Abstract: A heating, ventilation, air conditioning, and refrigeration (HVACR) system includes a first heat transfer circuit; a second heat transfer circuit; a fluid loop between the first heat transfer circuit and the second heat transfer circuit; a heat exchanger connecting to the fluid loop; and a controller. The controller is configured to determine an operation parameter of the system; and control the heat exchanger to remove heat from the fluid loop when the operation parameter is above a first threshold.

Abstract: A heating and cooling system including a first heat transfer circuit that includes a first heat exchanger and a second heat exchanger; a second heat transfer circuit that includes a third heat exchanger and a fourth heat exchanger; a coolant loop; and a controller. The controller selectively operates the heating and cooling system in: a heating mode, in which the heating and cooling system is configured to operate the first heat transfer circuit and the second heat transfer circuit in a cascaded operation to heat a first process fluid via heat transfer with the first heat exchanger, and a cooling mode, in which the heating and cooling system is configured to operate the first heat transfer circuit and the second heat transfer circuit in parallel operation to both provide cooling to a second process fluid via heat transfer with the fourth heat exchanger and the second heat exchanger.

Abstract: A free cooling system includes a circulation path including a pump and one or more heaters. The pump is configured to circulate a process fluid when the free cooling system is deactivated, and the one or more heaters are configured to add heat to the process fluid in the circulation path such that the process fluid remains above a freezing temperature of said process fluid.

Abstract: A method is for operating an expansion valve in a refrigerant circuit that includes a compressor, a condenser, the expansion valve, an evaporator, and a working fluid. The method includes determining a modified subcooling value based on a condenser working fluid discharge temperature, a condenser discharge subcooling setpoint, and one or more of a compressor discharge temperature and an evaporator approach temperature. The method also includes adjusting the expansion valve according to the modified subcooling value. A refrigerant circuit for a heating, ventilation, air conditioning, and refrigeration system includes a controller configured to operate the expansion valve according to a modified subcooling value.

Abstract: A free cooling system includes a circulation path including a pump and one or more heaters. The free cooling system can further include an isolation valve to isolate the circulation path from an active free cooling circulation path. The pump is configured to circulate a process fluid when the free cooling system is deactivated, and the one or more heaters are configured to add heat to the process fluid in the circulation path such that the process fluid remains above a freezing temperature of said process fluid.

Abstract: An embodiment of a buffer tank for a hydronic climate control system includes a buffer tank including an inlet port and an outlet port, an inlet line connected to the inlet port, and an outlet line connected to the outlet port. In addition, the buffer tank assembly includes a bypass line connected to the inlet line and the outlet line so that the buffer tank assembly defines a first flow path from the inlet line to the outlet line through the buffer tank and a second flow path from the inlet line to the outlet line through the bypass line. Further, the buffer tank assembly includes a flow control device in fluid communication with the buffer tank and the bypass line, wherein the flow control device is actuatable to control fluid flow along the first flow path and the second flow path.

Abstract: A method is for operating an expansion valve in a refrigerant circuit that includes a compressor, a condenser, the expansion valve, an evaporator, and a working fluid. The method includes determining a modified subcooling value based on a condenser working fluid discharge temperature, a condenser discharge subcooling setpoint, and one or more of a compressor discharge temperature and an evaporator approach temperature. The method also includes adjusting the expansion valve according to the modified subcooling value. A refrigerant circuit for a heating, ventilation, air conditioning, and refrigeration system includes a controller configured to operate the expansion valve according to a modified subcooling value.