Provided is a multi-type air conditioner, including: an outdoor unit having a liquid pipe through which a liquid refrigerant flows, and a gas pipe through which a gas refrigerant flows; a plurality of indoor units comprising a first indoor unit and a second indoor unit each connected to the liquid pipe and the gas pipe to circulate a refrigerant; a gas pipe connecting tube connecting the gas pipe and the plurality of indoor units so that a gas refrigerant flows therethrough; and a liquid pipe connecting tube connecting the liquid pipe and the plurality of indoor units so that a liquid refrigerant flows therethrough. The first indoor unit may include: a first indoor heat exchanger comprising a first heat exchanger configured to perform heat exchange between indoor air and a refrigerant, and a second heat exchanger configured to perform heat exchange between indoor air and a refrigerant and arranged in a stacked fashion with the first heat exchanger; a first indoor fan configured to blow air to the first heat exchanger and the second heat exchanger; a first liquid branch pipe connecting the liquid pipe connecting tube and the first heat exchanger so that a refrigerant flows therethrough; a first gas branch pipe connecting the gas pipe connecting tube and the second heat exchanger so that a refrigerant flows therethrough; a first heat exchanger connecting pipe connected to the first heat exchanger so that a refrigerant flows therethrough; a second heat exchanger connecting pipe connected to the second heat exchanger so that a refrigerant flows therethrough; a return pipe having one side connected to the first gas branch pipe and the other side connected to the first heat exchanger connecting pipe and the second heat exchanger connecting pipe; a first indoor expansion valve disposed at the second heat exchanger connecting pipe, wherein an opening amount of the first indoor expansion valve is adjusted in response to an input signal from a controller to selectively expand a flowing refrigerant; and a first expansion valve disposed in the return pipe, wherein an opening amount of the first expansion valve is adjusted in response to an input signal from the controller to selectively expand a flowing refrigerant.

Since the multi-type air conditioner according to the present disclosure can operate the first heat exchanger as a condenser and the second heat exchanger as an evaporator among the indoor heat exchangers, it is possible to constantly operate the dehumidifying mode while maintaining a room temperature within a predetermined range.

A refrigeration system includes a refrigeration subsystem and a coolant subsystem. The refrigeration subsystem is configured to circulate a refrigerant between an evaporator (12,22) within which a refrigerant absorbs heat and a gas cooler/condenser (2) within which the refrigerant rejects heat to provide cooling to a temperature-controlled space. The coolant subsystem includes a heat exchanger (61) coupled to the refrigeration subsystem at an outlet of the gas cooler/condenser and configured to transfer heat from the refrigerant exiting the gas cooler/condenser to an external coolant when the external coolant flows through the heat exchanger, a control valve (64), and a controller (50) configured to operate the control valve to control a flow of at least one of the refrigerant or the external coolant through the heat exchanger based on a temperature of the external coolant relative to a temperature of the refrigerant exiting the gas cooler/condenser.

An air-conditioning apparatus includes a controller configured to control operations of an outdoor fan. The controller has a voltage acquisition unit configured to acquire drive voltages of the outdoor fan at set time intervals while the rotation speed of the outdoor fan is maintained at a reference rotation speed, a determination unit configured to determine whether or not an acquired drive voltage is equal to or greater than a lower limit threshold and less than an upper limit threshold, an extraction unit configured to calculate an evaluation value by extracting a drive voltage determined to be equal to or greater than the lower limit threshold and less than the upper limit threshold, and a defrosting determination unit configured to decide to defrost the outdoor heat exchanger if the calculated evaluation value is equal to or greater than an evaluation threshold.

An air-conditioner includes: a refrigerant circuit through which a refrigerant flows, the refrigerant circuit being formed of a compressor, a switching valve, a first heat exchanger, an expansion valve, and a second heat exchanger connected to one another by a first pipe; a heat-transfer medium circuit through which a heat-transfer medium flows, the heat-transfer medium circuit being formed of a pump, the first heat exchanger, and a third heat exchanger connected to one another by a second pipe; and control device that controls the compressor and the pump. In an operation of the air-conditioner performed before entering a defrosting operation, the control device increases a frequency of the compressor, as compared to the frequency of the compressor in a heating operation, and reduces a rotational speed of the pump, as compared to the rotational speed of the pump in the heating operation.

Systems and methods for controlled subcooling of working fluid in a heating, ventilation, air conditioning and refrigeration (HVACR) system through a suction line heat exchanger are disclosed. The suction line heat exchanger may receive a first fluid flow travelling to a suction of the compressor in the HVACR system and second flow of working fluid that is travelling from a heat exchanger receiving the discharge of the compressor to an expansion device. Superheating of the first working fluid may be determined based on temperature measurements prior to and following the suction line heat exchanger. The superheating may be used to control the quantity of the second flow of working fluid introduced into the suction line heat exchanger, for example to maintain superheat that is below a threshold value. These systems may include chillers and heat pump systems, and methods may be applied to chillers or heat pump systems.

A device and process for refuelling containers with pressurized gas comprising a pressurized gas source, a transfer circuit intended to be removably connected to a container, the device comprising a refrigeration system for cooling the gas flowing from the gas source prior to its entering into the container and comprising a refrigerant cooling loop circuit comprising, arranged in series, a compressor, a condenser section, an expansion valve and an evaporator section, the refrigeration system comprising a cold source in heat exchange with the condenser section and a heat exchanger located in the transfer circuit and comprising a heat exchange section between the gas flowing in the transfer circuit and the evaporator section, the device comprising an electronic controller configured to switch the refrigeration system in first standby mode when the device is not refuelling a container wherein the compressor is switched off when the temperature of the heat exchanger is equal or below a predefined first standby temperature threshold and for started and operated for producing cooling power and cooling the heat exchanger when the sensed temperature of the heat exchanger is above a second standby threshold temperature.

A heat pump system includes a refrigerant circuit in which a compressor, a refrigerant flow path included in a heat medium heat exchanger, an expansion valve, and a heat source side heat exchanger are connected, the heat medium heat exchanger including the refrigerant flow path and a heat medium flow path; a heat medium feed path connected to the heat medium flow path included in the heat medium heat exchanger; an indoor unit connected to the heat medium feed path and configured to condition air inside a room; a room temperature sensor configured to detect an indoor temperature in the room; a heat medium temperature sensor configured to detect a temperature of a heat medium that flows into the indoor unit; and a controller configured to control the refrigerant circuit or the indoor unit by using a set temperature in the room.

A relay includes a first relay unit and a second relay unit provided between an outdoor unit and an indoor unit to allow refrigerant to circulate between the first relay unit and the outdoor unit and between the second relay unit and the outdoor unit, and a heat medium circuit connecting the first relay unit and the second relay unit to the indoor unit to allow a heat medium to circulate through the heat medium circuit. The second relay unit is installed above or on a top of the first relay unit.

An air conditioning apparatus includes, a first heat exchanger, a second heat exchanger configured to exchange heat between a first heat medium and a second heat medium, flow rate control valves, and a pump. In a heating mode, a controller is configured to open the flow rate control valve corresponding to a heat exchanger, of the third heat exchangers, to which a request for air conditioning has been made, and to dose the flow rate control valve(s) corresponding to a heat exchanger(s), of the third heat exchangers, to which the request for air conditioning has not been made. In a defrosting mode, when a temperature of the second heat medium is lower than a first determination temperature, the controller is configured to open at least one of the flow rate control valve(s) corresponding to the heat exchanger(s) to which the request for air conditioning has not been made.

A refrigeration cycle apparatus includes a refrigerant circuit, by pipes, connecting a compressor, a flow switching device, a first heat exchanger, an expansion device, and a second heat exchanger. As refrigerant to be circulated through the refrigerant circuit, any one of a refrigerant having saturated gas temperature under standard atmospheric pressure that is higher than that of R32 and a refrigerant mixture mainly composed of the refrigerant is used. The refrigerant circuit includes an internal heat exchanger configured to exchange heat between the refrigerant flowing through a refrigerant-inlet side of the second heat exchanger and the refrigerant flowing through a refrigerant-outlet side of the second heat exchanger.