An air conditioning apparatus is equipped with an indoor fan, an indoor heat exchanger, and a control unit. The indoor heat exchanger generates conditioned air by exchanging heat between refrigerant and room air. The control unit sets operating modes. The control unit controls the rotational speed of the indoor fan. More specifically, in a case where the operating mode has been switched from one to the other of a normal heating mode and a hot air mode in which the conditioned air higher in temperature than in the normal heating mode is generated, the control unit lowers the rotational speed at a second rate that is slower than a first rate which is a rate of decrease in the rotational speed in a case where the operating mode is set to the normal heating mode.

A pressure control device for controlling a compressor includes a pressure sensor configured to measure pressure of a pressure line and a processing circuit. The processing circuit is configured to receive the measured pressure of the pressure line from the pressure sensor and control the compressor based on a set-point and the measured pressure. The pressure control device includes a mechanical switch sensitive to the pressure of the pressure line and configured to move between an open position and a closed position responsive to the pressure of the pressure line. Movement of the mechanical switch into one of the open position or the closed position causes the compressor to turn off and overrides the control of the compressor by the processing circuit.

An air conditioner and a control method for the same, the air conditioner including an air conditioning unit including a compressor, a first heat exchanger, an expansion valve, and a second heat exchanger; and a controller configured to obtain enthalpy of a refrigerant flowing in the air conditioning unit, obtain an air conditioning capacity using a circulation amount of the refrigerant and the obtained enthalpy of the refrigerant, obtain efficiency based on the obtained air conditioning capacity and supplied power, and control the air conditioning unit according to the obtained efficiency.

A compressor system for an air conditioning service system includes a compressor having a compressor case and a compressor head, an inlet, an outlet, a low side passage fluidly connecting the inlet to the compressor head, and a high side passage fluidly connecting the outlet to the compressor head. A low side return passage fluidly connects the compressor case with the low side passage and a first valve is positioned at least partially in the low side return passage and configured to control flow in the low side return passage.

A heat pump controller for use in a heat exchange system includes a computing device and a user interface coupled to the computing device. The computing device is configured to initiate a defrost cycle based on one of a plurality of user-selectable defrost modes, and the user interface is configured to display the user-selectable defrost modes and receive a user selection corresponding to one of the user-selectable defrost modes.

An air-conditioning apparatus includes indoor units including a plurality of use side heat exchangers that exchange heat between air and a heat medium, and a heat medium relay unit having a plurality of heat exchangers related to heat medium. A plurality of pumps deliver the heat medium involved in heating or cooling performed by the plurality of heat exchangers related to heat medium to each passage and circulate the heat medium. A plurality of heat medium flow switching devices perform switching so that the heat medium from a selected passage flows into and flows out of each use side heat exchanger. An expansion tank is connected to a passage alleviates a pressure change caused by a volumetric change of the heat medium, and a pressure equalizing pipe connects each inlet passage or each outlet passage of the heat medium sending devices.

A cryopump system includes: a plurality of cryopumps; a plurality of compressor units arranged to operate in parallel in accordance with a control output, respectively, to supply refrigerant gas to the plurality of cryopumps; and a cryopump controller operative to determine the control output for each of the plurality of compressor units. The cryopump controller adjusts a preset value for at least one of the compressor units, the preset value being utilized to determine the control output, so that operation statuses of the respective compressor units are substantially equalized.

A refrigeration apparatus includes a compressor receiving refrigerant through an injection pipe and of discharging the refrigerant, a condenser, an electronic expansion valve connected by piping to another end of the injection pipe, a subcooling coil, a solenoid valve configured to control inflowing of the refrigerant through the injection pipe into the compressor, an injection bypass pipe connecting the injection pipe and a pipe on a suction side of the compressor, a solenoid valve configured to control passage of the refrigerant flowing through the injection bypass pipe, a high-low pressure bypass pipe connecting a pipe on a discharge side of the compressor and the pipe on the suction side of the compressor, a solenoid valve configured to control passage of the refrigerant through the high-low pressure bypass pipe, and a controller configured to control a frequency of the compressor and opening and closing of each of the solenoid valves.

Methods of controlling a cooling unit and embodiments of a cooling unit are disclosed. A method of improving efficiency of the cooling unit includes detecting a degree of opening of a hot gas bypass valve configured to divert a portion of coolant from a compressor to a heat exchanger of the cooling unit, and adjusting a condenser discharge pressure based on the detected degree of opening. Aspects may increase cooling efficiency at partial cooling requirements. Fluctuations in refrigerant pressure at low cooling capacities and condenser medium inlet temperature may be avoided. Minimum condenser water inlet temperature for a water-cooled cooling unit may also be reduced.

A control valve according to one embodiment includes a shaft that transmits the solenoidal force to a valve element. A solenoid includes a bottomed sleeve into which the pressure of refrigerant is introduced, a core secured coaxially to the sleeve, a plunger, contained in the sleeve on its bottom side, which is displaceable integrally with the shaft in a direction of axis line, a first spring that applies the biasing force in a valve opening direction to the shaft, a second spring that applies the biasing force in a valve closing direction to the plunger, and a shaft support member, which is press-fitted such that the shaft support member is secured to an inner wall of the sleeve near its bottom portion. The second spring is set between the shaft support member and the plunger.