A computing device calculates an evaporating temperature Te* and a dew-point temperature Tdew* from a quality X, a temperature glide ΔT determined by a difference between a boiling temperature and a dew-point temperature at a predetermined pressure, and a refrigerant temperature detected by second temperature detection device.

A heating, ventilation, and air conditioning (HVAC) system for regulating humidity of an enclosed space. The HVAC system includes an evaporator coil. A metering device is fluidly coupled to the evaporator coil. A variable-speed compressor is fluidly coupled to the condenser coil and the evaporator coil and a controller is operatively coupled to the variable-speed compressor. A humidity sensor is operatively coupled to the controller and exposed to the enclosed space. Responsive to a determination that the relative humidity of the enclosed space exceeds the maximum humidity threshold, the controller adjusts a speed of the variable-speed compressor to increase latent capacity of the HVAC system. Responsive to a determination that the relative humidity of the enclosed space falls below the minimum humidity threshold, the controller adjusts a speed of the variable-speed compressor to decrease latent capacity of the HVAC system.

A method for managing and controlling a heat pump based on a compression/expansion thermodynamic cycle of an operating fluid including at least: first and second heat exchangers; an expansion valve; and a compressor. The compressor is able to suck and compress a wet operating fluid. A plurality of temperature sensors detects the delivery temperatures Tm of the compressor, an evaporation temperature SST in the first exchanger, and a condensation temperature SDT in the second exchanger. The temperature difference between the lubricating oil in the compressor and the operating fluid at the compressor delivery is kept equal to or greater than a safety threshold OIL_SH such that there is no condensation of the operating fluid in the lubricating oil.

Heat pump type heating apparatus capable of performing a continuous dual-stage operation without stopping a high stage side compressor even when a return temperature of a heating medium reaches a prescribed high temperature and, thereby, improving a sense of being insufficiently warmed due to stoppage of the high stage side compressor or a sense of being insufficiently warmed due to execution of frequent defrosting operations. The heat pump type heating apparatus includes an internal heat exchanger (a second internal heat exchanger) that performs heat exchange between a low-temperature refrigerant on a low-pressure side of a low stage side refrigeration circuit and a high-temperature refrigerant on a high-pressure side of a high stage side refrigerant circuit, a bypass pipe bypassing the internal heat exchanger, and flow path control means that controls a refrigerant flow to each of the internal heat exchanger and the bypass pipe.

A method for calibrating a temperature sensor arranged in a vapor compression system is disclosed. The opening degree of an expansion device is alternatingly increased and decreased. Simultaneously a temperature of refrigerant entering the evaporator and a temperature of refrigerant leaving the evaporator are monitored. For each cycle of the opening degree of the expansion device, a maximum temperature, T.sub.1, max, of refrigerant entering the evaporator, and a minimum temperature, T.sub.2, min, of refrigerant leaving the evaporator are registered. A calibration value, ΔT.sub.1, is calculated as ΔT.sub.1=C−(T.sub.2, min−T.sub.1, max) for each cycle, and a maximum calibration value, among the calculated values is selected. Finally, temperature measurements performed by the first temperature sensor are adjusted by an amount defined by ΔT.sub.1, max.

Systems and methods for disrupting a flow of refrigerant within a heat exchanger assembly. One embodiment provides a method that includes receiving, with a controller, a first signal from a first sensor, the first signal indicative of a pressure of the refrigerant flowing through the heat exchanger. The method includes setting, with the controller, an operating frequency of a valve based on the first signal. The operating frequency includes a rate at which the valve actuates between a first valve position that sets a first refrigerant flow rate through the heat exchanger and a second valve position that sets a second refrigerant flow rate through the heat exchanger. The method includes controlling, with the controller, operation of a solenoid to actuate the valve at the operating frequency.

A method of controlling a transport climate control system includes detecting for leaking of working fluid from a climate control circuit. The method also includes isolating a high-pressure side of the climate control circuit when leaking of the working fluid is detected. A method of controlling a transport climate control circuit includes detecting for overcharge and/or an undercharge of the climate control circuit. A transport climate control system includes a climate control circuit and a climate controller that is configured to detect for working fluid leaking from the climate control circuit. The climate controller configured to isolate a high-pressure side of the climate control circuit when leaking of the working fluid is detected.

An air conditioner includes a liquid pressure adjusting expansion valve that is located in an outdoor liquid refrigerant pipe at a part thereof closer to a liquid refrigerant communication pipe than to a refrigerant cooler and configured to reduce a pressure of a refrigerant so that a refrigerant flows through the liquid refrigerant communication pipe in a gas-liquid two-phase state and so that the refrigerant flows through an outlet of a refrigerant cooler in a liquid state.

A refrigerant control system includes: a charge module configured to determine an amount of refrigerant that is present within a first portion of a refrigeration system within a building; and an isolation module configured to selectively open and close an isolation valve of the refrigeration system and to, via the isolation valve, maintain the amount of refrigerant within the first portion within the building below a predetermined amount of the refrigerant.

A cooling system includes an evaporator coil and a compressor fluidly coupled to the evaporator coil. A circulation fan is arranged to direct air through the evaporator coil and through a discharge air duct into a conditioned space. At least one sensor is disposed in at least one of the discharge air duct, the conditioned space, and the evaporator coil. An HVAC controller is electrically coupled to the at least one sensor and electrically coupled to the compressor. The HVAC controller is configured to receive a measurement of an HVAC parameter from the at least one sensor, determine if the HVAC parameter indicates frost formation on the evaporator coil, and, responsive to a determination that the HVAC parameter indicates frost formation on the evaporator coil, raise a saturated suction temperature of the evaporator coil.