Abstract: In an apparatus having a refrigeration cycle, the refrigeration cycle is formed by annularly connecting a compressor, a condenser, an expansion device and an evaporator with one another, the apparatus uses propane, isobutane or ethane as a refrigerant, and uses refrigerating machine oil having less mutual solubility with the refrigerant, and a dryer is provided in the refrigeration cycle for absorbing water. In stead of the dryer, an additive which reacts with water may be included in said refrigerating machine oil. With this arrangement, the amount of the refrigerant can be reduced, and the long term reliability of the apparatus can be obtained.

Abstract: A method for taking custody of, transporting and installing an air conditioner having an outdoor unit which uses a flammable refrigerant and includes a refrigeration cycle comprising a compressor, an expansion device and an outdoor heat exchanger which are connected to one another through pipes, wherein the outdoor unit is shipped from a factory while the refrigeration cycle is evacuated to produce a vacuum, the outdoor unit is kept in custody and transported in a state in which the vacuum in the refrigeration cycle is maintained, and when the outdoor unit is installed, the flammable refrigerant is charged into the refrigeration cycle.

Abstract: In a compressor of a refrigeration cycle using an HC-based refrigerant and a lubricant having specific gravity greater than that of the HC-based refrigerant and having no or no or less mutual solubility with the HC-based refrigerant, an oil reservoir is formed on a bottom of the compressor, the oil reservoir is provided at its portion with a recess, a suction port of a lubricant suction pipe for supplying the lubricant to a compressor mechanism is provided in the recess. With this feature, it is possible to sufficiently supply the lubricant to the compressor even when the lubricant has no or less mutual solubility, so that even if the amount of the lubricant is reduced, the lubricant can be sufficiently sucked from an inlet port of a lubricant pumping pipe and supplied to the compressor mechanism.

Abstract: In a refrigerant leakage warning device for an apparatus having a refrigeration cycle using a flammable refrigerant as a refrigerant, when leakage of the refrigerant occurs, measures how to cope after the leakage of refrigerant occurs are indicated on an indoor unit. Therefore, the user can see the indication of the leakage and take the measures to cope with it, and it is possible to hold the damage at a minimum, and to enhance the safety.

Abstract: In an apparatus having a refrigeration cycle, the refrigeration cycle is formed by annularly connecting a compressor, a condenser, an expansion device and an evaporator with one another, the apparatus uses propane, isobutane or ethane as a refrigerant, and uses refrigerating machine oil having less mutual solubility with the refrigerant, and a dryer is provided in the refrigeration cycle for absorbing water. In stead of the dryer, an additive which reacts with water may be included in said refrigerating machine oil. With this arrangement, the amount of the refrigerant can be reduced, and the long term reliability of the apparatus can be obtained.

Abstract: A refrigeration cycle that controls the deposit of foreign matter at inlet or outlet of a capillary tube, which forms an expansion device in the refrigeration, regardless of changeover from a cooling operation to a heating operation. In particular, in a refrigeration cycle using an alternative refrigerant, a junction is provided for joining an end of a capillary tube forming an expansion device to the piping through which the refrigerant flows. The junction has a slope defined by the inside diameter thereof, which gradually decreases from the side of the junction that joins the piping to the side of the junction that joined the capillary tube. An end portion of the capillary tube projects into the junction at the piping side. The projecting end of the capillary tube is opened obliquely to the axial line of the capillary tube. A hole is formed in the peripheral wall of the projecting end of the capillary tube.

Abstract: A refrigeration cycle that controls the deposit of foreign matter at inlet or outlet of a capillary tube, which forms an expansion device in the refrigeration, regardless of changeover from a cooling operation to a heating operation. In particular, in a refrigeration cycle using an alternative refrigerant, a junction is provided for joining an end of a capillary tube forming an expansion device to the piping through which the refrigerant flows. The junction has a slope defined by the inside diameter thereof, which gradually decreases from the side of the junction that joins the piping to the side of the junction that joined the capillary tube. An end portion of the capillary tube projects into the junction at the piping side. The projecting end of the capillary tube is opened obliquely to the axial line of the capillary tube. A hole is formed in the peripheral wall of the projecting end of the capillary tube.

Abstract: A multi-system air conditioner comprises an exterior unit including a compressor and a plurality of interior units, each being installed in a room and including a heat exchanger and an expansion valve therefor. An opening degree of the expansion valve in an interior unit is controlled based on not only the superheat degree of the compressor but also the room temperature difference. Further, the control based on the superheat degree is carried out by means of the fuzzy logical calculation on superheat degree value. A rotational speed of the compressor is controlled based on not only the load capacity of the room but also the room temperature difference. Further, a control based on the fuzzy logical calculation on the pressure value is added. A feed forward control is also added so as to shorten the transient time.