Systems and Methods to Control Operation of Heat Pump Assemblies Having Reheat Coils

Abstract

A heat pump system is disclosed. The heat pump system may include a compressor, a reheat coil configured to receive a refrigerant from the compressor, and a valve configured to control a flow of the refrigerant to the reheat coil. The heat pump system may be configured to operate in a cooling mode or a heating mode based on a direction of flow of refrigerant through the heat pump system. The valve may route hot refrigerant from the compressor to the reheat coil when the heat pump system is operating in the heating mode.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to and the benefit of U.S. provisional Application No. 63 / 765,841, filed Mar. 3, 2025, which is hereby incorporated by reference herein in its entirety.FIELD

[0002] The present disclosure relates to systems and methods to control operation of heat pump assemblies having reheat coils and more specifically to systems and methods to control a flow of refrigerant in a reheat coil of a heat pump assembly that can operate in a cooling mode and a heating mode.BACKGROUND

[0003] Refrigerant circuits or heat pump assemblies are used in Heating, Ventilation, and Air Conditioning (HVAC) systems. A heat pump assembly typically includes a compressor, an evaporator, an expansion valve, and a condenser. It is known that an HVAC system causes moisture present in ambient air to condense on the cool evaporator coil when the ambient air has relatively high humidity level and the HVAC system operates in a cooling mode. Condensation of the moisture on the evaporator coil ensures that the humidity level of the air inside the room / building, where the HVAC system is installed, is reduced and within a comfortable range for the room occupants.BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The detailed description is set forth with reference to the accompanying drawings. The use of the same reference numerals may indicate similar or identical items. Various embodiments may utilize elements and / or components other than those illustrated in the drawings, and some elements and / or components may not be present in various embodiments. Elements and / or components in the figures are not necessarily drawn to scale. Throughout this disclosure, depending on the context, singular and plural terminology may be used interchangeably.

[0005] FIG. 1 depicts a block diagram of an exemplary heat pump system including a first heat pump assembly in accordance with one or more embodiments of the present disclosure.

[0006] FIG. 2 depicts a block diagram of an exemplary second heat pump assembly in accordance with one or more embodiments of the present disclosure.

[0007] FIG. 3 depicts a block diagram of an exemplary third heat pump assembly in accordance with one or more embodiments of the present disclosure.

[0008] FIG. 4 depicts a block diagram of an exemplary fourth heat pump assembly in accordance with one or more embodiments of the present disclosure.

[0009] FIG. 5 depicts a block diagram of a controller in accordance with one or more embodiments of the present disclosure.

[0010] FIG. 6 depicts a flow diagram of an exemplary method to control an operation of a valve of a heat pump assembly in accordance with one or more embodiments of the present disclosure.DETAILED DESCRIPTION

[0011] The present disclosure is directed towards a heat pump system (“system”) that may be part of a Heating, Ventilation, and Air Conditioning (HVAC) unit, a packaged terminal air conditioner (PTAC) unit, a window unit, a vertical packaged unit, a Variable Refrigerant Flow (VRF) system, a ducted system, a packaged rooftop system, a split unit, an indoor / outdoor unit, and / or the like. Although the present disclosure is described in the context of an HVAC system, the description should not be construed as limited only to HVAC systems.

[0012] The system may operate in a heating mode or a cooling mode. The system may heat a room / building (where the system is installed) when the system operates in the heating mode and may cool the room / building when the system operates in the cooling mode.

[0013] The system may include a plurality of components / modules including, but not limited to, a heat pump assembly, a controller, a sensor unit, etc. The heat pump assembly may include a compressor, a first heat exchanger, a second heat exchanger, an expansion valve, a reversing valve, a modulating valve or a solenoid valve, and a reheat coil. The compressor, the first heat exchanger, the second heat exchanger and the expansion valve may be connected via a refrigerant tubing. During the operation of the heat pump assembly, a refrigerant may flow through these components via the refrigerant tubing. The reversing valve may reverse the flow of refrigerant in the heat pump assembly to switch the operating mode of the system between the cooling mode and the heating mode.

[0014] In some aspects, the second heat exchanger may be located inside the room / building (or otherwise be in heat exchange with the room / building via one or more ducts) and may cause heating / cooling of the room based on the operating mode of the system. Further, the first heat exchanger may be located outside of the room. In an exemplary aspect, the second heat exchanger may be a condenser and the first heat exchanger may be an evaporator when the system operates in the heating mode. When the system operates in the heating mode (i.e., when the system heats the room), the reversing valve may cause the refrigerant in a high temperature, high pressure vapor state output from the compressor to flow towards the second heat exchanger, which may condense the refrigerant to a liquid phase. The heat that the second heat exchanger provides while condensing the refrigerant from the vapor state to the liquid state may heat the room. In this manner, the system heats the room via the second heat exchanger when the system operates in the heating mode.

[0015] The refrigerant output from the second heat exchanger may flow to the expansion valve and then to the first heat exchanger where the refrigerant is converted into vapor state. The refrigerant output from the first heat exchanger flows to the compressor, thus completing the vapor cycle of the heat pump assembly.

[0016] In some aspects, the heat exchanger (e.g., the second heat exchanger) that is located inside the room / building (or in heat exchange with the room / building via one or more ducts) may be of a smaller size than the heat exchanger (e.g., the first heat exchanger) that is located outside the room / building (or otherwise in heat exchange with the outdoor ambient environment). Consequently, when the system operates in the heating mode, “refrigerant imbalance” may occur in the heat pump assembly (due to the size difference between the coils of the first heat exchanger and the second heater exchanger). In some aspects, the refrigerant imbalance occurs as the total surface area for heat exchange is different in the first heat exchanger relative to the second heat exchanger due to the size difference in their coils. Conventionally, this refrigerant imbalance is handled by storing some of the “excess” refrigerant in an accumulator (or elsewhere) in the system; however, such a method of handling the refrigerant imbalance reduces the capacity of the system in the heating mode (vs. the capacity of the system in the cooling mode).

[0017] To overcome the challenges associated with the conventional method of handling refrigerant imbalance described above, the system, as proposed in the present disclosure, includes the reheat coil that is disposed parallel to the second heat exchanger. The reheat coil and the second heat exchanger in combination acts as an effective “bigger” indoor coil or heat exchanger of the system, and thus increases the capacity of the system in the heating mode.

[0018] When the system is operating in the heating mode, the system may route some refrigerant in a high temperature state output from the compressor towards the reheat coil, which may be connected in parallel to the second heat exchanger in the room / building (or be in heat exchange with the room / building via one or more ducts). The reheat coil may operate in a similar manner as the second heat exchanger and may act as an “extension” of the second heat exchanger. The reheat coil and the second heat exchanger may collectively transfer heat to the room when the refrigerant in high temperature state flows through them, thereby facilitating in heating the room / building (or increasing the room temperature).

[0019] In some aspects, the reheat coil may not be of the same size as the second heat exchanger. Specifically, in an exemplary aspect, the reheat coil may be smaller in size than the second heat exchanger. Consequently, when the refrigerant flows through both the reheat coil and the second heat exchanger in the heating mode, the pressure drop of the refrigerant in the reheat coil may be less than the refrigerant pressure drop in the second heat exchanger (due to the smaller size of the reheat coil). It may be appreciated that if the refrigerant pressure drop is less in the reheat coil, more refrigerant may tend to flow through the reheat coil as compared to the second heat exchanger. This may be an undesirable scenario and may affect the heating of the room.

[0020] To avoid such a scenario, the system may include a modulating valve that may modulate the flow of refrigerant from the compressor to the reheat coil (or control an amount of refrigerant that flows to the reheat coil), thereby controlling / modulating an amount of refrigerant that is provided to the reheat coil. In some aspects, the modulating valve may be disposed after the reheat coil (or at the output of the reheat coil) in the heat pump assembly. In an exemplary aspect, the controller may control the operation of the modulating valve based on the pressure of refrigerant flowing through the reheat coil and the second heat exchanger. In some aspects, the controller may control the operation of the modulating valve such that the refrigerant pressure in both the reheat coil and the second heat exchanger may be equivalent (or substantially equivalent), so that the refrigerant does not tend to flow more towards one coil than the other. As an example, the controller may cause the modulating valve to enable more refrigerant to flow through the reheat coil when the refrigerant pressure in the reheat coil may be dropping (or be less than the refrigerant pressure in the second heat exchanger). Similarly, the controller may cause the modulating valve to enable less refrigerant to flow through the reheat coil when the refrigerant pressure in the reheat coil may be high (or be more than the refrigerant pressure in the second heat exchanger). In this manner, the controller enables the reheat coil to effectively act as an “extension” of the second heat exchanger and prevents a scenario where one coil receives more refrigerant than the other (thereby preventing pressure imbalance in the heat pump assembly).

[0021] In further aspects, when the system includes a solenoid valve (as opposed to the modulating valve described above), the solenoid valve may enable or disable the flow of refrigerant from the compressor to the reheat coil (and may not regulate / control an amount of refrigerant that flows into the reheat coil) based on the pressure of refrigerant flowing through the reheat coil and the second heat exchanger.

[0022] The system may operate in a similar but reverse manner when the system operates in the cooling mode (i.e., when the system cools the room). When the system operates in the cooling mode, the reversing valve may cause the refrigerant in a high temperature, high pressure vapor state output from the compressor to flow towards the first heat exchanger, which may condense the refrigerant to a liquid phase. In this case, the first heat exchanger may be the condenser and the second heat exchanger (that is located in the room / building or be in heat exchange with the room / building via one or more ducts) may be the evaporator. The first heat exchanger may output the refrigerant to the expansion valve, which may transfer the refrigerant to the second heat exchanger. The second heat exchanger may vaporize the refrigerant and transfer the refrigerant in vapor state to the compressor, thus completing the vapor cycle of the heat pump assembly. In some aspects, the second heat exchanger extracts heat from the room to vaporize the refrigerant, thereby cooling the room when the system operates in the cooling mode.

[0023] There may be instances when the system may cause the second heat exchanger to cool below the set point temperature when the system operates in the cooling mode to effectively cause the moisture present in the ambient air of the room to condense on the cool second heat exchanger coils (thereby reducing the humidity level in the room). While cooling the second heat exchanger coils in this manner may reduce the humidity level in the room, it may, in some instances, cause the room temperature to become too cold for the room occupants. To make the ambient temperature in the room comfortable for the occupants (and equivalent to or within a threshold of the set point temperature), the controller may cause some amount of refrigerant in hot temperature state to flow in the reheat coil, which may cause the reheat coil to transfer some heat to the room (thereby increasing the room temperature to the set point temperature). In this case, the controller may control / regulate the amount of refrigerant that flows to the reheat coil via the modulating valve based on the pressure of refrigerant flowing through the reheat coil and the first heat exchanger. In another embodiment, the position of the modulating valve may be pre-fixed (e.g., when the system is operating at a higher end of operating frequency), and may not be changed by the controller based on pressure readings described above. In this case, the pre-fixed position of the modulating valve may ensure optimal flow of refrigerant through the reheat coil for a wide range of expected indoor and outdoor temperatures. In yet another embodiment, the position of the modulating valve may be adjusted based on temperature readings near the output of the modulating valve or the expansion valve (instead of or in addition to using the pressure readings). In some aspects, the pressure readings may be made at the same place in the heat pump assembly where the temperature readings are made.

[0024] In alternative aspects, when the system includes the solenoid valve, the controller may cause the solenoid valve to enable or disable the flow of refrigerant from the compressor to the reheat coil based on the pressure of refrigerant flowing through the reheat coil and the first heat exchanger.

[0025] Although certain examples of the disclosed technology are explained in detail herein, it is to be understood that other examples, embodiments, and implementations of the disclosed technology are contemplated. Accordingly, it is not intended that the disclosed technology is limited in its scope to the details of construction and arrangement of components expressly set forth in the following description or illustrated in the drawings. The disclosed technology can be implemented in a variety of examples and can be practiced or carried out in various ways. In particular, the presently disclosed subject matter is described in the context of being a system and method for controlling an operation of a heat pump assembly of a Heating, Ventilation, and Air Conditioning (HVAC) system, a packaged terminal air conditioner (PTAC) unit, a window unit, a vertical packaged unit, a Variable Refrigerant Flow (VRF) system, a ducted system, a packaged rooftop system, a split unit, and / or the like. The present disclosure, however, is not so limited, and can be applicable in other contexts.

[0026] Furthermore, the terms “cold” and “hot,” as used in the present disclosure, are relative and may mean different degrees of varying temperatures and ranges based on the context. Thus, the terms “cold” and “hot” should not be limited to any temperature or temperature range.

[0027] Turning now to the drawings, FIG. 1 depicts a block diagram of an exemplary heat pump system 100 (or system 100). The system 100 may be part of a Heating, Ventilation, and Air Conditioning (HVAC) unit / system that may be configured to cool or heat an interior portion of a room / building based on an operating mode of the system 100. In other aspects, the system 100 may be part of a packaged terminal air conditioner (PTAC) unit, a window unit, a vertical packaged unit, a Variable Refrigerant Flow (VRF) system, a ducted system, a packaged rooftop system, a split unit, and / or the like. Although the present disclosure is described in the context of an HVAC system, the description should not be construed as limited only to HVAC systems.

[0028] The system 100 may include a plurality of units including, but not limited to, a heat pump assembly 102, a controller 104, and a sensor unit 106. The system 100 may include a plurality of additional components that are not shown in FIG. 1 for the sake of simplicity and conciseness (e.g., a housing, a user interface, etc.).

[0029] The heat pump assembly 102 may include a plurality of components that may be connected via a refrigerant tubing 108, through which, during the heat pump assembly operation, a refrigerant may flow in a clockwise or counterclockwise direction (based on an operating mode of the system 100, as described later below). The refrigerant may be selected from a variety of materials. The refrigerant may be any material capable of supplying favorable thermodynamic properties to a heat pump system. The refrigerant, for example, may be selected based on a desired boiling point, a high heat of vaporization, a moderate liquid density, a high critical temperature, and / or other aspects. Accordingly, the refrigerant may be any chlorofluorocarbon, chlorofluoroolefin, hydrochlorofluorocarbon, hydrochlorofluoroolefin, hydrofluorocarbon, hydrofluoroolefin, hydrochlorocarbon, hydrochloroolefin, hydrocarbon, hydroolefin, perfluorocarbon, perfluoroolefin, perchlorocarbon, perchloroolefin, halon, or haloalkane. For example, the refrigerant may be any refrigerant designated as such by, and compliant with, the standards, rules, and regulations set forth by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) (e.g., ASHRAE Standard 34-2019). For example, the refrigerant may be R-410A or R-134a. In some embodiments, the refrigerant may be or may include a hydrofluoroolefin, such as HFO-1234yf or blends thereof, including R-454B.

[0030] Example of the components of the heat pump assembly 102 include, but are not limited to, a first heat exchanger 110, a compressor 112, a second heat exchanger 114 and an expansion device 116 (hereinafter referred to as expansion valve 116) connected by the refrigerant tubing 108, through which, during heat pump operation, the refrigerant may flow.

[0031] In some aspects, the system 100 may operate either in a heating mode or a cooling mode based on the direction of the flow of refrigerant through the components of the heat pump assembly 102. The system 100 may heat the interior portion of the room / building (e.g., during winter season) when the system 100 operates in the heating mode, and the system 100 may cool the interior portion of the room / building (e.g., during summer season) when the system 100 operates in the cooling mode. The direction of the flow of refrigerant in the heat pump assembly 102 depends on the mode in which the system 100 may be operating. In the exemplary view of the heat pump assembly 102 depicted in FIG. 1, the system 100 is operating in the heating mode. An exemplary view of the heat pump assembly 102 in which the system 100 is operating in the cooling mode is depicted in FIG. 2 and described later in the description below.

[0032] The heat pump assembly 102 may further include a reversing valve 118 (or a first reversing valve 118) that may reverse the flow of refrigerant in the heat pump assembly 102 to switch the operating mode of the system 100 between the heating mode and the cooling mode based on command signals received from the controller 104 (and user input). When the system 100 operates in the heating mode, the refrigerant may flow from an outlet of the compressor 112 to the first reversing valve 118, which may cause the refrigerant to flow into an inlet of the second heat exchanger 114. The second heat exchanger 114 may be a condenser and disposed inside the room / building (or otherwise be in heat exchange with the room / building via one or more ducts) when the system 100 operates in the heating mode. The refrigerant may then flow from an outlet of the second heat exchanger 114 to the expansion valve 116 and then through the first heat exchanger 110 to the inlet of the compressor 112 via the first reversing valve 118.

[0033] When the system 100 operates in the heating mode, the first heat exchanger 110 may be an evaporator (having evaporator coils and fan, not shown) and the second heat exchanger 114 may be a condenser (as described above) having condenser coils and fans (not shown). During operation, the compressor 112 may output the refrigerant in a vapor state towards the second heat exchanger 114 via the first reversing valve 118. The refrigerant output from the compressor 112 may be in a high temperature and high pressure state. The second heat exchanger 114 may receive the refrigerant from the compressor 112 via the refrigerant tubing 108 and may condense the refrigerant into liquid state. In some aspects, the heat that the second heat exchanger 114 provides while condensing the refrigerant phase from vapor to liquid may be used to heat the room in which the second heat exchanger 114 may be located (or thermally connected with via one or more ducts). Specifically, the condenser fan may blow air towards the interior portion of the room via the condenser coils, which may transfer the heat from the condenser coils to the room's interior portion, thereby heating the room. In this manner, the system 100 may heat the room when the system 100 operates in the heating mode.

[0034] The second heat exchanger 114 may further output the refrigerant in a liquid state towards the expansion valve 116 via the refrigerant tubing 108. The refrigerant output from the second heat exchanger 114 may be at high pressure and medium-to-high temperature state. The expansion valve 116 may receive the refrigerant from the second heat exchanger 114 and may output the refrigerant in a low pressure, low temperature state towards the first heat exchanger 110 via the refrigerant tubing 108. The refrigerant output from the expansion valve 116 may be in a mixture of liquid and vapor states.

[0035] The first heat exchanger 110 may receive the refrigerant from the expansion valve 116 and may vaporize the refrigerant into a low pressure, vapor state refrigerant. The first heat exchanger 110 may include a fan (not shown) that may draw air from ambient environment and blow it towards the first heat exchanger 110. The first heat exchanger 110 may draw heat / warmth from the air that is received from the fan and may transfer the warmth towards the refrigerant received from the expansion valve 116, thereby vaporizing the refrigerant. The first heat exchanger 110 may output the refrigerant in vapor state towards the compressor 112 via the first reversing valve 118. The compressor 112 may receive the refrigerant from the first heat exchanger 110 and may “compress” the refrigerant to output the refrigerant in a high pressure, high temperature state towards the second heat exchanger 114 via the first reversing valve 118, as described above. In this manner, the refrigerant flows through the heat pump assembly 102 when the system 100 operates in the heating mode, causing the interior portion of the room to be heated by the second heat exchanger 114.

[0036] In some aspects, the compressor 112 may be a pump that provides additional pressure to the refrigerant to enable the refrigerant to flow through the defined path as indicated in FIG. 1. The compressor 112 may be of any type. For example, the compressor 112 may be a positive displacement compressor, a reciprocating compressor, a rotary screw compressor, a rotary vane compressor, a rolling piston compressor, a scroll compressor, a diaphragm compressor, a dynamic compressor, an axial compressor, or any other form of compressor that can be integrated into the heat pump assembly 102 for the particular application.

[0037] In some aspects, the heat exchanger (e.g., the second heat exchanger 114) that is located in the interior portion of the room / building or be in heat exchange with the room / building via one or more ducts may be of a smaller size than the heat exchanger (e.g., the first heat exchanger 110) that is located outside the room / building. Consequently, when the system 100 operates in the heating mode, “refrigerant imbalance” may occur in the heat pump assembly 102 due to the difference in the coil sizes of the first heat exchanger 110 as compared to the second heat exchanger 114.

[0038] To effectively handle the challenge of refrigerant imbalance in the system 100, the system 100, as proposed in the present disclosure, may include a reheat coil 120 that is disposed parallel to the second heat exchanger 114. For example, air may be directed by one or more fans to pass over / through the second heat exchanger 114 and then pass over / through the reheat coil 120 before being directed to the interior portion of the room for heating or cooling. In the heating mode, the reheat coil 120 and the second heat exchanger 114 in combination may act as an effective “bigger” indoor coil or heat exchanger and thus increase the capacity of the system 100 in the heating mode.

[0039] The reheat coil 120 may be similar to the second heat exchanger 114, and may provide heat to the room / building, in addition to the heat that the second heat exchanger 114 provides. In some aspects, the reheat coil 120 may be located in the interior portion of the room / building or be in heat exchange with the room / building via one or more ducts to effectively provide heat to the room.

[0040] The reheat coil 120 may receive some amount of refrigerant in a high pressure, high temperature vapor state from the compressor 112 and condense the received refrigerant into a liquid state similar to the operation of the second heat exchanger 114. In some aspects, the reheat coil 120 may operate in a similar manner as the second heat exchanger 114 and may be connected in parallel to the second heat exchanger 114 in the heat pump assembly 102. The reheat coil 120 may condense the refrigerant in a vapor state received from the compressor 112 to a liquid state and may output the refrigerant in the liquid state (similar to the operation of the second heat exchanger 114). The heat that the reheat coil 120 provides while condensing the refrigerant phase from vapor to liquid may be used to heat the interior portion of the room in which the reheat coil 120 may be located. In this manner, the reheat coil 120 acts as an extension of the second heat exchanger 114 and increases the “effective” size of the indoor coil of the system 100 to reduce the refrigerant imbalance described above.

[0041] In some aspects, the reheat coil 120 may not be of the same size as the second heat exchanger 114. Specifically, in an exemplary aspect, the reheat coil 120 may be smaller in size than the second heat exchanger 114. Consequently, when the refrigerant flows through both the reheat coil 120 and the second heat exchanger 114 in the heating mode, the pressure drop of the refrigerant in the reheat coil 120 may be less than the refrigerant pressure drop in the second heat exchanger 114 (due to the smaller size of the reheat coil 120). It may be appreciated that if the refrigerant pressure drop is less in the reheat coil 120, more refrigerant may tend to flow through the reheat coil 120 as compared to the second heat exchanger 114. This may be an undesirable scenario and may affect the heating of the room / building.

[0042] To avoid such a scenario, the system 100 / heat pump assembly 102 may additionally include a valve 122 (or a modulating valve 122) that may control / regulate the flow of refrigerant from the compressor 112 to the reheat coil 120 based on the pressure of refrigerant flowing through the reheat coil 120 and the second heat exchanger 114. In an exemplary aspect, the valve 122 may be disposed after the reheat coil 120 or at the output of the reheat coil 120 in the heat pump assembly 102. In some aspects, in addition to controlling / modulating the flow of refrigerant in the reheat coil 120, the valve 122 may operate like an expansion valve, similar to the expansion valve 116. As an example, the refrigerant in liquid phase that the reheat coil 120 outputs may enter the modulating valve 122, which may output the refrigerant in a low pressure, low temperature state towards an outlet port of the expansion valve 116 or the first heat exchanger 110 via the refrigerant tubing 108. The refrigerant output from the modulating valve 122 may be in a mixture of liquid and vapor states.

[0043] The modulating valve 122 may be configured to operate in a fully closed position, a fully open position, and a partially open position based on command signals received from the controller 104. In another embodiment, the position of the valve 122 may be pre-fixed (e.g., when the system 100 is operating at a higher end of operating frequency), and may not be changed by the controller 104 based on pressure readings described above. In this case, the pre-fixed position of the valve 122 may ensure optimal flow of refrigerant through the reheat coil 120 for a wide range of expected indoor and outdoor temperatures. In yet another embodiment, the position of the valve 122 may be adjusted based on temperature readings near the output of the valve 122 or the expansion valve 116 (instead of or in addition to using the pressure readings). In some aspects, the pressure readings may be made at the same place in the heat pump assembly 102 where the temperature readings are made.

[0044] The modulating valve 122 may disable the flow of refrigerant from the compressor 112 to the reheat coil 120 when the modulating valve 122 operates in the fully closed position.

[0045] The modulating valve 122 may enable a maximum amount of refrigerant to flow from the compressor 112 to the reheat coil 120 (depending on the reheat coil 120 capacity / size) when the modulating valve 122 operates in the fully open position. Further, the modulating valve 122 may modulate the flow of refrigerant (between the maximum amount and zero flow of refrigerant) from the compressor 112 to the reheat coil 120 when the modulating valve 122 operates in the partially open position. In an exemplary aspect, the modulating valve 122 may modulate or regulate the flow of refrigerant from the compressor 112 to the reheat coil 120 based on an opening percentage of the modulating valve 122 in the partially open position. In some aspects, the controller 104 may control the opening percentage of the modulating valve 122 based on the pressure of refrigerant flowing through the reheat coil 120 and the second heat exchanger 114 by transmitting command signals to the modulating valve 122. In some aspects, the controller 104 may control the opening percentage of the modulating valve 122 such that the refrigerant pressure in both the reheat coil 120 and the second heat exchanger 114 may be equivalent (or substantially equivalent), so that the refrigerant does not tend to flow more towards one coil than the other. As an example, the controller 104 may cause the modulating valve 122 to enable more refrigerant to flow through the reheat coil 120 when the refrigerant pressure in the reheat coil 120 may be dropping (or be less than the refrigerant pressure in the second heat exchanger 114). Similarly, the controller 104 may cause the modulating valve 122 to enable less refrigerant to flow through the reheat coil 120 when the refrigerant pressure in the reheat coil 120 may be high (or be more than the refrigerant pressure in the second heat exchanger 114). In this manner, the controller 104 enables the reheat coil 120 to effectively act as an “extension” of the second heat exchanger 114, and prevents a scenario where one coil receives more refrigerant than the other.

[0046] The system 100 / heat pump assembly 102 may further include a first check valve 124 and a second check valve 126 that may be connected on the refrigerant tubing 108 downstream of the modulating valve 122. In some instances, the first and second check valves 124, 126 may be in parallel with each other along the refrigerant tubing 108. In some aspects, the first check valve 124 may be connected between an outlet port of the modulating valve 122 and an outlet port of the expansion valve 116 / an inlet port of the first heat exchanger 110, as shown in FIG. 1. Further, the second check valve 126 may be connected between the outlet port of the modulating valve 122 and an inlet port of the expansion valve 116 / an outlet port of the second heat exchanger 114. In some aspects, the first and second check valves 124, 126 may be configured to disable the flow of refrigerant in liquid phase through the check valves 124, 126. Stated another way, the first and second check valves 124, 126 may not enable refrigerant in the liquid phase to pass through.

[0047] Consequently, since the second heat exchanger 114 outputs the refrigerant in the liquid phase (as described above) when the system 100 operates in the heating mode, the second check valve 126 may disable the flow of refrigerant from the second heat exchanger 114 towards the modulating valve 122 when the system 100 operates in the heating mode. By disabling the flow of liquid refrigerant, the second check valve 126 prevents the refrigerant in the liquid phase (received from the second heat exchanger 114) from getting mixed with the refrigerant received from the modulating valve 122 (that may be a mixture of liquid and vapor phase), which in turn ensures that only the liquid phase refrigerant enters the inlet port of the expansion valve 116. It may be appreciated that the expansion valve 116 operates efficiently when it receives the refrigerant in the liquid phase. Therefore, the second check valve 126 ensures that the expansion valve 116 operates efficiently by blocking the mixing of the refrigerant in the liquid and vapor phase at the inlet port of the expansion valve 116.

[0048] The controller 104 may communicatively couple with the components of the heat pump assembly 102 and the sensor unit 106 and control the operation of one or more components of the heat pump assembly 102 based on inputs obtained from the sensor unit 106. In some aspects, the sensor unit 106 may include one or more pressure sensors configured to measure refrigerant pressure in the reheat coil 120, the first heat exchanger 110, the second heat exchanger 114, etc., and one or more temperature sensors, humidity sensors, and / or the like. The sensor unit 106 may transmit inputs to the controller 104, which may control the operation of one or more components of the heat pump assembly 102 based on the obtained inputs. For example, the controller 104 may control the operation of the modulating valve 122 to control the flow of refrigerant from the compressor 112 to the reheat coil 120 based on the refrigerant pressures in the reheat coil 120 and the second heat exchanger 114, as described below.

[0049] In operation, the controller 104 may first determine the operating mode of the system 100 in which the system user desires the system 100 to operate based on user inputs (obtained via a system user interface). For example, the controller 104 may determine whether the user desires the system 100 to operate in the cooling mode or the heating mode based on the user inputs. Responsive to determining that the user desires the system 100 to operate in the heating mode, the controller 104 may transmit a command signal to the first reversing valve 118 to cause the first reversing valve 118 to route the refrigerant output from the compressor 112 to the second heat exchanger 114, as described above.

[0050] Further, the controller 104 may compare the refrigerant pressures in the second heat exchanger 114 and the reheat coil 120 based on the inputs obtained from the sensor unit 106. The controller 104 may then transmit a command signal to control the operation of the modulating valve 122 based on the difference between the refrigerant pressures in the second heat exchanger 114 and the reheat coil 120, such that the refrigerant pressure in both the reheat coil 120 and the second heat exchanger 114 may become equivalent (or substantially equivalent), as described above. The controller 104 may perform such an action to ensure that the refrigerant does not flow more towards one coil than the other.

[0051] In the example embodiment described above, the controller 104 may regulate (i.e., increase or decrease) the flow of refrigerant into the reheat coil 120 by adjusting the opening percentage of the modulating valve 122. The controller 104 may adjust the opening percentage of the modulating valve 122 based on a difference between the refrigerant pressures in the reheat coil 120 and the second heat exchanger 114. In an exemplary aspect, the controller 104 may increase the opening percentage (thereby increasing the flow of refrigerant into the reheat coil 120) when the refrigerant pressure in the reheat coil 120 may be lower than the refrigerant pressure in the second heat exchanger 114.

[0052] In a similar manner, the controller 104 may decrease the opening percentage (thereby decreasing the flow of refrigerant into the reheat coil 120) when the refrigerant pressure in the reheat coil 120 may be greater than the refrigerant pressure in the second heat exchanger 114.

[0053] In this manner, the controller 104 may adjust the flow of refrigerant from the compressor 112 to the reheat coil 120 based on the inputs (e.g., refrigerant pressure values) measured by the sensor unit 106.

[0054] FIG. 2 depicts a block diagram of the heat pump assembly 102 when the system 100 operates in the cooling mode, in accordance with one or more embodiments of the present disclosure. As described above, the system 100 may cool the interior portion of the room when the system 100 operates in the cooling mode. The flow of refrigerant may be reversed (as compared to the flow depicted in FIG. 1) when the system 100 operates in the cooling mode.

[0055] When the system 100 operates in the cooling mode, the first reversing valve 118 may cause the compressor 112 to output the refrigerant in the vapor state towards the first heat exchanger 110, as shown in FIG. 2. In this case, the first heating exchanger 110 may be the condenser (and the second heat exchanger 114 may be the evaporator). The first heat exchanger 110 may receive the refrigerant from the compressor 112 via the refrigerant tubing 108 and may condense the refrigerant into a liquid state. The first heat exchanger 110 may further output the refrigerant in liquid state towards the expansion valve 116 via the refrigerant tubing 108. The refrigerant output from the first heat exchanger 110 may be at a high pressure and medium-to-high temperature state. The expansion valve 116 may receive the refrigerant from the first heat exchanger 110 and may output the refrigerant in a low pressure, low temperature state towards the second heat exchanger 114 via the refrigerant tubing 108. The refrigerant output from the expansion valve 116 may be in a mixture of liquid and vapor states.

[0056] The second heat exchanger 114 may receive the refrigerant from the expansion valve 116 and may vaporize the refrigerant into a low pressure, vapor state refrigerant. The second heat exchanger 114 may include a fan (not shown) that may draw air from ambient environment and blow it towards the second heat exchanger 114. The second heat exchanger 114 may draw heat / warmth from the air that is received from the fan and may transfer the warmth towards the refrigerant received from the expansion valve 116, thereby vaporizing the refrigerant. The second heat exchanger 114 may output the refrigerant in a vapor state towards the compressor 112 via the first reversing valve 118. The compressor 112 may receive the refrigerant from the second heat exchanger 114 and may “compress” the refrigerant to output the refrigerant in a high pressure, high temperature state towards the first heat exchanger 110 via the first reversing valve 118, as described above. In this manner, the refrigerant flows through the heat pump assembly 102 when the system 100 operates in the cooling mode.

[0057] As described above, the second heat exchanger 114 draws heat / warmth from the air that is received from the fan. Since the second heat exchanger 114 is located in the room / building (or be in heat exchange with the room / building via one or more ducts), the second heat exchanger 114 draws / extracts the heat from the interior portion of the room (to vaporize the refrigerant, as described above), thereby cooling the room.

[0058] In some aspects, when the ambient humidity level may be high, the controller 104 may cause the heat pump assembly 102 to operate to a cold temperature so that moisture may condense on the cool surface of the second heat exchanger 114. This may remove the humidity from the interior portion of the room, thereby making the ambient environment comfortable for the room occupants. In some aspects, while causing the moisture to condense on the cool surface of the second heat exchanger 114, the ambient temperature in the room may become colder (sometimes even cooler than the set point temperature). To ensure that the ambient temperature in the room does not become “too cold” for the room occupants (i.e., lower than the set point temperature), the controller 104 may cause the reheat coil 120 to transfer some heat into the interior portion of the room (even though the system 100 may be operating in the cooling mode) to make the ambient temperature in the room comfortable for the occupants.

[0059] Similar to the operation described above in conjunction with FIG. 1, in this case, the controller 104 may control the operation of the modulating valve 122 based on the refrigerant pressures in the reheat coil 120 and the first heat exchanger 110. For example, the controller 104 may cause the opening percentage of the modulating valve 122 to increase when the refrigerant pressure in the reheat coil 120 may be low (and vice-versa).

[0060] Furthermore, when the system 100 operates in the cooling mode, the first check valve 124 may disable the flow of refrigerant from the first heat exchanger 110 towards the modulating valve 122 to ensure that the refrigerant in the liquid phase does not mix with the refrigerant output from the modulating valve 122, as described above in conjunction with FIG. 1.

[0061] The functions of the components of the heat pump assembly 102 / system 100 depicted in FIG. 2 are similar to the functions described above in conjunction with FIG. 1 and hence are not described again here for the sake of simplicity and conciseness.

[0062] FIG. 3 depicts a block diagram of an exemplary heat pump assembly 300 in accordance with one or more embodiments of the present disclosure. FIG. 3 depicts the heat pump assembly 300 when the system 100 operates in the heating mode. The heat pump assembly 300 may be similar to the heat pump assembly 102 described above in conjunction with FIG. 1; however, instead of the modulating valve 122, the heat pump assembly 300 may include a solenoid valve302. Further, instead of the first and second check valves 124, 126, the heat pump assembly 300 may include a second reversing valve 304. The remaining components of the heat pump assembly 300 and their functions are same as the components / functions described above in conjunction with the heat pump assembly 102.

[0063] The solenoid valve 302 may operate in a fully closed position and a fully open position. The solenoid valve 302 may enable the flow of refrigerant from the compressor 112 to the reheat coil 120 when the solenoid valve 302 operates in the fully open position and may disable the flow of refrigerant from the compressor 112 to the reheat coil 120 when the solenoid valve 302 operates in the fully closed position.

[0064] The controller 104 may transmit a command signal to cause the solenoid valve 302 to operate in the fully open position when, e.g., the refrigerant pressure in the reheat coil 120 may be lower than the refrigerant pressure in the second heat exchanger 114, thereby enabling the refrigerant to flow from the compressor 112 to the reheat coil 120. Similarly, the controller 104 may transmit a command signal to cause the solenoid valve 302 to operate in the fully closed position when, e.g., the refrigerant pressure in the reheat coil 120 may be greater than the refrigerant pressure in the second heat exchanger 114, thereby disabling the flow of refrigerant from the compressor 112 into the reheat coil 120.

[0065] The second reversing valve 304 may enable the flow of refrigerant from the reheat coil 120 to the first heat exchanger 110 via the expansion valve 116 when the system 100 operates in the heating mode, as shown in FIG. 3. Specifically, in this case, the second reversing valve 304 may route the refrigerant output from the reheat coil 120 towards the inlet port of the expansion valve 116, which then transfers the refrigerant to the first heat exchanger 110, as shown in FIG. 3.

[0066] In some instances, the heat pump assembly 300 may be a split unit. For example, in a split unit configuration, the line 306 represent the boundary of components that are located indoors (i.e., the indoor unit) and components that are disposed outdoors (i.e., the outdoor unit). In particular, in some instances, all components located within the line 306 form the indoor unit, and all components located outside of the line 306 form the outdoor unit. In this manner, as depicted, there are three connections running between the indoor unit and the outdoor unit. This configuration can apply to any “split” system, including, but not limited to, mini-splits and VRF, where the indoor section is remote from the outdoor section. The indoor coil and reheat coil may be co-located, separated from the outdoor section by a line set. The heat pump assembly 300, however, may be any suitable configuration, including a Heating, Ventilation, and Air Conditioning (HVAC) unit, a packaged terminal air conditioner (PTAC) unit, a window unit, a vertical packaged unit, a Variable Refrigerant Flow (VRF) system, a ducted system, a packaged rooftop system, a split unit, an indoor / outdoor unit, and / or the like.

[0067] During operation, the controller 104 may first determine the operating mode of the system 100 in which the system user desires the system 100 to operate and transmit a command signal to the first reversing valve 118 to cause the first reversing valve 118 to route the refrigerant output from the compressor 112 to the second heat exchanger 114 when the user desires the system 100 to operate in the heating mode, as described above.

[0068] Further, the controller 104 may compare the refrigerant pressures in the reheat coil 120 and the second heat exchanger 114. Responsive to determining that the refrigerant pressure in the reheat coil 120 is greater than the refrigerant pressure in the second heat exchanger 114, the controller 104 may transmit a command signal to cause the solenoid valve 302 to operate in the fully closed position. On the other hand, responsive to determining that the refrigerant pressure in the reheat coil 120 is lower than the refrigerant pressure in the second heat exchanger 114, the controller 104 may transmit a command signal to cause the solenoid valve 302 to operate in the fully open position. Stated another way, responsive to determining that the refrigerant pressure in the reheat coil 120 is lower than the refrigerant pressure in the second heat exchanger 114, the controller 104 may cause the solenoid valve 302 to enable the flow of refrigerant from the compressor 112 to the reheat coil 120. In this case, the controller 104 may additionally transmit a command signal to cause the second reversing valve 304 to enable the flow of refrigerant from the outlet of the solenoid valve 302 to the inlet of the expansion valve 116, thereby enabling the refrigerant in liquid phase output from the reheat coil 120 and the second heat exchanger 114 to “merge” before entering the expansion valve 116.

[0069] FIG. 4 depicts a block diagram of the heat pump assembly 300 when the system 100 operates in the cooling mode, in accordance with one or more embodiments of the present disclosure. As described above, the flow of refrigerant may be reversed (as compared to the flow depicted in FIG. 3) when the system 100 operates in the cooling mode.

[0070] In this case, the functions / operations of the components of the heat pump assembly 300 may the same as the functions / operations of the components of the heat pump assembly 102 when the system operates in the cooling mode, as described above in conjunction with FIG. 2.

[0071] Further, in this case as well, the controller 104 may control the operation of the solenoid valve 302 based on the refrigerant pressures in the reheat coil 120 and the first heat exchanger 110. For example, the controller 104 may cause the solenoid valve 302 to operate in the fully open position when the refrigerant pressure in the reheat coil 120 may be low (and vice-versa).

[0072] Furthermore, when the system 100 operates in the cooling mode, the second reversing valve 304 may enable the flow of refrigerant from the reheat coil 120 to the second heat exchanger 114 via the expansion valve 116. When the system 100 is operating in the cooling mode and the solenoid valve 302 is in the fully open position, the controller 104 may transmit a command signal to cause the second reversing valve 304 to enable the flow of refrigerant from the outlet of the solenoid valve 302 to the inlet of the expansion valve 116, thereby enabling the refrigerant in a liquid phase output from the reheat coil 120 and the first heat exchanger 110 to “merge” before entering the expansion valve 116.

[0073] FIG. 5 depicts a block diagram of the controller 104 in accordance with one or more embodiments of the present disclosure. The controller 104 may include a plurality of components including, but not limited to, a processor 505, a memory 510, and a communication interface 515. The controller 104 may be a computing device configured to receive data, determine actions based on the received data (e.g., the inputs obtained from the sensor unit 106) and output a control signal instructing one or more system components to perform one or more actions.

[0074] In some aspects, the controller 104 may be configured to send and receive wireless or wired signals, and the signals may be analog or digital signals. The wireless signals may include Bluetooth, BLE, WiFi, ZigBee, infrared, microwave radio, or any other type of wireless communication signals as may be suitable for a particular system application. The hard-wired signals can include communication signals between any directly wired connections between the controller 104 and other system components. For example, the controller 104 can have a hard-wired 24 Volts Direct Current (VDC) connection to the sensors included in the sensor unit 106 described above.

[0075] Alternatively, the controller 104 may communicate with the sensors via a digital connection. The digital connection can include a connection such as an Ethernet or a serial connection and can utilize any suitable communication protocol for the system application, such as Modbus, fieldbus, PROFIBUS, SafetyBus, Ethernet / IP, and / or the like. Furthermore, the controller 104 can utilize a combination of wireless, hard-wired, and analog or digital communication signals to communicate with and control the various system components. A person ordinarily skilled in the art may appreciate that the above configurations are given merely as non-limiting examples, and the actual configuration can vary depending on the particular system application.

[0076] The memory 510 may store a program and / or instructions associated with the functions and methods described herein. The processor 505 may be configured to execute the program and / or instructions stored in the memory 510. The memory 510 can include one or more suitable types of memory (e.g., volatile or non-volatile memory, random access memory (RAM), read only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, floppy disks, hard disks, removable cartridges, flash memory, a redundant array of independent disks (RAID), and the like) for storing files including the operating system, application programs (including, for example, a web browser application, a widget or gadget engine, and or other applications, as necessary), executable instructions and data. One, some, or all of the processing techniques or methods described herein can be implemented as a combination of executable instructions and data within the memory 510.

[0077] The communication interface 515 may be configured to send or receive communication signals between the various system components. The communication interface 515 can include hardware, firmware, and / or software that allows the processor 505 to communicate with the other components via wired or wireless networks, whether local or wide area, private or public, as known in the art. The communication interface 515 can also provide access to a cellular network, the Internet, a local area network, or another wide-area network as suitable for the particular system application.

[0078] Additionally, the controller 104 may have or be in communication with a user interface (not shown) for receiving inputs from the system user. The user interface may be installed locally on the system 100.

[0079] The function of the controller 104 is already described above in conjunction with FIGS. 1-4, and hence is not described again here for the sake of simplicity and conciseness.

[0080] FIG. 6 depicts a flow diagram of an exemplary method 600 to control an operation of a valve of a heat pump assembly in accordance with one or more embodiments of the present disclosure. FIG. 6 may be described with continued reference to prior figures. The following process is exemplary and not confined to the steps described hereafter. Moreover, alternative embodiments may include more or less steps than are shown or described herein and may include these steps in a different order than the order described in the following example embodiments.

[0081] The method 600 may start at step 602. At step 604, the method 600 may include determining, by the controller 104, a desired operating mode of the system 100 based on user inputs. At step 606, the method 600 may include causing, by the controller 104, the system 100 to operate in the desired operating mode. For example, the controller 104 may cause the system 100 to operate in the heating mode or the cooling mode, based on the user inputs.

[0082] At step 608, the method 600 may include comparing, by the controller 104, the refrigerant pressures in the reheat coil 120 and the first / second heat exchanger 110, 114 (depending on the mode of operation of the system 100). At step 610, the method 600 may include controlling, by the controller 104, the operation of the valve (e.g., the modulating valve 122 or the solenoid valve 302) of the system 100 based on the comparison, as described above.

[0083] The method 600 may stop at step 612.

[0084] In the above disclosure, reference has been made to the accompanying drawings, which form a part hereof, which illustrate specific implementations in which the present disclosure may be practiced. It is understood that other implementations may be utilized, and structural changes may be made without departing from the scope of the present disclosure. References in the specification to “one embodiment,”“an embodiment,”“an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a feature, structure, or characteristic is described in connection with an embodiment, one skilled in the art will recognize such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0085] It should also be understood that the word “example” as used herein is intended to be non-exclusionary and non-limiting in nature. More particularly, the word “example” as used herein indicates one among several examples, and it should be understood that no undue emphasis or preference is being directed to the particular example being described.

[0086] With regard to the processes, systems, methods, heuristics, etc. described herein, it should be understood that, although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps described herein could be omitted. In other words, the descriptions of processes herein are provided for the purpose of illustrating various embodiments and should in no way be construed so as to limit the claims.

[0087] Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the above description. The scope should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the application is capable of modification and variation.

[0088] All terms used in the claims are intended to be given their ordinary meanings as understood by those knowledgeable in the technologies described herein unless an explicit indication to the contrary is made herein. In particular, use of the singular articles such as “a,”“the,”“said,” etc., should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary. Conditional language, such as, among others, “can,”“could,”“might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments could include, while other embodiments may not include, certain features, elements, and / or steps. Thus, such conditional language is not generally intended to imply that features, elements, and / or steps are in any way required for one or more embodiments.

Examples

Embodiment Construction

[0011]The present disclosure is directed towards a heat pump system (“system”) that may be part of a Heating, Ventilation, and Air Conditioning (HVAC) unit, a packaged terminal air conditioner (PTAC) unit, a window unit, a vertical packaged unit, a Variable Refrigerant Flow (VRF) system, a ducted system, a packaged rooftop system, a split unit, an indoor / outdoor unit, and / or the like. Although the present disclosure is described in the context of an HVAC system, the description should not be construed as limited only to HVAC systems.

[0012]The system may operate in a heating mode or a cooling mode. The system may heat a room / building (where the system is installed) when the system operates in the heating mode and may cool the room / building when the system operates in the cooling mode.

[0013]The system may include a plurality of components / modules including, but not limited to, a heat pump assembly, a controller, a sensor unit, etc. The heat pump assembly may include a compressor, a fi...

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to and the benefit of U.S. provisional Application No. 63 / 765,841, filed Mar. 3, 2025, which is hereby incorporated by reference herein in its entirety.FIELD

[0002] The present disclosure relates to systems and methods to control operation of heat pump assemblies having reheat coils and more specifically to systems and methods to control a flow of refrigerant in a reheat coil of a heat pump assembly that can operate in a cooling mode and a heating mode.BACKGROUND

[0003] Refrigerant circuits or heat pump assemblies are used in Heating, Ventilation, and Air Conditioning (HVAC) systems. A heat pump assembly typically includes a compressor, an evaporator, an expansion valve, and a condenser. It is known that an HVAC system causes moisture present in ambient air to condense on the cool evaporator coil when the ambient air has relatively high humidity level and the HVAC system operates in a cooling mode. Condensation of the moisture on the evaporator coil ensures that the humidity level of the air inside the room / building, where the HVAC system is installed, is reduced and within a comfortable range for the room occupants.BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The detailed description is set forth with reference to the accompanying drawings. The use of the same reference numerals may indicate similar or identical items. Various embodiments may utilize elements and / or components other than those illustrated in the drawings, and some elements and / or components may not be present in various embodiments. Elements and / or components in the figures are not necessarily drawn to scale. Throughout this disclosure, depending on the context, singular and plural terminology may be used interchangeably.

[0005] FIG. 1 depicts a block diagram of an exemplary heat pump system including a first heat pump assembly in accordance with one or more embodiments of the present disclosure.

[0006] FIG. 2 depicts a block diagram of an exemplary second heat pump assembly in accordance with one or more embodiments of the present disclosure.

[0007] FIG. 3 depicts a block diagram of an exemplary third heat pump assembly in accordance with one or more embodiments of the present disclosure.

[0008] FIG. 4 depicts a block diagram of an exemplary fourth heat pump assembly in accordance with one or more embodiments of the present disclosure.

[0009] FIG. 5 depicts a block diagram of a controller in accordance with one or more embodiments of the present disclosure.

[0010] FIG. 6 depicts a flow diagram of an exemplary method to control an operation of a valve of a heat pump assembly in accordance with one or more embodiments of the present disclosure.DETAILED DESCRIPTION

[0011] The present disclosure is directed towards a heat pump system (“system”) that may be part of a Heating, Ventilation, and Air Conditioning (HVAC) unit, a packaged terminal air conditioner (PTAC) unit, a window unit, a vertical packaged unit, a Variable Refrigerant Flow (VRF) system, a ducted system, a packaged rooftop system, a split unit, an indoor / outdoor unit, and / or the like. Although the present disclosure is described in the context of an HVAC system, the description should not be construed as limited only to HVAC systems.

[0012] The system may operate in a heating mode or a cooling mode. The system may heat a room / building (where the system is installed) when the system operates in the heating mode and may cool the room / building when the system operates in the cooling mode.

[0013] The system may include a plurality of components / modules including, but not limited to, a heat pump assembly, a controller, a sensor unit, etc. The heat pump assembly may include a compressor, a first heat exchanger, a second heat exchanger, an expansion valve, a reversing valve, a modulating valve or a solenoid valve, and a reheat coil. The compressor, the first heat exchanger, the second heat exchanger and the expansion valve may be connected via a refrigerant tubing. During the operation of the heat pump assembly, a refrigerant may flow through these components via the refrigerant tubing. The reversing valve may reverse the flow of refrigerant in the heat pump assembly to switch the operating mode of the system between the cooling mode and the heating mode.

[0014] In some aspects, the second heat exchanger may be located inside the room / building (or otherwise be in heat exchange with the room / building via one or more ducts) and may cause heating / cooling of the room based on the operating mode of the system. Further, the first heat exchanger may be located outside of the room. In an exemplary aspect, the second heat exchanger may be a condenser and the first heat exchanger may be an evaporator when the system operates in the heating mode. When the system operates in the heating mode (i.e., when the system heats the room), the reversing valve may cause the refrigerant in a high temperature, high pressure vapor state output from the compressor to flow towards the second heat exchanger, which may condense the refrigerant to a liquid phase. The heat that the second heat exchanger provides while condensing the refrigerant from the vapor state to the liquid state may heat the room. In this manner, the system heats the room via the second heat exchanger when the system operates in the heating mode.

[0015] The refrigerant output from the second heat exchanger may flow to the expansion valve and then to the first heat exchanger where the refrigerant is converted into vapor state. The refrigerant output from the first heat exchanger flows to the compressor, thus completing the vapor cycle of the heat pump assembly.

[0016] In some aspects, the heat exchanger (e.g., the second heat exchanger) that is located inside the room / building (or in heat exchange with the room / building via one or more ducts) may be of a smaller size than the heat exchanger (e.g., the first heat exchanger) that is located outside the room / building (or otherwise in heat exchange with the outdoor ambient environment). Consequently, when the system operates in the heating mode, “refrigerant imbalance” may occur in the heat pump assembly (due to the size difference between the coils of the first heat exchanger and the second heater exchanger). In some aspects, the refrigerant imbalance occurs as the total surface area for heat exchange is different in the first heat exchanger relative to the second heat exchanger due to the size difference in their coils. Conventionally, this refrigerant imbalance is handled by storing some of the “excess” refrigerant in an accumulator (or elsewhere) in the system; however, such a method of handling the refrigerant imbalance reduces the capacity of the system in the heating mode (vs. the capacity of the system in the cooling mode).

[0017] To overcome the challenges associated with the conventional method of handling refrigerant imbalance described above, the system, as proposed in the present disclosure, includes the reheat coil that is disposed parallel to the second heat exchanger. The reheat coil and the second heat exchanger in combination acts as an effective “bigger” indoor coil or heat exchanger of the system, and thus increases the capacity of the system in the heating mode.

[0018] When the system is operating in the heating mode, the system may route some refrigerant in a high temperature state output from the compressor towards the reheat coil, which may be connected in parallel to the second heat exchanger in the room / building (or be in heat exchange with the room / building via one or more ducts). The reheat coil may operate in a similar manner as the second heat exchanger and may act as an “extension” of the second heat exchanger. The reheat coil and the second heat exchanger may collectively transfer heat to the room when the refrigerant in high temperature state flows through them, thereby facilitating in heating the room / building (or increasing the room temperature).

[0019] In some aspects, the reheat coil may not be of the same size as the second heat exchanger. Specifically, in an exemplary aspect, the reheat coil may be smaller in size than the second heat exchanger. Consequently, when the refrigerant flows through both the reheat coil and the second heat exchanger in the heating mode, the pressure drop of the refrigerant in the reheat coil may be less than the refrigerant pressure drop in the second heat exchanger (due to the smaller size of the reheat coil). It may be appreciated that if the refrigerant pressure drop is less in the reheat coil, more refrigerant may tend to flow through the reheat coil as compared to the second heat exchanger. This may be an undesirable scenario and may affect the heating of the room.

[0020] To avoid such a scenario, the system may include a modulating valve that may modulate the flow of refrigerant from the compressor to the reheat coil (or control an amount of refrigerant that flows to the reheat coil), thereby controlling / modulating an amount of refrigerant that is provided to the reheat coil. In some aspects, the modulating valve may be disposed after the reheat coil (or at the output of the reheat coil) in the heat pump assembly. In an exemplary aspect, the controller may control the operation of the modulating valve based on the pressure of refrigerant flowing through the reheat coil and the second heat exchanger. In some aspects, the controller may control the operation of the modulating valve such that the refrigerant pressure in both the reheat coil and the second heat exchanger may be equivalent (or substantially equivalent), so that the refrigerant does not tend to flow more towards one coil than the other. As an example, the controller may cause the modulating valve to enable more refrigerant to flow through the reheat coil when the refrigerant pressure in the reheat coil may be dropping (or be less than the refrigerant pressure in the second heat exchanger). Similarly, the controller may cause the modulating valve to enable less refrigerant to flow through the reheat coil when the refrigerant pressure in the reheat coil may be high (or be more than the refrigerant pressure in the second heat exchanger). In this manner, the controller enables the reheat coil to effectively act as an “extension” of the second heat exchanger and prevents a scenario where one coil receives more refrigerant than the other (thereby preventing pressure imbalance in the heat pump assembly).

[0021] In further aspects, when the system includes a solenoid valve (as opposed to the modulating valve described above), the solenoid valve may enable or disable the flow of refrigerant from the compressor to the reheat coil (and may not regulate / control an amount of refrigerant that flows into the reheat coil) based on the pressure of refrigerant flowing through the reheat coil and the second heat exchanger.

[0022] The system may operate in a similar but reverse manner when the system operates in the cooling mode (i.e., when the system cools the room). When the system operates in the cooling mode, the reversing valve may cause the refrigerant in a high temperature, high pressure vapor state output from the compressor to flow towards the first heat exchanger, which may condense the refrigerant to a liquid phase. In this case, the first heat exchanger may be the condenser and the second heat exchanger (that is located in the room / building or be in heat exchange with the room / building via one or more ducts) may be the evaporator. The first heat exchanger may output the refrigerant to the expansion valve, which may transfer the refrigerant to the second heat exchanger. The second heat exchanger may vaporize the refrigerant and transfer the refrigerant in vapor state to the compressor, thus completing the vapor cycle of the heat pump assembly. In some aspects, the second heat exchanger extracts heat from the room to vaporize the refrigerant, thereby cooling the room when the system operates in the cooling mode.

[0023] There may be instances when the system may cause the second heat exchanger to cool below the set point temperature when the system operates in the cooling mode to effectively cause the moisture present in the ambient air of the room to condense on the cool second heat exchanger coils (thereby reducing the humidity level in the room). While cooling the second heat exchanger coils in this manner may reduce the humidity level in the room, it may, in some instances, cause the room temperature to become too cold for the room occupants. To make the ambient temperature in the room comfortable for the occupants (and equivalent to or within a threshold of the set point temperature), the controller may cause some amount of refrigerant in hot temperature state to flow in the reheat coil, which may cause the reheat coil to transfer some heat to the room (thereby increasing the room temperature to the set point temperature). In this case, the controller may control / regulate the amount of refrigerant that flows to the reheat coil via the modulating valve based on the pressure of refrigerant flowing through the reheat coil and the first heat exchanger. In another embodiment, the position of the modulating valve may be pre-fixed (e.g., when the system is operating at a higher end of operating frequency), and may not be changed by the controller based on pressure readings described above. In this case, the pre-fixed position of the modulating valve may ensure optimal flow of refrigerant through the reheat coil for a wide range of expected indoor and outdoor temperatures. In yet another embodiment, the position of the modulating valve may be adjusted based on temperature readings near the output of the modulating valve or the expansion valve (instead of or in addition to using the pressure readings). In some aspects, the pressure readings may be made at the same place in the heat pump assembly where the temperature readings are made.

[0024] In alternative aspects, when the system includes the solenoid valve, the controller may cause the solenoid valve to enable or disable the flow of refrigerant from the compressor to the reheat coil based on the pressure of refrigerant flowing through the reheat coil and the first heat exchanger.

[0025] Although certain examples of the disclosed technology are explained in detail herein, it is to be understood that other examples, embodiments, and implementations of the disclosed technology are contemplated. Accordingly, it is not intended that the disclosed technology is limited in its scope to the details of construction and arrangement of components expressly set forth in the following description or illustrated in the drawings. The disclosed technology can be implemented in a variety of examples and can be practiced or carried out in various ways. In particular, the presently disclosed subject matter is described in the context of being a system and method for controlling an operation of a heat pump assembly of a Heating, Ventilation, and Air Conditioning (HVAC) system, a packaged terminal air conditioner (PTAC) unit, a window unit, a vertical packaged unit, a Variable Refrigerant Flow (VRF) system, a ducted system, a packaged rooftop system, a split unit, and / or the like. The present disclosure, however, is not so limited, and can be applicable in other contexts.

[0026] Furthermore, the terms “cold” and “hot,” as used in the present disclosure, are relative and may mean different degrees of varying temperatures and ranges based on the context. Thus, the terms “cold” and “hot” should not be limited to any temperature or temperature range.

[0027] Turning now to the drawings, FIG. 1 depicts a block diagram of an exemplary heat pump system 100 (or system 100). The system 100 may be part of a Heating, Ventilation, and Air Conditioning (HVAC) unit / system that may be configured to cool or heat an interior portion of a room / building based on an operating mode of the system 100. In other aspects, the system 100 may be part of a packaged terminal air conditioner (PTAC) unit, a window unit, a vertical packaged unit, a Variable Refrigerant Flow (VRF) system, a ducted system, a packaged rooftop system, a split unit, and / or the like. Although the present disclosure is described in the context of an HVAC system, the description should not be construed as limited only to HVAC systems.

[0028] The system 100 may include a plurality of units including, but not limited to, a heat pump assembly 102, a controller 104, and a sensor unit 106. The system 100 may include a plurality of additional components that are not shown in FIG. 1 for the sake of simplicity and conciseness (e.g., a housing, a user interface, etc.).

[0029] The heat pump assembly 102 may include a plurality of components that may be connected via a refrigerant tubing 108, through which, during the heat pump assembly operation, a refrigerant may flow in a clockwise or counterclockwise direction (based on an operating mode of the system 100, as described later below). The refrigerant may be selected from a variety of materials. The refrigerant may be any material capable of supplying favorable thermodynamic properties to a heat pump system. The refrigerant, for example, may be selected based on a desired boiling point, a high heat of vaporization, a moderate liquid density, a high critical temperature, and / or other aspects. Accordingly, the refrigerant may be any chlorofluorocarbon, chlorofluoroolefin, hydrochlorofluorocarbon, hydrochlorofluoroolefin, hydrofluorocarbon, hydrofluoroolefin, hydrochlorocarbon, hydrochloroolefin, hydrocarbon, hydroolefin, perfluorocarbon, perfluoroolefin, perchlorocarbon, perchloroolefin, halon, or haloalkane. For example, the refrigerant may be any refrigerant designated as such by, and compliant with, the standards, rules, and regulations set forth by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) (e.g., ASHRAE Standard 34-2019). For example, the refrigerant may be R-410A or R-134a. In some embodiments, the refrigerant may be or may include a hydrofluoroolefin, such as HFO-1234yf or blends thereof, including R-454B.

[0030] Example of the components of the heat pump assembly 102 include, but are not limited to, a first heat exchanger 110, a compressor 112, a second heat exchanger 114 and an expansion device 116 (hereinafter referred to as expansion valve 116) connected by the refrigerant tubing 108, through which, during heat pump operation, the refrigerant may flow.

[0031] In some aspects, the system 100 may operate either in a heating mode or a cooling mode based on the direction of the flow of refrigerant through the components of the heat pump assembly 102. The system 100 may heat the interior portion of the room / building (e.g., during winter season) when the system 100 operates in the heating mode, and the system 100 may cool the interior portion of the room / building (e.g., during summer season) when the system 100 operates in the cooling mode. The direction of the flow of refrigerant in the heat pump assembly 102 depends on the mode in which the system 100 may be operating. In the exemplary view of the heat pump assembly 102 depicted in FIG. 1, the system 100 is operating in the heating mode. An exemplary view of the heat pump assembly 102 in which the system 100 is operating in the cooling mode is depicted in FIG. 2 and described later in the description below.

[0032] The heat pump assembly 102 may further include a reversing valve 118 (or a first reversing valve 118) that may reverse the flow of refrigerant in the heat pump assembly 102 to switch the operating mode of the system 100 between the heating mode and the cooling mode based on command signals received from the controller 104 (and user input). When the system 100 operates in the heating mode, the refrigerant may flow from an outlet of the compressor 112 to the first reversing valve 118, which may cause the refrigerant to flow into an inlet of the second heat exchanger 114. The second heat exchanger 114 may be a condenser and disposed inside the room / building (or otherwise be in heat exchange with the room / building via one or more ducts) when the system 100 operates in the heating mode. The refrigerant may then flow from an outlet of the second heat exchanger 114 to the expansion valve 116 and then through the first heat exchanger 110 to the inlet of the compressor 112 via the first reversing valve 118.

[0033] When the system 100 operates in the heating mode, the first heat exchanger 110 may be an evaporator (having evaporator coils and fan, not shown) and the second heat exchanger 114 may be a condenser (as described above) having condenser coils and fans (not shown). During operation, the compressor 112 may output the refrigerant in a vapor state towards the second heat exchanger 114 via the first reversing valve 118. The refrigerant output from the compressor 112 may be in a high temperature and high pressure state. The second heat exchanger 114 may receive the refrigerant from the compressor 112 via the refrigerant tubing 108 and may condense the refrigerant into liquid state. In some aspects, the heat that the second heat exchanger 114 provides while condensing the refrigerant phase from vapor to liquid may be used to heat the room in which the second heat exchanger 114 may be located (or thermally connected with via one or more ducts). Specifically, the condenser fan may blow air towards the interior portion of the room via the condenser coils, which may transfer the heat from the condenser coils to the room's interior portion, thereby heating the room. In this manner, the system 100 may heat the room when the system 100 operates in the heating mode.

[0034] The second heat exchanger 114 may further output the refrigerant in a liquid state towards the expansion valve 116 via the refrigerant tubing 108. The refrigerant output from the second heat exchanger 114 may be at high pressure and medium-to-high temperature state. The expansion valve 116 may receive the refrigerant from the second heat exchanger 114 and may output the refrigerant in a low pressure, low temperature state towards the first heat exchanger 110 via the refrigerant tubing 108. The refrigerant output from the expansion valve 116 may be in a mixture of liquid and vapor states.

[0035] The first heat exchanger 110 may receive the refrigerant from the expansion valve 116 and may vaporize the refrigerant into a low pressure, vapor state refrigerant. The first heat exchanger 110 may include a fan (not shown) that may draw air from ambient environment and blow it towards the first heat exchanger 110. The first heat exchanger 110 may draw heat / warmth from the air that is received from the fan and may transfer the warmth towards the refrigerant received from the expansion valve 116, thereby vaporizing the refrigerant. The first heat exchanger 110 may output the refrigerant in vapor state towards the compressor 112 via the first reversing valve 118. The compressor 112 may receive the refrigerant from the first heat exchanger 110 and may “compress” the refrigerant to output the refrigerant in a high pressure, high temperature state towards the second heat exchanger 114 via the first reversing valve 118, as described above. In this manner, the refrigerant flows through the heat pump assembly 102 when the system 100 operates in the heating mode, causing the interior portion of the room to be heated by the second heat exchanger 114.

[0036] In some aspects, the compressor 112 may be a pump that provides additional pressure to the refrigerant to enable the refrigerant to flow through the defined path as indicated in FIG. 1. The compressor 112 may be of any type. For example, the compressor 112 may be a positive displacement compressor, a reciprocating compressor, a rotary screw compressor, a rotary vane compressor, a rolling piston compressor, a scroll compressor, a diaphragm compressor, a dynamic compressor, an axial compressor, or any other form of compressor that can be integrated into the heat pump assembly 102 for the particular application.

[0037] In some aspects, the heat exchanger (e.g., the second heat exchanger 114) that is located in the interior portion of the room / building or be in heat exchange with the room / building via one or more ducts may be of a smaller size than the heat exchanger (e.g., the first heat exchanger 110) that is located outside the room / building. Consequently, when the system 100 operates in the heating mode, “refrigerant imbalance” may occur in the heat pump assembly 102 due to the difference in the coil sizes of the first heat exchanger 110 as compared to the second heat exchanger 114.

[0038] To effectively handle the challenge of refrigerant imbalance in the system 100, the system 100, as proposed in the present disclosure, may include a reheat coil 120 that is disposed parallel to the second heat exchanger 114. For example, air may be directed by one or more fans to pass over / through the second heat exchanger 114 and then pass over / through the reheat coil 120 before being directed to the interior portion of the room for heating or cooling. In the heating mode, the reheat coil 120 and the second heat exchanger 114 in combination may act as an effective “bigger” indoor coil or heat exchanger and thus increase the capacity of the system 100 in the heating mode.

[0039] The reheat coil 120 may be similar to the second heat exchanger 114, and may provide heat to the room / building, in addition to the heat that the second heat exchanger 114 provides. In some aspects, the reheat coil 120 may be located in the interior portion of the room / building or be in heat exchange with the room / building via one or more ducts to effectively provide heat to the room.

[0040] The reheat coil 120 may receive some amount of refrigerant in a high pressure, high temperature vapor state from the compressor 112 and condense the received refrigerant into a liquid state similar to the operation of the second heat exchanger 114. In some aspects, the reheat coil 120 may operate in a similar manner as the second heat exchanger 114 and may be connected in parallel to the second heat exchanger 114 in the heat pump assembly 102. The reheat coil 120 may condense the refrigerant in a vapor state received from the compressor 112 to a liquid state and may output the refrigerant in the liquid state (similar to the operation of the second heat exchanger 114). The heat that the reheat coil 120 provides while condensing the refrigerant phase from vapor to liquid may be used to heat the interior portion of the room in which the reheat coil 120 may be located. In this manner, the reheat coil 120 acts as an extension of the second heat exchanger 114 and increases the “effective” size of the indoor coil of the system 100 to reduce the refrigerant imbalance described above.

[0041] In some aspects, the reheat coil 120 may not be of the same size as the second heat exchanger 114. Specifically, in an exemplary aspect, the reheat coil 120 may be smaller in size than the second heat exchanger 114. Consequently, when the refrigerant flows through both the reheat coil 120 and the second heat exchanger 114 in the heating mode, the pressure drop of the refrigerant in the reheat coil 120 may be less than the refrigerant pressure drop in the second heat exchanger 114 (due to the smaller size of the reheat coil 120). It may be appreciated that if the refrigerant pressure drop is less in the reheat coil 120, more refrigerant may tend to flow through the reheat coil 120 as compared to the second heat exchanger 114. This may be an undesirable scenario and may affect the heating of the room / building.

[0042] To avoid such a scenario, the system 100 / heat pump assembly 102 may additionally include a valve 122 (or a modulating valve 122) that may control / regulate the flow of refrigerant from the compressor 112 to the reheat coil 120 based on the pressure of refrigerant flowing through the reheat coil 120 and the second heat exchanger 114. In an exemplary aspect, the valve 122 may be disposed after the reheat coil 120 or at the output of the reheat coil 120 in the heat pump assembly 102. In some aspects, in addition to controlling / modulating the flow of refrigerant in the reheat coil 120, the valve 122 may operate like an expansion valve, similar to the expansion valve 116. As an example, the refrigerant in liquid phase that the reheat coil 120 outputs may enter the modulating valve 122, which may output the refrigerant in a low pressure, low temperature state towards an outlet port of the expansion valve 116 or the first heat exchanger 110 via the refrigerant tubing 108. The refrigerant output from the modulating valve 122 may be in a mixture of liquid and vapor states.

[0043] The modulating valve 122 may be configured to operate in a fully closed position, a fully open position, and a partially open position based on command signals received from the controller 104. In another embodiment, the position of the valve 122 may be pre-fixed (e.g., when the system 100 is operating at a higher end of operating frequency), and may not be changed by the controller 104 based on pressure readings described above. In this case, the pre-fixed position of the valve 122 may ensure optimal flow of refrigerant through the reheat coil 120 for a wide range of expected indoor and outdoor temperatures. In yet another embodiment, the position of the valve 122 may be adjusted based on temperature readings near the output of the valve 122 or the expansion valve 116 (instead of or in addition to using the pressure readings). In some aspects, the pressure readings may be made at the same place in the heat pump assembly 102 where the temperature readings are made.

[0044] The modulating valve 122 may disable the flow of refrigerant from the compressor 112 to the reheat coil 120 when the modulating valve 122 operates in the fully closed position.

[0045] The modulating valve 122 may enable a maximum amount of refrigerant to flow from the compressor 112 to the reheat coil 120 (depending on the reheat coil 120 capacity / size) when the modulating valve 122 operates in the fully open position. Further, the modulating valve 122 may modulate the flow of refrigerant (between the maximum amount and zero flow of refrigerant) from the compressor 112 to the reheat coil 120 when the modulating valve 122 operates in the partially open position. In an exemplary aspect, the modulating valve 122 may modulate or regulate the flow of refrigerant from the compressor 112 to the reheat coil 120 based on an opening percentage of the modulating valve 122 in the partially open position. In some aspects, the controller 104 may control the opening percentage of the modulating valve 122 based on the pressure of refrigerant flowing through the reheat coil 120 and the second heat exchanger 114 by transmitting command signals to the modulating valve 122. In some aspects, the controller 104 may control the opening percentage of the modulating valve 122 such that the refrigerant pressure in both the reheat coil 120 and the second heat exchanger 114 may be equivalent (or substantially equivalent), so that the refrigerant does not tend to flow more towards one coil than the other. As an example, the controller 104 may cause the modulating valve 122 to enable more refrigerant to flow through the reheat coil 120 when the refrigerant pressure in the reheat coil 120 may be dropping (or be less than the refrigerant pressure in the second heat exchanger 114). Similarly, the controller 104 may cause the modulating valve 122 to enable less refrigerant to flow through the reheat coil 120 when the refrigerant pressure in the reheat coil 120 may be high (or be more than the refrigerant pressure in the second heat exchanger 114). In this manner, the controller 104 enables the reheat coil 120 to effectively act as an “extension” of the second heat exchanger 114, and prevents a scenario where one coil receives more refrigerant than the other.

[0046] The system 100 / heat pump assembly 102 may further include a first check valve 124 and a second check valve 126 that may be connected on the refrigerant tubing 108 downstream of the modulating valve 122. In some instances, the first and second check valves 124, 126 may be in parallel with each other along the refrigerant tubing 108. In some aspects, the first check valve 124 may be connected between an outlet port of the modulating valve 122 and an outlet port of the expansion valve 116 / an inlet port of the first heat exchanger 110, as shown in FIG. 1. Further, the second check valve 126 may be connected between the outlet port of the modulating valve 122 and an inlet port of the expansion valve 116 / an outlet port of the second heat exchanger 114. In some aspects, the first and second check valves 124, 126 may be configured to disable the flow of refrigerant in liquid phase through the check valves 124, 126. Stated another way, the first and second check valves 124, 126 may not enable refrigerant in the liquid phase to pass through.

[0047] Consequently, since the second heat exchanger 114 outputs the refrigerant in the liquid phase (as described above) when the system 100 operates in the heating mode, the second check valve 126 may disable the flow of refrigerant from the second heat exchanger 114 towards the modulating valve 122 when the system 100 operates in the heating mode. By disabling the flow of liquid refrigerant, the second check valve 126 prevents the refrigerant in the liquid phase (received from the second heat exchanger 114) from getting mixed with the refrigerant received from the modulating valve 122 (that may be a mixture of liquid and vapor phase), which in turn ensures that only the liquid phase refrigerant enters the inlet port of the expansion valve 116. It may be appreciated that the expansion valve 116 operates efficiently when it receives the refrigerant in the liquid phase. Therefore, the second check valve 126 ensures that the expansion valve 116 operates efficiently by blocking the mixing of the refrigerant in the liquid and vapor phase at the inlet port of the expansion valve 116.

[0048] The controller 104 may communicatively couple with the components of the heat pump assembly 102 and the sensor unit 106 and control the operation of one or more components of the heat pump assembly 102 based on inputs obtained from the sensor unit 106. In some aspects, the sensor unit 106 may include one or more pressure sensors configured to measure refrigerant pressure in the reheat coil 120, the first heat exchanger 110, the second heat exchanger 114, etc., and one or more temperature sensors, humidity sensors, and / or the like. The sensor unit 106 may transmit inputs to the controller 104, which may control the operation of one or more components of the heat pump assembly 102 based on the obtained inputs. For example, the controller 104 may control the operation of the modulating valve 122 to control the flow of refrigerant from the compressor 112 to the reheat coil 120 based on the refrigerant pressures in the reheat coil 120 and the second heat exchanger 114, as described below.

[0049] In operation, the controller 104 may first determine the operating mode of the system 100 in which the system user desires the system 100 to operate based on user inputs (obtained via a system user interface). For example, the controller 104 may determine whether the user desires the system 100 to operate in the cooling mode or the heating mode based on the user inputs. Responsive to determining that the user desires the system 100 to operate in the heating mode, the controller 104 may transmit a command signal to the first reversing valve 118 to cause the first reversing valve 118 to route the refrigerant output from the compressor 112 to the second heat exchanger 114, as described above.

[0050] Further, the controller 104 may compare the refrigerant pressures in the second heat exchanger 114 and the reheat coil 120 based on the inputs obtained from the sensor unit 106. The controller 104 may then transmit a command signal to control the operation of the modulating valve 122 based on the difference between the refrigerant pressures in the second heat exchanger 114 and the reheat coil 120, such that the refrigerant pressure in both the reheat coil 120 and the second heat exchanger 114 may become equivalent (or substantially equivalent), as described above. The controller 104 may perform such an action to ensure that the refrigerant does not flow more towards one coil than the other.

[0051] In the example embodiment described above, the controller 104 may regulate (i.e., increase or decrease) the flow of refrigerant into the reheat coil 120 by adjusting the opening percentage of the modulating valve 122. The controller 104 may adjust the opening percentage of the modulating valve 122 based on a difference between the refrigerant pressures in the reheat coil 120 and the second heat exchanger 114. In an exemplary aspect, the controller 104 may increase the opening percentage (thereby increasing the flow of refrigerant into the reheat coil 120) when the refrigerant pressure in the reheat coil 120 may be lower than the refrigerant pressure in the second heat exchanger 114.

[0052] In a similar manner, the controller 104 may decrease the opening percentage (thereby decreasing the flow of refrigerant into the reheat coil 120) when the refrigerant pressure in the reheat coil 120 may be greater than the refrigerant pressure in the second heat exchanger 114.

[0053] In this manner, the controller 104 may adjust the flow of refrigerant from the compressor 112 to the reheat coil 120 based on the inputs (e.g., refrigerant pressure values) measured by the sensor unit 106.

[0054] FIG. 2 depicts a block diagram of the heat pump assembly 102 when the system 100 operates in the cooling mode, in accordance with one or more embodiments of the present disclosure. As described above, the system 100 may cool the interior portion of the room when the system 100 operates in the cooling mode. The flow of refrigerant may be reversed (as compared to the flow depicted in FIG. 1) when the system 100 operates in the cooling mode.

[0055] When the system 100 operates in the cooling mode, the first reversing valve 118 may cause the compressor 112 to output the refrigerant in the vapor state towards the first heat exchanger 110, as shown in FIG. 2. In this case, the first heating exchanger 110 may be the condenser (and the second heat exchanger 114 may be the evaporator). The first heat exchanger 110 may receive the refrigerant from the compressor 112 via the refrigerant tubing 108 and may condense the refrigerant into a liquid state. The first heat exchanger 110 may further output the refrigerant in liquid state towards the expansion valve 116 via the refrigerant tubing 108. The refrigerant output from the first heat exchanger 110 may be at a high pressure and medium-to-high temperature state. The expansion valve 116 may receive the refrigerant from the first heat exchanger 110 and may output the refrigerant in a low pressure, low temperature state towards the second heat exchanger 114 via the refrigerant tubing 108. The refrigerant output from the expansion valve 116 may be in a mixture of liquid and vapor states.

[0056] The second heat exchanger 114 may receive the refrigerant from the expansion valve 116 and may vaporize the refrigerant into a low pressure, vapor state refrigerant. The second heat exchanger 114 may include a fan (not shown) that may draw air from ambient environment and blow it towards the second heat exchanger 114. The second heat exchanger 114 may draw heat / warmth from the air that is received from the fan and may transfer the warmth towards the refrigerant received from the expansion valve 116, thereby vaporizing the refrigerant. The second heat exchanger 114 may output the refrigerant in a vapor state towards the compressor 112 via the first reversing valve 118. The compressor 112 may receive the refrigerant from the second heat exchanger 114 and may “compress” the refrigerant to output the refrigerant in a high pressure, high temperature state towards the first heat exchanger 110 via the first reversing valve 118, as described above. In this manner, the refrigerant flows through the heat pump assembly 102 when the system 100 operates in the cooling mode.

[0057] As described above, the second heat exchanger 114 draws heat / warmth from the air that is received from the fan. Since the second heat exchanger 114 is located in the room / building (or be in heat exchange with the room / building via one or more ducts), the second heat exchanger 114 draws / extracts the heat from the interior portion of the room (to vaporize the refrigerant, as described above), thereby cooling the room.

[0058] In some aspects, when the ambient humidity level may be high, the controller 104 may cause the heat pump assembly 102 to operate to a cold temperature so that moisture may condense on the cool surface of the second heat exchanger 114. This may remove the humidity from the interior portion of the room, thereby making the ambient environment comfortable for the room occupants. In some aspects, while causing the moisture to condense on the cool surface of the second heat exchanger 114, the ambient temperature in the room may become colder (sometimes even cooler than the set point temperature). To ensure that the ambient temperature in the room does not become “too cold” for the room occupants (i.e., lower than the set point temperature), the controller 104 may cause the reheat coil 120 to transfer some heat into the interior portion of the room (even though the system 100 may be operating in the cooling mode) to make the ambient temperature in the room comfortable for the occupants.

[0059] Similar to the operation described above in conjunction with FIG. 1, in this case, the controller 104 may control the operation of the modulating valve 122 based on the refrigerant pressures in the reheat coil 120 and the first heat exchanger 110. For example, the controller 104 may cause the opening percentage of the modulating valve 122 to increase when the refrigerant pressure in the reheat coil 120 may be low (and vice-versa).

[0060] Furthermore, when the system 100 operates in the cooling mode, the first check valve 124 may disable the flow of refrigerant from the first heat exchanger 110 towards the modulating valve 122 to ensure that the refrigerant in the liquid phase does not mix with the refrigerant output from the modulating valve 122, as described above in conjunction with FIG. 1.

[0061] The functions of the components of the heat pump assembly 102 / system 100 depicted in FIG. 2 are similar to the functions described above in conjunction with FIG. 1 and hence are not described again here for the sake of simplicity and conciseness.

[0062] FIG. 3 depicts a block diagram of an exemplary heat pump assembly 300 in accordance with one or more embodiments of the present disclosure. FIG. 3 depicts the heat pump assembly 300 when the system 100 operates in the heating mode. The heat pump assembly 300 may be similar to the heat pump assembly 102 described above in conjunction with FIG. 1; however, instead of the modulating valve 122, the heat pump assembly 300 may include a solenoid valve302. Further, instead of the first and second check valves 124, 126, the heat pump assembly 300 may include a second reversing valve 304. The remaining components of the heat pump assembly 300 and their functions are same as the components / functions described above in conjunction with the heat pump assembly 102.

[0063] The solenoid valve 302 may operate in a fully closed position and a fully open position. The solenoid valve 302 may enable the flow of refrigerant from the compressor 112 to the reheat coil 120 when the solenoid valve 302 operates in the fully open position and may disable the flow of refrigerant from the compressor 112 to the reheat coil 120 when the solenoid valve 302 operates in the fully closed position.

[0064] The controller 104 may transmit a command signal to cause the solenoid valve 302 to operate in the fully open position when, e.g., the refrigerant pressure in the reheat coil 120 may be lower than the refrigerant pressure in the second heat exchanger 114, thereby enabling the refrigerant to flow from the compressor 112 to the reheat coil 120. Similarly, the controller 104 may transmit a command signal to cause the solenoid valve 302 to operate in the fully closed position when, e.g., the refrigerant pressure in the reheat coil 120 may be greater than the refrigerant pressure in the second heat exchanger 114, thereby disabling the flow of refrigerant from the compressor 112 into the reheat coil 120.

[0065] The second reversing valve 304 may enable the flow of refrigerant from the reheat coil 120 to the first heat exchanger 110 via the expansion valve 116 when the system 100 operates in the heating mode, as shown in FIG. 3. Specifically, in this case, the second reversing valve 304 may route the refrigerant output from the reheat coil 120 towards the inlet port of the expansion valve 116, which then transfers the refrigerant to the first heat exchanger 110, as shown in FIG. 3.

[0066] In some instances, the heat pump assembly 300 may be a split unit. For example, in a split unit configuration, the line 306 represent the boundary of components that are located indoors (i.e., the indoor unit) and components that are disposed outdoors (i.e., the outdoor unit). In particular, in some instances, all components located within the line 306 form the indoor unit, and all components located outside of the line 306 form the outdoor unit. In this manner, as depicted, there are three connections running between the indoor unit and the outdoor unit. This configuration can apply to any “split” system, including, but not limited to, mini-splits and VRF, where the indoor section is remote from the outdoor section. The indoor coil and reheat coil may be co-located, separated from the outdoor section by a line set. The heat pump assembly 300, however, may be any suitable configuration, including a Heating, Ventilation, and Air Conditioning (HVAC) unit, a packaged terminal air conditioner (PTAC) unit, a window unit, a vertical packaged unit, a Variable Refrigerant Flow (VRF) system, a ducted system, a packaged rooftop system, a split unit, an indoor / outdoor unit, and / or the like.

[0067] During operation, the controller 104 may first determine the operating mode of the system 100 in which the system user desires the system 100 to operate and transmit a command signal to the first reversing valve 118 to cause the first reversing valve 118 to route the refrigerant output from the compressor 112 to the second heat exchanger 114 when the user desires the system 100 to operate in the heating mode, as described above.

[0068] Further, the controller 104 may compare the refrigerant pressures in the reheat coil 120 and the second heat exchanger 114. Responsive to determining that the refrigerant pressure in the reheat coil 120 is greater than the refrigerant pressure in the second heat exchanger 114, the controller 104 may transmit a command signal to cause the solenoid valve 302 to operate in the fully closed position. On the other hand, responsive to determining that the refrigerant pressure in the reheat coil 120 is lower than the refrigerant pressure in the second heat exchanger 114, the controller 104 may transmit a command signal to cause the solenoid valve 302 to operate in the fully open position. Stated another way, responsive to determining that the refrigerant pressure in the reheat coil 120 is lower than the refrigerant pressure in the second heat exchanger 114, the controller 104 may cause the solenoid valve 302 to enable the flow of refrigerant from the compressor 112 to the reheat coil 120. In this case, the controller 104 may additionally transmit a command signal to cause the second reversing valve 304 to enable the flow of refrigerant from the outlet of the solenoid valve 302 to the inlet of the expansion valve 116, thereby enabling the refrigerant in liquid phase output from the reheat coil 120 and the second heat exchanger 114 to “merge” before entering the expansion valve 116.

[0069] FIG. 4 depicts a block diagram of the heat pump assembly 300 when the system 100 operates in the cooling mode, in accordance with one or more embodiments of the present disclosure. As described above, the flow of refrigerant may be reversed (as compared to the flow depicted in FIG. 3) when the system 100 operates in the cooling mode.

[0070] In this case, the functions / operations of the components of the heat pump assembly 300 may the same as the functions / operations of the components of the heat pump assembly 102 when the system operates in the cooling mode, as described above in conjunction with FIG. 2.

[0071] Further, in this case as well, the controller 104 may control the operation of the solenoid valve 302 based on the refrigerant pressures in the reheat coil 120 and the first heat exchanger 110. For example, the controller 104 may cause the solenoid valve 302 to operate in the fully open position when the refrigerant pressure in the reheat coil 120 may be low (and vice-versa).

[0072] Furthermore, when the system 100 operates in the cooling mode, the second reversing valve 304 may enable the flow of refrigerant from the reheat coil 120 to the second heat exchanger 114 via the expansion valve 116. When the system 100 is operating in the cooling mode and the solenoid valve 302 is in the fully open position, the controller 104 may transmit a command signal to cause the second reversing valve 304 to enable the flow of refrigerant from the outlet of the solenoid valve 302 to the inlet of the expansion valve 116, thereby enabling the refrigerant in a liquid phase output from the reheat coil 120 and the first heat exchanger 110 to “merge” before entering the expansion valve 116.

[0073] FIG. 5 depicts a block diagram of the controller 104 in accordance with one or more embodiments of the present disclosure. The controller 104 may include a plurality of components including, but not limited to, a processor 505, a memory 510, and a communication interface 515. The controller 104 may be a computing device configured to receive data, determine actions based on the received data (e.g., the inputs obtained from the sensor unit 106) and output a control signal instructing one or more system components to perform one or more actions.

[0074] In some aspects, the controller 104 may be configured to send and receive wireless or wired signals, and the signals may be analog or digital signals. The wireless signals may include Bluetooth, BLE, WiFi, ZigBee, infrared, microwave radio, or any other type of wireless communication signals as may be suitable for a particular system application. The hard-wired signals can include communication signals between any directly wired connections between the controller 104 and other system components. For example, the controller 104 can have a hard-wired 24 Volts Direct Current (VDC) connection to the sensors included in the sensor unit 106 described above.

[0075] Alternatively, the controller 104 may communicate with the sensors via a digital connection. The digital connection can include a connection such as an Ethernet or a serial connection and can utilize any suitable communication protocol for the system application, such as Modbus, fieldbus, PROFIBUS, SafetyBus, Ethernet / IP, and / or the like. Furthermore, the controller 104 can utilize a combination of wireless, hard-wired, and analog or digital communication signals to communicate with and control the various system components. A person ordinarily skilled in the art may appreciate that the above configurations are given merely as non-limiting examples, and the actual configuration can vary depending on the particular system application.

[0076] The memory 510 may store a program and / or instructions associated with the functions and methods described herein. The processor 505 may be configured to execute the program and / or instructions stored in the memory 510. The memory 510 can include one or more suitable types of memory (e.g., volatile or non-volatile memory, random access memory (RAM), read only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, floppy disks, hard disks, removable cartridges, flash memory, a redundant array of independent disks (RAID), and the like) for storing files including the operating system, application programs (including, for example, a web browser application, a widget or gadget engine, and or other applications, as necessary), executable instructions and data. One, some, or all of the processing techniques or methods described herein can be implemented as a combination of executable instructions and data within the memory 510.

[0077] The communication interface 515 may be configured to send or receive communication signals between the various system components. The communication interface 515 can include hardware, firmware, and / or software that allows the processor 505 to communicate with the other components via wired or wireless networks, whether local or wide area, private or public, as known in the art. The communication interface 515 can also provide access to a cellular network, the Internet, a local area network, or another wide-area network as suitable for the particular system application.

[0078] Additionally, the controller 104 may have or be in communication with a user interface (not shown) for receiving inputs from the system user. The user interface may be installed locally on the system 100.

[0079] The function of the controller 104 is already described above in conjunction with FIGS. 1-4, and hence is not described again here for the sake of simplicity and conciseness.

[0080] FIG. 6 depicts a flow diagram of an exemplary method 600 to control an operation of a valve of a heat pump assembly in accordance with one or more embodiments of the present disclosure. FIG. 6 may be described with continued reference to prior figures. The following process is exemplary and not confined to the steps described hereafter. Moreover, alternative embodiments may include more or less steps than are shown or described herein and may include these steps in a different order than the order described in the following example embodiments.

[0081] The method 600 may start at step 602. At step 604, the method 600 may include determining, by the controller 104, a desired operating mode of the system 100 based on user inputs. At step 606, the method 600 may include causing, by the controller 104, the system 100 to operate in the desired operating mode. For example, the controller 104 may cause the system 100 to operate in the heating mode or the cooling mode, based on the user inputs.

[0082] At step 608, the method 600 may include comparing, by the controller 104, the refrigerant pressures in the reheat coil 120 and the first / second heat exchanger 110, 114 (depending on the mode of operation of the system 100). At step 610, the method 600 may include controlling, by the controller 104, the operation of the valve (e.g., the modulating valve 122 or the solenoid valve 302) of the system 100 based on the comparison, as described above.

[0083] The method 600 may stop at step 612.

[0084] In the above disclosure, reference has been made to the accompanying drawings, which form a part hereof, which illustrate specific implementations in which the present disclosure may be practiced. It is understood that other implementations may be utilized, and structural changes may be made without departing from the scope of the present disclosure. References in the specification to “one embodiment,”“an embodiment,”“an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a feature, structure, or characteristic is described in connection with an embodiment, one skilled in the art will recognize such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0085] It should also be understood that the word “example” as used herein is intended to be non-exclusionary and non-limiting in nature. More particularly, the word “example” as used herein indicates one among several examples, and it should be understood that no undue emphasis or preference is being directed to the particular example being described.

[0086] With regard to the processes, systems, methods, heuristics, etc. described herein, it should be understood that, although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps described herein could be omitted. In other words, the descriptions of processes herein are provided for the purpose of illustrating various embodiments and should in no way be construed so as to limit the claims.

[0087] Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the above description. The scope should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the application is capable of modification and variation.

[0088] All terms used in the claims are intended to be given their ordinary meanings as understood by those knowledgeable in the technologies described herein unless an explicit indication to the contrary is made herein. In particular, use of the singular articles such as “a,”“the,”“said,” etc., should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary. Conditional language, such as, among others, “can,”“could,”“might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments could include, while other embodiments may not include, certain features, elements, and / or steps. Thus, such conditional language is not generally intended to imply that features, elements, and / or steps are in any way required for one or more embodiments.

Examples

Embodiment Construction

[0011]The present disclosure is directed towards a heat pump system (“system”) that may be part of a Heating, Ventilation, and Air Conditioning (HVAC) unit, a packaged terminal air conditioner (PTAC) unit, a window unit, a vertical packaged unit, a Variable Refrigerant Flow (VRF) system, a ducted system, a packaged rooftop system, a split unit, an indoor / outdoor unit, and / or the like. Although the present disclosure is described in the context of an HVAC system, the description should not be construed as limited only to HVAC systems.

[0012]The system may operate in a heating mode or a cooling mode. The system may heat a room / building (where the system is installed) when the system operates in the heating mode and may cool the room / building when the system operates in the cooling mode.

[0013]The system may include a plurality of components / modules including, but not limited to, a heat pump assembly, a controller, a sensor unit, etc. The heat pump assembly may include a compressor, a fi...

Claims

1. A heat pump system, comprising:a compressor;a reheat coil configured to receive a refrigerant from the compressor; anda valve configured to control a flow of the refrigerant to the reheat coil,wherein the heat pump system is configured to operate in a cooling mode or a heating mode based on a direction of flow of refrigerant through the heat pump system, and wherein the valve is configured to route hot refrigerant from the compressor to the reheat coil when the heat pump system is operating in the heating mode.

2. The heat pump system of claim 1, further comprising a first heat exchanger, a second heat exchanger, and an expansion valve, wherein the refrigerant output from the reheat coil is routed towards the expansion valve.

3. The heat pump system of claim 2, further comprising a first reversing valve configured to reverse the flow of refrigerant in the heat pump system to switch an operating mode of the heat pump system between the heating mode and the cooling mode, wherein the compressor outputs the refrigerant to the first heat exchanger when the operating mode is the cooling mode, and wherein the compressor outputs the refrigerant to the second heat exchanger when the operating mode is the heating mode.

4. The heat pump system of claim 3, wherein the valve is a modulating valve configured to operate in a closed position, a partially open position, and a fully open position, wherein the modulating valve is configured to modulate the flow of refrigerant from the compressor to the reheat coil based on an opening percentage of the modulating valve in the partially open position, and wherein the refrigerant output from the reheat coil is routed, via the modulating valve, towards an outlet port of the expansion valve.

5. The heat pump system of claim 4, wherein the modulating valve disables the flow of refrigerant from the compressor to the reheat coil when the modulating valve operates in the fully closed position.

6. The heat pump system of claim 4 further comprising a first check valve disposed between the modulating valve and the first heat exchanger and a second check valve disposed between the modulating valve and the second heat exchanger, wherein the first check valve is configured to disable the flow of refrigerant from the first heat exchanger towards the modulating valve when the operating mode is the cooling mode, and wherein the second check valve is configured to disable the flow of refrigerant from the second heat exchanger towards the modulating valve when the operating mode is the heating mode.

7. The heat pump system of claim 3, wherein the valve is a solenoid valve configured to operate in a fully closed position and a fully open position, wherein the solenoid valve enables the flow of refrigerant from the compressor to the reheat coil when the solenoid valve operates in the fully open position, wherein the solenoid valve disables the flow of refrigerant from the compressor to the reheat coil when the solenoid valve operates in the fully closed position, and wherein the refrigerant output from the reheat coil is routed, via the solenoid valve, towards an inlet port of the expansion valve.

8. The heat pump system of claim 7, further comprising a second reversing valve configured to enable the flow of refrigerant from the reheat coil to the second heat exchanger via the expansion valve when the operating mode is the cooling mode and enable the flow of refrigerant from the reheat coil to the first heat exchanger via the expansion valve when the operating mode is the heating mode.

9. The heat pump system of claim 2, further comprising a controller configured to control an operation of the valve to control the flow of refrigerant in the reheat coil.

10. The heat pump system of claim 9, further comprising a sensor unit configured to determine refrigerant pressures in the reheat coil, the first heat exchanger and the second heat exchanger, wherein the controller controls the operation of the valve based on the refrigerant pressures in the reheat coil and the first heat exchanger or the second heat exchanger.

11. A heat pump system comprising:a heat pump assembly comprising a plurality of components connected in series via a refrigerant tubing, wherein a refrigerant flows through the plurality of components via the refrigerant tubing and wherein the plurality of components comprises a compressor, a first heat exchanger, a second heat exchanger, and an expansion device;a reversing valve configured to reverse a flow of refrigerant in the heat pump assembly to switch an operating mode of the heat pump system between a heating mode and a cooling mode, wherein the compressor outputs the refrigerant to the first heat exchanger when the operating mode is the cooling mode and wherein the compressor outputs the refrigerant to the second heat exchanger when the operating mode is the heating mode;a reheat coil configured to receive the refrigerant from the compressor; anda modulating valve configured to control the flow of refrigerant in the reheat coil, wherein the modulating valve is configured to route hot refrigerant from the compressor to the reheat coil when the heat pump system is operating in the heating mode, and wherein the refrigerant output from the reheat coil is routed, via the modulating valve, towards an outlet port of the expansion device.

12. The heat pump system of claim 11, wherein the modulating valve is configured to operate in a fully closed position, a partially open position, and a fully open position, wherein the modulating valve is configured to modulate the flow of refrigerant from the compressor to the reheat coil based on an opening percentage of the modulating valve in the partially open position, and wherein the modulating valve disables the flow of refrigerant from the compressor to the reheat coil when the modulating valve operates in the fully closed position.

13. The heat pump system of claim 12, further comprising a first check valve disposed between the modulating valve and the first heat exchanger and a second check valve disposed between the modulating valve and the second heat exchanger.

14. The heat pump system of claim 13, wherein the first check valve is configured to disable the flow of refrigerant from the first heat exchanger towards the modulating valve when the operating mode is the cooling mode, and wherein the second check valve is configured to disable the flow of refrigerant from the second heat exchanger towards the modulating valve when the operating mode is the heating mode.

15. The heat pump system of claim 11 further comprising a controller configured to control an operation of the modulating valve to control the flow of refrigerant in the reheat coil.

16. The heat pump system of claim 15 further comprising a sensor unit configured to determine refrigerant pressures in the reheat coil, the first heat exchanger and the second heat exchanger, wherein the controller controls the operation of the valve based on the refrigerant pressures in the reheat coil and the first heat exchanger or the second heat exchanger.

17. A heat pump system comprising:a heat pump assembly comprising a plurality of components connected in series via a refrigerant tubing, wherein a refrigerant flows through the plurality of components via the refrigerant tubing and wherein the plurality of components comprises a compressor, a first heat exchanger, a second heat exchanger, and an expansion valve;a first reversing valve configured to reverse a flow of refrigerant in the heat pump assembly to switch an operating mode of the heat pump system between a heating mode and a cooling mode, wherein the compressor outputs the refrigerant to the first heat exchanger when the operating mode is the cooling mode and wherein the compressor outputs the refrigerant to the second heat exchanger when the operating mode is the heating mode;a reheat coil configured to receive the refrigerant from the compressor;a solenoid valve configured to operate in a fully closed position and a fully open position, wherein the solenoid valve is configured to control the flow of refrigerant in the reheat coil, wherein the solenoid valve is configured to route hot refrigerant from the compressor to the reheat coil when the heat pump system is operating in the heating mode, and wherein the refrigerant output from the reheat coil is routed, via the solenoid valve, towards an inlet port of the expansion valve; anda second reversing valve configured to enable the flow of refrigerant from the reheat coil to the second heat exchanger via the expansion valve when the operating mode is the cooling mode and enable the flow of refrigerant from the reheat coil to the first heat exchanger via the expansion valve when the operating mode is the heating mode.

18. The heat pump system of claim 17, wherein the solenoid valve enables the flow of refrigerant from the compressor to the reheat coil when the solenoid valve operates in the fully open position, and wherein the solenoid valve disables the flow of refrigerant from the compressor to the reheat coil when the solenoid valve operates in the fully closed position.

19. The heat pump system of claim 17, further comprising a controller configured to control an operation of the solenoid valve to control the flow of refrigerant in the reheat coil.

20. The heat pump system of claim 19, further comprising a sensor unit configured to determine refrigerant pressures in the reheat coil, the first heat exchanger and the second heat exchanger, wherein the controller controls the operation of the valve based on the refrigerant pressures in the reheat coil and the first heat exchanger or the second heat exchanger.

Images