressure vapor refrigerant. The low-pressure vapor refrigerant then enters compressor 230, where it is compressed into high-pressure vapor refrigerant, and the cycle repeats. In a part-load mode, as shown in Figure 2 and typically used during off-peak hours, the control system 212 is programmed to operate the system components so that the TESD 240 can be charged alternately or concurrently with providing part-load cooling capacity for space conditioning. In part-load mode, at least some of the refrigerant can flow through both the TESD 240 and the evaporator 222. The use of the bypass flow paths and expansion devices 209 and 210 in part-load mode depends on the load on system 200 and ambient conditions. However, to charge the TESD 240, the TESD 204 absorbs more energy than it discharges. Again, the charging of the TESD 240 can occur at the same operating temperature as the evaporator 222, or alternatively, it can occur at different temperatures.As described above, this would be controlled by expansion devices 209 and 210 working together. The thermal energy discharge from the TESD 240 and the additional refrigerant subcooling improve the performance of the entire HVAC 200 system by making the refrigeration cycle more efficient. A more efficient cycle reduces strain on the electrical grid, lowers electricity costs, and allows for a smaller HVAC 200 system. Using the TESD 240 can also offer other advantages, such as enhanced dehumidification, a wider operating range for the HVAC 200 system, reduced compressor discharge temperature, and improved system reliability. Another advantage The TESD 240's PLQfrLn / ZZnZ / B / YIAI feature allows it to be charged at a different time than when it is discharged, such as when there is no cooling load on the HVAC 200 system or when electricity costs are lower. The TESD 240 can then be discharged during periods of higher load demand or off-peak electricity hours to reduce the operating costs of the HVAC 200 system. Another potential benefit is the additional cooling capacity provided by the TESD 240 during extraction operations. Furthermore, although not shown in detail, the TESD 240 can also be discharged to cool the control system 212 or other electronic components. It should also be noted that the HVAC 200 system can be one circuit in a multi-circuit system, some of which may also have TESD and others may not. Furthermore, the circuits with TESD do not need to operate synchronously. One circuit can be operating in one mode, such as charging a TESD, while another circuit is discharging a TESD or in a conventional cooling mode. With reference now to FIGURE 4, the figure is a simplified block diagram of another configuration of an HVAC 400 system. The HVAC 400 system includes a compressor 430, an outdoor heat exchanger or condenser 424, a first control valve 402, a first expansion device (“TESD”) 409, a second control valve 404, a TESD 440, a third control valve 406, a fourth control valve 408, a second expansion device (evaporator) 410, an indoor heat exchanger or evaporator 422, and a control system 412. The control system 412 is in electronic communication (wired or wireless) with the compressor 430, the control valves 402, 404, 406, and 408, and the expansion devices 409 and 410, and is programmed to select among multiple operating modes depending on the load on the system. HVAC 400, environmental conditions and / or user input as described below. The HVAC 400 system is similar to the HVAC 200 system in that the TESD 440 is charged and discharged with thermal energy to further subcool the refrigerant in the HVAC 400 system. Similar components in the HVAC 400 system receive similar part numbers, and therefore, a further explanation of their operation will not be discussed. However, unlike the HVAC 200 system, there is no need for two distinct charging and discharging modes because a separate charging system or secondary cooling circuit 450 charges the TESD 440. When charging the TESD 440, typically during off-peak charging hours, the control system 412 is programmed to operate a charging compressor 452 to compress a refrigerant in the charging system 450 into a vapor refrigerant that flows through an external charging heat exchanger or a charging condenser 454, where the refrigerant condenses into high-pressure liquid refrigerant.The 412 control system is programmed to control the flow of refrigerant by controlling the operation of the 452 compressor and the other components of the charging circuit based on the load in the 400 HVAC system and the ambient conditions. The refrigerant then flows through a charge expansion device 456, where the charge refrigerant expands into predominantly liquid refrigerant at low pressure. The predominantly liquid, low-pressure refrigerant then enters the TESD 440 via a flow path through thermal energy storage media within the TESD 440. The thermal storage media can be any medium suitable for storing and discharging thermal energy over a period of time, such as water, glycol, or eutectic material. The flow of the charge refrigerant through the TESD 440 charges it with thermal energy by absorbing heat from the refrigerant through a heat exchange process that reduces the temperature of the medium within the TESD 440, thereby lowering the refrigerant pressure and causing the charge refrigerant to evaporate. The amount of media charged in the TESD 440 depends on the overall capacity of the charging system (450) and the anticipated cooling loads in the main HVAC system (400).The low-pressure vapor refrigerant then enters compressor 452, where it is compressed into a high-pressure vapor refrigerant, and the cycle can be repeated. In a discharge mode, typically used during higher loads or peak load times, the control system 412 is programmed to operate the compressor 430 to compress the refrigerant into a high-pressure vapor refrigerant that flows through the condenser 424, where the refrigerant condenses into a high-pressure liquid refrigerant. The high-pressure liquid refrigerant then flows through the TESD 440 with the thermal energy storage media charged. The thermally charged storage media absorbs heat from the refrigerant, further subcooling it to improve performance, as explained earlier with reference to Figures 2, 3A, and 3B. Subcooling the refrigerant increases the cooling capacity of the HVAC system 400 compared to not using the TESD 440 by allowing a higher heat absorption rate in the additional cycle stages discussed below.The amount of refrigerant flowing through the TESD 440, and therefore the amount of subcooling, depends on the overall load demands of the HVAC 400 system and the ambient conditions. The subcooled refrigerant then enters the second 410 expansion device, where it expands into a predominantly liquid, low-pressure refrigerant. As mentioned earlier, the subcooling allows the second 410 expansion device to operate more efficiently because all the refrigerant is in liquid form. The low-pressure liquid refrigerant then enters the 422 evaporator, where it evaporates into a low-pressure vapor refrigerant. The low-pressure vapor refrigerant then enters the 430 compressor, where it is compressed into a compressed vapor refrigerant, and the cycle repeats. With reference now to FIGURE 5, FIGURE 5 is a simplified block diagram of another configuration of an HVAC 500 system. The HVAC 500 system includes a compressor 530, an outdoor heat exchanger or condenser 524, a first control valve 502, a first expansion device (“TESD”) 509, a TESD 540, a second control valve 506, a third control valve 508, a second expansion device (evaporator) 510, an indoor heat exchanger or evaporator 522, and a control system 512. The control system 512 is an electronic (wired or wireless) communication system for the compressor 530, the control valves 502, 506, 508, and the The PLQfrLn / ZZnZ / B / YILI expansion devices 509 and 510 are programmed to select from multiple operating modes based on the load in the HVAC 500 system and / or user input, as described below. The HVAC 500 system also includes a separate cooling circuit 550, the components and operation of which are described below. In load mode, typically used during off-peak hours, control system 512 is programmed to operate compressor 530 to compress the refrigerant into a high-pressure vapor that flows through condenser 524, where it condenses into a high-pressure liquid. Control system 512 is programmed to regulate refrigerant flow by controlling the operation of compressor 530 and other components based on the HVAC system load 500 and ambient conditions. Control system 512 is also programmed to operate the first control valve 502 to allow high-pressure liquid refrigerant to enter the TESD 509 expansion device, which may be a variable expansion device and is adjusted by control system 512 to expand and decrease the pressure in the refrigerant. The refrigerant then flows through the TESD 540, which includes a flow path through a thermal energy storage medium within the TESD 540. The flow of refrigerant through the TESD 540 charges it with thermal energy by absorbing heat from the refrigerant through a heat exchange process. This results in a reduction of the temperature of the medium in the TESD 540, a reduction in refrigerant pressure, and partial or total evaporation of the refrigerant.The amount of media loading in the TESD 540 depends on the total capacity of the HVAC 500 system, the anticipated cooling loads in the system, and the ambient conditions. The control system 512 is also programmed to operate the second control valve 506 so that at least a portion of the low-pressure refrigerant flows through a bypass flow path 518, diverting it from and preventing it from flowing through the evaporator 522. The low-pressure refrigerant then re-enters the compressor 530, where it is recompressed into a high-pressure refrigerant, and the cycle is repeated. As described above, the TESD 540 charge can be provided individually or in conjunction with the partial-charge operation of the evaporator 522. In a discharge mode, as shown in FIGURE 5 and illustrated in FIGURE 6 and typically used during higher load times or maximum load, the control system 512 is programmed to operate the compressor 530 to compress the refrigerant into a high-pressure vapor refrigerant that flows through the condenser 524, where the refrigerant is condensed into a high-pressure liquid refrigerant. The control system 512 is also programmed to operate the first control valve 502 so that at least a portion of the high-pressure liquid refrigerant flows through a bypass flow path 516, thereby bypassing the TESD expansion device 509 and the TESD 540 and remaining as a high-pressure liquid. The 512 control system is also programmed to operate the second valve of PLQfrLn / ZZnZ / B / YIAI control 506 allows refrigerant to enter the second expansion device 510, where it expands into low-pressure liquid refrigerant. If the second expansion device is not required, control system 512 can also control the third control valve 508 to direct the refrigerant to bypass the second expansion device 510 by flowing through a bypass flow path 520. The low-pressure liquid refrigerant then enters the evaporator 522, where it evaporates into low-pressure vapor refrigerant. The low-pressure vapor refrigerant then enters the compressor 530, where it is compressed into high-pressure vapor refrigerant, and the cycle repeats. Also during unloading mode, the control system 512 is programmed to operate a cooling pump 552 to circulate a cooling fluid through the cooling circuit 550. The cooling fluid exiting the pump 552 flows through the TESD 540 with the thermal energy storage media charged. The thermally charged storage media absorbs heat from the fluid, thus cooling the fluid in the cooling circuit 550. The cooling fluid then flows to a heat exchanger 560, which is positioned upstream of the evaporator 522 with respect to the airflow, to adjust the temperature of the air flowing over the evaporator 522. Cooling the refrigerant and thus preconditioning the air flowing over the evaporator 522 increases the cooling capacity of the HVAC system 500 compared to not using the TESD 540.Precooling the airflow over evaporator 522 allows evaporator 522 to operate more efficiently without requiring further refrigerant pressure reduction, as shown by dotted line 660 in Figure 6. Requiring less expansion allows for a higher rate of heat absorption in later stages of the cycle. The amount of refrigerant flowing through TESD 540, and therefore the overall cooling capacity of HVAC system 500, depends on the overall load demands of HVAC system 500 and ambient conditions. Figure 7 is a block diagram of a 700 controller that can be used in control systems to control HVAC systems as described above. The 700 controller includes at least one 702 processor, a 704 non-transient computer-readable medium, an optional 706 network communication module, optional 708 input / output devices, and an optional 710 display, all interconnected via a 712 system bus. In at least one configuration, the 708 input / output device and the 710 display can be combined into a single device, such as a touchscreen. The software instructions executable by the 702 processor to implement the software instructions stored within the 700 controller, according to the illustrative configurations described herein, can be stored on the 704 non-transient computer-readable medium or some other non-transient computer-readable medium. Although not explicitly shown in FIGURE 7, it will be recognized that the 700 controller can connect to one or more public and / or private networks via appropriate network connections. It will also be recognized that software instructions can be loaded onto the non-transient, computer-readable 704 medium from an appropriate storage medium or via wired or wireless means. PLQfrLn / ZZnZ / B / YIAI It should be noted that each of the HVAC systems of the modalities shown and described in this document are configured and can operate in a standard cooling mode of a typical refrigeration cycle of compressor, condenser, expansion device and evaporator. While aspects of the present description may be subject to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular embodiments described. Rather, the invention is to cover all modifications, equivalents, and alternatives that fall within the spirit and scope of the invention as defined in the following appended claims. For example, certain embodiments described herein contemplate use with a motorized fan instead of an induction fan, or without any fan at all. Furthermore, the rotating equipment (e.g., motors) and valves described herein are intended to operate at specific speeds or variable speeds via a reversing circuit, for example.Furthermore, internal and external oven communication can be achieved through wired or wireless communications, including well-known communication protocols such as Wi-Fi, 802.11(x), and Bluetooth, to name just a few. NOVELTY OF THE INVENTION Having described the present invention, the following is considered novel and is therefore claimed as property:

Claims

1. A heating, ventilation, and air conditioning (“HVAC”) system for use with a refrigerant, the HVAC system being characterized in that it comprises: a compressor operable for compressing the refrigerant; a condenser located downstream of the compressor and configured to condense the refrigerant flowing through it; an evaporator expansion device located downstream of the condenser and configured to reduce the pressure of the refrigerant flowing through it; an evaporator located downstream of the evaporator expansion device and upstream of the compressor, the evaporator being configured to vaporize the refrigerant flowing through it; a thermal energy storage device (“TESD”) including in-line thermal energy storage means between the condenser and the evaporator;and a control system comprising a controller programmed to: operate the compressor and evaporator expansion device to control the flow of refrigerant through the HVAC system; control the flow of refrigerant through the TESD to charge the TESD with thermal energy; and control the flow of refrigerant through the evaporator expansion device and the evaporator and discharge the thermal energy from the charged TESD to improve the performance of the HVAC system.

2. The HVAC system according to claim 1, characterized in that when the TESD is charged, the controller is programmed to control the flow of refrigerant through an expansion device of the TESD upstream of the TESD.

3. The HVAC system according to claim 1, characterized in that when the TESD is charged, the controller is programmed to control at least a portion of the refrigerant flow to divert the evaporator expansion device and the evaporator.

4. The HVAC system according to claim 1, characterized in that when the TESD is charged, the controller is programmed to control at least a portion of the refrigerant flow to divert the evaporator expansion device and flow through the evaporator.

5. The HVAC system according to claim 1, characterized in that the controller is programmed to control at least a portion of the refrigerant flow to prevent TESD.

6. The HVAC system according to claim 1, characterized in that upon unloading the TESD, the controller is programmed to control the refrigerant flow to divert an expansion device from the TESD upstream of the TESD and flow through the TESD.

7. The HVAC system according to claim 1, characterized in that when discharging the TESD, the controller is programmed to control the refrigerant flow to divert a TESD expansion device upstream of the TESD and at least a portion of the refrigerant flow to divert the evaporator expansion device and the evaporator.

8. The HVAC system according to claim 1, characterized in that when discharging the TESD, the controller is programmed to control the refrigerant flow to divert an upstream TESD expansion device and at least a portion of the refrigerant flow to divert the evaporator expansion device and flow through the evaporator.

9. The HVAC system according to claim 1, characterized in that when discharging the TESD, the controller is programmed to control at least a portion of the refrigerant flow to divert the TESD and an expansion device upstream of the TESD.

10. The HVAC system according to claim 9, characterized in that upon discharge of the TESD, the controller is further programmed to control the operation of a pump to flow a fluid in a secondary cooling circuit separate from the refrigerant flow of the HVAC system and through the TESD to cool the fluid and then through a heat exchanger upstream of the evaporator with respect to the airflow, with the cooled airflow from the heat exchanger flowing over the evaporator to enhance the performance of the evaporator.

11. The HVAC system according to claim 10, characterized in that the performance of the evaporator is improved by allowing the evaporator to operate more efficiently and without further reduction of the refrigerant pressure.

12. The HVAC system according to claim 1, characterized in that the controller is programmed to control at least a portion of the refrigerant flow to divert the evaporator expansion device and the evaporator and flow through the compressor, condenser and TESD to charge the TESD.

13. The HVAC system according to claim 1, characterized in that the compressor, condenser, evaporator expansion device, evaporator and TESD comprise one circuit in a multi-circuit HVAC system, the remaining circuits optionally comprising TESD.

14. The HVAC system according to claim 1, characterized in that the controller is programmed to direct the flow of refrigerant through the TESD and the evaporator and to control the evaporator expansion device and a TESD expansion device upstream of the TESD to charge the TESD and also to vaporize the refrigerant flowing through the evaporator.

15. The HVAC system according to claim 1, characterized in that the controller is programmed to control a TESD expansion device upstream of the TESD together with the evaporator expansion device to control the TESD charge and vaporize the refrigerant flowing through the evaporator.

16. The HVAC system according to claim 1, characterized in that the performance of the HVAC system is improved by charging the TESD at a temperature that is equal to or higher than the evaporation temperature of the refrigerant in the evaporator so that the discharge of the TESD PLQfrLn / zznz / e / YiAi cools the refrigerant and ensures that the refrigerant is in liquid form before expansion in the evaporator expansion device.

17. The HVAC system according to claim 1, characterized in that the performance of the HVAC system is improved by charging the TESD at a temperature below the evaporation temperature of the refrigerant in the evaporator in such a way that the enthalpy of the refrigerant is reduced before the refrigerant flows through the evaporator, thereby improving evaporation by the evaporator.

18. The HVAC system according to claim 1, characterized in that the controller is programmed to control the refrigerant flow based on at least one load in the HVAC system or the surrounding environment.

19. A control system for a heating, ventilation, and air conditioning (“HVAC”) system comprising a compressor, a condenser, an evaporator expansion device, and an evaporator for temperature control with a refrigerant, the HVAC system further comprising a thermal energy storage device (TESD) comprising in-line thermal energy storage means between the condenser and the evaporator, the control system characterized in that it comprises a controller programmed to: operate the compressor and the evaporator expansion device to control the flow of refrigerant through the HVAC system; control the flow of refrigerant through the TESD to charge the TESD with thermal energy; and control the flow of refrigerant through the evaporator expansion device and the evaporator and discharge the thermal energy from the charged TESD to improve the performance of the HVAC system.

20. The control system according to claim 19, characterized in that when the TESD is charged, the controller is programmed to control the flow of refrigerant through an expansion device of the TESD upstream of the TESD.

21. The HVAC system according to claim 19, characterized in that when TESD is charged, the controller is programmed to control at least a portion of the refrigerant flow to prevent TESD.

22. The control system according to claim 19, characterized in that when the TESD is discharged, the controller is programmed to control the flow of refrigerant to divert an expansion device from the TESD upstream of the TESD and flow through the TESD.

23. The HVAC system according to claim 19, characterized in that when the TESD is discharged, the controller is programmed to control the refrigerant flow to divert the TESD and an upstream TESD expansion device.

24. The control system of claim 23, wherein when the TESD is discharged, the controller is further programmed to control the operation of a pump to flow a fluid in a secondary cooling circuit separate from the HVAC system refrigerant flow and through the TESD to cool the fluid and then through a heat exchanger upstream of the evaporator with respect to the airflow, with the cooled airflow from the heat exchanger flowing over the evaporator to enhance the evaporator's performance.

25. The HVAC system of claim 24, wherein the performance of the evaporator is improved by allowing the evaporator to operate more efficiently and without further reduction of the refrigerant pressure.

26. The HVAC system according to claim 19, characterized in that when TESD is discharged, the controller is programmed to control at least a portion of the refrigerant flow to prevent TESD.

27. The HVAC system according to claim 19, characterized in that the controller is programmed to control the flow of refrigerant to divert the evaporator expansion device and the evaporator and flow through the compressor, condenser and TESD to charge the TESD.

28. The HVAC system according to claim 19, characterized in that the compressor, condenser, evaporator expansion device, evaporator and TESD comprise one circuit in a multi-circuit system, the remaining circuits optionally comprising TESD.

29. The HVAC system according to claim 19, characterized in that the controller is programmed to direct the flow of refrigerant through the TESD and the evaporator and to control the evaporator expansion device and a TESD expansion device upstream of the TESD to charge the TESD and also to vaporize the refrigerant flowing through the evaporator.

30. The HVAC system according to claim 19, characterized in that the performance of the HVAC system is improved by charging the TESD at a temperature that is equal to or higher than the evaporation temperature of the refrigerant in the evaporator, so that the discharge from the TESD cools the refrigerant and ensures that the refrigerant is in liquid form prior to expansion in the evaporator expansion device.

31. The HVAC system according to claim 19, characterized in that the performance of the HVAC system is improved by charging the TESD at a temperature below the evaporation temperature of the refrigerant in the evaporator in such a way that the enthalpy of the refrigerant is reduced before the refrigerant flows through the evaporator, thereby improving evaporation by the evaporator.

32. The HVAC system according to claim 19, characterized in that the controller is programmed to control the refrigerant flow based on at least one load in the HVAC system or the surrounding environment.

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