Abstract: A heat pump system includes a refrigerant circuit including a compressor, a reversing valve, a first heat exchanger, a second heat exchanger, a reheat heat exchanger, and a three-way valve. The reversing valve is configured to receive refrigerant from the compressor and adjust between a first configuration to direct the refrigerant toward the three-way valve and a second configuration to direct the refrigerant toward the first heat exchanger. The three-way valve is configured to adjust between a first position to direct the refrigerant between the reversing valve and the second heat exchanger and a second position to direct the refrigerant from the reversing valve to the reheat heat exchanger.

Abstract: A heat pump system includes a refrigerant circuit that has a compressor, a first heat exchanger, a second heat exchanger, a reheat heat exchanger, a modulating valve, and a reversing valve. The reversing valve is configured to transition between a first configuration to direct refrigerant from the compressor toward the modulating valve and a second configuration to direct the refrigerant from the compressor toward the first heat exchanger. The heat pump system also includes control circuitry configured to concurrently maintain the reversing valve in the first configuration and adjust a position of the modulating valve to direct a first portion of the refrigerant from the modulating valve to the second heat exchanger and a second portion of the refrigerant from the modulating valve to the reheat heat exchanger based on an operating mode of the heat pump system.

Abstract: A heating, ventilation, and/or air conditioning (HVAC) system includes a first condenser coil of a refrigerant circuit, wherein the first condenser coil is configured to receive a first refrigerant flow from a compressor of the refrigerant circuit, a modulating valve of the refrigerant circuit, and control circuitry communicatively coupled to the modulating valve. The modulating valve is configured to receive a second refrigerant flow from the compressor and configured to direct the second refrigerant flow to a second condenser coil of the refrigerant circuit and to a reheat coil of the refrigerant circuit in a parallel flow arrangement, and the control circuitry is configured to operate the modulating valve to apportion the second refrigerant flow between the second condenser coil and the reheat coil based on a detected operating parameter of an air flow directed across the reheat coil.

Abstract: A heat pump system includes a refrigerant circuit that has a compressor, a first heat exchanger, a second heat exchanger, a reheat heat exchanger, a modulating valve, and a reversing valve. The reversing valve is configured to transition between a first configuration to direct refrigerant from the compressor toward the modulating valve and a second configuration to direct the refrigerant from the compressor toward the first heat exchanger. The heat pump system also includes control circuitry configured to concurrently maintain the reversing valve in the first configuration and adjust a position of the modulating valve to direct a first portion of the refrigerant from the modulating valve to the second heat exchanger and a second portion of the refrigerant from the modulating valve to the reheat heat exchanger based on an operating mode of the heat pump system.

Abstract: A heating, ventilation, and/or air conditioning (HVAC) system includes a first condenser coil of a refrigerant circuit, wherein the first condenser coil is configured to receive a first refrigerant flow from a compressor of the refrigerant circuit, a modulating valve of the refrigerant circuit, and a control circuitry communicatively coupled to the modulating valve. The modulating valve is configured to receive a second refrigerant flow from the compressor and configured to direct the second refrigerant flow to a second condenser coil of the refrigerant circuit and to a reheat coil of the refrigerant circuit in a parallel flow arrangement, and the control circuitry is configured to operate the modulating valve to apportion the second refrigerant flow between the second condenser coil and the reheat coil based on a detected operating parameter of an air flow directed across the reheat coil.

Abstract: A heat pump system includes a refrigerant circuit comprising a compressor, a reversing valve, a first heat exchanger, a second heat exchanger, a reheat heat exchanger, and a three-way valve. The reversing valve is configured to receive refrigerant from the compressor and adjust between a first configuration to direct the refrigerant toward the three-way valve and a second configuration to direct the refrigerant toward the first heat exchanger. The three-way valve is configured to adjust between a first position to direct the refrigerant between the reversing valve and the second heat exchanger and a second position to direct the refrigerant from the reversing valve to the reheat heat exchanger.

Abstract: A heating, ventilation, and/or air conditioning (HVAC) system includes a first condenser coil of a refrigerant circuit, wherein the first condenser coil is configured to receive a first refrigerant flow from a compressor of the refrigerant circuit, a modulating valve of the refrigerant circuit, and control circuitry communicatively coupled to the modulating valve. The modulating valve is configured to receive a second refrigerant flow from the compressor and configured to direct the second refrigerant flow to a second condenser coil of the refrigerant circuit and to a reheat coil of the refrigerant circuit in a parallel flow arrangement, and the control circuitry is configured to operate the modulating valve to apportion the second refrigerant flow between the second condenser coil and the reheat coil based on a detected operating parameter of an air flow directed across the reheat coil.

Abstract: A heat pump system includes a refrigerant circuit that has a compressor, a first heat exchanger, a second heat exchanger, a reheat heat exchanger, a modulating valve, and a reversing valve. The reversing valve is configured to transition between a first configuration to direct refrigerant from the compressor toward the modulating valve and a second configuration to direct the refrigerant from the compressor toward the first heat exchanger. The heat pump system also includes control circuitry configured to concurrently maintain the reversing valve in the first configuration and adjust a position of the modulating valve to direct a first portion of the refrigerant from the modulating valve to the second heat exchanger and a second portion of the refrigerant from the modulating valve to the reheat heat exchanger based on an operating mode of the heat pump system.

Abstract: A method for dehumidification and controlling system pressure in a refrigeration system includes providing a refrigeration system having a compressor, a condenser and an evaporator connected in a closed refrigerant loop. Each of the condenser and evaporator have a plurality of refrigerant circuits. A first heat transfer fluid is flowed over the condenser and a second heat transfer fluid is flowed over the evaporator. At least one of the refrigerant circuits of the condenser is isolated to provide a decreased amount of heat transfer area within the condenser and to increase the refrigerant pressure within the refrigeration system when the refrigerant pressure within the refrigeration system is at or below a predetermined pressure. At least one of the refrigerant circuits of the evaporator is isolated to dehumidify and maintain the temperature of the second heat transfer fluid at or above a predetermined temperature when dehumidification is required.

Abstract: An HVAC system including a compressor, a condenser and an evaporator arrangement connected in a closed refrigerant loop. The evaporator arrangement includes a plurality of refrigerant circuits. The evaporator arrangement also includes at least one distributor configured to distribute and deliver refrigerant to each circuit of the plurality of circuits. The plurality of circuits are arranged into a first and second set of circuits. The evaporator arrangement also includes a valve configured and disposed to isolate the first set of circuits from refrigerant flow from the condenser and provide flow of refrigerant from the compressor in a dehumidification operation of the HVAC system.

Abstract: An HVAC system including a compressor, a condenser and an evaporator connected in a closed refrigerant loop. The evaporator includes a plurality of refrigerant circuits. The evaporator also includes at least one distributor configured to distribute and deliver refrigerant to each circuit of the plurality of circuits. The plurality of circuits are arranged into a first and second set of circuits. The evaporator also includes a valve configured and disposed to isolate the first set of circuits from refrigerant flow from the condenser and provide flow of refrigerant from the compressor in a dehumidification operation of the HVAC system.

Abstract: A humidity control method is provided for a multi-stage cooling system having two or more refrigerant circuits that balances humidity control and cooling demand. Each refrigerant circuit includes a compressor, a condenser and an evaporator. A hot gas reheat circuit having a hot gas reheat coil is connected to one of the refrigerant circuits and is placed in fluid communication with the output airflow from the evaporator of that refrigerant circuit to provide additional dehumidification to the air when humidity control is requested. The hot gas reheat circuit bypasses the condenser of the refrigerant circuit during humidity control. Humidity control is only performed during cooling operations and ventilation operations.

Abstract: A humidity control method is provided for a multi-stage cooling system having two or more refrigerant circuits. A hot gas re-heat circuit having a hot gas re-heat coil, an evaporator and a compressor, such as the evaporator and compressor utilized in one of the refrigerant circuits, is provided. The hot gas re-heat coil is placed in fluid communication with the output airflow from the evaporator of the re-heat circuit. Humidity control is performed during cooling operations and ventilation operations. During a first stage cooling operation using only one refrigerant circuit and having a low cooling demand, the request for humidity control activates the hot gas re-heat circuit for dehumidification and activates a second refrigerant circuit to provide cooling capacity. During a second stage cooling operation using multiple refrigerant circuits and having a high cooling demand, the request for humidity control is suspended until completion of the second stage cooling demand.

Abstract: A method and system for controlling refrigerant pressure in an HVAC system. The method includes providing a compressor, a condenser and an evaporator connected in a closed refrigerant loop. The condenser has a header arrangement capable of distributing refrigerant to a plurality of refrigerant circuits within the condenser. The header arrangement also is capable of selectively isolating at least one of the circuits from refrigerant flow. Refrigerant pressure is sensed at a predetermined location in the refrigeration system. At least one of the circuits is isolated when the refrigerant pressure is less than or equal to a predetermined pressure.

Abstract: A humidity control method is provided for a multi-stage cooling system having two or more refrigerant circuits that balances humidity control and cooling demand. Each refrigerant circuit includes a compressor, a condenser and an evaporator. A hot gas reheat circuit having a hot gas reheat coil is connected to one of the refrigerant circuits and is placed in fluid communication with the output airflow from the evaporator of that refrigerant circuit to provide additional dehumidification to the air when humidity control is requested. The hot gas reheat circuit bypasses the condenser of the refrigerant circuit during humidity control. Humidity control is only performed during cooling operations and ventilation operations.

Abstract: A humidity control method is provided for a multi-stage cooling system having two or more refrigerant circuits that balances humidity control and cooling demand. Each refrigerant circuit includes a compressor, a condenser and an evaporator. A hot gas reheat circuit having a hot gas reheat coil is connected to one of the refrigerant circuits and is placed in fluid communication with the output airflow from the evaporator of that refrigerant circuit to provide additional dehumidification to the air when humidity control is requested. The hot gas reheat circuit bypasses the condenser of the refrigerant circuit during humidity control. Humidity control is only performed during cooling operations and ventilation operations.

Abstract: A system and humidity control method is provided for a multi-stage cooling system having two or more refrigerant circuits that balances humidity control and cooling demand. Each refrigerant circuit includes a compressor, a condenser and an evaporator. A hot gas reheat circuit having a hot gas reheat coil is connected to one of the refrigerant circuits and is placed in fluid communication with the output airflow from the evaporator of that refrigerant circuit to provide additional dehumidification to the air when humidity control is requested. The hot gas reheat circuit bypasses the condenser of the refrigerant circuit during humidity control. Humidity control is performed during cooling operations and ventilation operations. During a first stage cooling operation using only one refrigerant circuit and having a low cooling demand, the request for humidity control activates the hot gas reheat circuit for dehumidification and activates a second refrigerant circuit to provide cooling capacity.

Abstract: A humidity control method is provided for a multi-stage cooling system having two or more refrigerant circuits that balances humidity control and cooling demand. Each refrigerant circuit includes a compressor, a condenser and an evaporator. A hot gas reheat circuit having a hot gas reheat coil is connected to one of the refrigerant circuits and is placed in fluid communication with the output airflow from the evaporator of that refrigerant circuit to provide additional dehumidification to the air when humidity control is requested. The hot gas reheat circuit bypasses the condenser of the refrigerant circuit during humidity control. Humidity control is only performed during cooling operations and ventilation operations. During a first stage cooling operation using only one refrigerant circuit and having a low cooling demand, the request for humidity control activates the hot gas reheat circuit for dehumidification and activates a second refrigerant circuit to provide cooling capacity.

Abstract: A method of controlling an economizer is provided. A heating, ventilating, and air conditioning unit is operated in one of a heating mode and a cooling mode to provide conditioned air to a plurality of zones. A first temperature representative of air returned to the unit from the plurality of zones is sensed and a second temperature representative of the outdoor air is sensed. An economizer is modulated to increase the amount of outdoor air entering the unit when the first temperature falls below a cooling setpoint, the second temperature is greater than the first temperature, and the unit is operating in the cooling mode. The economizer is also modulated to increase the amount of outdoor air entering the unit when the first temperature rises above a heating setpoint, the second temperature is lower than the first temperature, and the unit is operating in the heating mode.

Abstract: A method and system for controlling the temperature of air returned to a conditioning unit in a zoned system is disclosed. The system includes a heating, ventilating, and air conditioning (HVAC) unit that has an economizer. The HVAC unit is connected to a plurality of zones by a supply duct and a return duct. A temperature sensor is provided to sense the temperature of air returning to the HVAC unit. A main control increases the amount of outdoor air entering the system through the economizer when the temperature of the returned air is excessively warm or excessively cold.