Hvac systems and methods for reheat operation

Abstract

Systems and methods are presented that enable a heating, ventilating, and air conditioning (HVAC) system to store refrigerant within a reheat circuit. In one instance, the HVAC system includes a valve, having a first position and a second position, configured to selectively control a flow of refrigerant into a reheat coil. When in the second position, the valve enables a hot refrigerant to flow from a compressor through the reheat coil. When in the first position, the valve stops the hot refrigerant from flowing through the reheat coil but still allows refrigerant to circulate through the closed-conduit refrigeration circuit. In the first position, refrigerant remains stored in the reheat circuit, which includes the reheat coil. Other systems and methods are presented.

1 . A method of regulating humidity in air conditioned by a heating, ventilating, and air conditioning system, the method comprising:
 moving conditioned air across a reheat coil;   while moving the conditioned air, actuating a valve having a first position and a second position into the second position to start a flow of refrigerant through the reheat coil;   while moving the conditioned air, actuating the valve into the first position to stop the flow of refrigerant through the reheat coil;   storing a refrigerant in the reheat coil when the valve is in the first position;   wherein, in the second position, the valve establishes a first flow pathway between a first discharge line and a supply line to the reheat coil; and   wherein, in the first position, the valve establishes a second flow pathway between the first discharge line and a second discharge line.   
     
     
         2 . The method of  claim 1 , wherein the valve comprises a bleed-port reheat valve. 
     
     
         3 . The method of  claim 1 , wherein the valve comprises a heat-pump reversing valve. 
     
     
         4 . The method of  claim 1 , wherein the valve comprises a heat-pump reversing valve and the method further comprises:
 blocking refrigerant flow towards the heat-pump reversing valve along the second discharge line while the heat-pump reversing valve is in the second position;   blocking refrigerant flow towards the heat-pump reversing valve along the supply line while the heat-pump reversing valve is in the first position;   wherein, in the second position, the heat-pump reversing valve further establishes fluid communication between a suction line and the second discharge line; and   wherein, in the first position, the heat-pump reversing valve further establishes fluid communication between the suction line and the supply line.   
     
     
         5 . The method of  claim 1 , further comprising:
 measuring a humidity of conditioned air relative to a reference humidity;   actuating the valve into the second position if the measured humidity is greater than the threshold humidity and the valve is in the first position; and   actuating the valve into the first position if the measured humidity is less than or equal to the threshold humidity and the valve is in the second position.   
     
     
         6 . The system of  claim 1 , wherein the step of actuating the valve into the second position and the step of actuating the valve into the first position comprises using a humidistat. 
     
     
         7 . A heating, ventilating, and air conditioning system for regulating a moisture content of conditioned air, the system comprising:
 a closed-conduit refrigeration circuit having an evaporator, a compressor, a valve, and a microchannel condenser,   wherein the evaporator is fluidly-coupled to the compressor through a suction line,   wherein the compressor is fluidly-coupled to the valve through a first discharge line, and   wherein the valve is fluidly-coupled to the microchannel condenser through a second discharge line;   a reheat coil proximate the evaporator, the reheat coil having an inlet and an outlet, the inlet fluidly-coupled to the valve through a supply line, the outlet fluidly-coupled to the second discharge line through a return line; and   wherein the valve is configured to selectively control a flow of refrigerant into the reheat coil.   
     
     
         8 . The system of  claim 7 , wherein the valve comprises a bleed-port reheat valve. 
     
     
         9 . The system of  claim 7 , wherein the valve comprises a heat-pump reversing valve. 
     
     
         10 . The system of  claim 7 , wherein the valve comprises a heat-pump reversing valve and the system further comprises:
 a first check valve fluidly-coupled to the supply line and oriented to prevent refrigerant from flowing towards the heat-pump reversing valve; and   a second check valve fluidly-coupled to the second discharge line between the heat-pump reversing valve and a junction formed by the return line and the second discharge line, the second check valve oriented to prevent refrigerant from flowing towards the heat-pump reversing valve.   
     
     
         11 . The system of  claim 7 , further comprising a refrigerant disposed therein. 
     
     
         12 . The system of  claim 7 , further comprising a humidistat configured to actuate the valve in response to humidity measured in air conditioned by the system being greater than a humidity threshold.