A reversible HVAC heating/cooling refrigerant system includes a novel valve system that allows an outdoor heat exchanger to function as a subcooler during a cooling or defrost mode and function as a receiver tank for storing excess liquid refrigerant during a heating mode. In the heating mode, a coo
A reversible HVAC heating/cooling refrigerant system includes a novel valve system that allows an outdoor heat exchanger to function as a subcooler during a cooling or defrost mode and function as a receiver tank for storing excess liquid refrigerant during a heating mode. In the heating mode, a cooling expansion valve is kept slightly open to flood the subcooler with liquid refrigerant while a heating expansion valve is regulated to maintain a desired level of superheat at the suction side of the refrigerant system's compressor. The novel valve system also serves as a pressure relief valve to protect the subcooler from excess pressure caused by thermal expansion of liquid refrigerant trapped within the subcooler.
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1. A refrigerant system being operable in at least a heating mode and containing a refrigerant in heat transfer relationship with an outside fluid for ultimately heating a comfort zone or a process, the refrigerant system comprising: a heat exchanger system containing at least some of the refrigeran
1. A refrigerant system being operable in at least a heating mode and containing a refrigerant in heat transfer relationship with an outside fluid for ultimately heating a comfort zone or a process, the refrigerant system comprising: a heat exchanger system containing at least some of the refrigerant;a compressor periodically drawing the refrigerant at a suction pressure and discharging the refrigerant at a discharge pressure, thereby providing the refrigerant system with a high-pressure side and a low-pressure side; anda pressure relief valve defining an inlet and an outlet, the inlet is connected in fluid communication with the heat exchanger system, the outlet is connected in fluid communication with the low-pressure side, the pressure relief valve opens to release at least some of the refrigerant from within the heat exchanger system in response to the refrigerant within the heat exchanger system exceeding a maximum pressure limit, wherein the maximum pressure limit is even greater than the discharge pressure of the compressor. 2. The refrigerant system of claim 1, wherein the heat exchanger system includes a main coil and a subcooler, the main coil absorbs heat from the outside fluid, and the subcooler stores a trapped amount of refrigerant in a liquid state. 3. The refrigerant system of claim 2, wherein the inlet of the pressure relief valve is connected in fluid communication with the subcooler. 4. The refrigerant system of claim 2, wherein the refrigerant can exceed the maximum pressure limit by virtue of the refrigerant thermally expanding within the subcooler. 5. The refrigerant system of claim 1, further comprising a directional valve, and the pressure relief valve further defines a pilot port connected in fluid communication with the directional valve, the directional valve couples the pilot port in fluid communication selectively to the low-pressure side and the high-pressure side. 6. A refrigerant system containing a refrigerant and being selectively operable in a heating mode and a cooling mode for respectively heating and cooling a comfort zone or a process, wherein the refrigerant system absorbs heat from an outside fluid when the refrigerant system is in the heating mode heating the comfort zone or process and releases heat to the outside fluid when the refrigerant system is in the cooling mode cooling the comfort zone or process, the refrigerant system comprising: an exterior heat exchanger system that includes a main coil and a subcooler, the exterior heat exchanger system is arranged to release heat to the outside fluid when the refrigerant system is in the cooling mode and absorb heat from the outside fluid when the refrigerant system is in the heating mode, the main coil defines a first main port and a second main port in refrigerant fluid communication with each other through the main coil, the subcooler defines a first subcooler port and a second subcooler port in refrigerant fluid communication with each other through the subcooler; anda valve system with pressure relief, the valve system defines a coil valve port and a subcooler valve port, the coil valve port is connected in refrigerant fluid communication with the second main port of the main coil, the subcooler valve port is connected in refrigerant fluid communication with the second subcooler port of the subcooler, the valve system has an open position and a closed position such that:a) in the open position, the valve system connects the coil valve port in refrigerant fluid communication with the subcooler valve port;b) in the closed position, the valve system substantially blocks refrigerant fluid communication therethrough between the coil valve port and the subcooler valve port;c) the valve system is in the open position when the refrigerant system is in the cooling mode;d) the valve system is in the closed position when the refrigerant system is in the heating mode while the refrigerant within the subcooler is below a predetermined pressure limit; ande) the valve system is in the open position when the refrigerant system is in the heating mode while the refrigerant within the subcooler is above the predetermined pressure limit. 7. The refrigerant system of claim 6, wherein the valve system includes a valve housing that defines the coil valve port, the subcooler valve port, and a valve seat; the valve seat defines an opening between the coil valve port and the subcooler valve port, the refrigerant system further comprises a valve element disposed within the valve housing and being movable relative to the valve seat such that the valve element engages the valve seat to obstruct the opening when the valve system is in the closed position, and the valve element is spaced apart from the valve seat to uncover the opening when the valve system is in the open position, whereby the valve element moves to selectively obstruct and clear refrigerant flow through the valve housing. 8. The refrigerant system of claim 7, wherein the valve housing defines an annular passageway that encircles the opening, the annular passageway and the opening are each in fluid communication with only one of the coil valve port and the subcooler valve port when the valve system is in the closed position. 9. The refrigerant system of claim 7, wherein the refrigerant system includes a high pressure side and a lower pressure side, and the valve housing further defines a pilot port connected in fluid communication selectively to the high pressure side and the low pressure side such that a change in pressure at the pilot port urges the valve system between the open position and the closed position. 10. The refrigerant system of claim 7, further comprising a spring disposed within the valve housing such that the spring urges the valve element toward the valve seat. 11. The refrigerant system of claim 7, wherein during the cooling mode, refrigerant flows sequentially through the first main port of the main coil, through the main coil, through the second main port of the main coil, through the coil valve port of the valve housing, through the valve housing, through the subcooler valve port of the valve housing, through the second subcooler port of the subcooler, through the subcooler, and through the first subcooler port of the subcooler. 12. The refrigerant system of claim 6, wherein during the heating mode, refrigerant condenses in the subcooler. 13. The refrigerant system of claim 6, wherein the outside fluid is a current of air, and further comprising a fan forcing the current of air across the exterior heat exchanger system, wherein the first main port is generally upstream of the second main port with reference to the current of air during the cooling mode, and the first subcooler port is generally downstream of the second subcooler port with reference to the current of air during the cooling mode. 14. The refrigerant system of claim 6, wherein the refrigerant condenses in the subcooler during the heating mode. 15. The refrigerant system of claim 6, further comprising a cooling expansion valve and a heating expansion valve connected in refrigerant fluid communication with the exterior heat exchanger system such that: a) in the cooling mode, the heating expansion valve is substantially closed, and the refrigerant flows sequentially from the first subcooler port through the cooling expansion valve, andb) in the heating mode, the refrigerant flows sequentially from the heating expansion valve, through the second main port and through the main coil while the cooling expansion valve is partially open to flood the subcooler with refrigerant in liquid form. 16. The refrigerant system of claim 15, wherein the refrigerant system is further operable in a transition mode during a period after the heating mode and before the cooling mode, and further comprising a compressor connected to force the refrigerant through the refrigerant system and a fan disposed in air fluid communication with the exterior heat exchanger system, wherein: a) the compressor is inactive during the transition mode,b) the fan is inactive during the transition mode,c) the cooling expansion valve is at least partially open during the transition mode, andd) the heating expansion valve is at least partially open during the transition mode. 17. The refrigerant system of claim 16, further comprising a receiver tank connected in refrigerant fluid communication with the cooling expansion valve and the heating expansion valve, wherein at least some refrigerant from at least one of the subcooler and the receiver tank flows to the main coil during the transition mode. 18. A method of operating a refrigerant system that is selectively operable in a heating mode and a cooling mode, wherein the refrigerant system includes a main coil and a subcooler containing a refrigerant that is in heat transfer relationship with an outside fluid, the method comprising: in the cooling mode, releasing heat from the main coil and the subcooler to the outside fluid;in the heating mode, transferring heat from the outside fluid to the main coil as the refrigerant flows therethrough;in the heating mode, trapping within the subcooler at least some of the refrigerant, wherein most of the refrigerant trapped within the subcooler is in a liquid state; andreleasing at least some of the refrigerant from within the subcooler if the refrigerant within the subcooler reaches a predetermined maximum pressure limit while still retaining substantially all of the refrigerant within the refrigerant system. 19. The method of claim 18, wherein the refrigerant system also includes a compressor capable of discharging the refrigerant at a maximum discharge pressure, wherein the maximum discharge pressure is less than the predetermined maximum pressure limit.
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이 특허에 인용된 특허 (5)
Shapiro-Baruch Ian (Syracuse NY), Air conditioner with dehumidifying mode.
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