JP2014070835A - Refrigeration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the number of pressure sensors, in a refrigeration device including a refrigerant circuit in which a plurality of use-side heat exchangers evaporating at different temperatures are connected in parallel with each other.SOLUTION: A controller 100 is configured to calculate a first refrigerant enthalpy h1 on the basis of evaporation pressure LP1 of first and second refrigeration heat exchangers 32, 42 derived by a pressure sensor 92 and a first refrigerant temperature T1 on the side of the first and second refrigeration heat exchangers 32, 42 of an evaporation pressure adjustment valve 3 detected by a temperature sensor 96, and to calculate evaporation pressure LP2 of an indoor heat exchanger 22 on the basis of the first refrigerant enthalpy h1 and a second refrigerant temperature T2 on the side of the indoor heat exchanger 22 of the evaporation pressure adjustment valve 3 detected by a temperature sensor 97.

Description

    The present invention relates to a refrigeration apparatus including a refrigerant circuit in which a plurality of usage-side heat exchangers that evaporate at different temperatures are connected in parallel to each other.

    Conventionally, a plurality of usage-side heat exchangers are provided with a refrigerant circuit connected in parallel to each other, and the evaporation temperature of each usage-side heat exchanger during cooling operation in which each usage-side heat exchanger functions as an evaporator is determined. A refrigeration apparatus that controls to different temperatures is known (for example, see Patent Document 1 below). Some refrigeration apparatuses of this type use a pressure sensor to detect the evaporation temperature of each use side heat exchanger. Specifically, for example, when there are two usage-side heat exchangers, that is, first and second usage-side heat exchangers, they are provided on the outflow side of the first and second usage-side heat exchangers that function as evaporators. The evaporation pressures of the first and second usage-side heat exchangers are detected by the pressure sensor, and the evaporation temperature is derived by calculating the pressure-equivalent saturation temperature from the detected value.

JP 2009-180451 A

    However, in the method for deriving the evaporation temperature as described above, a pressure sensor is required for each use-side heat exchanger. Here, the pressure sensor discharges the refrigerant to the outside of the refrigerant circuit although the amount is small. For this reason, when a plurality of pressure sensors are used, there is a risk of adversely affecting the environment in which the refrigeration apparatus is installed. Further, when the pressure sensor is replaced in this way, there is a problem that the replacement cannot be easily performed because the leakage of the refrigerant is managed or the pressure resistance specification is required. In addition, the pressure sensor is more expensive than the temperature sensor and has a problem that the failure rate is high due to the movable part.

    The present invention has been made in view of such a point, and an object of the present invention is to provide the number of pressure sensors in a refrigeration apparatus including a refrigerant circuit in which a plurality of use side heat exchangers that evaporate at different temperatures are connected in parallel to each other. It is to reduce.

    The first invention includes a compression mechanism (13), a heat source side heat exchanger (12), an expansion mechanism (23, 33, 43), and at least first and second usage side heat exchangers (22, 32, 42). A refrigerant circuit (2) having a plurality of use side heat exchangers (22, 32, 42) connected in parallel to each other, and the first and second use side heat exchangers (22, 32, 42). A refrigeration apparatus including a first evaporating pressure adjusting valve (3) for evaporating at a different temperature, wherein the pressure deriving mechanism derives the first evaporating pressure (LP1) of the first use side heat exchanger (32, 42). (92) and a first temperature sensor (96) for detecting the temperature (T1) of the first refrigerant on the first use side heat exchanger (32, 42) side of the first evaporation pressure regulating valve (3) A second temperature sensor (97) for detecting the temperature (T2) of the second refrigerant on the second use side heat exchanger (22) side of the first evaporation pressure regulating valve (3), and the pressure deriving mechanism ( 92) derived from the first evaporation pressure (LP1 ) And the temperature (T1) of the first refrigerant detected by the first temperature sensor (96), a first calculation unit (114) for calculating the enthalpy (h1) of the first refrigerant, and the first calculation unit From the enthalpy (h1) of the first refrigerant calculated by (114) and the temperature (T2) of the second refrigerant detected by the second temperature sensor (97), the second use side heat exchanger (22) A second calculation unit (115) for calculating the second evaporation pressure (LP2).

    In the first invention, first, in the first calculation unit (114), the first evaporating pressure (LP1) derived by the pressure deriving mechanism (92) and the first refrigerant detected by the first temperature sensor (96). The enthalpy (h1) of the first refrigerant is calculated from the temperature (T1). Here, since the pressure of the refrigerant does not change between the first usage side heat exchanger (32, 42) and the first evaporation pressure regulating valve (3), the first usage of the first evaporation pressure regulating valve (3). The pressure of the first refrigerant on the side heat exchanger (32, 42) side becomes equal to the first evaporation pressure (LP1) derived by the pressure deriving mechanism (92). Therefore, the enthalpy (h1) of the first refrigerant is calculated from the first evaporation pressure (LP1) equal to the pressure of the first refrigerant and the temperature (T1) of the first refrigerant. Next, in the second calculator (115), the pressure of the second refrigerant is calculated from the temperature (T2) of the second refrigerant and the enthalpy (h1) of the first refrigerant. Here, before and after the throttling of the first evaporating pressure regulating valve (3), only the pressure drops while the enthalpy is kept constant, so the enthalpy (h1) of the first refrigerant and the enthalpy of the second refrigerant are Will be equal. In addition, since the refrigerant pressure does not change between the second usage side heat exchanger (22) and the first evaporation pressure regulating valve (3), the second usage side heat exchange of the first evaporation pressure regulating valve (3) is performed. The pressure of the second refrigerant on the condenser (22) side is equal to the second evaporation pressure (LP2) in the second usage-side heat exchanger (22). Accordingly, the second evaporating pressure (LP2) of the second use side heat exchanger (22) is calculated from the enthalpy (h1) of the first refrigerant and the temperature (T2) of the second refrigerant equal to the enthalpy of the second refrigerant. .

    In a second aspect based on the first aspect, the pressure derivation mechanism (92) detects the first evaporation pressure (LP1) of the first use side heat exchanger (32, 42). The first and second use side heat exchanges based on the first evaporation pressure (LP1) by the pressure sensor (92) and the second evaporation pressure (LP2) by the second calculation unit (115). A valve control unit (132) for controlling the operation of the first evaporating pressure adjusting valve (3) so that the evaporators (22, 32, 42) evaporate at different temperatures; the heat source side heat exchanger (12); 1 heat source side casing (3), the pressure sensor (92), the first calculation unit (114), the second calculation unit (115), and the valve control unit (132) are accommodated in the heat source side casing ( 10a), and the first temperature sensor (96) and the second temperature sensor (97) are provided in the heat source side casing (10a).

    By the way, for example, when the valve control unit (132) controls the operation of the first evaporation pressure regulating valve (3) based on the evaporation temperature of the second usage side heat exchanger (22), the second usage side heat The evaporating temperature of the second usage side heat exchanger (22) is detected in the casing in which the exchanger (22) is accommodated, and the detected temperature is converted into data and provided in the heat source side casing (10a). It is necessary to transmit to the valve control unit (132). That is, it is necessary to provide a device for transmitting and receiving the evaporation temperature of the second usage side heat exchanger (22) in the heat source side casing (10a).

    In the second aspect of the invention, the valve control unit (132) includes the first evaporation pressure (LP1) detected by the pressure sensor (92), and the first evaporation pressure (LP1) and the first evaporation pressure adjustment in the overheating region. Based on the first evaporating pressure (LP2) calculated by the first calculating unit (114) and the second calculating unit (115) from the temperatures (T2) of the first and second refrigerants before and after the valve (3). The first evaporating pressure adjusting valve (3) is configured to control the operation. Therefore, all means for deriving the first and second evaporation pressures (LP2) used for controlling the operation of the first evaporation pressure adjusting valve (3) are accommodated in the heat source side casing (10a). Therefore, an apparatus for transmitting and receiving data between the casing that houses the use side heat exchanger and the heat source side casing (10a) is not required.

    In a third aspect based on the first or second aspect, the first temperature sensor (96) and the second temperature sensor (97) are provided in the vicinity of the first evaporation pressure regulating valve (3). ing.

    In the third invention, the first temperature sensor (96) and the second temperature sensor (97) are provided at positions close to each other with the first evaporation pressure regulating valve (3) interposed therebetween. That is, the first and second temperature sensors (97) detect the temperature of the refrigerant immediately before the inflow of the first evaporation pressure adjusting valve (3) and the temperature of the refrigerant immediately after the outflow of the first evaporation pressure adjusting valve (3). The Rukoto.

    In a fourth aspect based on any one of the first to third aspects, the first evaporating pressure regulating valve (3) includes the gas side end of the second usage side heat exchanger (22) and the compression mechanism. (13) between the suction side end of the second use side heat exchanger (22) and the first use side heat exchanger (32, 42) so that the evaporation temperature is higher than that of the first use side heat exchanger (32, 42). The second evaporating pressure (LP2) of the second usage side heat exchanger (22) is adjusted.

    In 4th invention, the evaporation temperature of a 2nd utilization side heat exchanger (22) becomes higher than the evaporation temperature of a 1st utilization side heat exchanger (32,42) by a 1st evaporation pressure regulating valve (3). In this way, the second evaporation pressure (LP2) of the second usage side heat exchanger (22) is adjusted.

    According to a fifth invention, in any one of the first to third inventions, the first evaporating pressure regulating valve (3) includes the gas side end of the first use side heat exchanger (22) and the compression mechanism. (13) between the suction side end of the first use side heat exchanger (22) and the second use side heat exchanger (32, 42) so that the evaporation temperature is higher than that of the second use side heat exchanger (32, 42). The first evaporating pressure (LP2) of the first usage side heat exchanger (22) is adjusted.

    In 5th invention, the evaporation temperature of a 1st utilization side heat exchanger (22) becomes higher than the evaporation temperature of a 2nd utilization side heat exchanger (32,42) by a 1st evaporation pressure regulating valve (3). Thus, the 1st evaporation pressure (LP2) of the 1st use side heat exchanger (22) is adjusted.

    In a sixth aspect based on the fourth aspect, the refrigerant circuit (2) further includes a third usage side heat exchanger (152), and a gas side end of the third usage side heat exchanger (152). Between the inlet side end of the first evaporation pressure regulating valve (3), the evaporation temperature of the third usage side heat exchanger (152) is higher than the evaporation temperature of the second usage side heat exchanger (22). A second evaporation pressure adjusting valve (143) that adjusts the third evaporation pressure (LP3) of the third usage side heat exchanger (152) to be higher, and the second evaporation pressure adjusting valve (143) of the second evaporation pressure adjusting valve (143). A third temperature sensor (146) for detecting the temperature (T3) of the third refrigerant on the second usage side heat exchanger (22) side, and the third usage side heat exchanger of the second evaporation pressure regulating valve (143). A fourth temperature sensor (147) for detecting the temperature (T4) of the fourth refrigerant on the (152) side, the second evaporation pressure (LP2) calculated by the second calculation unit (115), and the third temperature sensor. The third calculation unit (118) that calculates the enthalpy (h2) of the third refrigerant from the temperature (T3) of the third refrigerant detected by the sensor (146), and the third calculation unit (118) From the enthalpy (h2) of the third refrigerant and the temperature (T4) of the fourth refrigerant detected by the fourth temperature sensor (147), a third evaporating pressure (LP3) of the third use side heat exchanger (152) is obtained. ) To calculate a fourth calculation unit (119).

    In the sixth invention, first, in the third calculation section (118), the third refrigerant detected by the second evaporation pressure (LP2) calculated by the second calculation section (115) and the third temperature sensor (146). The enthalpy (h2) of the third refrigerant is calculated from the temperature (T3). Here, since the pressure of the refrigerant does not change between the second usage-side heat exchanger (22) and the second evaporation pressure adjustment valve (143), the second usage-side heat of the second evaporation pressure adjustment valve (143). The pressure of the third refrigerant on the exchanger (22) side is equal to the second evaporation pressure (LP2) derived by the second calculation unit (115). Therefore, the enthalpy (h2) of the third refrigerant is calculated from the second evaporation pressure (LP2) equal to the pressure of the third refrigerant and the temperature (T3) of the third refrigerant. Next, in the fourth calculation unit (119), the pressure of the fourth refrigerant is calculated from the temperature (T4) of the fourth refrigerant and the enthalpy (h2) of the third refrigerant. Here, before and after the throttling of the second evaporation pressure regulating valve (143), only the pressure drops while the enthalpy is kept constant, so the enthalpy of the third refrigerant (h2) and the enthalpy of the fourth refrigerant are Will be equal. Further, since the pressure of the refrigerant does not change between the third usage side heat exchanger (152) and the second evaporation pressure adjustment valve (143), the third usage side heat exchange of the second evaporation pressure adjustment valve (143). The pressure of the fourth refrigerant on the condenser (152) side becomes equal to the third evaporation pressure (LP3) of the third usage-side heat exchanger (152). Therefore, the third evaporating pressure (LP3) of the third usage side heat exchanger (152) is calculated from the enthalpy (h2) of the third refrigerant and the temperature (T4) of the fourth refrigerant equal to the enthalpy of the fourth refrigerant. .

    In a seventh aspect based on the fifth aspect, the refrigerant circuit (2) further includes a fourth usage side heat exchanger (172), and the gas side of the second usage side heat exchanger (32, 42). Between the end of the fourth utilization side heat exchanger (172) and the gas side end of the fourth utilization side heat exchanger (172) between the end portion and the suction side end of the compression mechanism (13). Third evaporation for adjusting the fourth evaporation pressure (LP4) of the fourth usage side heat exchanger (172) so that the evaporation temperature becomes higher than the evaporation temperature of the second usage side heat exchanger (32, 42). A pressure adjusting valve (163) and a fifth temperature sensor (T5) for detecting the temperature (T5) of the fifth refrigerant on the second use side heat exchanger (32, 42) side of the third evaporating pressure adjusting valve (163); 166), a sixth temperature sensor (167) for detecting the temperature (T6) of the sixth refrigerant on the fourth use side heat exchanger (172) side of the third evaporation pressure regulating valve (163), 2 calculation part (115) A fifth calculator for calculating an enthalpy (h3) of the fifth refrigerant from the second evaporation pressure (LP1) calculated by the first temperature and the temperature (T5) of the fifth refrigerant detected by the fifth temperature sensor (166). (122), the enthalpy (h3) of the fifth refrigerant calculated by the fifth calculator (122), and the temperature (T6) of the sixth refrigerant detected by the sixth temperature sensor (167). And a sixth calculator (123) for calculating a fourth evaporation pressure (LP4) of the four usage side heat exchanger (172).

    In the seventh invention, first, in the fifth calculation unit (122), the fifth refrigerant detected by the second evaporation pressure (LP1) calculated by the second calculation unit (115) and the fifth temperature sensor (166). The enthalpy (h3) of the fifth refrigerant is calculated from the temperature (T5). Here, since the pressure of the refrigerant does not change between the second usage side heat exchanger (32, 42) and the third evaporation pressure regulating valve (163), the second usage of the third evaporation pressure regulating valve (163). The pressure of the fifth refrigerant on the side heat exchanger (32, 42) side becomes equal to the second evaporation pressure (LP1) derived by the second calculation unit (115). Therefore, the enthalpy (h3) of the fifth refrigerant is calculated from the second evaporation pressure (LP1) equal to the pressure of the fifth refrigerant and the temperature of the fifth refrigerant. Next, in the sixth calculator (123), the pressure of the sixth refrigerant is calculated from the temperature (T6) of the sixth refrigerant and the enthalpy (h3) of the fifth refrigerant. Here, before and after the throttling of the third evaporating pressure regulating valve (163), only the pressure drops while the enthalpy is kept constant, so the enthalpy (h3) of the fifth refrigerant and the enthalpy of the sixth refrigerant are Will be equal. Further, since the pressure of the refrigerant does not change between the fourth usage side heat exchanger (172) and the third evaporation pressure adjustment valve (163), the fourth usage side heat exchange of the third evaporation pressure adjustment valve (163). The pressure of the sixth refrigerant on the vessel (172) side is equal to the fourth evaporation pressure (LP4) of the fourth usage side heat exchanger (172). Therefore, the fourth evaporation pressure (LP4) of the fourth usage side heat exchanger (172) is calculated from the enthalpy (h3) of the fifth refrigerant and the temperature (T6) of the sixth refrigerant equal to the enthalpy of the sixth refrigerant. .

    According to the first invention, the first evaporating pressure (LP1) of the first use side heat exchanger (32, 42) and the first use side heat exchanger (32, 42) of the first evaporating pressure regulating valve (3). ) Side first refrigerant enthalpy (h1) calculated from the temperature (T1) of the first refrigerant and the second refrigerant on the second use side heat exchanger (22) side of the first evaporating pressure regulating valve (3). The second evaporation pressure (LP2) of the second usage side heat exchanger (22) was calculated from the temperature (T2) of the second. Therefore, the second evaporation pressure (LP2) in the second usage side heat exchanger (22) is calculated without providing a pressure sensor for detecting the second evaporation pressure (LP2) of the second usage side heat exchanger (22). can do. That is, the evaporation pressure and the evaporation temperature of each use side heat exchanger can be derived without providing a pressure sensor for each use side heat exchanger as in the conventional refrigeration apparatus. Therefore, the number of pressure sensors can be reduced in a refrigeration apparatus including a refrigerant circuit in which a plurality of usage-side heat exchangers that evaporate at different temperatures are connected in parallel to each other. Therefore, the possibility of adversely affecting the environment where the refrigeration apparatus is installed can be reduced. Also, the temperature sensor is less expensive than the pressure sensor, is easy to replace, and has a low failure rate. By using the temperature sensor instead of the pressure sensor, the entire device can be configured at low cost and replaced. It can be performed easily and inexpensively.

    Further, according to the second invention, the first evaporating pressure (LP1) and the temperatures (T2) of the first refrigerant and the second refrigerant before and after the first evaporating pressure regulating valve (3) in the superheated region are used. 2 Since the evaporation pressure (LP2) is calculated, all of the sensors, valve control unit (132), and calculation units (114, 115) required for controlling the operation of the first evaporation pressure regulating valve (3) It can be accommodated in the heat source side casing (10a). Therefore, the sensor can be easily installed, and means for transmitting and receiving detected data such as temperature between the heat source side casing (10a) and the casing in which the second usage side heat exchanger (22) is accommodated. There is no need to provide it. Therefore, the entire apparatus can be configured inexpensively and easily.

    By the way, when the installation positions of the first temperature sensor (96) and the second temperature sensor (97) are separated, for example, the temperature sensor on the downstream side of the first evaporation pressure adjustment valve (3) is the first evaporation pressure adjustment valve. When installed at a position away from (3), the refrigerant depressurized in the first evaporation pressure regulating valve (3) absorbs heat, for example, by passing in the vicinity of the heat source side heat exchanger (12), and enthalpys. Is higher than the enthalpy of the refrigerant on the upstream side of the first evaporation pressure adjusting valve (3) when passing near the temperature sensor on the downstream side of the first evaporation pressure adjusting valve (3). There is. In such a case, the second evaporation pressure (LP2) of the second usage side heat exchanger (22) cannot be accurately calculated.

    However, according to the third invention, the first temperature sensor (96) and the second temperature sensor (97) are provided at positions close to each other with the first evaporation pressure adjusting valve (3) interposed therebetween. The second evaporation pressure (LP2) of the use side heat exchanger (22) can be accurately calculated. Therefore, without providing a pressure sensor for detecting the second evaporation pressure (LP2) of the second usage side heat exchanger (22), the second evaporation pressure of the second usage side heat exchanger (22) is obtained using the temperature sensor. (LP2) and evaporation temperature can be calculated accurately.

    Moreover, according to 4th invention, the 1st utilization side heat exchanger (32,42) with a low evaporation temperature among the 1st utilization side heat exchanger (32,42) and the 2nd utilization side heat exchanger (22). 42) The first evaporating pressure (LP1) is derived by the pressure deriving mechanism (92) and the refrigerant temperatures (T1, T2) before and after the first evaporating pressure regulating valve (3) are detected to easily evaporate the evaporating temperature. The second evaporation pressure (LP2) of the second usage side heat exchanger (22) having a high value can be calculated.

    Moreover, according to 5th invention, the 1st utilization side heat exchanger (22) with a high evaporation temperature among a 1st utilization side heat exchanger (22) and a 2nd utilization side heat exchanger (32,42). The first evaporating pressure (LP2) is derived by the pressure deriving mechanism (98) and the refrigerant temperatures before and after the first evaporating pressure regulating valve (3) are detected, so that the second use side heat having a low evaporating temperature can be easily obtained. The second evaporation pressure (LP1) of the exchanger (32, 42) can be calculated.

    Moreover, according to 6th invention, the 2nd utilization side heat exchanger (22) side of the 2nd evaporation pressure (LP2) of the 2nd utilization side heat exchanger (22) and the 2nd evaporation pressure regulating valve (143) The third refrigerant enthalpy (h2) calculated from the third refrigerant temperature (T3) and the temperature of the fourth refrigerant on the third use side heat exchanger (152) side of the second evaporation pressure regulating valve (143) From (T4), the third evaporation pressure (LP3) of the third usage-side heat exchanger (152) was calculated. Therefore, the third evaporating pressure (LP3) of the third usage side heat exchanger (152) is calculated without providing a pressure sensor for detecting the third evaporating pressure (LP3) of the third usage side heat exchanger (152). can do.

    Further, according to the seventh invention, the second evaporation pressure (LP1) of the second usage side heat exchanger (32, 42) and the second usage side heat exchanger (32 of the third evaporation pressure regulating valve (163)). , 42) side enthalpy (h3) of the fifth refrigerant calculated from the temperature (T5) of the fifth refrigerant on the side, and the fourth usage side heat exchanger (172) side of the third evaporation pressure regulating valve (163). The fourth evaporation pressure (LP4) of the fourth usage side heat exchanger (172) was calculated from the temperature of the six refrigerants (T6). Therefore, the 4th evaporation pressure (LP4) of the 4th use side heat exchanger (172) is calculated, without providing the pressure sensor which detects the 4th evaporation pressure (LP4) of the 4th use side heat exchanger (172). can do.

FIG. 1 is a piping system diagram illustrating the configuration of the refrigeration apparatus according to the first embodiment. FIG. 2 is a block diagram illustrating a configuration of the controller according to the first embodiment. FIG. 3 is a piping diagram illustrating the refrigerant flow during the cooling / cooling operation of the refrigeration apparatus according to the first embodiment. FIG. 4 is a Ph diagram illustrating a refrigeration cycle during the cooling / cooling operation of the refrigeration apparatus according to the first embodiment. FIG. 5 is a piping diagram illustrating the refrigerant flow during the cooling / cooling operation of the refrigeration apparatus according to the second embodiment. FIG. 6 is a piping diagram illustrating the refrigerant flow during the cooling / cooling operation of the refrigeration apparatus according to the third embodiment. FIG. 7 is a block diagram illustrating a configuration of a controller according to the third embodiment. FIG. 8 is a Ph diagram illustrating a refrigeration cycle during a cooling / cooling operation of the refrigeration apparatus according to the third embodiment. FIG. 9 is a piping diagram illustrating the refrigerant flow during the cooling / cooling operation of the refrigeration apparatus according to the third embodiment. FIG. 10 is a block diagram illustrating a configuration of a controller according to the fourth embodiment. FIG. 11 is a Ph diagram illustrating the refrigeration cycle during the cooling / cooling operation of the refrigeration apparatus according to the fourth embodiment.

    Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1 of the Invention
The refrigeration apparatus according to Embodiment 1 is installed in, for example, a convenience store, and performs air conditioning in the store and cooling of a showcase or the like.

-Overall configuration-
As shown in FIG. 1, the refrigeration apparatus (1) includes an outdoor unit (10), an indoor unit (20), a first refrigeration unit (30), a second refrigeration unit (40), and a controller (100). And. The outdoor unit (10) is provided with an outdoor circuit (11) as a heat source side circuit having an outdoor heat exchanger (heat source side heat exchanger) (12). The indoor unit (20) is provided with an indoor circuit (use side circuit) (21) having an indoor heat exchanger (second use side heat exchanger) (22). The first refrigeration unit (30) is provided with a first refrigeration circuit (use side circuit) (31) having a first refrigeration heat exchanger (first use side heat exchanger) (32). The second refrigeration unit (40) is provided with a second refrigeration circuit (use side circuit) (41) having a second refrigeration heat exchanger (42). A refrigerant circuit (2) that performs a vapor compression refrigeration cycle is configured by connecting a plurality of usage-side circuits (21, 31, 41) in parallel to the outdoor circuit (11).

    The outdoor circuit (11) and each use side circuit (21, 31, 41) include a first gas side communication pipe (51), a first liquid side communication pipe (52), a second gas side communication pipe (53), and They are connected to each other by the second liquid side connecting pipe (54). Specifically, one end of the first gas side communication pipe (51) is connected to the gas side end of the indoor circuit (21), and the other end is connected to the first gas side closing valve (71) of the outdoor circuit (11). It is connected. One end of the first liquid side connecting pipe (52) is connected to the liquid side end of the indoor circuit (21), and the other end is connected to the first liquid side shut-off valve (72) of the outdoor circuit (11). One end side of the second gas side communication pipe (53) branches into a first branch gas pipe (53a) and a second branch gas pipe (53b), and the other end is a second gas side closing valve of the outdoor circuit (11). (73) connected. The tip of the first branch gas pipe (53a) is connected to the gas side end of the first refrigeration circuit (31), and the tip of the second branch gas pipe (53b) is the gas of the second refrigeration circuit (41). Connected to the side edge. One end side of the second liquid side connecting pipe (54) branches into a first branch liquid pipe (54a) and a second branch liquid pipe (54b), and the other end is a second liquid side closing valve of the outdoor circuit (11). (74) connected. The tip of the first branch liquid pipe (54a) is connected to the liquid side end of the first refrigeration circuit (31), and the tip of the second branch liquid pipe (54b) is the liquid of the second refrigeration circuit (41). Connected to the side edge.

<Outdoor unit>
The outdoor unit (10) is installed outdoors and includes the outdoor circuit (11) and an outdoor casing (heat source side casing) (10a) that accommodates the outdoor circuit (11). The outdoor circuit (11) includes the outdoor heat exchanger (12), the compression mechanism (13), the outdoor expansion valve (14), the receiver (15), and the first to third oil separators (17a, 17b). 17c), first and second four-way switching valves (18, 19), and four closing valves (71, 72, 73, 74).

    The compression mechanism (13) includes first to third compressors (13a, 13b, 13c). Each of the first to third compressors (13a, 13b, 13c) is configured as a hermetic scroll compressor having a compression chamber formed by meshing a fixed scroll and a movable scroll. In the first to third compressors (13a, 13b, 13c), a suction port (not shown) is opened at the suction position of each compression chamber, a discharge port (not shown) is opened at the discharge position, and is intermediate at the intermediate position. A port (not shown) is open.

    The first compressor (13a) constitutes a variable capacity compressor. That is, the first compressor (13a) is configured such that the rotational speed is variable by inverter control. On the other hand, the second compressor (13b) and the third compressor (13c) constitute a fixed capacity compressor having a constant rotational speed. The second compressor (13b) and the third compressor (13c) may be variable capacity compressors. The first to third compressors (13a, 13b, 13c) have a suction pipe (55) connected to the suction side and a discharge pipe (56) connected to the discharge side.

    The suction pipe (55) has an inflow side branched into a first inflow branch pipe (55a) and a second inflow branch pipe (55b). The first inflow branch pipe (55a) is connected to the second gas side stop valve (73), while the second inflow branch pipe (55b) is connected to the second port of the second four-way switching valve (19). ing. Further, the outflow side of the suction pipe (55) branches into a first outflow branch pipe (55c), a second outflow branch pipe (55d), and a third outflow branch pipe (55e). The first outflow branch pipe (55c) is connected to the suction side end of the first compressor (13a), and the second outflow branch pipe (55d) is connected to the suction side end of the second compressor (13b); The third outflow branch pipe (55e) is connected to the suction side end of the third compressor (13c). The suction pipe (55) is provided with a filter (55f).

    The discharge pipe (56) has an inflow side branched into a first inflow branch pipe (56a), a second inflow branch pipe (56b), and a third inflow branch pipe (56c). The first inflow branch pipe (56a) is connected to the discharge side end of the first compressor (13a), the second inflow branch pipe (56b) is connected to the discharge side end of the second compressor (13b), The third inflow branch pipe (56c) is connected to the discharge side end of the third compressor (13c). The first to third inflow branch pipes (56a, 56b, 56c) are provided with check valves (CV1, CV2, CV3), respectively. These check valves (CV1, CV2, CV3) allow the refrigerant to flow from the first to third compressors (13a, 13b, 13c) to the four-way switching valve (18, 19) and in the reverse direction. Block the flow of refrigerant. Further, the discharge pipe (56) has an outflow side branched into a first outflow branch pipe (56d) and a second outflow branch pipe (56e). The first outlet branch pipe (56d) is connected to the first port of the first four-way selector valve (18), and the second outlet branch pipe (56e) is connected to the first port of the second four-way selector valve (19). Has been.

    The first to third oil separators (17a, 17b, 17c) are in the middle of the inflow branch pipes (56a, 56b, 56c) of the discharge pipe (56) and are connected to the compressors (13a, 13b, 13c). ) And each check valve (CV1, CV2, CV3). The first to third oil separators (17a, 17b, 17c) separate the lubricating oil mixed in the refrigerant discharged from the first to third compressors (13a, 13b, 13c) connected thereto, The lubricant is returned to the first to third compressors (13a, 13b, 13c). Specifically, the lubricating oil separated from the refrigerant in the first to third oil separators (17a, 17b, 17c) was connected to each of the first to third oil separators (17a, 17b, 17c). The oil is returned to the inflow end side of an injection pipe (81) described later via the oil return pipe (50). The oil return pipe (50) is branched into three on the inflow side, and each branch pipe is connected to each oil separator (17a, 17b, 17c). Each branch pipe of the oil return pipe (50) has a check valve (CV11, CV12, CV13) and capillary tube (48a, 48a, 48b, 48c). Each check valve (CV11, CV12, CV13) allows the lubricating oil to flow from the oil separator (17a, 17b, 17c) to the injection pipe (81) and prevents the lubricating oil from flowing in the reverse direction. .

    The first and second four-way selector valves (18, 19) are in a first state (state indicated by a solid line in FIG. 1) in which the first port communicates with the third port and the second port communicates with the fourth port. , The first port communicates with the fourth port and the second port communicates with the third port (a state indicated by a broken line in FIG. 1). The refrigeration apparatus can perform various operations by the switching operation of the first and second four-way switching valves (18, 19).

    A first outlet branch pipe (56d) is connected to the first port of the first four-way selector valve (18). The second port of the first four-way selector valve (18) is connected to the fourth port of the second four-way selector valve (19) via the connection pipe (57). The third port of the first four-way selector valve (18) is connected to the gas side end of the outdoor heat exchanger (12) via the outdoor gas pipe (58). The fourth port of the first four-way selector valve (18) is connected to the first gas side shut-off valve (71) via the first gas pipe (62).

    A second outlet branch pipe (56e) is connected to the first port of the second four-way selector valve (19). The second port of the second four-way selector valve (19) is connected to the second inflow branch pipe (55b). The third port of the second four-way selector valve (19) is sealed. As described above, the fourth port of the second four-way selector valve (19) is connected to the second port of the first four-way selector valve (18) via the connecting pipe (57).

    The communication pipe (57) is provided with an evaporation pressure adjusting valve (3) according to the present invention. The evaporating pressure regulating valve (3) evaporates the refrigerant at different temperatures in the indoor heat exchanger (22) and the first and second refrigeration heat exchangers (32, 42) during the cooling cooling operation described later. Thus, the evaporation pressure of the indoor heat exchanger (22) is adjusted.

    The outdoor heat exchanger (12) is a fin-and-tube heat exchanger, and an outdoor fan (12a) is provided in the vicinity thereof. In the outdoor heat exchanger (12), heat is exchanged between the refrigerant flowing inside and the outside air blown by the outdoor fan (12a). The outdoor fan (12a) is accommodated in the outdoor casing (10a) together with the outdoor circuit (11).

    The outdoor heat exchanger (12) has a liquid side end connected to the top of the receiver (15) via a first liquid pipe (59). The bottom of the receiver (15) is connected to the first liquid side shut-off valve (72) via the second liquid pipe (60). The first liquid pipe (59) and the second liquid pipe (60) are provided with check valves (CV4, CV5), respectively. The check valve (CV4) of the first liquid pipe (59) allows the refrigerant to flow from the outdoor heat exchanger (12) to the top of the receiver (15) and prevents the refrigerant from flowing in the reverse direction. The check valve (CV5) of the second liquid pipe (60) allows the refrigerant to flow from the bottom of the receiver (15) to the first liquid side shut-off valve (72) and prevents the refrigerant from flowing in the reverse direction. To do.

    A bypass pipe (61) is provided between the first liquid pipe (59) and the second liquid pipe (60). One end of the bypass pipe (61) is connected to the upstream side of the check valve (CV4) of the first liquid pipe (59), and the other end is upstream of the check valve (CV5) of the second liquid pipe (60). Connected to the side. An outdoor expansion valve (14) is provided in the middle of the bypass pipe (61). The outdoor expansion valve (14) is an electronic expansion valve whose opening degree can be adjusted. The second liquid pipe (60) is provided with a defrost heat exchanger (75) and a supercooling heat exchanger (76).

    The defrost heat exchanger (75) is provided in the vicinity of the outdoor heat exchanger (12), and is configured such that the high-pressure liquid refrigerant stored in the receiver (15) always flows inside. The defrost heat exchanger (75) prevents the outdoor heat exchanger (12) from frosting with the high-pressure liquid refrigerant flowing inside.

    The supercooling heat exchanger (76) includes a high pressure side channel (76a) and a low pressure side channel (76b). The supercooling heat exchanger (76) is configured such that the refrigerant flowing through the high pressure side flow path (76a) and the low pressure side flow path (76b) exchanges heat so that the high pressure side flow path (76a) is supercooled. ing. The high-pressure channel (76a) constitutes a part of the downstream side of the defrost heat exchanger (75) of the second liquid pipe (60). A filter (76c) and a sight glass (76d) are provided on the downstream side of the high-pressure channel (76a) of the second liquid pipe (60). On the other hand, the low pressure side flow path (76b) is a first branch pipe (77) that connects the upstream side of the check valve (CV5) of the second liquid pipe (60) and an inflow end of an injection pipe (81) described later. Part of. A supercooling expansion valve (78) is provided on the upstream side of the low pressure side flow path (76b) of the first branch pipe (77). The supercooling expansion valve (78) is an electronic expansion valve whose opening degree can be adjusted.

    Between the downstream side of the check valve (CV5) of the second liquid pipe (60) and the downstream side of the check valve (CV4) of the first liquid pipe (59), there is a second branch pipe (79). Is provided. The second branch pipe (79) is provided with a check valve (CV6). The check valve (CV6) allows the refrigerant to flow from the second liquid pipe (60) to the first liquid pipe (59) and prevents the refrigerant from flowing in the reverse direction.

    A third branch pipe (80) is provided between the downstream side of the check valve (CV6) of the second branch pipe (79) and the upstream side of the check valve (CV4) of the first liquid pipe (59). Is provided. The third branch pipe (80) is provided with a check valve (CV7). The check valve (CV7) allows the refrigerant to flow from the second branch pipe (79) to the first liquid pipe (59) and prevents the refrigerant from flowing in the reverse direction.

    As described above, the injection pipe (81) has an inflow end connected to the first branch pipe (77) and an outflow end branched into three. Specifically, the outflow end of the injection pipe (81) branches to the first to third injection pipes (81a, 81b, 81c). Each injection pipe (81a, 81b, 81c) is connected to an intermediate pressure port that communicates with an intermediate pressure compression chamber of each compressor (13a, 13b, 13c). Each injection pipe (81a, 81b, 81c) is provided with an expansion valve (82a, 82b, 82c). Each expansion valve (82a, 82b, 82c) is configured by an electronic expansion valve with variable opening. Each injection pipe (81a, 81b, 81c) constitutes an injection circuit for introducing a gas refrigerant from the supercooling heat exchanger (76) to the compression chamber of the intermediate pressure of each compressor (13a, 13b, 13c). . In this way, a system that introduces the gas refrigerant into the compression chamber of the intermediate pressure of each compressor (13a, 13b, 13c) is configured as a so-called economizer system.

    Various sensors are provided in the outdoor circuit (11). Specifically, on the upstream side of each oil separator (17a, 17b, 17c) of each inflow branch pipe (56a, 56b, 56c) of the discharge pipe (56), each compressor (13a, 13b, 13c) Discharge temperature sensors (90a, 90b, 90c) for detecting the temperature of the discharged refrigerant are provided. The discharge pipe (56) is provided with a discharge pressure sensor (91) for detecting the pressure of the refrigerant discharged from each compressor (13a, 13b, 13c). On the other hand, the suction pipe (55) is provided with a suction pressure sensor (pressure sensor) (92) for detecting the pressure of the suction refrigerant of each compressor (13a, 13b, 13c).

    In the vicinity of the outdoor heat exchanger (12), an outdoor temperature sensor (12b) for detecting the outdoor outdoor temperature is provided. Further, a temperature sensor (94) and a pressure sensor (95) are provided on the downstream side of the low pressure side flow path (76b) of the supercooling heat exchanger (76) of the first branch pipe (77). The temperature sensor (94) and pressure sensor (95) detect the temperature and pressure of the refrigerant flowing out of the low pressure side flow path (76b) of the supercooling heat exchanger (76) and flowing into the injection pipe (81), respectively. To do.

    The second inflow branch pipe (55b) connected to the second port of the second four-way selector valve (19) is provided with a temperature sensor (first temperature sensor) (96). Further, the first gas pipe (62) connecting the fourth port of the first four-way selector valve (18) and the first gas side closing valve (71) includes a temperature sensor (second temperature sensor) (97). Is provided. These two temperature sensors (96, 97) detect the temperatures of the refrigerant on the upstream side and downstream side of the evaporating pressure regulating valve (3), respectively, during the cooling / cooling operation described later. The temperature is used to calculate the evaporation pressure of the first and second refrigeration heat exchangers (32, 42). The temperature sensor (96, 97) is accommodated in the outdoor casing (10a).

<Indoor unit>
The indoor unit (20) is installed indoors and includes the indoor circuit (21) and an indoor casing (20a) that houses the indoor circuit (21). The indoor circuit (21) has a gas side end connected to the first gas side connecting pipe (51) and a liquid side end connected to the first liquid side connecting pipe (52). The indoor circuit (21) is provided with an indoor heat exchanger (22), an indoor expansion valve (expansion mechanism) (23), and a filter (24) in this order from the gas side end. The indoor heat exchanger (22) is constituted by a cross fin type fin-and-tube heat exchanger, and an indoor fan (22a) is provided in the vicinity thereof. The indoor fan (22a) is housed in the indoor casing (20a) together with the indoor circuit (21). In the indoor heat exchanger (22), heat exchange is performed between the refrigerant flowing inside and the indoor air blown by the indoor fan (22a). An indoor temperature sensor (22b) for detecting the temperature of the indoor air is provided in the vicinity of the indoor heat exchanger (22). The indoor expansion valve (23) is an electronic expansion valve whose opening degree can be adjusted.

<Refrigerated unit>
The first and second refrigeration units (30, 40) respectively have the refrigeration circuit (31, 41) and a refrigeration showcase (30a, 40a) that accommodates the refrigeration circuit (31, 41). ing.

    The first refrigeration circuit (31) of the first refrigeration unit (30) has a gas side end connected to the first branch gas pipe (53a) of the second gas side connection pipe (53) and a liquid side end of the second refrigeration unit (30). It is connected to the first branch liquid pipe (54a) of the liquid side communication pipe (54). The first refrigeration circuit (31) is provided with a first refrigeration heat exchanger (32), an internal expansion valve (expansion mechanism) (33), and an electromagnetic valve (34) in order from the gas side end. . The first refrigeration heat exchanger (32) is configured by a cross fin type fin-and-tube heat exchanger, and an internal fan (32a) is provided in the vicinity thereof. The internal fan (32a) is housed in the refrigerated showcase (30a) together with the first refrigeration circuit (31). In the first refrigeration heat exchanger (32), heat is exchanged between the refrigerant flowing in the interior and the air inside the refrigerated showcase (30a) blown by the internal fan (32a). Further, an internal temperature sensor (32b) for detecting the temperature of the internal air is provided in the vicinity of the first refrigeration heat exchanger (32). The internal expansion valve (33) is a temperature-sensitive expansion valve, and a temperature-sensitive cylinder is attached to the gas side of the first refrigeration heat exchanger (32). When the first refrigeration heat exchanger (32) functions as an evaporator, the internal expansion valve (33) is opened based on the refrigerant temperature on the outlet side of the first refrigeration heat exchanger (32). Is adjusted.

    On the other hand, the second refrigeration circuit (41) of the second refrigeration unit (40) has a gas side end connected to the second branch gas pipe (53b) of the second gas side connection pipe (53) and a liquid side end. It is connected to the second branch liquid pipe (54b) of the second liquid side connecting pipe (54). The second refrigeration circuit (41) is provided with a second refrigeration heat exchanger (42), an internal expansion valve (expansion mechanism) (43), and an electromagnetic valve (44) in this order from the gas side end. . The 2nd refrigeration heat exchanger (42) is comprised by the cross fin type fin and tube type heat exchanger, and the internal fan (42a) is provided in the vicinity. The internal fan (42a) is housed in the refrigerated showcase (40a) together with the second refrigeration circuit (41). In the second refrigeration heat exchanger (42), heat exchange is performed between the refrigerant flowing inside and the air inside the refrigerated showcase (40a) blown by the internal fan (42a). Further, in the vicinity of the second refrigeration heat exchanger (42), an internal temperature sensor (42b) for detecting the temperature of the internal air is provided. The internal expansion valve (43) is a temperature-sensitive expansion valve, and a temperature-sensitive cylinder is attached to the gas side of the second refrigeration heat exchanger (42). When the second refrigeration heat exchanger (42) functions as an evaporator, the internal expansion valve (43) is opened based on the refrigerant temperature on the outlet side of the second refrigeration heat exchanger (42). Is adjusted.

<controller>
The controller (100) receives the detection values of the various sensors described above and controls the operation of the refrigeration apparatus (1) by controlling various devices (various valves, various fans, etc.) based on the detection values. is there.

    As shown in FIG. 2, the controller (100) includes an evaporation temperature deriving unit (110) for deriving the evaporation temperature of each use side heat exchanger (22, 32, 42), and all the use side heat exchangers (22). , 32, 42) function as an evaporator, and execute a cooling cooling operation in which the refrigerant evaporates at different temperatures in the indoor heat exchanger (22) and the first and second refrigeration heat exchangers (32, 42). And an operation control unit (130).

    The evaporating temperature deriving unit (110) is configured to evaporate the evaporating temperatures of the first and second refrigeration heat exchangers (32, 42) constituting the first use side heat exchanger according to the present invention during the cooling cooling operation. And a second evaporation temperature deriving unit (112) for deriving the evaporation temperature of the indoor heat exchanger (22) constituting the second use side heat exchanger according to the present invention. And have.

    The first evaporating temperature deriving unit (111) derives evaporating temperatures of the first and second refrigeration heat exchangers (32, 42) based on the detected value of the suction pressure sensor (92). Here, the suction pressure (low pressure (LP1)) detected by the suction pressure sensor (92) is equal to the evaporation pressure (first evaporation pressure) of the first and second refrigeration heat exchangers (32, 42). Therefore, the first evaporating temperature deriving unit (111) includes a saturation temperature calculating unit (113) that calculates a pressure-equivalent saturation temperature from the suction pressure detected by the suction pressure sensor (92), and the saturation temperature calculating unit (113) ) Is derived as the evaporation temperature of the first and second refrigeration heat exchangers (32, 42).

    On the other hand, the second evaporation temperature deriving unit (112) includes an enthalpy calculation unit (first calculation unit) (114), an evaporation pressure calculation unit (second calculation unit) (115), and a saturation temperature calculation unit (116). Have. In the following, the refrigerant on the first and second refrigeration heat exchangers (first use side heat exchangers) (32, 42) side of the evaporation pressure adjusting valve (3) is referred to as a first refrigerant, and the evaporation pressure adjusting valve. The refrigerant on the indoor heat exchanger (second utilization side heat exchanger) (22) side in (3) will be described as the second refrigerant.

    The enthalpy calculating unit (114) is configured to detect the evaporation pressure (first evaporation pressure) of the first and second refrigeration heat exchangers (32, 42) detected by the suction pressure sensor (92) during the cooling cooling operation. ) And the temperature of the first refrigerant detected by the temperature sensor (96), the enthalpy of the first refrigerant is calculated. The evaporating pressure calculating unit (115) is configured to calculate an enthalpy of the first refrigerant calculated by the enthalpy calculating unit (114) and a temperature of the second refrigerant detected by the temperature sensor (97) during the cooling / cooling operation. The pressure of the second refrigerant is calculated. Here, since the pressure of the refrigerant does not change between the evaporation pressure regulating valve (3) and the indoor heat exchanger (22), the pressure of the second refrigerant is the evaporation pressure (second evaporation) of the indoor heat exchanger (22). Pressure). Therefore, the evaporation pressure calculation unit (115) is configured to calculate the pressure of the second refrigerant calculated as described above as the evaporation pressure of the indoor heat exchanger (22). The saturation temperature calculation unit (116) calculates a pressure equivalent saturation temperature from the evaporation pressure of the indoor heat exchanger (22) calculated by the evaporation pressure calculation unit (115).

    The second evaporating temperature deriving unit (112) includes the indoor heat exchanger (22) derived by the enthalpy calculating unit (114), the evaporating pressure calculating unit (115), and the saturation temperature calculating unit (116) as described above. The evaporating pressure equivalent saturation temperature is derived as the evaporating temperature of the indoor heat exchanger (22).

    The operation control unit (130) includes a cooling / cooling operation execution unit (131) and a different temperature evaporation control unit (132). The cooling / cooling operation execution unit (131) controls various devices and various valves, and the outdoor heat exchanger (12) functions as a condenser in the refrigerant circuit (2), and all the use side heat exchangers (22, 32, 42) is configured to execute a cooling and cooling operation in which the refrigerant circulates so as to function as an evaporator. In addition, the different temperature evaporation control unit (132) is configured so that the refrigerant has different temperatures in the indoor heat exchanger (22) and the first and second refrigeration heat exchangers (32, 42) during the cooling and cooling operation. The opening of the evaporation pressure adjusting valve (3) is adjusted to evaporate. Specifically, the different temperature evaporation control unit (132) is configured such that the evaporation temperature of the indoor heat exchanger (22) derived by the second evaporation temperature deriving unit (112) is the first evaporation temperature deriving unit (111). The degree of opening of the evaporating pressure adjusting valve (3) is adjusted so as to be higher by a predetermined temperature than the evaporating temperature of the first and second refrigeration heat exchangers (32, 42) derived from.

    The operation control unit (130) includes the cooling and cooling operation execution unit (131), the outdoor heat exchanger (12) and the indoor heat exchanger (22) function as a condenser, and the first and second refrigeration units. Heating / cooling operation in which the heat exchanger (32, 42) functions as an evaporator, heating operation in which the indoor heat exchanger (22) functions as a condenser and the outdoor heat exchanger (12) functions as an evaporator, and You may have an execution part which performs each of the cooling operation in which an outdoor heat exchanger (12) functions as a condenser, and an indoor heat exchanger (22) functions as an evaporator.

-Driving action-
In the refrigeration apparatus (1), as described above, the cooling / cooling operation execution unit (131) of the operation control unit (130) of the controller (100) causes the indoor unit (20) to A cooling cooling operation is performed in which the inside of the refrigerator is cooled by the refrigeration unit (30, 40).

    Specifically, the cooling / cooling operation execution unit (131) switches the first and second four-way switching valves (18, 19) to the first state and controls the outdoor expansion valve (14) to be fully closed. . The cooling / cooling operation execution unit (131) controls the electromagnetic valves (34, 44) of the first and second refrigeration circuits (31, 41) to be in an open state and also opens the opening of the indoor expansion valve (23). Adjustments are made as appropriate, and the operation of the first to third compressors (13a, 13b, 13c) is started. As a result, as indicated by the thick line in FIG. 3, in the refrigerant circuit (2), the heat source side heat exchanger (12) functions as a condenser, while all the use side heat exchangers (22, 32, 42) The refrigerant circulates so as to function as an evaporator, and a vapor compression refrigeration cycle as shown in FIG. 4 is performed. In FIG. 3, the flow of the lubricating oil flowing through the oil return pipe (50) is not shown. In FIG. 3, all of the first to third compressors (13a, 13b, 13c) are in an operating state, but the cooling / cooling operation execution unit (131) Based on the low pressure (LP1) detected by the suction pressure sensor (92), the capacity control of the first compressor (13a) and the switching control between the start and stop of the second and third compressors (13b, 13c) are performed. And operate according to the cooling load. Therefore, when the cooling load is small, the operation of the second and third compressors (13b, 13c) is stopped.

    Further, the different temperature evaporation control unit (132) derives the evaporation temperature of the indoor heat exchanger (22) derived by the second evaporation temperature deriving unit (112) from the first evaporation temperature deriving unit (111). The opening degree of the evaporating pressure adjusting valve (3) is adjusted so as to be higher than the evaporating temperature of the first and second refrigeration heat exchangers (32, 42) by a predetermined temperature.

    By controlling the various devices and valves by the operation control unit (130) as described above, the refrigerant circulates in the refrigerant circuit (2) as follows.

    The refrigerant compressed by the first to third compressors (13a, 13b, 13c) joins in the discharge pipe (56) after the lubricating oil is separated in each oil separator (17a, 17b, 17c), 1 Passes through the four-way selector valve (18) and the outdoor gas pipe (58) and flows into the outdoor heat exchanger (12). In the outdoor heat exchanger (12), the refrigerant dissipates heat to the outdoor air and condenses. The liquid refrigerant condensed in the outdoor heat exchanger (12) flows into the receiver (15) through the first liquid pipe (59) and is stored in the receiver (15).

    The liquid refrigerant stored in the receiver (15) flows out of the receiver (15) and flows through the second liquid pipe (60) toward the first liquid side shut-off valve (72). At that time, it passes through the defrost heat exchanger (75) and the supercooling heat exchanger (76).

    In the defrost heat exchanger (75), the high-pressure liquid refrigerant dissipates heat, and the high-pressure liquid refrigerant after the heat release flows into the high-pressure channel (76a) of the supercooling heat exchanger (76). On the other hand, the low-pressure channel (76b) of the supercooling heat exchanger (76) passes through the high-pressure channel (76a) and then branches from the second liquid pipe (60) to the first branch pipe (77). The branched refrigerant decompressed by the cooling expansion valve (78) flows in. The branch refrigerant flowing in the low pressure side flow path (76b) evaporates by exchanging heat with the high pressure liquid refrigerant flowing in the high pressure side flow path (76a), while the high pressure liquid refrigerant in the high pressure side flow path (76a) is low in pressure. Heat is released to the branching refrigerant in the side flow path (76b) so that a supercooled state is achieved. The liquid refrigerant in the supercooled state in this way is branched into two, one passing through the second liquid side closing valve (74) and flowing into the second liquid side connecting pipe (54), and the other being It passes through the first liquid side closing valve (72) and flows into the first liquid side connecting pipe (52). On the other hand, the evaporated refrigerant in the low-pressure channel (76b) flows into the injection pipe (81). The opening degree of the supercooling expansion valve (78) is adjusted so that, for example, the superheat degree of the refrigerant flowing through the injection pipe (81) becomes a desired superheat degree (for example, 5 ° C.). The superheat degree of the refrigerant flowing through the injection pipe (81) is derived from the detection values of the temperature sensor (94) and the pressure sensor (95) for injection.

    The liquid refrigerant that has flowed into the second liquid side connecting pipe (54) branches into two and flows into the first branch liquid pipe (54a) and the second branch liquid pipe (54b). The liquid refrigerant flowing into the first branch liquid pipe (54a) flows into the first refrigeration circuit (31) of the first refrigeration unit (30), while the liquid refrigerant flowing into the second branch liquid pipe (54b) is And flows into the second refrigeration circuit (41) of the second refrigeration unit (40). The liquid refrigerant that has flowed into each refrigeration circuit (31, 41) is depressurized by each internal expansion valve (33, 43), and then flows into the first and second refrigeration heat exchangers (32, 42). . In the first and second refrigeration heat exchangers (32, 42), the refrigerant absorbs heat from the internal air and evaporates. As a result, the internal air is cooled. The refrigerant evaporated in each of the first and second refrigeration heat exchangers (32, 42) flows from each refrigeration circuit (31, 41) to the first branch gas pipe (53a) of the second gas side communication pipe (53). And flow into the second branch gas pipe (53b), and eventually merge. The refrigerant merged in the second gas side communication pipe (53) passes through the second gas side stop valve (73) and then flows into the first inflow branch pipe (55a) of the suction pipe (55).

    The liquid refrigerant flowing into the first liquid side connecting pipe (52) is decompressed by the indoor expansion valve (23) and then flows into the indoor heat exchanger (22). In the indoor heat exchanger (22), the refrigerant absorbs heat from the indoor air and evaporates. As a result, room air is cooled. The opening of the indoor expansion valve (23) is adjusted to a predetermined opening based on the detected value of the indoor temperature sensor (22b) and the set temperature in the room. For example, the opening degree of the indoor expansion valve (23) is adjusted so that the detected value of the indoor temperature sensor (22b) becomes a desired temperature (for example, 20 ° C.). The refrigerant evaporated in the indoor heat exchanger (22) passes through the first gas side communication pipe (51), the first gas pipe (62), and the first four-way switching valve (18) to the communication pipe (57). Inflow. The refrigerant that has flowed into the communication pipe (57) is further depressurized by the evaporation pressure regulating valve (3), and then the second inflow branch pipe (55b) of the suction pipe (55) through the second four-way switching valve (19). ).

    The opening degree of the evaporation pressure adjusting valve (3) is determined by the indoor heat derived by the second evaporation temperature deriving unit (112) by the different temperature evaporation control unit (132) of the operation control unit (130) as described above. The evaporating temperature of the exchanger (22) is adjusted to be higher by a predetermined temperature than the evaporating temperature of the first and second refrigeration heat exchangers (32, 42) derived by the first evaporating temperature deriving unit (111). Is done.

    After the refrigerant flowing into the first inflow branch pipe (55a) and the second inflow branch pipe (55b) of the suction pipe (55) merges as described above, the first outflow branch pipe (55c), Branches into the two outflow branch pipes (55d) and the third outflow branch pipe (55e). The refrigerant flowing into the first to third outflow branch pipes (55c, 55d, 55e) is sucked into the corresponding first to third compressors (13a, 13b, 13c) and compressed.

    On the other hand, the refrigerant that has flowed into the injection pipe (81) branches to the first to third injection pipes (81a, 81b, 81c), and then intermediates between the corresponding first to third compressors (13a, 13b, 13c). Introduced into the pressure compression chamber. Thereby, the discharge gas temperature of a 1st-3rd compressor (13a, 13b, 13c) falls. Further, the lubricating oil separated from the refrigerant discharged from the first to third compressors (13a, 13b, 13c) in the first to third oil separators (17a, 17b, 17c) passes through the oil return pipe (50). Returned to the injection pipe (81).

    As described above, in the cooling and cooling operation, the evaporating pressure regulating valve (3) causes the indoor heat exchanger (22) of the indoor circuit (21) and the first and second refrigeration circuits (31, 41) to be the first. And the evaporation pressure of a refrigerant | coolant differs in the 2nd refrigeration heat exchanger (32,42). Specifically, the evaporation pressure of the indoor heat exchanger (22) becomes higher than the evaporation pressure of the first and second refrigeration heat exchangers (32, 42). As a result, the refrigerant evaporates at different temperatures in the indoor heat exchanger (22) and the first and second refrigeration heat exchangers (32, 42). Specifically, the evaporation temperature of the indoor heat exchanger (22) becomes higher than the evaporation temperatures of the first and second refrigeration heat exchangers (32, 42). For example, the evaporation of the indoor heat exchanger (22) The temperature becomes + 5 ° C., and the evaporation temperature of the first and second refrigeration heat exchangers (32, 42) becomes −10 ° C.

<Derivation of evaporation temperature>
The evaporation temperature deriving unit (110) of the controller (100) derives the evaporation temperatures of the first and second refrigeration heat exchangers (32, 42) and the indoor heat exchanger (22) during the cooling and cooling operation. To do.

    First, the evaporating temperatures of the first and second refrigeration heat exchangers (32, 42) are derived by the first evaporating temperature deriving unit (111) of the controller (100). The first evaporation temperature deriving unit (111) is saturated from the pressure of the first refrigerant equal to the evaporation pressure (LP1) of the first and second refrigeration heat exchangers (32, 42) detected by the suction pressure sensor (92). A temperature-corresponding saturation temperature is calculated by the temperature calculation unit (113), and the saturation temperature is derived as the evaporation temperature of the first and second refrigeration heat exchangers (32, 42).

    Next, the evaporation temperature of the indoor heat exchanger (22) is derived by the second evaporation temperature deriving unit (112) of the controller (100). Specifically, first, the first refrigerant equal to the evaporation pressure (LP1) of the first and second refrigeration heat exchangers (32, 42) detected by the suction pressure sensor (92) by the enthalpy calculation unit (114). And the temperature (T1) of the first refrigerant detected by the temperature sensor (96), the enthalpy (h1) of the first refrigerant is calculated. Specifically, as shown in the Ph diagram of FIG. 4, the isobaric line of the first refrigerant pressure equal to the evaporation pressure (LP1) of the first and second refrigeration heat exchangers (32, 42) The enthalpy (h1) of the first refrigerant is calculated from the intersection with the isotherm of the temperature (T1) of the first refrigerant. Then, from the temperature (T2) of the second refrigerant detected by the temperature sensor (97) and the enthalpy (h1) of the first refrigerant calculated by the enthalpy calculation unit (114) by the evaporation pressure calculation unit (115). The pressure of the second refrigerant is calculated. Here, usually, only the pressure drops while the enthalpy is kept constant before and after the throttling like the pressure regulating valve. In other words, the enthalpy of the second refrigerant before flowing out of the indoor heat exchanger (22) and flowing into the evaporation pressure adjusting valve (3) is the enthalpy (h1) of the first refrigerant flowing out of the evaporation pressure adjusting valve (3). be equivalent to. Therefore, the pressure of the second refrigerant flowing out of the indoor heat exchanger (22) and flowing into the evaporation pressure regulating valve (3) is determined from the enthalpy (h1) of the first refrigerant and the temperature (T2) of the second refrigerant. Can do. Specifically, as shown in the Ph diagram of FIG. 4, the indoor heat exchanger is determined from the intersection of the enthalpy line of the enthalpy (h1) of the first refrigerant and the isotherm of the temperature (T2) of the second refrigerant. A pressure of the second refrigerant equal to the evaporation pressure (LP2) of (22) is calculated. Then, the saturation temperature calculation unit (113) calculates a pressure equivalent saturation temperature of the pressure of the second refrigerant equal to the evaporation pressure (LP2) of the indoor heat exchanger (22) calculated by the evaporation pressure calculation unit (115), The temperature is derived as the evaporation temperature of the indoor heat exchanger (22).

-Effect of Embodiment 1-
According to the first embodiment, the evaporation pressure (LP1) of the first and second refrigeration heat exchangers (32, 42) and the first and second refrigeration heat exchangers (32) of the evaporation pressure regulating valve (3). , 42) the first refrigerant enthalpy (h1) calculated from the first refrigerant temperature (T1), and the second refrigerant temperature on the indoor heat exchanger (22) side of the evaporation pressure regulating valve (3). From this, the evaporation pressure (LP2) of the indoor heat exchanger (22) was calculated. Therefore, the evaporation pressure (LP2) of the indoor heat exchanger (22) can be calculated without providing a pressure sensor that detects the evaporation pressure of the indoor heat exchanger (22). That is, the evaporation pressure and the evaporation temperature of each use side heat exchanger can be derived without providing a pressure sensor for each use side heat exchanger as in the conventional refrigeration apparatus. Therefore, the number of pressure sensors can be reduced in the refrigeration apparatus (1) including the refrigerant circuit (2) in which a plurality of usage-side heat exchangers that evaporate at different temperatures are connected in parallel. Therefore, the possibility of adverse effects on the environment in which the refrigeration apparatus (1) is installed can be reduced. Also, the temperature sensor is less expensive than the pressure sensor, is easy to replace, and has a low failure rate. By using the temperature sensor instead of the pressure sensor, the entire device can be configured at low cost and replaced. It can be performed easily and inexpensively.

    Further, according to the first embodiment, the pressure derivation mechanism for deriving the evaporation pressure of the first and second refrigeration heat exchangers (32, 42) is constituted by the suction pressure sensor (92). Here, the low-pressure pressure, which is the detected value of the suction pressure sensor (92), is adjusted so that the refrigerant evaporates at different temperatures in each use side heat exchanger (22, 32, 42) as described above. It is used not only for controlling 3) but also for capacity control of the first to third compressors (13a, 13b, 13c) and for adjusting the opening degree of the supercooling expansion valve (78). As described above, the number of pressure sensors can be further reduced by using the pressure sensor (92) for detecting the low-pressure pressure, which is also used for other applications, for controlling the evaporation pressure regulating valve (3).

    By the way, for example, if the different temperature evaporation control unit (132) controls the operation of the evaporation pressure adjusting valve (3) based on the evaporation temperature of the indoor heat exchanger (22), the indoor heat exchanger (22) In the accommodated indoor casing (20a), the evaporation temperature of the indoor heat exchanger (22) is detected, and the detected temperature is converted into data, and then the different temperature evaporation controller (132) provided in the outdoor casing (10a). ) Need to be sent. That is, it is necessary to provide a device for transmitting and receiving the evaporation temperature of the indoor heat exchanger (22) in the outdoor casing (10a).

    However, according to the first embodiment, the different temperature evaporation control unit (132) includes the first refrigerant and the second refrigerant before and after the evaporation pressure (LP1) of the first refrigerant and the evaporation pressure regulating valve (3) in the superheated region. Since the evaporating pressure (LP2) of the second refrigerant is calculated using the refrigerant temperatures (T1, T2), each sensor and different temperature evaporating control unit required for controlling the operation of the evaporating pressure regulating valve (3) (132) and all of the calculation units (114, 115) can be accommodated in the outdoor casing (10a). Therefore, a means for easily installing sensors and transmitting / receiving detection data such as temperature between the outdoor casing (10a) and the indoor casing (20a) in which the indoor heat exchanger (22) is accommodated is provided. There is no need to provide it. Therefore, the entire apparatus can be configured inexpensively and easily.

    Further, according to the first embodiment, the temperature sensor (96) that detects the temperature (T1) of the first refrigerant and the temperature sensor (97) that detects the temperature (T2) of the second refrigerant include the evaporation pressure adjusting valve ( It is provided at a position close to 3). Here, when the installation positions of the temperature sensor (96) for detecting the temperature (T1) of the first refrigerant and the temperature sensor (97) for detecting the temperature (T2) of the second refrigerant are separated, for example, evaporating pressure When the temperature sensor (96) on the downstream side of the regulating valve (3) is installed at a position away from the evaporation pressure regulating valve (3), the refrigerant reduced in the evaporation pressure regulating valve (3) is, for example, outdoor heat Since the enthalpy is absorbed by passing through the vicinity of the exchanger (12) and the enthalpy rises, when passing near the temperature sensor on the downstream side of the evaporation pressure adjusting valve (3), the upstream of the evaporation pressure adjusting valve (3) The value may be higher than the enthalpy of the refrigerant on the side. In such a case, the evaporation pressure (LP2) of the indoor heat exchanger (22) cannot be accurately calculated. However, as described above, since the two temperature sensors (96, 97) are provided close to each other with the evaporation pressure regulating valve (3) interposed therebetween, the evaporation pressure (LP2) of the indoor heat exchanger (22) is reduced. It can be calculated accurately. Therefore, without providing a pressure sensor for detecting the evaporation pressure (LP2) of the indoor heat exchanger (22), the evaporation pressure (LP2) and evaporation of the indoor heat exchanger (22) using the temperature sensor (96,97). The temperature can be calculated accurately.

<< Embodiment 2 of the Invention >>
As shown in FIG. 5, the refrigeration apparatus of Embodiment 2 includes a first four-way switching valve (in the refrigerant circuit (2) of the refrigeration apparatus of Embodiment 1 instead of the suction pressure sensor (pressure sensor) (92)). A pressure sensor (98) is provided in the first gas pipe (62) that connects the fourth port of 18) and the first gas side shut-off valve (71).

    In Embodiment 2, the indoor heat exchanger (22) constitutes the first usage-side heat exchanger according to the present invention, while the first and second refrigeration heat exchangers (32, 42) are the first according to the present invention. 2 Construct a use side heat exchanger. Therefore, during the cooling and cooling operation, the refrigerant on the indoor heat exchanger (22) side of the evaporation pressure adjustment valve (3) becomes the first refrigerant, and the first and second refrigeration heat exchanges of the evaporation pressure adjustment valve (3). The refrigerant on the container (32, 42) side becomes the second refrigerant. The temperature sensor (97) provided in the first gas pipe (62) constitutes the first temperature sensor according to the present invention for detecting the temperature of the first refrigerant, and is provided in the second inflow branch pipe (55b). The temperature sensor (96) constitutes a second temperature sensor according to the present invention for detecting the temperature of the second refrigerant.

<controller>
In Embodiment 2, the first evaporating temperature deriving unit (111) of the evaporating temperature deriving unit (110) derives the evaporating temperature of the indoor heat exchanger (22) constituting the first usage side heat exchanger according to the present invention. Is configured to do. On the other hand, the second evaporating temperature deriving unit (112) of the evaporating temperature deriving unit (110) includes the first and second refrigeration heat exchangers (32, 42) constituting the second utilization side heat exchanger according to the present invention. The evaporating temperature is derived.

    Specifically, in the second embodiment, the first evaporation temperature deriving unit (111) derives the evaporation temperature of the indoor heat exchanger (22) based on the detected value of the pressure sensor (98). Here, the pressure detected by the pressure sensor (98) is equal to the evaporation pressure (first evaporation pressure) (LP2) of the indoor heat exchanger (22). Therefore, the first evaporating temperature deriving unit (111) includes a saturation temperature calculating unit (113) that calculates a pressure-equivalent saturation temperature from the pressure detected by the pressure sensor (98), and the saturation temperature calculating unit (113) The calculated temperature is derived as the evaporation temperature of the indoor heat exchanger (22).

    On the other hand, the second evaporating temperature deriving unit (112) includes the enthalpy calculating unit (first calculating unit) (114), the evaporating pressure calculating unit (second calculating unit) (115), and the saturation temperature calculating unit also in the second embodiment. Part (116).

    The enthalpy calculating unit (114) is configured so that the evaporation pressure (first evaporation pressure) of the indoor heat exchanger (22) detected by the pressure sensor (98) and the temperature sensor (97) are detected during the cooling / cooling operation. The enthalpy of the first refrigerant is calculated from the detected temperature (T2) of the first refrigerant. The evaporating pressure calculating unit (115) is configured so that, during the cooling / cooling operation, the enthalpy (h1) of the first refrigerant calculated by the enthalpy calculating unit (114) and the second refrigerant detected by the temperature sensor (96). The pressure of the second refrigerant is calculated from the temperature (T1). Here, since the pressure of the refrigerant does not change between the evaporation pressure regulating valve (3) and the first and second refrigeration heat exchangers (32, 42), the pressure of the second refrigerant is the first and second refrigeration. It becomes equal to the evaporation pressure (second evaporation pressure) (LP1) of the heat exchanger for use (32, 42). Therefore, the evaporation pressure calculation unit (115) calculates the pressure of the second refrigerant calculated as described above as the evaporation pressure (LP1) of the first and second refrigeration heat exchangers (32, 42). It is configured. The saturation temperature calculation unit (116) calculates a pressure equivalent saturation temperature from the evaporation pressure (LP1) of the first and second refrigeration heat exchangers (32, 42) calculated by the evaporation pressure calculation unit (115). .

    The second evaporating temperature deriving unit (112) includes the first and second refrigeration units derived by the enthalpy calculating unit (114), the evaporating pressure calculating unit (115), and the saturation temperature calculating unit (116) as described above. The saturation temperature corresponding to the evaporation pressure of the heat exchanger (32, 42) is derived as the evaporation temperature of the first and second refrigeration heat exchangers (32, 42).

    The operation control unit (130) includes a cooling / cooling operation execution unit (131) and a different temperature evaporation control unit (132). The cooling / cooling operation execution unit (131) controls various devices and various valves, and the outdoor heat exchanger (12) functions as a condenser in the refrigerant circuit (2), and all the use side heat exchangers (22, 32, 42) is configured to execute a cooling and cooling operation in which the refrigerant circulates so as to function as an evaporator. In addition, the different temperature evaporation control unit (132) is configured so that the refrigerant has different temperatures in the indoor heat exchanger (22) and the first and second refrigeration heat exchangers (32, 42) during the cooling and cooling operation. The opening of the evaporation pressure adjusting valve (3) is adjusted to evaporate. Specifically, the different temperature evaporation control unit (132) is configured such that the evaporation temperature of the indoor heat exchanger (22) derived by the first evaporation temperature deriving unit (111) is equal to the second evaporation temperature deriving unit (112). The degree of opening of the evaporating pressure adjusting valve (3) is adjusted so as to be higher by a predetermined temperature than the evaporating temperature of the first and second refrigeration heat exchangers (32, 42) derived from.

<Derivation of evaporation temperature>
With the configuration as described above, in the refrigeration apparatus (1) of Embodiment 2, the evaporation temperature is derived as follows.

    The evaporating temperature deriving section (110) of the controller (100) derives the evaporating temperatures of the indoor heat exchanger (22) and the first and second refrigeration heat exchangers (32, 42) during the cooling and cooling operation. To do.

    First, the evaporation temperature of the indoor heat exchanger (22) is derived by the first evaporation temperature deriving unit (111) of the controller (100). The first evaporating temperature deriving unit (111) corresponds to the pressure by the saturation temperature calculating unit (113) from the pressure of the first refrigerant equal to the evaporating pressure (LP2) of the indoor heat exchanger (22) detected by the pressure sensor (98). The saturation temperature is calculated, and the saturation temperature is derived as the evaporation temperature of the indoor heat exchanger (22).

    Next, the evaporation temperature of the first and second refrigeration heat exchangers (32, 42) is derived by the second evaporation temperature deriving unit (112) of the controller (100). Specifically, the pressure and temperature sensor (97) of the first refrigerant equal to the evaporation pressure (LP2) of the indoor heat exchanger (22) detected by the pressure sensor (98) is first detected by the enthalpy calculation unit (114). The enthalpy (h1) of the first refrigerant is calculated from the detected temperature (T2) of the first refrigerant. Specifically, as shown in the Ph diagram of FIG. 4, the first refrigerant enthalpy (from the intersection of the first refrigerant pressure (LP2) isobaric line and the first refrigerant temperature (T2) isotherm ( h1) is calculated. Then, from the temperature (T1) of the second refrigerant detected by the temperature sensor (96) and the enthalpy (h1) of the first refrigerant calculated by the enthalpy calculation unit (114) by the evaporation pressure calculation unit (115). The pressure of the second refrigerant is calculated. Here, usually, only the pressure drops while the enthalpy is kept constant before and after the throttling like the pressure regulating valve. That is, the enthalpy of the second refrigerant flowing out of the evaporation pressure adjusting valve (3) is equal to the enthalpy (h1) of the first refrigerant flowing out of the indoor heat exchanger (22) and flowing into the evaporation pressure adjusting valve (3). . Therefore, the pressure of the second refrigerant flowing out of the evaporation pressure regulating valve (3) from the enthalpy (h1) of the first refrigerant and the temperature (T1) of the second refrigerant, that is, the first and second refrigeration heat exchangers (32 , 42) can be obtained. Specifically, as shown in the Ph diagram of FIG. 4, the second refrigerant is determined from the intersection of the isoenthalpy of the enthalpy (h1) of the first refrigerant and the isotherm of the temperature (T1) of the second refrigerant. The pressure is calculated. Then, the saturation temperature calculator (113) calculates the pressure of the second refrigerant equal to the evaporation pressure (LP1) of the first and second refrigeration heat exchangers (32, 42) calculated by the evaporation pressure calculator (115). A pressure-equivalent saturation temperature is calculated, and the temperature is derived as the evaporation temperature of the first and second refrigeration heat exchangers (32, 42).

    As described above, also in the second embodiment, the evaporation pressure (LP2) of the indoor heat exchanger (22) having a high evaporation temperature among the plurality of use side heat exchangers that evaporate at different temperatures is derived by the pressure sensor (98). By detecting the refrigerant temperature (T1, T2) before and after the evaporation pressure regulating valve (3), the evaporation pressure (LP1) of the first and second refrigeration heat exchangers (32, 42) having a low evaporation temperature can be easily achieved. Can be calculated. That is, also in Embodiment 2, the evaporation pressure and the evaporation temperature of each use side heat exchanger can be derived without providing a pressure sensor for each use side heat exchanger as in the conventional refrigeration apparatus. Therefore, the number of pressure sensors can be reduced in the refrigeration apparatus (1) including the refrigerant circuit (2) in which a plurality of usage-side heat exchangers that evaporate at different temperatures are connected in parallel. Therefore, the possibility of adverse effects on the environment in which the refrigeration apparatus (1) is installed can be reduced. Also, the temperature sensor is less expensive than the pressure sensor, is easy to replace, and has a low failure rate. By using the temperature sensor instead of the pressure sensor, the entire device can be configured at low cost and replaced. It can be performed easily and inexpensively.

<< Embodiment 3 of the Invention >>
As shown in FIG. 6, the refrigeration apparatus of Embodiment 3 is similar to the refrigeration apparatus of Embodiment 1 except that the second indoor unit (150), the second evaporating pressure regulating valve (143), the bypass passage (144), and the third temperature sensor. (146) and a fourth temperature sensor (147) are added. Only the parts different from the first embodiment will be described below.

    The second indoor unit (150) is provided with an indoor circuit (151) as a utilization side circuit having a second indoor heat exchanger (152) constituting the third utilization side heat exchanger according to the present invention. . On the other hand, one end of the second gas pipe (63) is connected to the middle part of the first gas pipe (62) in the outdoor circuit (11) of the outdoor unit (10). The other end of the second gas pipe (63) is connected to the third gas side shut-off valve (64). The gas side end of the indoor circuit (151) is connected to the third gas side shut-off valve (64) of the outdoor circuit (11) via the third gas side connecting pipe (141), and the liquid side of the indoor circuit (151) The end is connected to the middle part of the first liquid side connecting pipe (52) via the third liquid side connecting pipe (142).

<Second indoor unit>
The second indoor unit (150) is installed indoors and includes the indoor circuit (151) and an indoor casing (150a) that houses the indoor circuit (151). The indoor circuit (151) is provided with a second indoor heat exchanger (152), an indoor expansion valve (expansion mechanism) (153), and a filter (154) in this order from the gas side end. The second indoor heat exchanger (152) is configured by a cross fin type fin-and-tube heat exchanger, and an indoor fan (152a) is provided in the vicinity thereof. The indoor fan (152a) is accommodated in the indoor casing (150a) together with the indoor circuit (151). In the second indoor heat exchanger (152), heat is exchanged between the refrigerant flowing inside and the indoor air blown by the indoor fan (152a). In addition, an indoor temperature sensor (152b) for detecting the temperature of the indoor air is provided in the vicinity of the second indoor heat exchanger (152). The indoor expansion valve (153) is an electronic expansion valve whose opening degree can be adjusted.

<Second evaporation pressure regulating valve, bypass passage>
The second evaporation pressure adjusting valve (143) is provided in the third gas side communication pipe (141). The second evaporating pressure regulating valve (143) is configured so that the refrigerant evaporates at different temperatures in the second indoor heat exchanger (152) and the indoor heat exchanger (22) during the cooling cooling operation described later. The evaporation pressure of the indoor heat exchanger (152) is adjusted. Further, a bypass passage (144) that bypasses the second evaporation pressure regulating valve (143) is connected to the third gas side communication pipe (141). The bypass passage (144) is provided with a check valve (145). The check valve (145) allows the refrigerant to flow from the outdoor unit (10) side of the bypass passage (144) toward the second indoor unit (150), and prevents the refrigerant from flowing in the reverse direction.

<Temperature sensor>
The temperature sensor (third temperature sensor) (146) is provided on the indoor heat exchanger (22) side of the second evaporation pressure regulating valve (143) of the third gas side communication pipe (141). On the other hand, the temperature sensor (fourth temperature sensor) (147) is provided on the second indoor heat exchanger (152) side of the second evaporation pressure regulating valve (143) of the third gas side communication pipe (141). Yes. These two temperature sensors (146, 147) are for detecting the temperatures of the refrigerant on the upstream side and the downstream side of the second evaporating pressure regulating valve (143), respectively, during the cooling cooling operation described later. The temperature is used to calculate the evaporation pressure of the second indoor heat exchanger (152).

<controller>
The controller (100) receives the detection values of the various sensors described above and controls the operation of the refrigeration apparatus (1) by controlling various devices (various valves, various fans, etc.) based on the detection values. is there.

    As shown in FIG. 7, the controller (100) includes an evaporation temperature deriving unit (110) for deriving the evaporation temperature of each use side heat exchanger (22, 32, 42, 152) and all the use side heat exchangers (22 , 32, 42, 152) function as an evaporator, and the indoor heat exchanger (22), the second indoor heat exchanger (152), and the first and second refrigeration heat exchangers (32, 42) have different refrigerants. And an operation control unit (130) that executes a cooling and cooling operation that evaporates at a temperature.

    The evaporation temperature deriving unit (110) constitutes the third usage-side heat exchanger according to the present invention in addition to the first evaporation temperature deriving unit (111) and the second evaporation temperature deriving unit (112) of the first embodiment. A third evaporation temperature deriving unit (117) for deriving the evaporation temperature of the second indoor heat exchanger (152) is provided.

    The third evaporating temperature deriving unit (117) includes an enthalpy calculating unit (third calculating unit) (118), an evaporating pressure calculating unit (fourth calculating unit) (119), and a saturation temperature calculating unit (120). ing. Hereinafter, the refrigerant on the indoor heat exchanger (second use side heat exchanger) (22) side of the second evaporation pressure adjusting valve (143) is referred to as a third refrigerant, and the second evaporation pressure adjusting valve (143) The refrigerant on the second indoor heat exchanger (third use side heat exchanger) (152) side will be described as the fourth refrigerant.

    The enthalpy calculation unit (118) is configured to calculate the indoor heat exchanger (22) calculated by the evaporation pressure calculation unit (second calculation unit) (115) of the second evaporation temperature deriving unit (112) during the cooling / cooling operation. ) Evaporation pressure (second evaporation pressure) and the temperature of the third refrigerant detected by the temperature sensor (146), the enthalpy of the third refrigerant is calculated. The evaporating pressure calculating unit (119) is configured to calculate the enthalpy of the third refrigerant calculated by the enthalpy calculating unit (118) and the temperature of the fourth refrigerant detected by the temperature sensor (147) during the cooling / cooling operation. The pressure of the fourth refrigerant is calculated. Here, since the pressure of the refrigerant does not change between the second evaporation pressure regulating valve (143) and the second indoor heat exchanger (152), the pressure of the fourth refrigerant is the same as that of the second indoor heat exchanger (152). It becomes equal to the evaporation pressure (fourth evaporation pressure). Therefore, the evaporation pressure calculation unit (119) is configured to calculate the pressure of the fourth refrigerant calculated as described above as the evaporation pressure of the second indoor heat exchanger (152). The saturation temperature calculation unit (120) calculates a pressure equivalent saturation temperature from the evaporation pressure of the second indoor heat exchanger (152) calculated by the evaporation pressure calculation unit (119).

    The third evaporating temperature deriving unit (117) includes the second indoor heat exchanger (118) derived by the enthalpy calculating unit (118), the evaporating pressure calculating unit (119), and the saturation temperature calculating unit (120) as described above. The saturation temperature corresponding to the evaporation pressure of 152) is derived as the evaporation temperature of the second indoor heat exchanger (152).

    The operation control unit (130) includes a cooling / cooling operation execution unit (131) and a different temperature evaporation control unit (132). The cooling / cooling operation execution unit (131) controls various devices and valves, and the outdoor heat exchanger (12) functions as a condenser in the refrigerant circuit (2), and all the use side heat exchangers (22, 152, 32, 42) is configured to execute a cooling and cooling operation in which the refrigerant circulates so as to function as an evaporator. Further, the different temperature evaporation control unit (132) is configured so that the indoor heat exchanger (22), the first and second refrigeration heat exchangers (32, 42), and the second indoor The opening degree of the evaporating pressure adjusting valve (3) and the second evaporating pressure adjusting valve (143) is adjusted so that the refrigerant evaporates at different temperatures in the heat exchanger (152) and the indoor heat exchanger (22). It is configured. Specifically, the different temperature evaporation control unit (132) is configured such that the evaporation temperature of the indoor heat exchanger (22) derived by the second evaporation temperature deriving unit (112) is the first evaporation temperature deriving unit (111). The degree of opening of the evaporating pressure adjusting valve (3) is adjusted so as to be higher by a predetermined temperature than the evaporating temperature of the first and second refrigeration heat exchangers (32, 42) derived from. The different temperature evaporation control unit (132) is configured so that the evaporation temperature of the second indoor heat exchanger (152) derived by the third evaporation temperature deriving unit (117) is the same as that of the second evaporation temperature deriving unit (112). The opening degree of the second evaporating pressure adjusting valve (143) is adjusted so that the evaporating temperature of the derived indoor heat exchanger (22) is higher by a predetermined temperature.

-Driving action-
In the refrigeration apparatus (1), as described above, the cooling / cooling operation execution unit (131) of the operation control unit (130) of the controller (100) causes the indoor unit (20) and the second unit in the refrigerant circuit (2). A cooling operation is performed in which the room is cooled by the two indoor units (150) and the interior of the refrigerator is cooled by the refrigeration units (30, 40). Specifically, as shown by a thick line in FIG. 6, in the refrigerant circuit (2), the heat source side heat exchanger (12) functions as a condenser, while all the use side heat exchangers (22, 152, 32, 42). ) Circulates so that it functions as an evaporator, and a vapor compression refrigeration cycle as shown in FIG. 8 is performed.

    The different temperature evaporation control unit (132) is configured such that the evaporation temperature of the indoor heat exchanger (22) derived by the second evaporation temperature deriving unit (112) is the first temperature derived by the first evaporation temperature deriving unit (111). And the opening degree of the evaporating pressure adjusting valve (3) is adjusted so as to be higher by a predetermined temperature than the evaporating temperature of the second refrigeration heat exchanger (32, 42). The different temperature evaporation control unit (132) is configured so that the evaporation temperature of the second indoor heat exchanger (152) derived by the third evaporation temperature deriving unit (117) is the same as that of the second evaporation temperature deriving unit (112). The opening degree of the second evaporating pressure adjusting valve (143) is adjusted so as to be higher than the evaporating temperature of the derived indoor heat exchanger (22) by a predetermined temperature.

    The refrigerant circulates in the refrigerant circuit (2) by controlling the various devices and valves by the operation control unit (130) as described above. The refrigerant is circulated in such a way that a part of the liquid refrigerant flowing into the first liquid side connecting pipe (52) passes through the second indoor unit (150) and the first gas pipe (62) of the outdoor unit (10). Since it is the same as in Embodiment 1 except that it flows into the refrigerant and merges with the refrigerant from the indoor unit (20), the description thereof is omitted.

    A part of the liquid refrigerant flowing into the third liquid side connecting pipe (142) from the first liquid side connecting pipe (52) is decompressed by the indoor expansion valve (153), and then the second indoor heat exchanger (152). Into the air and absorbs heat from the room air to evaporate. As a result, room air is cooled. The opening degree of the indoor expansion valve (153) is adjusted to a predetermined opening degree based on the detected value of the indoor temperature sensor (152b) and the indoor set temperature. For example, the opening degree of the indoor expansion valve (153) is adjusted so that the detected value of the indoor temperature sensor (152b) becomes a desired temperature (for example, 20 ° C.). The refrigerant evaporated in the second indoor heat exchanger (152) flows into the third gas side communication pipe (141) and is further depressurized in the second evaporation pressure adjusting valve (143). It flows into the first gas pipe (62).

    The opening degree of the second evaporation pressure regulating valve (143) was derived by the third evaporation temperature deriving unit (117) by the different temperature evaporation control unit (132) of the operation control unit (130) as described above. The evaporation temperature of the second indoor heat exchanger (152) is adjusted to be higher than the evaporation temperature of the indoor heat exchanger (22) derived by the second evaporation temperature deriving unit (112) by a predetermined temperature.

    The refrigerant from the second indoor unit (150) that has flowed into the first gas pipe (62) flows from the indoor unit (20) that has flowed into the first gas pipe (62) via the first gas side communication pipe (51). It merges with the refrigerant. Then, the refrigerant merged in the first gas pipe (62) passes through the first four-way switching valve (18) and flows into the communication pipe (57), and is further depressurized in the evaporation pressure adjusting valve (3). Then, it flows into the second inflow branch pipe (55b) of the suction pipe (55) through the second four-way switching valve (19).

    The opening degree of the evaporation pressure adjusting valve (3) is determined by the indoor heat derived by the second evaporation temperature deriving unit (112) by the different temperature evaporation control unit (132) of the operation control unit (130) as described above. The evaporating temperature of the exchanger (22) is adjusted to be higher by a predetermined temperature than the evaporating temperature of the first and second refrigeration heat exchangers (32, 42) derived by the first evaporating temperature deriving unit (111). Is done. Other refrigerant flows are the same as those in the first embodiment.

    As described above, in the cooling and cooling operation, in the same manner as in the first embodiment, the indoor heat exchanger (22) of the indoor circuit (21) and the first and second refrigeration circuits are controlled by the evaporation pressure regulating valve (3). The evaporating pressure of the refrigerant differs between the (31, 41) first and second refrigeration heat exchangers (32, 42). As a result, the refrigerant evaporates at different temperatures in the indoor heat exchanger (22) and the first and second refrigeration heat exchangers (32, 42). In the cooling and cooling operation, the second evaporation pressure regulating valve (143) causes the indoor heat exchanger (22) of the indoor circuit (21) and the second indoor heat exchanger (152) of the indoor circuit (151) to The evaporating pressure of the refrigerant is different. Specifically, the evaporation pressure of the second indoor heat exchanger (152) becomes higher than the evaporation pressure of the indoor heat exchanger (22). As a result, the refrigerant evaporates at different temperatures in the second indoor heat exchanger (152) and the indoor heat exchanger (22). Specifically, the evaporation temperature of the second indoor heat exchanger (152) is higher than the evaporation temperature of the indoor heat exchanger (22). For example, the evaporation temperature of the second indoor heat exchanger (152) is + 10 ° C. Thus, the evaporation temperature of the indoor heat exchanger (22) becomes + 5 ° C.

<Derivation of evaporation temperature>
The evaporating temperature deriving unit (110) of the controller (100) performs the first and second refrigeration heat exchangers (32, 42), the indoor heat exchanger (22), and the second indoor heat during the cooling and cooling operation. Deriving the evaporation temperature of the exchanger (152). The method for deriving the evaporation temperatures of the first and second refrigeration heat exchangers (32, 42) and the indoor heat exchanger (22) is the same as that in the first embodiment, and hence the second indoor heat exchanger will be described below. A method for deriving the evaporation temperature (152) will be described.

    The evaporation temperature of the second indoor heat exchanger (152) is derived by the third evaporation temperature deriving unit (117) of the controller (100). Specifically, first, it is equal to the evaporation pressure (LP2) of the indoor heat exchanger (22) calculated by the evaporation pressure calculation unit (115) of the second evaporation temperature deriving unit (112) by the enthalpy calculation unit (118). The enthalpy (h2) of the third refrigerant is calculated from the pressure of the second refrigerant and the temperature (T3) of the third refrigerant detected by the temperature sensor (146). Specifically, as shown in the Ph diagram of FIG. 8, an isobar of the pressure of the second refrigerant equal to the evaporation pressure (LP2) of the indoor heat exchanger (22) and the temperature (T3) of the third refrigerant. The enthalpy (h2) of the third refrigerant is calculated from the intersection with the isotherm. Then, from the temperature (T4) of the fourth refrigerant detected by the temperature sensor (147) and the enthalpy (h2) of the third refrigerant calculated by the enthalpy calculation unit (118) by the evaporation pressure calculation unit (119). The pressure of the fourth refrigerant is calculated. Here, usually, only the pressure drops while the enthalpy is kept constant before and after the throttling like the pressure regulating valve. That is, the enthalpy of the fourth refrigerant before flowing out of the second indoor heat exchanger (152) and flowing into the second evaporation pressure adjusting valve (143) is the third enthalpy flowing out of the second evaporation pressure adjusting valve (143). Equal to the enthalpy (h2) of the refrigerant. Therefore, the fourth refrigerant flowing out of the second indoor heat exchanger (152) from the enthalpy (h2) of the third refrigerant and the temperature (T4) of the fourth refrigerant and flowing into the second evaporating pressure regulating valve (143). The pressure, that is, the evaporation pressure (LP3) of the second indoor heat exchanger (152) can be obtained. Specifically, as shown in the Ph diagram of FIG. 8, the fourth refrigerant flows from the intersection of the isoenthalpy of the enthalpy (h2) of the third refrigerant and the isotherm of the temperature (T4) of the fourth refrigerant. The pressure is calculated. Then, the saturation temperature calculation unit (120) calculates the pressure equivalent saturation temperature from the pressure of the fourth refrigerant equal to the evaporation pressure (LP3) of the second indoor heat exchanger (152) calculated by the evaporation pressure calculation unit (119). The temperature is derived as the evaporation temperature of the second indoor heat exchanger (152).

    As described above, according to the third embodiment, the evaporation pressure (LP2) of the indoor heat exchanger (22) and the temperature (T3) of the third refrigerant on the indoor heat exchanger (22) side of the second evaporation pressure regulating valve (143). ) And the temperature (T4) of the fourth refrigerant on the second indoor heat exchanger (152) side of the second evaporating pressure regulating valve (143) from the enthalpy (h2) of the third refrigerant calculated from The evaporation pressure (LP3) of the heat exchanger (152) was calculated. Therefore, the evaporation pressure (LP3) of the second indoor heat exchanger (152) can be calculated without providing a pressure sensor for detecting the evaporation pressure (LP3) of the second indoor heat exchanger (152).

<< Embodiment 4 of the Invention >>
As shown in FIG. 9, the refrigeration apparatus of Embodiment 4 is similar to the refrigeration apparatus of Embodiment 2 except that the third refrigeration unit (170), the third evaporating pressure regulating valve (163), the temperature sensor (166), and the temperature sensor (167 ). Only the parts different from the second embodiment will be described below.

    The third refrigeration unit (170) includes a third refrigeration circuit (171) as a utilization side circuit having a third refrigeration heat exchanger (172) constituting the fourth utilization side heat exchanger according to the present invention. Is provided. The gas side end of the third refrigeration circuit (171) is connected to the middle part of the second gas side communication pipe (53) by the fourth gas side communication pipe (161), and the liquid in the third refrigeration circuit (171) The side end is connected to the middle part of the second liquid side connecting pipe (54) by the fourth liquid side connecting pipe (162).

<Third refrigeration unit>
The third refrigeration unit (170) includes a third refrigeration circuit (171) and a refrigerated showcase (170a) that accommodates the third refrigeration circuit (171). The third refrigeration circuit (171) is provided with a third refrigeration heat exchanger (172), an in-chamber expansion valve (173), and an electromagnetic valve (174) in this order from the gas side end. The third refrigeration heat exchanger (172) is constituted by a cross fin type fin-and-tube heat exchanger, and an internal fan (172a) is provided in the vicinity thereof. The internal fan (172a) is housed in the refrigerated showcase (170a) together with the third refrigeration circuit (171). In the third refrigeration heat exchanger (172), heat is exchanged between the refrigerant flowing inside and the air inside the refrigerated showcase (170a) blown by the internal fan (172a). Further, in the vicinity of the third refrigeration heat exchanger (172), an internal temperature sensor (172b) for detecting the temperature of the internal air is provided. The internal expansion valve (173) is a temperature-sensitive expansion valve, and a temperature-sensitive cylinder is attached to the gas side of the third refrigeration heat exchanger (172). That is, the internal expansion valve (173) is based on the refrigerant temperature on the outlet side of the third refrigeration heat exchanger (172) when the third refrigeration heat exchanger (172) functions as an evaporator. The opening is adjusted.

<Third evaporation pressure control valve>
The third evaporation pressure adjusting valve (163) is provided in the fourth gas side communication pipe (161). The third evaporating pressure regulating valve (163) allows the refrigerant to flow in the first and second refrigeration heat exchangers (32, 42) and the third refrigeration heat exchanger (172) during the cooling cooling operation described later. The evaporation pressure of the third refrigeration heat exchanger (172) is adjusted so as to evaporate at different temperatures.

<Temperature sensor>
The temperature sensor (fifth temperature sensor) (166) is provided on the refrigeration heat exchanger (31, 41) side of the third evaporation pressure regulating valve (163) of the fourth gas side communication pipe (161). . On the other hand, the temperature sensor (sixth temperature sensor) (167) is provided on the third refrigeration heat exchanger (172) side of the third evaporation pressure regulating valve (163) of the fourth gas side communication pipe (161). ing. These two temperature sensors (166, 167) detect the temperatures of the refrigerant on the upstream side and the downstream side of the third evaporating pressure regulating valve (163), respectively, during the cooling cooling operation described later. The temperature is used to calculate the evaporation pressure of the third refrigeration heat exchanger (172).

<controller>
The controller (100) receives the detection values of the various sensors described above and controls the operation of the refrigeration apparatus (1) by controlling various devices (various valves, various fans, etc.) based on the detection values. is there.

    As shown in FIG. 10, the controller (100) includes an evaporation temperature deriving unit (110) for deriving the evaporation temperature of each use side heat exchanger (22, 32, 42, 172), and all the use side heat exchangers (22 , 32, 42, 172) function as an evaporator, and refrigerant is generated in the indoor heat exchanger (22), the first and second refrigeration heat exchangers (32, 42), and the third refrigeration heat exchanger (172). And an operation control unit (130) that executes a cooling and cooling operation that evaporates at different temperatures.

    The said evaporating temperature derivation | leading-out part (110) is replaced with the 3rd evaporating temperature derivation | leading-out part (117) of Embodiment 2, The 3rd refrigeration heat exchanger (172 which comprises the 4th utilization side heat exchanger which concerns on this invention) (172) ) Has a fourth evaporation temperature deriving section (121) for deriving the evaporation temperature.

    The fourth evaporation temperature deriving unit (121) includes an enthalpy calculation unit (fifth calculation unit) (122), an evaporation pressure calculation unit (sixth calculation unit) (123), and a saturation temperature calculation unit (124). ing. In the following, the refrigerant on the first and second refrigeration heat exchangers (first use side heat exchangers) (32, 42) side of the third evaporation pressure regulating valve (163) is referred to as a fifth refrigerant, The refrigerant on the third refrigeration heat exchanger (fourth use side heat exchanger) (172) side of the evaporation pressure regulating valve (163) will be described as the sixth refrigerant.

    The enthalpy calculation unit (122) includes the first and second refrigeration calculated by the evaporation pressure calculation unit (second calculation unit) (115) of the second evaporation temperature deriving unit (112) during the cooling and cooling operation. The enthalpy of the fifth refrigerant is calculated from the evaporation pressure (second evaporation pressure) of the heat exchanger (32, 42) and the temperature of the fifth refrigerant detected by the temperature sensor (166). . The evaporating pressure calculating unit (123), based on the enthalpy of the fifth refrigerant calculated by the enthalpy calculating unit (122) and the temperature of the sixth refrigerant detected by the temperature sensor (167) during the cooling and cooling operation. The pressure of the sixth refrigerant is calculated. Here, since the pressure of the refrigerant does not change between the third evaporation pressure regulating valve (163) and the third refrigeration heat exchanger (172), the pressure of the sixth refrigerant is the third refrigeration heat exchanger (172 ) Evaporation pressure (fourth evaporation pressure). Therefore, the evaporation pressure calculation unit (123) is configured to calculate the pressure of the sixth refrigerant calculated as described above as the evaporation pressure of the third refrigeration heat exchanger (172). The saturation temperature calculation unit (124) calculates a pressure equivalent saturation temperature from the evaporation pressure of the third refrigeration heat exchanger (172) calculated by the evaporation pressure calculation unit (123).

    The fourth evaporating temperature deriving unit (121) includes a third refrigeration heat exchanger derived by the enthalpy calculating unit (122), the evaporating pressure calculating unit (123), and the saturation temperature calculating unit (124) as described above. The saturation temperature corresponding to the evaporation pressure of (172) is derived as the evaporation temperature of the third refrigeration heat exchanger (172).

    The operation control unit (130) includes a cooling / cooling operation execution unit (131) and a different temperature evaporation control unit (132). The cooling / cooling operation execution unit (131) controls various devices and various valves, and the outdoor heat exchanger (12) functions as a condenser in the refrigerant circuit (2), and all the use side heat exchangers (22, 32, 42, and 172) are configured to perform a cooling and cooling operation in which the refrigerant circulates so as to function as an evaporator. Further, the different temperature evaporation control unit (132) is configured so that, during the cooling and cooling operation, the indoor heat exchanger (22) and the first and second refrigeration heat exchangers (32, 42), In the second refrigeration heat exchanger (32, 42) and the third refrigeration heat exchanger (172), the evaporating pressure adjusting valve (3) and the third evaporating pressure adjusting valve ( 163) is configured to adjust the opening degree. Specifically, the different temperature evaporation control unit (132) is configured such that the evaporation temperature of the indoor heat exchanger (22) derived by the first evaporation temperature deriving unit (111) is equal to the second evaporation temperature deriving unit (112). The degree of opening of the evaporating pressure adjusting valve (3) is adjusted so as to be higher than the evaporating temperature of the first and second refrigeration heat exchangers (32, 42) derived from The different temperature evaporation control unit (132) is configured such that the evaporation temperature of the third refrigeration heat exchanger (172) derived by the fourth evaporation temperature deriving unit (121) is equal to the second evaporation temperature deriving unit (112). The degree of opening of the third evaporating pressure regulating valve (163) is adjusted so as to be higher by a predetermined temperature than the evaporating temperature of the first and second refrigeration heat exchangers (32, 42) derived from.

-Driving action-
In the refrigeration apparatus (1), as described above, the cooling / cooling operation execution unit (131) of the operation control unit (130) of the controller (100) causes the indoor unit (20) to A cooling cooling operation is performed in which the interior is cooled by the first to third refrigeration units (30, 40, 170). Specifically, as shown by a thick line in FIG. 9, in the refrigerant circuit (2), the heat source side heat exchanger (12) functions as a condenser, while all the use side heat exchangers (22, 32, 42, 172). ) Circulates so as to function as an evaporator, and a vapor compression refrigeration cycle as shown in FIG. 11 is performed.

    The different temperature evaporation control unit (132) is configured such that the evaporation temperature of the indoor heat exchanger (22) derived by the first evaporation temperature deriving unit (111) is the first temperature derived by the second evaporation temperature deriving unit (112). And the opening degree of the evaporating pressure adjusting valve (3) is adjusted so as to be higher by a predetermined temperature than the evaporating temperature of the second refrigeration heat exchanger (32, 42). The different temperature evaporation control unit (132) is configured such that the evaporation temperature of the third refrigeration heat exchanger (172) derived by the fourth evaporation temperature deriving unit (121) is equal to the second evaporation temperature deriving unit (112). The degree of opening of the third evaporating pressure regulating valve (163) is adjusted so as to be higher by a predetermined temperature than the evaporating temperature of the first and second refrigeration heat exchangers (32, 42) derived from.

    The refrigerant circulates in the refrigerant circuit (2) by controlling the various devices and valves by the operation control unit (130) as described above. In addition, the circulation of the refrigerant is such that a part of the liquid refrigerant flowing into the second liquid side connection pipe (54) passes through the third refrigeration unit (170) and flows into the second gas side connection pipe (53). Since it is the same as that of Embodiment 1 except for joining with the refrigerant from the first and second refrigeration units (30, 40), the description thereof is omitted.

    A part of the liquid refrigerant flowing into the fourth liquid side connecting pipe (162) from the second liquid side connecting pipe (54) is depressurized by the internal expansion valve (173), and then the third refrigeration heat exchanger ( 172) and absorbs heat from the internal air to evaporate. As a result, the internal air is cooled. The refrigerant evaporated in the third refrigeration heat exchanger (172) flows into the fourth gas side communication pipe (161) and is further depressurized in the third evaporation pressure adjusting valve (163), and then the second gas side communication. It flows into the pipe (53).

    The opening degree of the third evaporation pressure regulating valve (163) is derived by the fourth evaporation temperature deriving unit (121) by the different temperature evaporation control unit (132) of the operation control unit (130) as described above. The evaporation temperature of the third refrigeration heat exchanger (172) is a predetermined temperature higher than the evaporation temperatures of the first and second refrigeration heat exchangers (32, 42) derived by the second evaporation temperature deriving unit (112). Adjusted to be higher.

    The refrigerant from the third refrigeration unit (170) flowing into the second gas side communication pipe (53) merges with the refrigerant from the first and second refrigeration units (30, 40). And the refrigerant | coolant merged in the 2nd gas side connection piping (53) flows in into the 1st inflow branch pipe (55a) of a suction piping (55), after passing through the 2nd gas side closing valve (73).

    As described above, in the cooling and cooling operation, as in the second embodiment, the indoor heat exchanger (22) of the indoor circuit (21) and the first and second refrigeration circuits are controlled by the evaporation pressure regulating valve (3). The evaporating pressure of the refrigerant differs between the (31, 41) first and second refrigeration heat exchangers (32, 42). As a result, the refrigerant evaporates at different temperatures in the indoor heat exchanger (22) and the first and second refrigeration heat exchangers (32, 42). In the cooling / cooling operation, the third evaporating pressure regulating valve (163) and the first and second refrigeration heat exchangers (32, 42) of the first and second refrigeration circuits (31, 41) The evaporation pressure of the refrigerant is different from that of the third refrigeration heat exchanger (172) of the three refrigeration circuits (171). Specifically, the evaporation pressure of the third refrigeration heat exchanger (172) is higher than the evaporation pressure of the first and second refrigeration heat exchangers (32, 42). As a result, the refrigerant evaporates at different temperatures in the third refrigeration heat exchanger (172) and the first and second refrigeration heat exchangers (32, 42). Specifically, the evaporation temperature of the third refrigeration heat exchanger (172) is higher than the evaporation temperatures of the first and second refrigeration heat exchangers (32, 42). For example, the third refrigeration heat exchange The evaporation temperature of the vessel (172) is −5 ° C., and the evaporation temperature of the first and second refrigeration heat exchangers (32, 42) is −10 ° C.

<Derivation of evaporation temperature>
The evaporating temperature deriving unit (110) of the controller (100) is configured so that the second indoor heat exchanger (152), the first and second refrigeration heat exchangers (32, 42), and the first 3. Evaporation temperature of the refrigeration heat exchanger (172) is derived. The method for deriving the evaporation temperature of the indoor heat exchanger (22) and the first and second refrigeration heat exchangers (32, 42) is the same as that of the second embodiment. A method for deriving the evaporation temperature of the vessel (172) will be described.

    The evaporation temperature of the third refrigeration heat exchanger (172) is derived by the fourth evaporation temperature deriving unit (121) of the controller (100). Specifically, first, the enthalpy calculation unit (122) calculates the first and second refrigeration heat exchangers (32, 42) calculated by the evaporation pressure calculation unit (115) of the second evaporation temperature derivation unit (112). The enthalpy (h3) of the fifth refrigerant is calculated from the pressure of the second refrigerant equal to the evaporation pressure (LP1) and the temperature (T5) of the fifth refrigerant detected by the temperature sensor (166). Specifically, as shown in the Ph diagram of FIG. 11, the enthalpy of the fifth refrigerant (from the intersection of the isobaric line of the pressure (LP1) of the fifth refrigerant and the isotherm of the temperature (T5) of the fifth refrigerant) h3) is calculated. Then, from the temperature (T6) of the sixth refrigerant detected by the temperature sensor (167) and the enthalpy (h3) of the fifth refrigerant calculated by the enthalpy calculation unit (122) by the evaporation pressure calculation unit (123). The pressure of the sixth refrigerant is calculated. Here, usually, only the pressure drops while the enthalpy is kept constant before and after the throttling like the pressure regulating valve. In other words, the enthalpy of the sixth refrigerant before flowing out of the third refrigeration heat exchanger (172) and flowing into the third evaporation pressure regulating valve (163) is the third enthalpy flowing out of the third evaporation pressure regulating valve (163). Equal to 5 refrigerant enthalpies (h3). Therefore, the sixth refrigerant flows out of the third refrigeration heat exchanger (172) from the enthalpy (h3) of the fifth refrigerant and the temperature (T6) of the sixth refrigerant and flows into the third evaporation pressure regulating valve (163). That is, the evaporation pressure (LP4) of the third refrigeration heat exchanger (172) can be obtained. Specifically, as shown in the Ph diagram of FIG. 11, the sixth refrigerant is determined from the intersection of the isoenthalpy of the enthalpy (h3) of the fifth refrigerant and the isotherm of the temperature (T6) of the sixth refrigerant. The pressure is calculated. Then, the saturation temperature calculation unit (124) calculates the pressure equivalent saturation temperature from the pressure of the sixth refrigerant equal to the evaporation pressure (LP4) of the third refrigeration heat exchanger (172) calculated by the evaporation pressure calculation unit (123). The temperature is calculated and derived as the evaporation temperature of the third refrigeration heat exchanger (172).

    As described above, according to the fourth embodiment, the evaporation pressure (LP1) of the first and second refrigeration heat exchangers (32, 42) and the first and second refrigeration heats of the third evaporation pressure regulating valve (163). The enthalpy (h3) of the fifth refrigerant calculated from the temperature (T5) of the fifth refrigerant on the exchanger (32, 42) side, and the third refrigeration heat exchanger (172) of the third evaporation pressure regulating valve (163) The evaporation pressure (LP4) of the third refrigeration heat exchanger (172) is calculated from the temperature (T6) of the sixth refrigerant on the) side. Therefore, the evaporation pressure (LP4) of the third refrigeration heat exchanger (172) can be calculated without providing a pressure sensor for detecting the evaporation pressure (LP4) of the third refrigeration heat exchanger (172). .

<< Other Embodiments >>
About the said embodiment, it is good also as the following structures.

    In each said embodiment, although the refrigerant circuit (2) was comprised in the circuit which can switch between cooling and heating in an indoor unit (20,150), the circuit in which only cooling is possible may be sufficient.

    Further, the number of use side heat exchangers according to the present invention is not limited to those of the above embodiments. Two or more may be sufficient if it is plurality, and five or more may be sufficient.

    Further, in each of the above embodiments, the plurality of use side heat exchangers are configured by the indoor heat exchanger for air conditioning and the heat exchanger for refrigeration, but all of them are the heat exchanger for refrigeration or the indoor heat for air conditioning. It may be configured by an exchanger so that a plurality of use side heat exchangers evaporate at different temperatures.

    In each said embodiment, although the pressure derivation mechanism based on this invention was comprised by the pressure sensor, a pressure derivation mechanism is not restricted to a pressure sensor. For example, an evaporation temperature may be detected using a temperature sensor, and the evaporation pressure may be derived from the detected value.

    In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

    As described above, the present invention is useful for a refrigeration apparatus including a refrigerant circuit in which a plurality of usage-side heat exchangers that evaporate at different temperatures are connected in parallel to each other.

1 Refrigeration equipment
2 Refrigerant circuit
3 Evaporation pressure adjustment valve (first evaporation pressure adjustment valve)
10a Outdoor casing (heat source side casing)
12 Outdoor heat exchanger (heat source side heat exchanger)
13 Compression mechanism
23 Indoor expansion valve (expansion mechanism)
22 Indoor heat exchanger (2nd use side heat exchanger, 1st use side heat exchanger)
32 1st refrigeration heat exchanger (1st use side heat exchanger, 2nd use side heat exchanger)
33 Chamber expansion valve (expansion mechanism)
42 2nd refrigeration heat exchanger (1st utilization side heat exchanger, 2nd utilization side heat exchanger)
43 Chamber expansion valve (expansion mechanism)
92 Suction pressure sensor (pressure derivation mechanism, pressure sensor)
96 Temperature sensor (first temperature sensor)
97 Temperature sensor (second temperature sensor)
98 Pressure sensor (pressure derivation mechanism, pressure sensor)
114 Enthalpy calculation unit (first calculation unit)
115 Evaporation pressure calculation unit (second calculation unit)
118 Enthalpy calculation unit (third calculation unit)
119 Evaporation pressure calculation unit (fourth calculation unit)
122 Enthalpy calculator (fifth calculator)
123 Evaporation pressure calculation unit (sixth calculation unit)
132 Different temperature evaporation control unit (valve control unit)
143 Second evaporation pressure adjusting valve 146 Temperature sensor (third temperature sensor)
147 Temperature sensor (4th temperature sensor)
152 2nd indoor heat exchanger (3rd use side heat exchanger)
163 Third evaporation pressure regulating valve 166 Temperature sensor (fifth temperature sensor)
167 Temperature sensor (6th temperature sensor)
172 Third refrigeration heat exchanger (fourth use side heat exchanger)

Claims (7)

The compression mechanism (13), the heat source side heat exchanger (12), the expansion mechanism (23, 33, 43), and at least the first and second usage side heat exchangers (22, 32, 42) are connected in parallel to each other. A refrigerant circuit (2) having a plurality of usage-side heat exchangers (22, 32, 42) and a first temperature-evaporating first and second usage-side heat exchangers (22, 32, 42). A refrigeration apparatus comprising an evaporation pressure regulating valve (3),
A pressure deriving mechanism (92) for deriving the first evaporation pressure (LP1) of the first use side heat exchanger (32, 42);
A first temperature sensor (96) for detecting a temperature (T1) of the first refrigerant on the first use side heat exchanger (32, 42) side of the first evaporation pressure regulating valve (3);
A second temperature sensor (97) for detecting the temperature (T2) of the second refrigerant on the second use side heat exchanger (22) side of the first evaporation pressure regulating valve (3);
From the first evaporating pressure (LP1) derived by the pressure deriving mechanism (92) and the temperature (T1) of the first refrigerant detected by the first temperature sensor (96), the enthalpy (h1) of the first refrigerant. A first calculation unit (114) for calculating
From the enthalpy (h1) of the first refrigerant calculated by the first calculation unit (114) and the temperature (T2) of the second refrigerant detected by the second temperature sensor (97), the second use side heat exchange is performed. And a second calculation unit (115) for calculating the second evaporation pressure (LP2) of the vessel (22). In claim 1,
The pressure derivation mechanism (92) includes a pressure sensor (92) that detects a first evaporation pressure (LP1) of the first usage-side heat exchanger (32, 42),
Based on the first evaporation pressure (LP1) by the pressure sensor (92) and the second evaporation pressure (LP2) by the second calculation unit (115), the first and second usage side heat exchangers (22, 32, 42) a valve control unit (132) for controlling the operation of the first evaporation pressure regulating valve (3) so that the different temperature evaporates;
The heat source side heat exchanger (12), the first evaporation pressure adjusting valve (3), the pressure sensor (92), the first calculation unit (114), the second calculation unit (115), and the valve control unit (132) and a heat source side casing (10a) in which is housed,
The refrigeration apparatus, wherein the first temperature sensor (96) and the second temperature sensor (97) are provided in the heat source side casing (10a). In claim 1 or 2,
The refrigeration apparatus, wherein the first temperature sensor (96) and the second temperature sensor (97) are provided in the vicinity of the first evaporation pressure regulating valve (3). In any one of Claims 1 thru | or 3,
The first evaporation pressure regulating valve (3) is configured to exchange the second usage-side heat exchange between the gas side end of the second usage-side heat exchanger (22) and the suction side end of the compression mechanism (13). The second evaporation pressure (LP2) of the second use side heat exchanger (22) so that the evaporation temperature of the heat exchanger (22) is higher than the evaporation temperature of the first use side heat exchanger (32, 42). A refrigeration apparatus configured to be adjusted. In any one of Claims 1 thru | or 3,
The first evaporating pressure regulating valve (3) is configured to exchange the first usage side heat exchange between the gas side end of the first usage side heat exchanger (22) and the suction side end of the compression mechanism (13). The first evaporation pressure (LP2) of the first use side heat exchanger (22) so that the evaporation temperature of the heat exchanger (22) is higher than the evaporation temperature of the second use side heat exchanger (32, 42). A refrigeration apparatus configured to be adjusted. In claim 4,
The refrigerant circuit (2) further includes a third usage side heat exchanger (152),
The evaporation temperature of the third usage side heat exchanger (152) is between the gas side end of the third usage side heat exchanger (152) and the inflow side end of the first evaporation pressure regulating valve (3). A second evaporation pressure adjusting valve (143 that adjusts the third evaporation pressure (LP3) of the third use side heat exchanger (152) so as to be higher than the evaporation temperature of the second use side heat exchanger (22). )When,
A third temperature sensor (146) for detecting the temperature (T3) of the third refrigerant on the second use side heat exchanger (22) side of the second evaporation pressure regulating valve (143);
A fourth temperature sensor (147) for detecting the temperature (T4) of the fourth refrigerant on the third usage side heat exchanger (152) side of the second evaporation pressure regulating valve (143);
From the second evaporation pressure (LP2) calculated by the second calculation unit (115) and the temperature (T3) of the third refrigerant detected by the third temperature sensor (146), the enthalpy (h2) of the third refrigerant is calculated. ) To calculate a third calculation unit (118);
From the enthalpy (h2) of the third refrigerant calculated by the third calculator (118) and the temperature (T4) of the fourth refrigerant detected by the fourth temperature sensor (147), the third use side heat exchange is performed. And a fourth calculation unit (119) for calculating a third evaporation pressure (LP3) of the vessel (152). In claim 5,
The refrigerant circuit (2) further includes a fourth usage side heat exchanger (172),
A midway portion between the gas side end of the second usage side heat exchanger (32, 42) and the suction side end of the compression mechanism (13), and the gas side end of the fourth usage side heat exchanger (172) The fourth usage side heat exchanger (172) so that the evaporation temperature of the fourth usage side heat exchanger (172) is higher than the evaporation temperature of the second usage side heat exchanger (32, 42). 172) a third evaporation pressure adjusting valve (163) for adjusting the fourth evaporation pressure (LP4);
A fifth temperature sensor (166) for detecting a temperature (T5) of the fifth refrigerant on the second use side heat exchanger (32, 42) side of the third evaporation pressure regulating valve (163);
A sixth temperature sensor (167) for detecting the temperature (T6) of the sixth refrigerant on the fourth use side heat exchanger (172) side of the third evaporation pressure regulating valve (163);
From the second evaporation pressure (LP1) calculated by the second calculation unit (115) and the temperature (T5) of the fifth refrigerant detected by the fifth temperature sensor (166), the enthalpy (h3) of the fifth refrigerant is calculated. ) To calculate a fifth calculation unit (122);
From the enthalpy (h3) of the fifth refrigerant calculated by the fifth calculator (122) and the temperature (T6) of the sixth refrigerant detected by the sixth temperature sensor (167), the fourth use side heat exchange is performed. And a sixth calculating section (123) for calculating a fourth evaporation pressure (LP4) of the vessel (172).

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