Abstract: In a refrigeration system, a first non-inverter compressor (2B) backs up one of an inverter compressor (2A) and a second non-inverter compressor (2C) by switching of a third four-way selector valve (3C). The refrigeration system includes: a suction pressure detection section (81) for detecting the suction pressure of the first non-inverter compressor (2B) after the issue of a switching command to the third four-way selector valve (3C); a command holding section (82) for, when the detected pressure of the suction pressure detection section (81) becomes lower than a predetermined value, determining that the third four-way selector valve (3C) has malfunctioned and holding the switching command; and a compressor standby section (83) for, upon the command holding section (82) holding the switching command, stopping the first non-inverter compressor (2B) and putting it into standby for a predetermined time.

Abstract: In a refrigerant circuit (20), a refrigerator circuit (110) and a freezing circuit (30) are connected in parallel to an outdoor circuit (40). In the freezing circuit (30), a freezer circuit (130) and a booster circuit (140) are connected in series. A booster compressor (141) and a four-way switch valve (142) are provided in the booster circuit (140). During the time when a freezer heat exchanger (131) performs cooling operation for cooling the inside air, refrigerant evaporated in the freezer heat exchanger (131) is compressed in the booster compressor (141), and then, is sucked into a variable capacitance compressor (41). On the other hand, during defrosting of the freezer heat exchanger (131), the refrigerant evaporated in a refrigerator heat exchanger (111) is compressed in the booster compressor (141), and then, is supplied to the freezer heat exchanger (131).

Abstract: A pressure regulating valve (71) is connected to the discharge side of a low stage compressor (55) to make the pressure in the suction side of high stage compressors (11, 12) lower than the pressure in a dome of the low stage compressor (55). Further, an oil return path (72) is connected to the dome of the low stage compressor (55) at one end and to the suction side of the high stage compressors (11, 12) by bypassing the pressure regulating valve (71) at the other end. With this configuration, refrigeration oil accumulated in the dome of the low stage compressor (55) is returned to the high stage compressors (11, 12).

Abstract: A refrigeration system includes a controller (90) for controlling operation restart after a breaker trips owing to failure in electric systems for refrigeration system components. The controller (90) includes a sequential startup section (91) for, upon the operation restart, sequentially starting up target compressors (2A, 2B, 2C) and outdoor fans (F1, F2) previously selected from among the refrigeration system components, and failure processing section (92) for, if the breaker trips again during the sequential startup of the target compressors and outdoor fans, excluding the compressor or outdoor fan (2A, . . . ) supplied with electric power just before the breaker's trip from the target refrigeration system components to be started up by the sequential startup section (91). Thus, a failed component is identified by the failure processing section (92) and only the normal components, leaving out the failed component, are then started up, thereby resuming the operation.

Abstract: In the case where a 100 percent heat recovery operation mode is performed without using an outdoor heat exchanger in a refrigeration apparatus which is provided with utilization-side heat exchangers of a plurality of piping systems and in which liquid-side communication lines are arranged into a single line, a backflow prevention mechanism (37) for preventing liquid refrigerant exiting an indoor heat exchanger (41) from flowing in a direction other than in the direction of cold storage and freeze storage heat exchangers (45, 51) is disposed for providing stable flow of refrigeration through the circuit even when the temperature of outside air is low, whereby the capability to provide refrigeration is prevented from degrading.

Abstract: When a guard timer of a compressor (141) expires, an R2 signal from a control section (140) of an outdoor unit is turned on (Action I). If a control section (120) of a freezer unit recognizes from an inside temperature detected by a temperature sensor (124) that the R2 signal is turned on and a request for a shift to a freezer thermo-on state is raised (Action II), a freezer electromagnetic valve (121) is opened (Action III). In general, when the electromagnetic valve (121) is opened, it is supposed that an increase in refrigerant suction pressure is detected by a pressure sensor (146) and then the compressor (141) is actuated. However, if an outside air temperature is low, the refrigerant suction pressure remains lower than a predetermined value. Therefore, the control section (120) actuates a booster compressor (131) (Action IV) to raise the refrigerant suction pressure of the compressor (141).

Abstract: A refrigerator circuit (110) and a freezing circuit (30) are connected to an outdoor circuit (40) in parallel in a refrigerant circuit (20), and a freezer circuit (130) and a booster circuit (140) are connected in series in the freezing circuit (30). The booster circuit (140) includes a booster compressor (141) and three-way switching mechanisms (142, 160). During cooling operation of a freezing heat exchanger (131), first operation is performed in the three-way switching mechanisms (142, 160) so that the refrigerant evaporated in the freezing heat exchanger (131) is compressed in the booster compressor (141) and is sucked into a variable capacity compressor (41).

Abstract: A subcooling unit (200) includes a refrigerant passage (205) connected to liquid side communication pipes (21, 22) of a refrigerating apparatus (10). When a subcooling compressor (221) is operated, subcooling refrigerant circulates in the subcooling refrigerant circuit (220) to perform a refrigeration cycle, thereby cooling refrigerant of the refrigerating apparatus (10) which flows in the refrigerant passage (205). A controller (240) of the subcooling unit (200) receives the detection value of a suction pressure sensor (234) and a refrigerant temperature sensor (236). The controller (240) utilizes input signals from the sensors (234, 236) to control driving operation of the subcooling compressor (221) on the basis of information obtained within the subcooling unit (200). Thus, the operation of the subcooling compressor (221) can be controlled without sending and receiving a singal to and from the refrigerating apparatus (10) to which the subcooling unit (200) is incorporated.

Abstract: In a refrigerating apparatus in which a plurality of application-side heat exchangers (41, 45, 51) are connected to a heat-source side heat exchanger (4), liquid lines for a plurality of channels in a refrigerant circuit (1E) share a liquid side communication pipe (11) in order to reduce the number of pipes. Further, the liquid side communication pipe (11) is provided adjacent to a low-pressure gas side communication pipe (15) for at least one channel so as to contact it in order to supercool a liquid refrigerant by a low-pressure gas refrigerant. Thus, workability for connecting the pipes is improved and a refrigerating ability may not be decreased even if communication pipes (11, 15, 17) become long.

Abstract: In a refrigerant circuit (20), a refrigerator circuit (110) and a freezing circuit (30) are connected in parallel to an outdoor circuit (40). In the freezing circuit (30), a freezer circuit (130) and a booster circuit (140) are connected in series. A booster compressor (141) and a four-way switch valve (142) are provided in the booster circuit (140). During the time when a freezer heat exchanger (131) performs cooling operation for cooling the inside air, refrigerant evaporated in the freezer heat exchanger (131) is compressed in the booster compressor (141), and then, is sucked into a variable capacitance compressor (41). On the other hand, during defrosting of the freezer heat exchanger (131), the refrigerant evaporated in a refrigerator heat exchanger (111) is compressed in the booster compressor (141), and then, is supplied to the freezer heat exchanger (131).

Abstract: In the case where a 100 percent heat recovery operation mode is performed without using an outdoor heat exchanger in a refrigeration apparatus which is provided with utilization-side heat exchangers of a plurality of piping systems and in which liquid-side communication lines are arranged into a single line, a backflow prevention mechanism (37) for preventing liquid refrigerant exiting an indoor heat exchanger (41) from flowing in a direction other than in the direction of cold storage and freeze storage heat exchangers (45, 51) is disposed for providing stable flow of refrigeration through the circuit even when the temperature of outside air is low, whereby the capability to provide refrigeration is prevented from degrading.

Abstract: In a refrigerating apparatus comprising a plurality of application-side heat exchangers (41), (45, 51) for air-conditioning and for cold-storage/freezing, it is configured so as to be capable of corresponding to various types of operation patterns when a compression mechanism (2) is configured by two compressors (2A, 2B). In order to continue operation even if one compressor is broken, a switching mechanism such as a four-way selector valve (3C) is provided on the suction side of the two compressors (2A, 2B), so that a plurality of operation patterns can be performed in a predetermined operation mode.

Abstract: Disclosed is a refrigerating apparatus using a temperature sensitive expansion valve (46) as an expansion mechanism. In the refrigerating apparatus, a switching valve (7a) is disposed on the upstream side of an evaporator (45). The switching valve (7a) is closed for a while, thereby forcibly placing an outlet side of the evaporator (45) in the superheat state to increase the valve travel of the expansion valve (46). Thereafter, the switching valve (7a) is opened for liquid refrigerant to flow through the evaporator (45) so that a wettish operation is carried out. As a result of such arrangement, refrigerating machine oil that has accumulated in the evaporator (45) is reclaimed and returned to a compression mechanism (2D).

Abstract: A refrigerating apparatus including three compressors (2A, 2B, 2C) and application side heat exchangers (41) (45, 51) for two channels is formed so that a first compressor (2A) is used only for the application side heat exchangers (45, 51) in a first channel of a circuit, a third compressor (2C) is used only for the application side heat exchanger (41) in a second channel of the circuit, and a second compressor (2B) is used in a switchable manner between the application side heat exchangers (45, 51) in the first channel of the circuit and the application side heat exchanger (41) in the second channel of the circuit. Thus, not only the pipe arrangement at suction side is simplified, but also operation control is streamlined.

Abstract: In a refrigerating apparatus in which gas refrigerant is injected into suction pipes (10a, 10b) of compressors (2A, 2B) from an oil return passageway (21) and from a gas injection passageway, a liquid injection passageway (15) through which liquid refrigerant is injected into the suction side of compressors (2A, 2B) is provided and, in addition, the oil return passageway (21) and the gas injection passageway are connected to the liquid injection passageway (15), thereby making it possible to prevent the occurrence of abnormal noise due to the intermixing of gas refrigerants in the suction pipes (10a, 10b).

Abstract: In a refrigerating apparatus in which a plurality of application-side heat exchangers (41, 45, 51) are connected to a heat-source side heat exchanger (4), liquid lines for a plurality of channels in a refrigerant circuit (1E) share a liquid side communication pipe (11) in order to reduce the number of pipes. Further, the liquid side communication pipe (11) is provided adjacent to a low-pressure gas side communication pipe (15) for at least one channel so as to contact it in order to supercool a liquid refrigerant by a low-pressure gas refrigerant. Thus, workability for connecting the pipes is improved and a refrigerating ability may not be decreased even if communication pipes (11, 15, 17) become long.

Abstract: In a refrigerating apparatus (1) having application-side heat exchangers (41, 45, 51) for a plurality of systems for air-conditioning, for cold-storage/freezing and the like and a four-way switch valve (3C) and a plurality of check valves (7) on suction sides of compression mechanisms (2D, 2E) and formed from three compressors (2A, 2B, 2C) to allow the operation states to be switched, the number of compressors (2A, 2B, 2C) used at air-conditioning side and cold-storage/freezing side is limited to two at maximum, thereby achieving a simple circuit configuration in which the number of the check valves (7) to be provided in the suction sides of the compression mechanisms (2D, 2E) is reduced to one or two, suppressing the occurrence of chattering noise in check valves (7) and, also, preventing an ability from reducing due to a suction-side pressure loss.

Abstract: In a refrigerating apparatus comprising a plurality of application-side heat exchangers (41), (45, 51) for air-conditioning and for cold-storage/freezing, it is configured so as to be capable of corresponding to various types of operation patterns when a compression mechanism (2) is configured by two compressors (2A, 2B). In order to continue operation even if one compressor is broken, a switching mechanism such as a four-way selector valve (3C) is provided on the suction side of the two compressors (2A, 2B), so that a plurality of operation patterns can be performed in a predetermined operation mode.

Abstract: Disclosed is a refrigerating apparatus using a temperature sensitive expansion valve (46) as an expansion mechanism. In the refrigerating apparatus, a switching valve (7a) is disposed on the upstream side of an evaporator (45). The switching valve (7a) is closed for a while, thereby forcibly placing an outlet side of the evaporator (45) in the superheat state to increase the valve travel of the expansion valve (46). Thereafter, the switching valve (7a) is opened for liquid refrigerant to flow through the evaporator (45) so that a wettish operation is carried out. As a result of such arrangement, refrigerating machine oil that has accumulated in the evaporator (45) is reclaimed and returned to a compression mechanism (2D).

Abstract: A refrigerating apparatus including three compressors (2A, 2B, 2C) and application side heat exchangers (41) (45, 51) for two channels is formed so that a first compressor (2A) is used only for the application side heat exchangers (45, 51) in a first channel of a circuit, a third compressor (2C) is used only for the application side heat exchanger (41) in a second channel of the circuit, and a second compressor (2B) is used in a switchable manner between the application side heat exchangers (45, 51) in the first channel of the circuit and the application side heat exchanger (41) in the second channel of the circuit. Thus, not only the pipe arrangement at suction side is simplified, but also operation control is streamlined.