An exhaust heat recovery type of air-conditioning apparatus includes: an air-conditioning-side refrigerant circuit including a first flow switching device, a second flow switching device, and an exhaust-heat recovery heat exchanger connected in parallel to an outdoor heat exchanger and an indoor heat exchanger; and a refrigeration-side refrigerant circuit. The first flow switching device causes the outdoor heat exchanger to communicate with one of a discharge side and a suction side of a first compressor through a pipe. The second flow switching device causes the indoor heat exchanger to communicate with one of the discharge and suction sides of the first compressor through a pipe. The exhaust-heat recovery heat exchanger is connected to the suction side of the first compressor through a pipe, and causes heat exchange between refrigerants. Because of the above configuration, the exhaust heat recovery type of air-conditioning apparatus can use exhaust heat in any of operation modes.

The control section implements: a utilization cooling operation in which the thermal storage medium absorbs heat from the refrigerant and in which the refrigerant evaporates in the indoor heat exchanger, when the receiving section receives a first signal indicating a request for reduced use of power during an operation in which the room is cooled by the refrigerant evaporating in the indoor heat exchanger; and a cooling and cold thermal energy storage operation in which the refrigerant absorbs heat from the thermal storage medium and in which the refrigerant evaporates in the indoor heat exchanger, when the receiving section receives a second signal indicating a request for accelerated use of power during the operation in which the room is cooled by the refrigerant evaporating in the indoor heat exchanger.

In an operation mode in which an indoor heat exchanger is used as a condenser, a refrigeration cycle apparatus changes to an operation state in which a water heat exchanger provided to a hot water storage tank is used as an evaporator and refrigerant flowing through the water heat exchanger is evaporated by heat generated by a heat source such as an electric heater, under a low outdoor air temperature condition.

The present invention provides a heat pump system which comprises a compressor (110), a mode switch valve assembly (120), a mode switch flow path, and a first heat exchanger, a second heat exchanger and a heat recovery heat exchanger respectively connected between the mode switch valve assembly and the mode switch flow path, wherein the mode switch flow path is provided with a first flow path (160), a second flow path (170) and a third flow path (180) which converge at an intersection point, and at least the first flow path and the second flow path are respectively provided with a throttling section (161,171), and the first flow path, the second flow path and the third flow path are controllably switched on/off to realize different function modes. Therefore, a heat pump unit having a heat recovery function is provided, which has advantages of simple structure and high operational reliability, etc.

A transport refrigeration system is configured to set a first path, a second path, a third path, and fourth path selectively. The first path connects compressors in series. In the first path, interior heat exchangers each serve as an evaporator. The second path connects the compressors in series. In the second path, the interior heat exchangers each serve as a condenser. The third path connects the compressors in parallel. In the third path, at least one of the interior heat exchangers serve as the evaporator and the rest of the interior heat exchangers serve as the condenser. The fourth path connects the compressors in parallel. In the fourth path, the interior heat exchangers each serve as the condenser.

To avoid decline in the efficiency of a compressor at a low load, a thermal storage air conditioner has a refrigerant circuit (11) which has a compressor (22), an outdoor heat exchanger (23), and an indoor heat exchanger (72) and performs a refrigeration cycle, and a thermal storage section (60) which has a thermal storage medium and exchanges heat between the thermal storage medium and a refrigerant of the refrigerant circuit (11). The thermal storage air conditioner performs a simple cooling operation in which in the refrigerant circuit (11), the refrigerant is condensed in the outdoor heat exchanger (23) and evaporates in the indoor heat exchanger (72), and a cooling and cold thermal energy storage operation in which in the refrigerant circuit (11), the refrigerant is condensed in the outdoor heat exchanger (23) and evaporates in the indoor heat exchanger (72), and in which the thermal storage medium in the thermal storage section (60) is cooled by the refrigerant. The thermal storage air conditioner has an operation control section (100) which, if a rotational speed of the compressor (22) is slowed down to a predetermined lower reference value in the simple cooling operation, switches an operation of the thermal storage air conditioner from the simple cooling operation to the cooling and cold thermal energy storage operation to increase the rotational speed of the compressor (22).

A data center cooling system has an indoor portion wherein heat is absorbed from components in the data center, and an outdoor heat exchanger portion wherein outside air is used to cool a first heat transfer fluid (e.g., water) present in at least the outdoor heat exchanger portion of the cooling system during a first mode. When an appropriate time has been reached to switch from the first mode to a second mode, the outdoor heat exchanger portion of the data cooling system is switched to a second heat transfer fluid, which is a relatively low performance heat transfer fluid (compared to the first fluid). It has a second heat transfer fluid freezing point, lower than the first heat transfer fluid freezing point, and sufficiently low to operate without freezing when the outdoor air temperature drops below a first predetermined relationship with the first heat transfer fluid freezing point.

To avoid decline in the efficiency of a compressor at a low load, the thermal storage air conditioner has an operation controller which, if a rotational speed of the compressor is slowed down to a predetermined lower reference value in a simple cooling operation, switches operation of the thermal storage air conditioner from the simple cooling operation to a cooling and cold thermal energy storage operation to increase the rotational speed of the compressor. During the simple cooling operation refrigerant is condensed in the outdoor heat exchanger and evaporates in the indoor heat exchanger, and during a cooling and cold thermal energy storage operation the refrigerant is condensed in the outdoor heat exchanger, evaporates in the indoor heat exchanger, and the thermal storage medium in the thermal storage section is cooled by the refrigerant.

The present invention relates to an air conditioner. The air conditioner comprises: an indoor unit having an indoor heat exchanger installed therein; a first outdoor unit having a first outdoor heat exchanger and a first compressor installed therein; a second outdoor unit having a second outdoor heat exchanger and a second compressor installed therein; an auxiliary module which connects the indoor unit, the first outdoor unit, and the second outdoor unit; a first connection line by which the auxiliary module is connected to the first outdoor unit; a second connection line by which the auxiliary module is connected to the second outdoor unit; and a two-stage compression line by which the first outdoor unit is connected to the second outdoor unit.

Provided is an indoor unit for a refrigeration apparatus that is capable of detecting a refrigerant leak while suppressing condensation on a refrigerant gas sensor. An indoor unit (50) for an air conditioner (100) including a refrigerant circuit (10) includes a casing (60), an indoor fan (53), and a refrigerant gas sensor (81). The refrigerant circuit (10) has refrigerant charged therein, and performs a refrigeration cycle. The casing (60) houses at least a portion of the refrigerant circuit (10), and has a blow-out port (64) that opens in a direction other than an up-down direction. The indoor fan (53) is housed in the casing (60), and generates an air flow (F) directed from the blow-out port (64) to outside the casing (60). The refrigerant gas sensor (81) is capable of detecting a refrigerant gas below a bottom surface (63) of the casing (60).