A heating, ventilation, and/or air conditioning (HVAC) unit includes a first sensor disposed adjacent to an inlet of an evaporator configured to receive an airflow. The HVAC unit includes a second sensor disposed adjacent to an outlet of a reheat coil positioned downstream of the evaporator and configured to expel the airflow. The HVAC unit also includes a controller configured to regulate operation of a modulating reheat valve to adjust flow of a working fluid in thermal communication with the airflow to control a difference between a measurement of the first sensor and a measurement of the second sensor.

Methods for providing heating or cooling to a plurality of zones in a conditioned space, include adjusting a temperature of a primary airflow using a heating, ventilation, air conditioning, and refrigeration (HVACR) system including a heat pump circuit and distributing the primary airflow to a plurality of terminals in the zones. The methods further include directing heat from the heat pump circuit to at least one of the plurality of terminals and heating air at the at least one of the plurality of terminals using the heat directed from the heat pump circuit. The methods can further include utilizing sources and sinks of the heat pump circuit to efficiently provide the heating or cooling. Systems include the heat pump circuit, terminals, heat distribution, and can include a controller to operate those components.

A heating, ventilation, and/or air conditioning (HVAC) unit includes a first sensor disposed adjacent to an inlet of an evaporator configured to receive an airflow. The HVAC unit includes a second sensor disposed adjacent to an outlet of a reheat coil positioned downstream of the evaporator and configured to expel the airflow. The HVAC unit also includes a controller configured to regulate operation of a modulating reheat valve to adjust flow of a working fluid in thermal communication with the airflow to control a difference between a measurement of the first sensor and a measurement of the second sensor.

A reheat system of an air conditioning unit includes a bypass line that fluidly couples an outlet of a reheat coil to an input end of a metering device. Further, the reheat system includes a reheat exit line that fluidly couples the outlet of the reheat coil to an input of a condenser. A bypass valve is disposed in the bypass line and a reheat valve is disposed in the reheat exit line. A controller is configured to control the bypass valve and the reheat valve such that a refrigerant from the outlet of the reheat coil is routed to the metering device via the bypass line when an ambient temperature is greater than or equal to a cut-off temperature value that is indicative of a high ambient temperature condition at which the condenser begins operating as an evaporator.

A heating, ventilation, and/or air conditioning (HVAC) unit includes a first sensor disposed adjacent to an inlet of an evaporator configured to receive an airflow. The HVAC unit includes a second sensor disposed adjacent to an outlet of a reheat coil positioned downstream of the evaporator and configured to expel the airflow. The HVAC unit also includes a controller configured to regulate operation of a modulating reheat valve to adjust flow of a working fluid in thermal communication with the airflow to control a difference between a measurement of the first sensor and a measurement of the second sensor.

A reheat system of an air conditioning unit includes a bypass line that fluidly couples an outlet of a reheat coil to an input end of a metering device. Further, the reheat system includes a reheat exit line that fluidly couples the outlet of the reheat coil to an input of a condenser. A bypass valve is disposed in the bypass line and a reheat valve is disposed in the reheat exit line. A controller is configured to control the bypass valve and the reheat valve such that a refrigerant from the outlet of the reheat coil is routed to the metering device via the bypass line when an ambient temperature is greater than or equal to a cut-off temperature value that is indicative of a high ambient temperature condition at which the condenser begins operating as an evaporator.

A heating, ventilation, and/or air conditioning (HVAC) system includes a refrigerant circuit configured to circulate a refrigerant to condition an air flow within an air flow conduit and a reheat system fluidly separate from the refrigerant circuit, wherein the reheat system is configured to utilize a waste fluid from a waste heat source to reheat the air flow conditioned by the refrigerant circuit.

A reheat system of an air conditioning unit includes a bypass line that fluidly couples an outlet of a reheat coil to an input end of a metering device. Further, the reheat system includes a reheat exit line that fluidly couples the outlet of the reheat coil to an input of a condenser. A bypass valve is disposed in the bypass line and a reheat valve is disposed in the reheat exit line. A controller is configured to control the bypass valve and the reheat valve such that a refrigerant from the outlet of the reheat coil is routed to the metering device via the bypass line when an ambient temperature is greater than or equal to a cut-off temperature value that is indicative of a high ambient temperature condition at which the condenser begins operating as an evaporator.

A heating, ventilation, and/or air conditioning (HVAC) unit includes a first sensor disposed adjacent to an inlet of an evaporator configured to receive an airflow. The HVAC unit includes a second sensor disposed adjacent to an outlet of a reheat coil positioned downstream of the evaporator and configured to expel the airflow. The HVAC unit also includes a controller configured to regulate operation of a modulating reheat valve to adjust flow of a working fluid in thermal communication with the airflow to control a difference between a measurement of the first sensor and a measurement of the second sensor.

To reduce noise coming from an indoor unit in an air conditioning apparatus that has an outdoor unit that has a compressor and an outdoor heat exchanger, the indoor unit that has an indoor heat exchanger, and a liquid refrigerant connection pipe and a gas refrigerant connection pipe that interconnect both units and in which a liquid pressure adjusting expansion valve that reduces a pressure of a refrigerant flowing through the liquid refrigerant connection pipe in such a way that the refrigerant is in a gas-liquid two-phase state is provided in an outdoor liquid refrigerant pipe that interconnects the liquid-side end of the outdoor heat exchanger and the liquid refrigerant connection pipe. An external expansion valve unit having an external expansion valve that further reduces the pressure of the refrigerant whose pressure has been reduced in the liquid pressure adjusting expansion valve is provided in the outdoor liquid refrigerant pipe.