A method for air conditioning including installing an air conditioning unit at a desired location. The air conditioning unit includes a housing that has air supply inlets and exhaust air outlets. The housing encloses a mode control unit that switches a zone coil associated with a zone from a cooling mode to a heating mode by switching from a cooling medium to a heating medium flowing through the zone coil. The zone coil receives the heating or cooling medium and conditions incoming air from a supply fan to be exhausted in a zone associated with the zone coil. A variable refrigerant flow cooling/heating unit provides a cooling medium or a heating medium at varying rates to control a temperature of a zone.

A method for air conditioning including installing an air conditioning unit at a desired location. The air conditioning unit includes a housing that has air supply inlets and exhaust air outlets. The housing encloses a mode control unit that switches a zone coil associated with a zone from a cooling mode to a heating mode by switching from a cooling medium to a heating medium flowing through the zone coil. The zone coil receives the heating or cooling medium and conditions incoming air from a supply fan to be exhausted in a zone associated with the zone coil. A variable refrigerant flow cooling/heating unit provides a cooling medium or a heating medium at varying rates to control a temperature of a zone.

An HVAC system includes an evaporator coil disposed between a return air duct and a supply air duct. The system includes a compressor fluidically connected to the evaporator coil, and a blower for providing a flow of air through the HVAC system. The HVAC system includes a supply air recirculation line with a recirculation damper and an evaporator bypass line with a bypass damper. A controller of the HVAC determines a recirculation portion of a flow of air and causes the recirculation damper to move to divert the recirculation portion to the recirculation line, so the air recirculates through the HVAC system. The controller determines a bypass portion of a flow of air and causes the bypass damper to move to divert the bypass portion to the bypass line, so the bypass portion does not contact the evaporator coil.

Various embodiments include a system for controlling air temperature. The system can include a potable water piping system, a cooling system, and a heating system. The potable water piping system can include potable water supply piping and potable water return piping. The cooling system can be coupled to the potable water piping system. The cooling system can include a water-refrigerant heat exchanger; an air-refrigerant coil; a compressor coupled between the water-refrigerant heat exchanger and the air-refrigerant coil; and an expansion valve coupled between the water-refrigerant heat exchanger and the air-refrigerant coil. The heating system can be coupled to the potable water piping system. The heating system can include a hot water coil. The water-refrigerant heat exchanger can be coupled to the potable water supply piping and the potable water return piping. The hot water coil can be coupled to the potable water supply piping and the potable water return piping.

Various embodiments include a system for controlling air temperature. The system can include a potable water piping system, a cooling system, and a heating system. The potable water piping system can include potable water supply piping and potable water return piping. The cooling system can be coupled to the potable water piping system. The cooling system can include a water-refrigerant heat exchanger; an air-refrigerant coil; a compressor coupled between the water-refrigerant heat exchanger and the air-refrigerant coil; and an expansion valve coupled between the water-refrigerant heat exchanger and the air-refrigerant coil. The heating system can be coupled to the potable water piping system. The heating system can include a hot water coil. The water-refrigerant heat exchanger can be coupled to the potable water supply piping and the potable water return piping. The hot water coil can be coupled to the potable water supply piping and the potable water return piping.

An HVAC system includes an evaporator coil disposed between a return air duct and a supply air duct. The system includes a compressor fluidically connected to the evaporator coil, and a blower for providing a flow of air through the HVAC system. The HVAC system includes a supply air recirculation line with a recirculation damper and an evaporator bypass line with a bypass damper. A controller of the HVAC determines a recirculation portion of a flow of air and causes the recirculation damper to move to divert the recirculation portion to the recirculation line, so the air recirculates through the HVAC system. The controller determines a bypass portion of a flow of air and causes the bypass damper to move to divert the bypass portion to the bypass line, so the bypass portion does not contact the evaporator coil.

An HVAC system includes an evaporator coil disposed between a return air duct and a supply air duct. The system includes a compressor fluidically connected to the evaporator coil, and a blower for providing a flow of air through the HVAC system. A controller determines an operating mode of the HVAC system.

An HVAC system includes an evaporator coil disposed between a return air duct and a supply air duct. The system includes a compressor fluidically connected to the evaporator coil, and a blower for providing a flow of air through the HVAC system. A controller determines an operating mode of the HVAC system.

A method for air conditioning including installing an air conditioning unit at a desired location. The air conditioning unit includes a housing that has air supply inlets and exhaust air outlets. The housing encloses a mode control unit that switches a zone coil associated with a zone from a cooling mode to a heating mode by switching from a cooling medium to a heating medium flowing through the zone coil. The zone coil receives the heating or cooling medium and conditions incoming air from a supply fan to be exhausted in a zone associated with the zone coil. A variable refrigerant flow cooling/heating unit provides a cooling medium or a heating medium at varying rates to control a temperature of a zone.

A method for air conditioning including installing an air conditioning unit at a desired location. The air conditioning unit includes a housing that has air supply inlets and exhaust air outlets. The housing encloses a mode control unit that switches a zone coil associated with a zone from a cooling mode to a heating mode by switching from a cooling medium to a heating medium flowing through the zone coil. The zone coil receives the heating or cooling medium and conditions incoming air from a supply fan to be exhausted in a zone associated with the zone coil. A variable refrigerant flow cooling/heating unit provides a cooling medium or a heating medium at varying rates to control a temperature of a zone.