An attachment structure includes expansion valves used in a vehicle, and a housing to which the expansion valves are attached. The housing includes a flow path through which heat medium circulating in a heat pump cycle of an air conditioner of the vehicle flows, and the flow path is opened and closed by the expansion valves.

According to one embodiment, an air conditioner includes an outdoor unit including a control unit which controls an operation of a compressor, an expansion valve kit, at least one air-handling unit, and a controller. The control unit or the controller adjusts, when a parameter value indicating a change in temperature of air blown out of an indoor fan or a parameter value indicating a change in temperature of air sucked by the indoor fan is not within a range defined by a first threshold and a second threshold smaller than the first threshold, each of an opening degree of an indoor expansion valve and a change period of the opening degree or each of an operation frequency of the compressor and a change period of the operation frequency.

A refrigeration cycle device includes a flow path switching unit configured to determine whether an outside-air heat absorption unit is required to be defrosted. The flow path switching unit is further configured to: cause a heat medium to circulate separately between a first circulation circuit configured to cause the heat medium to circulate through a heat source and a second circulation circuit configured to cause the heat medium to circulate between an evaporation unit and the outside-air heat absorption unit, when it is determined that the outside-air heat absorption unit is not required to be defrosted; and switch a flow path of the heat medium to cause the heat medium in the first circulation circuit to circulate through the outside-air heat absorption unit, when it is determined that the outside-air heat absorption unit is required to be defrosted.

A refrigeration system including a storage chamber configured to store a product at a predetermined temperature. The storage chamber is defined by an inner wall. The inner wall at least partially defines an air plenum. The inner wall includes an opening wall surface, a floor surface, a rear wall surface and a ceiling wall surface. The system also includes a refrigerant circuit including a compressor, a condenser, a condenser fan, an evaporator and an evaporator fan arranged and disposed in an operable configuration to provide refrigeration to the storage chamber. The air plenum includes a conduit arranged and disposed to convey air from an air inlet across the evaporator and into a discharge chamber and out an air outlet. The air outlet is configured to discharge cooled air in a direction toward the opening wall surface.

A heat cycle system is a heat cycle system (1) using a working medium containing hydrofluoroolefin (HFO) that has a double bond in a molecule structure, the heat cycle system (1) having a compressor (10), a high-pressure side heat exchanger (12), a low-pressure side heat exchanger (14), an expansion mechanism (13), and an acid detection means (40) which is disposed in a discharge pipe (21) connecting the compressor (10) and the high-pressure side heat exchanger (12) and which detects acid generated by decomposition of the working medium in a heat cycle.

A heat cycle system is a heat cycle system (1) using a working medium containing hydrofluoroolefin (HFO) that has a double bond in a molecule structure, the heat cycle system (1) having a compressor (10), a high-pressure side heat exchanger (12), a low-pressure side heat exchanger (14), an expansion mechanism (13), and an acid detection means (40) which is disposed in a discharge pipe (21) connecting the compressor (10) and the high-pressure side heat exchanger (12) and which detects acid generated by decomposition of the working medium in a heat cycle.

A cooling device using a refrigeration cycle in which a refrigerant is circulated through a heat receiver, a compressor, a heat radiator, and an expansion valve includes: a gas-liquid separator configured to perform gas-liquid separation on the refrigerant supplied from the expansion valve; a pump configured to send a liquid phase refrigerant separated by the gas-liquid separator to the heat receiver; and a control unit configured to control opening and closing of a refrigerant flow path of the refrigeration cycle, and an operation and stop of the compressor and the pump, wherein the control unit starts the operation of the pump on condition that a net positive suction head of the pump has reached a predetermined value or more.

A refrigerating machine oil containing: a lubricating base oil; and a compound represented by the following formula (1): ##STR00001## wherein R.sup.1 and R.sup.2 each independently represent a monovalent hydrocarbon group, R.sup.3 represents a divalent hydrocarbon group, and R.sup.4 represents hydrogen atom or a monovalent hydrocarbon group, and the refrigerating machine oil having a kinematic viscosity at 100° C. of 0.5 mm.sup.2/s or more and 2.5 mm.sup.2/s or less.

There is disclosed a controlling method for a refrigerator comprising: a first defrosting step of performing defrosting for an evaporator, the first defrosting step which ends when the temperature of the evaporator reaches a first temperature; a pressure difference sensing step of measuring a difference between the pressure in a first through-hole arranged between an inlet hole for drawing air from a storage compartment and the evaporator and the pressure in a second through-hole arranged between an outlet hole for discharging air towards the storage compartment and the evaporator by using one differential pressure sensor; and a second defrosting step of performing additional defrosting for the evaporator when the measured pressure difference is a preset pressure or more.

Disclosed are systems and methods of flexibly cooling thermal loads by providing a complex compound system for burst mode cooling, a vapor compression system for ancillary cooling, and a thermal storage system for helping efficiently maintain and cool a thermal load such as a directed energy weapon system.