Abstract: A refrigerant circuit includes a compressor operable to compress a refrigerant, an expansion valve, an outdoor heat exchanger, an indoor heat exchanger in a fresh air inlet to a conditioned space, a recovery heat exchanger in an extracted air outlet from the conditioned space, and a reversing valve operable to direct a direction of refrigerant flow between a cooling mode and a heating mode.

Abstract: A refrigerant circuit includes a compressor operable to compress a refrigerant, an expansion valve, an outdoor heat exchanger, an indoor heat exchanger in a fresh air inlet to a conditioned space, a recovery heat exchanger in an extracted air outlet from the conditioned space, and a reversing valve operable to direct a direction of refrigerant flow between a cooling mode and a heating mode.

Abstract: A system includes a first set of coils that receive coolant from a first coolant line and provide the coolant to a second coolant line. A second set of coils that receive coolant from a third coolant line and provide the coolant to a fourth coolant line. A first valve regulates flow of coolant between the first and third coolant line. A second valve regulates flow of coolant between the second and the fourth coolant lines. A third valve regulates flow of coolant between the fourth coolant line and a fifth coolant line coupled to a water evaporator and a three-way valve. The three-way valve regulates flow of coolant between the fifth coolant line, the third coolant line, and a coolant input line. A fourth valve regulates flow of coolant between the second coolant line and a water condenser. A controller adjusts the valves to operate in a high temperature mode.

Abstract: A system includes a first set of coils receive coolant from a first coolant line and provide the coolant to a second coolant line. A second set of coils receive coolant from a third coolant line and provide the coolant to a fourth coolant line. A first valve regulates flow of coolant between the first and third coolant line. A second valve regulates flow of coolant between the second and the fourth coolant lines. A third valve regulates flow of coolant between the fourth coolant line and a fifth coolant line coupled to a water evaporator and a three-way valve. The three-way valve regulates flow of coolant between the fifth coolant line, the third coolant line, and a coolant input line. A fourth valve regulates flow of coolant between the second coolant line and a water condenser. A controller adjusts the valves to operate in an intermediate temperature mode.

Abstract: A system includes a first set of coils that receive coolant from a first coolant line and provide the coolant to a second coolant line. A second set of coils that receive coolant from a third coolant line and provide the coolant to a fourth coolant line. A first valve regulates flow of coolant between the first and third coolant line. A second valve regulates flow of coolant between the second and the fourth coolant lines. A third valve regulates flow of coolant between the fourth coolant line and a fifth coolant line coupled to a water evaporator and a three-way valve. The three-way valve regulates flow of coolant between the fifth coolant line, the third coolant line, and a coolant input line. A fourth valve regulates flow of coolant between the second coolant line and a water condenser. A controller adjusts the valves to operate in a low temperature mode.

Abstract: A method of defrost operation optimization in a heat pump includes launching a heating mode after completion of a performed defrost operation, measuring, after launching the heating mode, a heat transfer capability, determining if the measured heat transfer capability is less than or equal to a predetermined heat transfer capability limit for a non-iced condition, and reinforcing a next defrost operation if the measured heat transfer capability is greater than the predetermined gap limit.

Abstract: A HVAC system having an indoor heat exchanger having a first refrigerant passage extending in a first direction and a second refrigerant extending in a second direction opposite from the first direction, a first refrigerant circuit comprising a first compressor, a first expansion valve, a first outdoor heat exchanger, the first refrigerant passage, and a first reversing valve operable to control a direction of first refrigerant in the first refrigerant circuit, and a second refrigerant circuit comprising a second compressor, a second expansion valve, a second outdoor heat exchanger, the second refrigerant passage, and a second reversing valve operable to control a direction of second refrigerant in the second refrigerant circuit.

Abstract: A refrigerant circuit includes a compressor operable to compress a refrigerant, an expansion valve, an outdoor heat exchanger, an indoor heat exchanger in a fresh air inlet to a conditioned space, a recovery heat exchanger in an extracted air outlet from the conditioned space, and a reversing valve operable to direct a direction of refrigerant flow between a cooling mode and a heating mode.