Abstract: A refrigerant circuit (11) of an air conditioner (10) includes a compressor (20) and an expander (30). In the compressor (20), refrigerator oil is supplied from an oil reservoir (27) to a compression mechanism (21). In the expander (30), the refrigerator oil is supplied from an oil reservoir (37) to an expansion mechanism (31). The inner pressures of the compressor casing (24) and the expander casing (34) are the high pressure and the low pressure of the refrigeration cycle, respectively. An oil adjusting valve (52) is provided in an oil pipe (42) connecting the compressor casing (24) and the expander casing (34). The oil amount adjusting valve (52) is operated on the basis of an output signal of an oil level sensor (51). When the oil amount adjusting valve (52) is opened, the refrigerator oil flows from the oil reservoir (27) in the compressor casing (24) toward the oil reservoir (37) in the expander casing (34) through the oil pipe (42).

Abstract: In a refrigerant circuit (11), a compressor (20) and an expander (30) are provided separately. An expander casing (34) is connected to a delivery pipe (26) of the compressor (20) and high pressure refrigerant passes through the inside of the expander casing (34). Therefore, the compressor casing (24) and the expander casing (34) are equalized in their internal pressure. An oil distribution pipe (41) for connection of an oil sump (27) of the compressor (20) and an oil sump (37) of the expander (30) is provided with an oil regulating valve (52). The oil regulating valve (52) is controlled in response to a signal outputted from an oil level sensor (51). When the oil regulating valve (52) is opened, the oil sump (27) within the compressor casing (24) and the oil sump (37) within the expander casing (34) fluidly communicate with each other whereby refrigeration oil travels through the oil distribution pipe (41).

Abstract: Refrigerant sent from a heat source side circuit (14) to utilization side circuits (11, 12, 13) is made to be single-phase liquid by using cooling means (36, 45) or a vapor-liquid separator (35). Variable-opening utilization side expansion valves (51, 52, 53) are provided in the utilization side circuits (11, 12, 13) so that an expansion process in a refrigeration cycle is performed also in the circuits.

Abstract: A rotary type expander is provided with two rotary mechanism parts which differ from each other in displacement volume. The outflow side of the first rotary mechanism part of small displacement volume is fluidly connected to the inflow side of the second rotary mechanism part of large displacement volume. The processes by which the volume of a first low-pressure chamber in the first rotary mechanism part decreases and the volume of a second high-pressure chamber in the second rotary mechanism part increases are respectively in sync. Refrigerant at high pressure is first introduced into a first high-pressure chamber of the first rotary mechanism part. Thereafter, this high-pressure refrigerant passes through a communicating passage and then flows by way of the first low-pressure chamber into the second high-pressure chamber while expanding. The after-expansion refrigerant flows out to an outflow port from a second low-pressure chamber of the second rotary mechanism part.

Abstract: A refrigeration apparatus includes a compression mechanism, a heat source-side heat exchanger, a usage-side heat exchanger, a switching mechanism and an intermediate heat exchanger. Refrigerant discharged from a first-stage compression element is sequentially compressed by a second-stage compression element. Each of the heat source-side heat exchanger and the usage-side heat exchanger functions an evaporator or radiator. The switching mechanism is configured to switch between a cooling operation state and a heating operation state. The intermediate heat exchanger is configured to cool refrigerant discharged from the first-stage compression element and drawn into the second-stage compression element when the switching mechanism has been set to the cooling operation state, and to evaporate refrigerant whose heat is radiated in the usage-side heat exchanger when the switching mechanism has been set to the heating operation state.

Abstract: An expander includes a cylinder at which an inflow port and an outflow port are formed, a piston eccentrically disposed in the cylinder relative to a rotational shaft to form a fluid chamber between the piston and the cylinder, and a blade dividing the fluid chamber into a high pressure side and a low pressure side. The cylinder, the piston and the blade are arranged and configured such that the expander recovers power of a fluid depressurized in the fluid chamber. The cylinder has an inner diameter Dc, the inflow port has a diameter Di, and the outflow port has a diameter Do. The relationship 0.065×Dc?Di?0.13×Dc and/or 0.065×Dc?Do?0.13×Dc is satisfied.

Abstract: In a heat-source unit (15) which heats heating-medium water inside of a heat storage tank (16), a refrigerant circuit (30) is provided with a low-stage compressor (52), a high-stage compressor (62) and an expander (65) for power recovery. The low-stage compressor (52) is rotated by an electric motor (54) connected to a drive shaft (53) thereof. The high-stage compressor (62) is rotated by an electric motor (64) and the expander (65) connected to a drive shaft (63) thereof. A high-stage control section of a controller (90) adjusts the rotational speed of the high-stage compressor (62) in such a way that a value measured by an outlet water-temperature sensor (77) becomes a target temperature. A low-stage control section adjusts the rotational speed of the low-stage compressor (52) in such a way that a value measured by a discharge pressure sensor (74) becomes a target high pressure.

Abstract: A refrigerant circuit (11) includes an oil separator (60) configured to separate oil from high pressure refrigerant, and an oil feed circuit (70) configured to feed the oil separated in the oil separator (60) to a compression mechanism (20) so as to cool the refrigerant in the course of a compression phase of the compression mechanism (20). The oil feed circuit (70) includes a recovery mechanism (40) configured to recover energy of the oil separated in the oil separator (60). In the compression mechanism (20), the refrigerant is cooled by the oil, thereby reducing power of the compression mechanism (20). Simultaneously, in the recovery mechanism (40), power required to increase pressure of the oil in the compression mechanism (20) is recovered.

Abstract: A casing (31) houses therein an expansion mechanism (60) and a compression mechanism (50). The expansion mechanism (60) has a rear head (62) in which a pressure snubbing chamber (71) is provided. The pressure snubbing chamber (71) is divided by a piston (77) into an inflow/outflow chamber (72) which fluidly communicates with an inflow port (34) and a back pressure chamber (73) which fluidly communicates with the inside of the casing (31). The piston (77) is displaced in response to suction pressure variation whereby the volume of the inflow/outflow chamber (72) varies. This enables the inflow/outflow chamber (72) to directly perform supply of refrigerant to or suction of refrigerant from the inflow port (34) which is a source of pressure variation, thereby making it possible to effectively inhibit suction pressure variation.

Abstract: A positive displacement expander includes a volume change mechanism (90) for changing the volume of a first fluid chamber (72) of an expansion mechanism (60). The expansion mechanism (60) includes a first rotary mechanism (70) and a second rotary mechanism (80) each having a cylinder (71, 81) containing a rotor (75, 85). The first fluid chamber (72) of the first rotary mechanism (70) and a second fluid chamber (82) of the second rotary mechanism (80) are in fluid communication with each other to form an actuation chamber (66). Meanwhile, the first fluid chamber (72) of the first rotary mechanism (70) is smaller than the second fluid chamber (82) of the second rotary mechanism (80). The volume change mechanism (90) includes an auxiliary chamber (93) fluidly communicating with the first fluid chamber (72) and an auxiliary piston (92) for changing the volume of the auxiliary chamber (93). The auxiliary chamber (93) is in fluid communication with the first fluid chamber (72) of the first rotary mechanism (70).

Abstract: A first and a second expansion and compression machine (30, 40) having different volume ratios (Vc/Ve) are connected in parallel to a refrigerant circuit (10) of a refrigeration apparatus. Expanders (31, 41) of the expansion and compression machines (30, 40) are connected in parallel. Compressors (32, 42) of the expansion and compression machines (30, 40) are also connected in parallel. Upon variation in the operating condition of the refrigeration apparatus, the ratio of rotation speed between the expansion and compression machines (30, 40) is controlled by a controller (60). This, as a result, allows the refrigeration apparatus to operate at a COP close to an ideal condition.

Abstract: Refrigerant sent from a heat source side circuit (14) to utilization side circuits (11, 12, 13) is made to be single-phase liquid by using cooling means (36, 45) or a vapor-liquid separator (35). Variable-opening utilization side expansion valves (51, 52, 53) are provided in the utilization side circuits (11, 12, 13) so that an expansion process in a refrigeration cycle is performed also in the circuits.

Abstract: An on-off valve (70) is provided in an oil feed path (43). When liquid refrigerant enters the oil feed pipe (43) from the oil separator (22), the temperature of the liquid refrigerant whose pressure has been reduced in the on-off valve (70) dramatically decreases. When the amount of such a decrease in temperature detected by a temperature sensor (73) exceeds a specified amount, it is determined that the liquid refrigerant enters the oil feed pipe (43), and the on-off valve (70) is closed.

Abstract: A refrigerant circuit (11) in an air conditioner (10) includes a compressor (20) and an expander (30). In the compressor (20), refrigerant compressed by a compression mechanism (21) is discharged into the internal space of a compressor casing (24). In the compressor (20), refrigeration oil which has accumulated in the bottom of the compressor casing (24) is supplied to the compression mechanism (21). The refrigeration oil in the bottom of the compressor casing (24) is directly introduced into an expansion mechanism (31) of the expander (30) through an oil supply pipe (41).

Abstract: Two rotary mechanism parts (70, 80) are provided in a rotary expander (60). The first rotary mechanism part (70) is smaller in displacement volume than the second rotary mechanism part (80). A first low-pressure chamber (74) of the first rotary mechanism part (70) and a second high-pressure chamber (83) of the second rotary mechanism part (80) are fluidly connected together by a communicating passageway (64), thereby forming a single expansion chamber (66). High-pressure refrigerant introduced into the first rotary mechanism part (70) expands in the expansion chamber (66). An injection passageway (37) is fluidly connected to the communicating passageway (64). When an motor-operated valve (90) is placed in the open state, high-pressure refrigerant is introduced into the expansion chamber (66) also from the injection passageway (37). This makes it possible to inhibit the drop in power recovery efficiency, even in the condition that causes the actual expansion ratio to fall below the design expansion ratio.

Abstract: An air conditioning apparatus is filled with a supercritical refrigerant, and includes a compression mechanism, a radiator, an expansion mechanism, an evaporator, a first temperature detector, a target refrigerant temperature derivation unit, and a control unit. The target refrigerant temperature derivation unit uses at least a set temperature to determine a target refrigerant temperature, the set temperature being a temperature that is set relative to the air in the space in which the radiator is disposed, and the target refrigerant temperature being the target temperature of the refrigerant flowing between the outlet side of the radiator and the refrigerant inflow side of the expansion mechanism. The control unit controls the expansion mechanism so that the temperature detected by the first temperature detector corresponds to the target refrigerant temperature.

Abstract: A heat source side circuit (14) includes a gas-liquid separator (35) for the separation of refrigerant flowing therein from an expander (31) into liquid refrigerant and gas refrigerant and a cooling means (36, 45, 53, 55) for the cooling of liquid refrigerant heading from the gas-liquid separator (35) to a utilization side circuit (11). Since the refrigerant exiting the gas-liquid separator (35) is in a saturated liquid form, it always changes state to a subcooled state whenever cooled by the cooling means (36, 45, 53, 55).

Abstract: In a compression/expansion unit (30) serving as a fluid machine, both a compression mechanism (50) and an expansion mechanism (60) are housed in a single casing (31). An oil supply passageway (90) is formed in a shaft (40) by which the compression mechanism (50) and the expansion mechanism (60) are coupled together. Refrigeration oil accumulated in the bottom of the casing (31) is drawn up into the oil supply passageway (90) and is supplied to the compression mechanism (50) and to the expansion mechanism (60). Surplus refrigeration oil, which is supplied to neither of the compression and expansion mechanisms (50) and (60), is discharged out of the terminating end of the oil supply passageway (90) which opens at the upper end of the shaft (40). Thereafter, the surplus refrigeration oil flows into an oil return pipe (102) from a lead-out hole (101) and is returned back towards a second space (39).

Abstract: Oil supply grooves (74, 84) are formed respectively in a rotating shaft (70) of a compression mechanism (50) integral with an electric motor (40) and in a rotating shaft (80) of an expansion mechanism (60). The rotating shafts (70, 80) are coupled together by engagement between an engagement convex portion (85) and an engagement concave portion (75) which are formed respectively in shaft ends of the rotating shafts (70, 80). And, a seal groove (S) is formed in the peripheral surface of the engagement convex portion (85) and an O-ring (R) is engaged into the seal groove (S). Hereby, lubrication oil leakage from between the engagement convex portion (85) and the engagement concave portion (75) is prevented.

Abstract: A compressor (20) and an expander (30) are provided in a refrigerant circuit (11) of an air conditioner (10). In the compressor (20), refrigerator oil is supplied from an oil reservoir (27) to a compression mechanism (21). In the expander (30), the refrigerator oil is supplied from an oil reservoir (37) to an expansion mechanism (31). Internal spaces of a compressor casing (24) and an expander casing (34) communicate with each other through an equalizing pipe (41). An oil pipe (42) connecting the compressor casing (24) and the expander casing (34) is provided with an oil amount adjusting valve (52) operated on the basis of an output signal of an oil level sensor (51). When the oil amount adjusting valve (52) is opened, the oil reservoir (27) in the compressor casing (24) and the oil reservoir (37) in the expander casing (34) communicate with each other to allow the refrigerator oil to flow through the oil pipe (42).