A combined cooling and heating system including a district cooling grid having a feed conduit for an incoming flow of cooling fluid having a first temperature, and a return conduit for a return flow of cooling fluid having a second temperature, the second temperature being higher than the first temperature; a local cooling system being configured to absorb heat from a first building and comprising a heat exchanger having a heat exchanger inlet and a heat exchanger outlet; and a local heating system being configured to heat the first or a second building and comprising a heat pump having a heat pump inlet and a heat pump outlet. The heat exchanger inlet is connected to the feed conduit of the district cooling grid; and the heat pump inlet is connected to the return conduit of the district cooling grid and to the heat exchanger outlet.

A combined cooling and heating system including a district cooling grid having a feed conduit for an incoming flow of cooling fluid having a first temperature, and a return conduit for a return flow of cooling fluid having a second temperature, the second temperature being higher than the first temperature; a local cooling system being configured to absorb heat from a first building and comprising a heat exchanger having a heat exchanger inlet and a heat exchanger outlet; and a local heating system being configured to heat the first or a second building and comprising a heat pump having a heat pump inlet and a heat pump outlet. The heat exchanger inlet is connected to the feed conduit of the district cooling grid; and the heat pump inlet is connected to the return conduit of the district cooling grid and to the heat exchanger outlet.

An HVAC system includes a high-pressure subsystem and a low-pressure subsystem. After determining that refrigerant leak diagnostics should be performed, a controllable valve is closed between a condenser and compressor of the HVAC system. The compressor then operates until a predetermined input refrigerant pressure is reached. After the predetermined input refrigerant pressure is reached, operation of the compressor is stopped. After stopping operation of the compressor and waiting at least a predetermined wait time, the pressure in the low-pressure subsystem of the HVAC system is monitored. A rate of change of the pressure in the low-pressure subsystem is determined. If the rate of change is negative and a magnitude of the rate of change is greater than a threshold value, a leak location is determined to be in the low-pressure subsystem.

An HVAC system includes a high-pressure subsystem and a low-pressure subsystem. After determining that refrigerant leak diagnostics should be performed, a controllable valve is closed between a condenser and compressor of the HVAC system. The compressor then operates until a predetermined input refrigerant pressure is reached. After the predetermined input refrigerant pressure is reached, operation of the compressor is stopped. After stopping operation of the compressor and waiting at least a predetermined wait time, the pressure in the low-pressure subsystem of the HVAC system is monitored. A rate of change of the pressure in the low-pressure subsystem is determined. If the rate of change is negative and a magnitude of the rate of change is greater than a threshold value, a leak location is determined to be in the low-pressure subsystem.

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.

Systems and methods are configured to control operation of an HVAC system providing climate control for a zone of a structure. In various embodiments, a constrained optimization problem is performed to set control commands for controlling operation of the HVAC system to achieve one or more objectives while providing a supply air flow at an air temperature and a humidity ratio for the zone at a future time. For instance, the optimization problem may include a cost function having constraints based on a desired temperature setpoint and a humidity ratio for the zone. A value is set for each control command based on the performance of the constrained optimization problem to achieve at least one of the objectives and as a result, the supply air flow at the air temperature and humidity ratio is provided by the HVAC system at the future time to the zone based on the values.

A system for measuring and recharging an air conditioning system includes a vent sensor configured to be coupled to an outlet vent of an air conditioning system. The vent sensor is configured to measure at least one parameter of an air flow from the outlet vent. A processor is in signal communication with the vent sensor. The processor is configured to receive the at least one parameter of the air flow and determine a current refrigerant level of the air conditioning system.

An integrated device in an HVAC system is configured to modify an environmental condition of a building. The integrated device includes a valve configured to regulate a flow of a fluid through a conduit and an actuator. The actuator includes a motor and a drive device. The drive device is driven by the motor and coupled to the valve for driving the valve between multiple positions. The integrated device further includes a processing circuit coupled to the motor. The processing circuit is configured to detect device identifying information for the valve or the actuator and to detect the integrated device location within the building.

An integrated device in an HVAC system is configured to modify an environmental condition of a building. The integrated device includes a valve configured to regulate a flow of a fluid through a conduit and an actuator. The actuator includes a motor and a drive device. The drive device is driven by the motor and coupled to the valve for driving the valve between multiple positions. The integrated device further includes a processing circuit coupled to the motor. The processing circuit is configured to detect device identifying information for the valve or the actuator and to detect the integrated device location within the building.

Provided are a control method and apparatus for increasing the amount of a circulating refrigerant, and an air conditioner. The control method includes: when a refrigerating capacity need is equivalent to a heating capacity need in the operation of an air-conditioning system, determining whether the discharge temperature of a compressor is greater than a preset safety alert value; if the discharge temperature of the compressor is greater than the safety alert value, adjusting the frequency of a fan of an outdoor heat exchanger; and when the discharge temperature of the compressor is not greater than the safety alert value, controlling to stop the adjustment of the frequency of the fan, and maintaining the air-conditioning system to operate at the adjusted current frequency of the fan.