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.

Provided is a refrigerant cycle apparatus capable of suppressing detects caused by iodine even when a refrigerant containing iodine is used. An air conditioner includes a refrigerant circuit through which a refrigerant containing iodine circulates. The refrigerant circuit includes a component that is in contact with a refrigerant containing iodine, the component being made of metal other than aluminum or an aluminum alloy, or having a content of aluminum which is equal to or less than a ratio at which corrosion of aluminum occurs by iodine. The component is at least one of a component of a compressor, a component of a heat-source-side heat exchanger or a utilization-side heat exchanger, a component of an expansion valve, a drier, and a connection pipe.

In an embodiment, a method of preventing evaporator coil freeze in a heating, ventilation and air conditioning (HVAC) system is performed by a controller in the HVAC system. The method includes determining a reference saturated suction temperate (SST) via a sensor disposed in relation to an evaporator coil in the HVAC system. The method also includes determining whether the reference SST is below a minimum SST threshold. The method also includes, responsive to a determination that the reference SST is below the minimum SST threshold, increasing a discharge air temperature (DAT) setpoint.

In an embodiment, a method of preventing evaporator coil freeze in a heating, ventilation and air conditioning (HVAC) system is performed by a controller in the HVAC system. The method includes determining a reference saturated suction temperature (SST) via a sensor disposed in relation to an evaporator coil in the HVAC system. The method also includes determining whether the reference SST is below a minimum SST threshold. The method also includes, responsive to a determination that the reference SST is below the minimum SST threshold, increasing a discharge air temperature (DAT) setpoint.

An evaporator includes: an evaporator case that defines a food storage space therein; a cooling tube located at the evaporator case and filled with refrigerant; a foil heater attached to at least one surface of the evaporator case and configured to contact the evaporator case and to generate heat such that heat for defrosting is transferred to the evaporator case. A defrosting time is reduced in comparison to that of conventional natural defrosting, such that the freshness of food can be maintained, and the cooling efficiency, having been reduced by frost, is increased such that power consumption can be reduced. The foil heater is attached to a conventional roll-bond type evaporator case, and the present invention has an advantageous effect of facilitating the maintenance of the foil heater because of a structure in which the foil heater is attached to the evaporator case.

A compressor includes a housing, and an anticorrosive coating covering a surface of the housing. The anticorrosive coating includes a base layer applied on the surface of the housing, and a surface layer applied on the base layer. Both the base layer and the surface layer are organic coatings. Thus, the housing of the compressor is effectively separated from the external environment by means of the two organic coatings, so as to ensure that the compressor is not corroded; moreover, the anticorrosive coating does not contain a metal coating, thereby preventing the problem of the compressor being severely corroded due to an exposed metal coating.

A compressor includes a casing and a metallic coating. The casing includes a low-pressure casing part covering a low-pressure space and a high-pressure casing part covering a high-pressure space. The metallic coating is formed at least on a part of an outer surface of the casing. The metallic coating includes a low-pressure part coating formed in the low-pressure casing part, a high-pressure part coating formed in the high-pressure casing part, and a welded part coating formed in a welded part. At least either the average thickness of the low-pressure part coating or the average thickness of the welded part coating is greater than the average thickness of the high-pressure part coating.

A refrigeration cycle apparatus includes a refrigerant and a refrigeration cycle circuit. The refrigeration cycle circuit includes a compressor, and causes the refrigerant to circulate therethrough. The refrigerant is HFO-based refrigerant alone or a mixed refrigerant. In the mixed refrigerant, a mixing ratio of HFO-based refrigerant is equal to or more than 10% by weight. The compressor includes a motor. The motor includes a portion formed from a resin component. The resin component is made of PET, PA, or the like.

A method of preventing evaporator coil freeze in a heating, ventilation and air conditioning (HVAC) system is performed by a controller in the HVAC system. The method includes determining a reference saturated suction temperature (SST) via a sensor disposed in relation to an evaporator coil in the HVAC system. The method also includes determining whether the reference SST is below a minimum SST threshold. The method also includes, responsive to a determination that the reference SST is below the minimum SST threshold, increasing a discharge air temperature (DAT) setpoint.

A water electrolysis system includes a water electrolysis device; a water circulation circuit section including a water circulation pump; an antifreeze circulation circuit section including an antifreeze circulation pump; and a heat exchanger configured to perform heat exchange between the water circulation circuit section and the antifreeze circulation circuit section. Before water electrolysis is started by the water electrolysis device, a control device of the water electrolysis system circulates water by driving the water circulation pump and sets the antifreeze circulation pump to an operationally stopped state.