A refrigeration apparatus includes a refrigerant circuit switchable between a first operation of performing a refrigeration cycle in which a first compressor is stopped and a second compressor is driven and a second operation of performing a refrigeration cycle in which the first and second compressors and are driven. The refrigeration apparatus further includes a reduction mechanism configured to reduce a refrigerant flowing into the first compressor while a first condition is satisfied during the first operation. The first condition indicates that an internal pressure of the first compressor is lower than an evaporation pressure of an evaporator.

A safety system for a heat pump system includes a plurality of valve units each having refrigerant pipe portions with control valves, a refrigerant leakage detector, and a casing accommodating the valves and the refrigerant leakage detector and formed with first and second openings. The safety system further includes a connection structure connecting the internal spaces of the casings via the first and second openings, and a discharge structure connected to the connection structure or one of the casings and configured to discharge air from the internal space of the casing in which a refrigerant leakage has occurred. The casing has first and second lateral faces facing different directions, and the first opening is formed in the first lateral face and the second opening is formed in the second lateral face.

A valve opening circuit mounted on a heat pump device having a valve on a refrigerant circuit includes a DC electric path to which a DC voltage generated from an AC voltage for normal use is applied, a valve drive circuit that opens and closes the valve by using the DC voltage of the DC electric path, a control unit that acquires a control power source voltage based on the DC voltage of the DC electric path and controls the valve drive circuit, and a power feed port connected to the DC electric path and connectable to a DC power source line provided from outside for emergency. The control unit causes the valve drive circuit to open the valve when the AC voltage is lost and the DC voltage is fed from the DC power source line to the power feed port.

This air conditioning system includes a refrigerant circuit including an indoor heat exchanger of an indoor unit and an outdoor heat exchanger of an outdoor unit, and a detection unit capable of detecting a refrigerant leaking from the indoor unit. The detection unit is capable of switching between an energized state and a non-energized state on the basis of information on a refrigerant filling amount by which the refrigerant circuit is filled with the refrigerant.

A heat pump system provides at least six modes of heating, cooling, and/or domestic water heating operation, where domestic water heating may occur concurrently with heating or cooling a space in a structure. The heat pump system comprises a desuperheater positioned downstream of the compressor and operable as a desuperheater, a condenser or an evaporator, a source heat exchanger operable as either a condenser or an evaporator, a load heat exchanger operable as either a condenser or an evaporator, a reversing valve positioned downstream of the desuperheater heat exchanger and configured to alternately direct refrigerant flow from the desuperheater heat exchanger to one of the load heat exchanger and the source heat exchanger and to alternately return refrigerant flow from the other of the load heat exchanger and the source heat exchanger to the compressor, and an expansion valve positioned between the load heat exchanger and the source heat exchanger.

A heat pump system provides at least six modes of heating, cooling, and/or domestic water heating operation, where domestic water heating may occur concurrently with heating or cooling a space in a structure. The heat pump system comprises a desuperheater positioned downstream of the compressor and operable as a desuperheater, a condenser or an evaporator, a source heat exchanger operable as either a condenser or an evaporator, a load heat exchanger operable as either a condenser or an evaporator, a reversing valve positioned downstream of the desuperheater heat exchanger and configured to alternately direct refrigerant flow from the desuperheater heat exchanger to one of the load heat exchanger and the source heat exchanger and to alternately return refrigerant flow from the other of the load heat exchanger and the source heat exchanger to the compressor, and an expansion valve positioned between the load heat exchanger and the source heat exchanger.

Provided are a heat sink capable of suppressing overcooling of an electronic component which should not be overcooled and highly efficiently cooling only an electronic component which should be cooled, and a circuit device including the same. A heat sink includes a pipe and a cooling block. At least one projection is formed in the cooling block. The pipe is in contact with the projection. The pipe is arranged with a spacing from a portion of the cooling block other than the projection.

A refrigeration cycle apparatus comprises a refrigerant circuit, a water circuit, and a control device. The refrigerant circuit includes a compressor, a four-way valve, a heat exchanger, a fan, a diaphragm mechanism, a water heat exchanger, and an accumulator. Based on a value of a low-pressure sensor or a high-pressure sensor and a water temperature on an outlet side of the water heat exchanger, the refrigeration cycle apparatus determines whether or not there is an abnormality due to dirtiness adhered to a plate inside the water heat exchanger.

A single-stage carbon dioxide multi-split cooling and heating multifunctional central air conditioner, comprising a single-stage carbon dioxide circulation system using carbon dioxide as a circulation working medium; the single-stage carbon dioxide circulation system comprises an outdoor unit and a plurality of end heat exchangers provided in parallel; and the carbon dioxide medium performs cooling and/or heating in a circulating manner in a carbon dioxide compressor, an outdoor heat exchanger, a liquid storage tank and the end heat exchangers which are in communication with one another.

A single-stage carbon dioxide multi-split cooling and heating multifunctional central air conditioner, comprising a single-stage carbon dioxide circulation system using carbon dioxide as a circulation working medium; the single-stage carbon dioxide circulation system comprises an outdoor unit and a plurality of end heat exchangers provided in parallel; and the carbon dioxide medium performs cooling and/or heating in a circulating manner in a carbon dioxide compressor, an outdoor heat exchanger, a liquid storage tank and the end heat exchangers which are in communication with one another.