WO2007020885A1

WO2007020885A1 - Refrigerating apparatus

Info

Publication number: WO2007020885A1
Application number: PCT/JP2006/315914
Authority: WO
Inventors: Masaaki Takegami; Azuma Kondo; Kenji Tanimoto
Original assignee: Daikin Industries, Ltd.
Priority date: 2005-08-15
Filing date: 2006-08-11
Publication date: 2007-02-22
Also published as: TWI314983B; EP1916487A1; AU2006280834A1; CN101243294A; JP3982548B2; KR100912161B1; CN101243294B; KR20080025419A; TW200720608A; US20090077985A1; JP2007078338A

Abstract

A refrigerating apparatus comprising a refrigerant return mechanism (5) for returning a liquid refrigerant in a receiver (17) to a circulation route. Accordingly, the liquid refrigerant in the receiver (17) can be forcibly returned to the circulation route in such an operating state that the circulation route for the refrigerant is formed to return the refrigerant fed from compression mechanisms (11D, 11E) from a second use side unit (20) to the compression mechanisms (11D, 11E) through first use side units (30, 40).

Description

Specification

Refrigeration equipment

Technical field

TECHNICAL FIELD [0001] The present invention relates to a refrigeration apparatus, and in particular, a refrigeration apparatus having a plurality of use side heat exchanges for refrigeration / freezing and air conditioning, and capable of performing 100% heat recovery operation between each use side heat exchange. Is related to the position.

Background art

Conventionally, a refrigeration apparatus that performs a refrigeration cycle is known. This refrigeration apparatus is widely used as an air conditioner for cooling and heating a room and a refrigerator for a showcase for refrigeration / freezing food. Some of these refrigeration apparatuses perform both air conditioning and refrigeration / freezing (see, for example, Patent Document 1). This refrigeration unit is installed in a convenience store, for example, and it is possible to cool the air conditioner and the showcase in the store by installing only one refrigeration unit.

[0003] The refrigeration apparatus is provided in a use side unit such as a refrigeration / refrigeration showcase or an air conditioning indoor unit! / Several use side heat exchangers (refrigeration / refrigeration heat exchangers) And heat exchange for air conditioning) are parallel to the heat source side heat exchange (outdoor heat exchanger) of the heat source side unit (outdoor unit) installed outdoors, respectively, and the liquid side communication pipe and gas side communication pipe Connected by.

[0004] Here, when the refrigerant circuit has two systems of the first system side circuit for refrigeration and freezing and the second system side circuit for air conditioning, it is usually connected to each of the liquid line and the gas line. Two are used. On the other hand, there is also one in which two liquid lines share one liquid side connecting pipe to reduce the number of connecting pipes (see Patent Document 2).

[0005] Specifically, the refrigerant circuit of this apparatus is configured as shown in FIG. In the figure, (101) is an outdoor unit, (102) is an indoor unit, (103) is a refrigerated showcase (refrigerated unit), and (104) is a refrigerated showcase (refrigerated unit). The outdoor unit (101) is provided with a compression mechanism (105, 106), an outdoor heat exchanger (107), an outdoor expansion valve (108), and a receiver (109), and the indoor unit (102) has an indoor heat exchanger (air conditioner). Heat exchange (110) and indoor An expansion valve (111) is provided. The refrigeration showcase (103) is provided with a refrigeration heat exchanger (112) and a refrigeration expansion valve (113), and the refrigeration showcase (104) is provided with a refrigeration heat exchanger (114) and a refrigeration expansion valve (113). Expansion valve (115) and booster compressor (116) are provided.

[0006] The refrigerant circuit (120) of the refrigeration apparatus is configured such that the refrigerant circulates in the negative direction between the outdoor heat exchanger (107) and the refrigeration / refrigeration heat exchanger (112, 114). A first system side circuit for refrigeration and freezing, and a second system side circuit for air conditioning configured so that refrigerant circulates reversibly between the outdoor heat exchange (107) and the indoor heat exchange (110). It has. And one liquid side connecting pipe (121) is shared as the liquid line of each system.

[0007] In the above refrigeration system, the outdoor heat exchanger (107) installed outdoors can be used as a heat source to perform indoor air conditioning and cooling of each showcase, and without using the outdoor heat exchanger (107). In addition, it is possible to operate with 100% heat recovery for heating, refrigeration and freezing using indoor heat exchange (110) as a condenser and heat exchange for refrigeration and freezing (112, 114) as an evaporator. .

By the way, when performing a 100% heat recovery operation in the configuration of the refrigerant circuit (120) in which the liquid side communication pipe (121) is single, the refrigerant discharged from the compression mechanism (105, 106) The refrigerant circuit (120) forms a refrigerant circulation path that condenses in the indoor heat exchanger (110), evaporates in the refrigeration / refrigeration heat exchanger (112, 114), and returns to the compression mechanism (105, 106). Is done. In other words, at this time, the liquid refrigerant condensed in the indoor heat exchanger (110) does not flow from the receiver (109) to the heat source side heat exchanger (107), but instead of the refrigerated heat exchanger (112, 114).

[0009] However, for example, when the outside air temperature is low, the pressure in the receiver (109) decreases, so the pressure in the liquid side communication pipe (121) also decreases, and the liquid refrigerant from the indoor heat exchanger (110) becomes liquid side. There is a risk that the flow rate of refrigerant flowing to the refrigeration heat storage (l 12, 114) will be insufficient because it tends to flow into the receiver (109) from the communication pipe (121). If the refrigerant flow rate of the refrigerated heat exchanger (112, 114) is insufficient, the ability to cool the interior of each showcase (103, 104) will be reduced.

[0010] Therefore, in the refrigeration apparatus, the relief valve (117) is provided in the refrigerant passage from the liquid side communication pipe (121) to the receiver (109). This relief knob (117) is connected to the liquid side connecting pipe (12 This valve opens when the refrigerant pressure in 1) rises above a predetermined value, but remains closed until it reaches the predetermined value. The operating pressure of the relief valve (117) is set to a pressure higher than the pressure of the liquid side connecting pipe (121) during the 100% heat recovery operation, so that the liquid refrigerant is received by the receiver (109 ), And the refrigerant flow in the refrigerant circuit (120) is stabilized even at low outside temperatures so that the refrigeration capacity does not decrease.

[0011] It should be noted that in the above refrigeration apparatus, the outdoor heat exchanger (107) is capable of heating the refrigeration cycle where the evaporator serves as an evaporator. In that case, the relief valve (117) has a suction pressure of the compressor (106). In order to act, the relief valve (117) opens. During cooling operation, the refrigerant should not flow through the passage with the relief valve (117)! /.

Patent Document 1: Japanese Patent Laid-Open No. 2001-280749

Patent Document 2: JP-A-2005-134103

Disclosure of the invention

Problems to be solved by the invention

[0012] By the way, in the above-described apparatus, there are cases where the inflow of the refrigerant to the receiver cannot be completely prevented even when the relief valve is closed. Specifically, this is a case where refrigerant leaks at the relief valve. In this case, the refrigerant gradually flows into the receiver, and during the 100% heat recovery operation, almost no refrigerant flows out of the receiver. While the amount of refrigerant inside increases, there is a shortage of refrigerant in the refrigeration / freezing heat exchanger, which is the user side unit. The problem is that the ability to cool the interior of each showcase is reduced. Such a problem occurs similarly even when a valve mechanism (for example, a solenoid valve) of a type different from the relief valve is provided. Regardless of the type of valve mechanism, it is difficult to completely eliminate refrigerant leakage when a relatively high-pressure refrigerant is applied.

[0013] In addition, even when it is desired to prevent the refrigerant from flowing into the receiver, the relief valve may open due to excessively high refrigerant pressure acting on the relief valve. In this case, too, the relief valve may enter the receiver. If the refrigerant flows more than necessary, the ability to cool the interior of each showcase will be reduced due to the lack of refrigerant as described above.

[0014] The present invention has been made in view of the strong point, and an object of the present invention is to provide a refrigeration system in which a plurality of utilization side heat exchanges are provided, and a plurality of liquid lines share a single liquid side communication pipe. In the device, the shortage of refrigerant in the usage-side unit due to an increase in the amount of refrigerant in the receiver is prevented.

Means for solving the problem

[0015] The first invention includes a heat source side unit (10) having a compression mechanism (11D, 11E), a heat source side heat exchanger (15), and a receiver (17), and a first use side heat exchanger (31 , 41), a first user-side unit (30, 40) having a second user-side heat exchanger (21), a second user-side unit (20), and each unit (10, 20, 30, 40) is connected to the gas side connecting pipe (51, 52) and the liquid side connecting pipe (53, 54, 55) to form the refrigerant circuit (50). Includes a first gas side communication pipe (51) connected to the heat source side unit (10) and the first usage side unit (30, 40), the heat source side unit (10) and the second usage side. A second gas side connecting pipe (52) connected to the unit (20), and the liquid side connecting pipe (53, 54, 55) is connected to the heat source side pipe (10). Collected liquid pipe (53) and branched from the collected liquid pipe (53) to contact the first use side unit (30, 40). A first branch liquid pipe (54) and a second branch liquid pipe (55) branched from the collecting liquid pipe (53) and connected to the second usage side unit (20). For the device (1). In the refrigerant circuit (50), the refrigerant sent out from the compression mechanism (11D, 11E) flows through the second usage side unit (20), the first usage side unit (30, 40), and the compression mechanism. A refrigerant circulation path returning to (11D, 11E) can be formed, and a refrigerant return mechanism (5) for returning the liquid refrigerant in the receiver (17) to the circulation path is provided.

[0016] In a second invention according to the first invention, the refrigerant return mechanism (5) introduces the high-pressure refrigerant discharged from the compression mechanism (11D, 11E) into the receiver (17). An introduction pipe (71) is provided, and the liquid refrigerant in the receiver (17) is reduced by introducing the high-pressure refrigerant from the introduction pipe (71) into the receiver (17) and pressurizing the receiver (17). It returns to the circulation path through the collecting liquid pipe (53).

[0017] A third invention is the communication pipe (67) according to the first invention, wherein the refrigerant return mechanism (5) communicates the receiver (17) with the suction side of the compression mechanism (11D, 11E). ), The liquid refrigerant in the receiver (17) is sucked into the compression mechanism (11D, 11E) through the communication pipe (67) and returned to the circulation path.

[0018] In a fourth aspect based on the first aspect, the refrigerant return mechanism (5) includes the heat source side heat exchange. A communication mechanism (13) for communicating the receiver (17) to the discharge side of the compression mechanism (11D, 11E) via a container (15), and the receiver (17) Is connected to the discharge side of the compression mechanism (11D, 11E), and the high-pressure refrigerant discharged from the compression mechanism (11D, 11E) is caused to flow into the receiver (17), thereby liquid refrigerant in the receiver (17) Is returned to the circulation path through the collecting liquid pipe (53).

[0019] A fifth invention is directed to any one of the first to fourth inventions, from the first use side heat exchanger (31, 41) to the suction side of the compression mechanism (11D, 11E). Refrigerant in the receiver (17) when the detected value of the suction superheat degree detection means (79, 81) and the suction superheat degree detection means (79, 81) exceeds a predetermined value. Control means (95) for controlling the refrigerant return mechanism (5) so as to return the refrigerant to the circulation path.

[0020] A sixth aspect of the present invention is directed to any one of the first to fourth aspects of the present invention, wherein the superheat degree detecting means (75, 11) detects the superheat degree of the refrigerant discharged by the compression mechanism (11D, 11E). 76) and the refrigerant return mechanism (5) to return the refrigerant in the receiver (17) to the circulation path when the detected value of the discharge superheat degree detection means (75, 76) exceeds a predetermined value. And a control means (95) for controlling.

[0021] The seventh invention is the discharge refrigerant temperature detection means (76) for detecting the temperature of the refrigerant discharged by the compression mechanism (11D, 11E) in any one of the first to fourth inventions. Control means (95) for controlling the refrigerant return mechanism (5) to return the refrigerant in the receiver (17) to the circulation path when the detected value of the discharged refrigerant temperature detection means (76) becomes a predetermined value or more. ).

[0022] The eighth invention includes a heat source side unit (10) having a compression mechanism (11D, 11E), a heat source side heat exchanger (15), and a receiver (17), and a first use side heat exchanger (31 , 41), a first user-side unit (30, 40) having a second user-side heat exchanger (21), a second user-side unit (20), and each unit (10, 20, 30, 40) is connected to the gas side connecting pipe (51, 52) and the liquid side connecting pipe (53, 54, 55) to form the refrigerant circuit (50). Includes a first gas side communication pipe (51) connected to the heat source side unit (10) and the first usage side unit (30, 40), the heat source side unit (10) and the second usage side. A second gas side connecting pipe (52) connected to the unit (20), and the liquid side connecting pipe (53, 54, 55) is connected to the heat source side pipe. A collecting liquid pipe (53) connected to the first (10), and a first branch liquid pipe (54) branched from the collecting liquid pipe (53) and connected to the first use side unit (30, 40). And a second branch liquid pipe (55) branched from the collecting liquid pipe (53) and connected to the second usage side unit (20). Then, the refrigerant sent from the compression mechanism (11D, 11E) is supplied to the refrigerant circuit (50) by the second usage side unit (20) from the second usage side unit (20). A first operation mode that flows through the side unit (30, 40) and returns to the compression mechanism (11D, 11E), and the compression mechanism (1 ID, 11E) force is sent from the heat source side heat exchanger (15). There is provided a mechanism (12) for switching between the second operation mode that flows into the receiver (17) and then flows through the first user side unit (30, 40) and returns to the compression mechanism (11D, 11 E). The mechanism (12) switches from the first operation mode to the second operation mode, and the liquid refrigerant accumulated in the receiver (17) during the first operation mode passes through the collecting liquid pipe (53). 1 Return to the user unit (30, 40).

[0023] One action

In the first invention, the refrigerant sent out by the compression mechanism (11D, 11E) flows from the second usage side unit (20) through the first usage side unit (30, 40) to the compression mechanism (11D, 11E). In an operating state in which a circulation path for the returning refrigerant is formed, the liquid refrigerant in the receiver (17) can be forcibly returned to the circulation path by the refrigerant return mechanism (5). That is, as described above, there is a case where the refrigerant flows into the receiver (17) even if it tries to prevent the refrigerant from flowing into the receiver (17). In such a case, the refrigerant amount in the circulation path decreases. However, in the first invention, the liquid refrigerant in the receiver (17) is returned to the circulation path by the refrigerant return mechanism (5).

[0024] In the second invention, when returning the liquid refrigerant in the receiver (17) to the circulation path, the high-pressure gas refrigerant discharged from the compression mechanism (11D, 11E) is introduced into the receiver (71) by the introduction pipe (71). 17). When a high-pressure gas refrigerant is introduced into the receiver (17), the internal pressure rises and the liquid refrigerant inside is pushed out. Then, the liquid refrigerant whose receiver (17) force is also pushed out is returned to the circulation path through the collecting liquid pipe (53). As a result, in the receiver (17), the ratio of the gas refrigerant having a low density increases, and the ratio of the liquid refrigerant having a high density decreases. Then, the amount of refrigerant in the receiver (17) decreases, and the amount of refrigerant in the circulation path increases. In the third invention, when returning the liquid refrigerant in the receiver (17) to the circulation path, the communication pipe (67) connects the receiver (17) to the suction side of the compression mechanism (11D, 11E). . When the receiver (17) communicates with the suction side of the compression mechanism (11D, 11E), the liquid refrigerant inside is sucked into the compression mechanism (11D, 11E). As a result, the liquid refrigerant in the receiver (17) is forcibly returned to the circulation path, the refrigerant amount in the receiver (17) is decreased, and the refrigerant quantity in the circulation path is increased.

In the fourth invention, when returning the liquid refrigerant in the receiver (17) to the circulation path, the communication mechanism (13) causes the receiver (17) to be compressed via the heat source side heat exchanger (15). The high-pressure gas refrigerant discharged from the compression mechanism (11D, 11E) is communicated with the discharge side of 11D, 11E) and flows into the receiver (17). When a high-pressure gas refrigerant flows in the receiver (17), the interior of the receiver (17) is pressurized and the liquid refrigerant is pushed out, as in the second aspect of the invention. Then, the liquid refrigerant pushed out from the receiver (17) is returned to the circulation path through the collecting liquid pipe (53). As a result, the amount of refrigerant in the receiver (17) decreases and the amount of refrigerant in the circulation path increases.

[0027] The high-pressure gas refrigerant discharged from the compression mechanism (11D, 11E) is introduced into the receiver (17) through the heat source side heat exchanger (15). In the fourth aspect of the invention, the heat source side heat exchange (15) is used as a flow path for introducing the high-pressure gas refrigerant discharged from the compression mechanism (11D, 11E) to the receiver (17).

[0028] In the fifth invention, when the degree of superheat of the refrigerant directed from the first use side heat exchanger (31, 41) to the suction side of the compression mechanism (11D, 11E) becomes equal to or greater than a predetermined value, the refrigerant return mechanism The liquid refrigerant in the receiver (17) is returned to the circulation path by (5). By the way, in the first usage-side heat exchanger (31, 41), the smaller the refrigerant flow rate, the smaller the region where the gas-liquid two-phase refrigerant flows and the larger the region where the single-phase gas refrigerant flows. 1 The degree of superheat of the refrigerant flowing out from the use side heat exchanger (31, 41) increases. In other words, the superheat degree of the refrigerant flowing out from the first usage side heat exchanger (31, 41) reflects the refrigerant flow rate of the first usage side heat exchanger (31, 41), so that the suction superheat degree detection means If the detected value of (79, 81) is used, it is determined appropriately whether or not the first usage-side heat exchanger (31, 41) has insufficient power.

[0029] In the sixth invention, when the superheat degree of the refrigerant discharged from the compression mechanism (11D, 11E) exceeds a predetermined value, the liquid refrigerant in the receiver (17) is returned to the circulation path by the refrigerant return mechanism (5). It is doing so. By the way, as described above, the refrigerant flow rate of the first usage side heat exchanger (31, 41) is small. The higher the degree of superheat of the refrigerant that flows out from the first use side heat exchanger (31, 41) and is sucked into the compression mechanism (11D, 11E). As the degree of superheat of the refrigerant sucked into the compression mechanism (11D, 11E) increases, the degree of superheat of the refrigerant discharged from the compression mechanism (11D, 11E) also increases. In other words, the superheat degree of the refrigerant discharged from the compression mechanism (11D, 11E) reflects the refrigerant flow rate of the first usage side heat exchanger (31, 41), so the discharge superheat degree detecting means (75, 76) If the detected value is used, it is determined appropriately whether or not the refrigerant is deficient in the first use side heat exchange (31, 41).

[0030] In the seventh invention, when the temperature of the refrigerant discharged from the compression mechanism (11D, 11E) exceeds a predetermined value, the refrigerant in the receiver (17) is returned to the circulation path by the refrigerant return mechanism (5). I have to. By the way, as described above, the smaller the refrigerant flow rate in the first usage side heat exchanger (31, 41), the greater the degree of superheat of the refrigerant discharged from the compression mechanism (11D, 11E). And if the degree of superheat of the refrigerant is large, the temperature becomes high. That is, the temperature of the refrigerant discharged by the compression mechanism (11D, 11E) reflects the refrigerant flow rate of the first usage-side heat exchanger (31, 41), and therefore the discharge refrigerant temperature detection means (76) If the detected value is used, whether or not the refrigerant is insufficient in the first usage-side heat exchanger (31, 41) is appropriately determined.

[0031] In the eighth invention, when the liquid refrigerant accumulates in the receiver (17) during the first operation mode, the operation state is switched from the first operation mode to the second operation mode by the mechanism (12). The In the _second operation mode, as in the fourth invention, the high-pressure gas refrigerant discharged from the compression mechanism (11D, 11E) flows into the receiver (17) and pressurizes the interior thereof. The liquid refrigerant accumulated inside is pushed out. Then, the liquid coolant from which the receiver (17) force is also pushed out is returned to the first usage side unit (30, 40) through the collecting liquid pipe (53).

The invention's effect

[0032] In the present invention, the liquid refrigerant in the receiver (17) is removed by the refrigerant return mechanism (5) in the operation state in which the circulation path is formed in which the refrigerant amount decreases when the refrigerant flows into the receiver (17). It is possible to return to the circulation path. When the liquid refrigerant in the receiver (17) is returned to the circulation path, the amount of refrigerant flowing through each use side unit (20, 30, 40) increases. Therefore, before the refrigerant runs short in each user side unit (20, 30, 40), the liquid refrigerant in the receiver (17) is returned to the circulation path by the refrigerant return mechanism (5). (30, 40) can prevent the shortage of cooling medium, and the temperature adjustment capability of each user side unit (20, 30, 40) is reduced. Can be avoided.

[0033] Further, in the third invention, when the liquid refrigerant in the receiver (17) is returned to the circulation path, the compression mechanism (11D, 11E) sucks the liquid refrigerant in the receiver (17). The suction superheat degree of the compression mechanism (11D, 11 E) is lowered. Accordingly, the refrigerant can be returned to the circulation path to eliminate the refrigerant shortage, and at the same time, the suction superheat degree can be suppressed and the input of the compression mechanism (11D, 11E) can be reduced.

[0034] In the fourth invention, the refrigerant circuit (50) has a refrigeration cycle as a flow path for introducing the high-pressure gas refrigerant discharged from the compression mechanism (11D, 11E) into the receiver (17). Oh! / Utilizes heat source side heat exchange (15) that functions as an evaporator or condenser. That is, a part of the configuration of the refrigeration apparatus (1) is used as the refrigerant return mechanism (5). Therefore, the configuration of the refrigeration apparatus (1) having the refrigerant return mechanism (5) can be simplified.

[0035] In the fifth aspect of the invention, whether or not the refrigerant is insufficient in the first usage-side heat exchanger (31, 41) is determined from the first usage-side heat exchanger (31, 41) by the compression mechanism ( 11D, 11E) Focusing on the ability to determine the superheat power of the refrigerant toward the suction side, the refrigerant return mechanism (5) is controlled based on the detection value of the suction superheat detection means (79, 81). Yes. Therefore, the liquid refrigerant in the receiver (17) can be returned to the circulation path at an appropriate timing before the first usage-side heat exchanger (31, 41) runs short of the refrigerant. A decrease in cooling capacity at (31, 41) can be reliably avoided.

[0036] In the sixth aspect of the present invention, whether or not the refrigerant is insufficient in the first usage-side heat exchanger (31, 41) is determined based on the degree of superheat power of the refrigerant discharged by the compression mechanism (11D, 11E). Focusing on the possibility, the refrigerant return mechanism (5) is controlled based on the detection value of the discharge superheat degree detection means (75, 76). Accordingly, the liquid refrigerant in the receiver (17) can be returned to the circulation path at an appropriate timing before the first usage-side heat exchanger (31, 41) runs short of the refrigerant. A decrease in cooling capacity at (31, 41) can be reliably avoided.

[0037] In the seventh aspect of the invention, it is possible to determine whether or not the first use-side heat exchanger (31, 41) has a shortage of refrigerant and whether the temperature force of the refrigerant discharged by the compression mechanism (11D, 11E) can be determined. Taking note of the above, the refrigerant return mechanism (5) is controlled based on the detected value of the discharged refrigerant temperature detecting means (76). Therefore, before the refrigerant runs out in the first usage side heat exchanger (31, 41), an appropriate Since the liquid refrigerant in the receiver (17) can be returned to the circulation path by the ming, it is possible to reliably avoid the cooling capacity reduction in the first usage side heat exchange (31, 41).

[0038] In the eighth aspect of the invention, by switching from the first operation mode to the second operation mode, the liquid refrigerant that has accumulated in the receiver (17) during the first operation mode is used as the first usage-side unit. It is possible to return to (3 0, 40). Therefore, according to the eighth aspect of the present invention, it is possible to prevent a shortage of the amount of refrigerant circulating between each use side unit (20, 30, 40) and the compression mechanism (11D, 11E) in the first operation mode. Therefore, it is possible to avoid a decrease in temperature adjustment capability in each of the use side units (20, 30, 40).

Brief Description of Drawings

FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a refrigerant circuit diagram showing the operation of the cooling operation in the first embodiment.

FIG. 3 is a refrigerant circuit diagram illustrating the operation of the refrigeration operation in the first embodiment.

FIG. 4 is a refrigerant circuit diagram showing the operation of the first cooling / freezing operation in the first embodiment.

FIG. 5 is a refrigerant circuit diagram showing the operation of the second cooling / freezing operation in the first embodiment.

FIG. 6 is a refrigerant circuit diagram showing an operation of heating operation in the first embodiment.

[Fig. 7] Fig. 7 is a refrigerant circuit diagram showing an operation in a state where the electromagnetic valve force S of the hot gas bypass pipe in the first heating / refrigeration operation in the first embodiment is closed.

FIG. 8 is a refrigerant circuit diagram illustrating an operation in which the solenoid valve of the hot gas bypass pipe in the first heating / refrigeration operation in the first embodiment is in an open state.

FIG. 9 is a refrigerant circuit diagram showing the operation of the second heating and refrigeration operation in Embodiment 1.

FIG. 10 is a refrigerant circuit diagram showing the operation of the third heating / refrigeration operation in the first embodiment.

FIG. 11 is a refrigerant circuit diagram of a refrigeration apparatus according to Embodiment 2 of the present invention.

FIG. 12 is a refrigerant circuit diagram of a refrigeration apparatus according to Embodiment 2 of the present invention.

FIG. 13 is a refrigerant circuit diagram of a conventional refrigeration apparatus. Explanation of symbols

1 Refrigeration equipment

5 Refrigerant return mechanism

10 Outdoor unit (heat source side unit)

11D compression mechanism

HE compression mechanism

13 Second four-way selector valve (communication mechanism)

15 Outdoor heat exchanger (heat source side heat exchanger)

17 Resino

20 Indoor unit (second user side unit)

21 Indoor heat exchanger (second-use heat exchanger)

30 Refrigeration unit (i-th use side unit)

31 Refrigerated heat exchanger (first use side heat exchanger)

40 Refrigeration unit (Unit No.1 side)

41 Refrigeration heat exchanger (first use side heat exchanger)

50 Refrigerant circuit

50A first system side circuit

50B Second system side circuit

51 1st gas side communication piping (gas side communication piping)

52 Second gas side communication piping (Gas side communication piping)

53 Collecting liquid pipe (Liquid side connecting pipe)

54 1st branch liquid pipe (liquid side connection pipe)

55 Second branch pipe (Liquid side connecting pipe)

67 Liquid Ink Pipe (Communication Pipe)

71 Hot gas bypass pipe (introduction pipe)

75 High pressure sensor (Discharge superheat detection means)

76 Discharge temperature sensor (Discharge superheat detection means, discharge refrigerant temperature detection means)

79 Low pressure sensor (Suction superheat detection means) 81 Suction temperature sensor (Suction superheat detection means)

95 Controller (Control means)

BEST MODE FOR CARRYING OUT THE INVENTION

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

[Embodiment 1 of the Invention]

Embodiment 1 of the present invention will be described. A refrigerant circuit diagram of the refrigeration system (1) according to Embodiment 1 is shown in FIG. This refrigeration apparatus (1) is provided in a convenience store for cooling a refrigerated showcase and a refrigerated showcase and for cooling and heating the store.

[0043] The refrigeration apparatus (1) includes an outdoor unit (heat source side unit) (10), an indoor unit (second usage side unit) (20), a refrigeration unit (first usage side unit) (30), and a refrigeration unit. (First use side unit) (40) and each unit (10, 20, 30, 40) is connected by gas side communication pipe (51, 52) and liquid side connection pipe (53, 54, 55) Thus, a refrigerant circuit (50) for performing a vapor compression refrigeration cycle is configured.

[0044] The gas side connecting pipe (51, 52) includes an outdoor unit (10), a refrigeration unit (30), and a refrigeration unit.

1st gas side communication pipe (low pressure gas pipe) (51) connected to (40) and 2nd gas side communication pipe (52) connected to outdoor unit (10) and indoor unit (20) It is composed of The liquid side communication pipes (53, 54, 55) are connected to the collecting liquid pipe (53) connected to the outdoor unit (10), and the collecting liquid pipe (53) is branched to refrigerating unit (30) and refrigeration unit ( 40) and a second branch liquid pipe (55) connected to the indoor unit (20) by branching the collecting liquid pipe (53). . The first branch liquid pipe (54) is connected to the refrigeration side first branch liquid pipe (54a) on the refrigeration unit (30) side and the refrigeration side first branch liquid pipe (54b) on the refrigeration unit (40) side. It is configured. In the first embodiment, the outdoor unit of the liquid side communication pipe (53, 54, 55) (the collecting liquid pipe (53), which is a part of the 10 M rule, is used for the indoor unit (20) and the refrigeration / refrigeration unit (30, 40). ) A three-pipe connection piping structure is used by sharing the same with the other.

[0045] The indoor unit (20) is configured to perform switching between a cooling operation and a heating operation, and is installed, for example, in a sales floor. The refrigeration unit (30) is installed in a refrigerated showcase to cool the air inside the showcase. The refrigeration unit (40) is installed in a refrigeration showcase to cool the air in the showcase. Chamber The knit (20), the refrigeration unit (30), and the refrigeration unit (40) are not shown in the figure, but in this embodiment 1, two indoor units (20) are connected in parallel, 30) is connected in parallel with 8 units, and one refrigeration unit (40) is connected.

[0046] The refrigerant circuit (50) includes an outdoor unit (10) that is a heat source side unit, a refrigeration unit (30) and a refrigeration unit (40) that are first use side units, and the refrigerant is Refrigerant is reversible, consisting of the first system side circuit (50A) for refrigeration 'freezing circulated in the-direction, the outdoor unit (10) that is the heat source side unit, and the indoor unit (20) that is the second usage side unit. And a second system side circuit (50B) for air conditioning.

[0047] <Outdoor unit>

The outdoor unit (10) includes an inverter compressor (11A) as a first compressor, a first non-inverter compressor (11B) as a second compressor, and a second non-inverter compression as a third compressor. A first four-way switching valve (12), a second four-way switching valve (13), and a third four-way switching valve (14), and an outdoor heat that is a heat source side heat exchanger And an exchanger (15). The outdoor heat exchanger (15) is, for example, a cross-fin type fin 'and' tube type heat exchanger ^, and an outdoor fan (16) that is a heat source fan is arranged in close proximity.

[0048] Each of the compressors (11A, 11B, 11C) is constituted by, for example, a hermetic high-pressure dome type scroll compressor. The inverter compressor (11A) is a variable capacity compressor whose capacity is variable stepwise or continuously by electric motor force S inverter control. The first non-inverter compressor (11B) and the second non-inverter compressor (11C) are constant capacity compressors in which an electric motor is always driven at a constant rotational speed.

[0049] The inverter compressor (11A), the first non-inverter compressor (11B), and the second non-inverter compressor (11C) constitute the compression mechanism (11D, 11E) of the refrigeration apparatus (1), The compression mechanism (1 ID, 11E) includes a first system compression mechanism (11D) and a second system compression mechanism (11E). Specifically, when the compressor mechanism (11D, 11E) is in operation, the inverter compressor (11A) and the first non-inverter compressor (11B) constitute the first system compressor mechanism (11D), and the second non-in When the barter compressor (11C) constitutes the second system compression mechanism (11E), the inverter compressor (11A) constitutes the first system compression mechanism (11D), and the first non-inverter compressor ( 11B) and the second non-inverter compressor (11C) constitute the second system compression mechanism (11E) There is power S. In other words, the inverter compressor (11A) is fixedly used for the first system side circuit (50A) for refrigeration / refrigeration, and the second non-inverter compressor (11C) is fixedly used for the second system side circuit (50B) for air conditioning. On the other hand, the first non-inverter compressor (11B) can be switched between the first system side circuit (50A) and the second system side circuit (50B).

[0050] Each of the discharge pipes (56a, 56b, 56c) of the inverter compressor (11A), the first non-inverter compressor (11B) and the second non-inverter compressor (11C) is a single high-pressure gas pipe. (Discharge piping) (57) connected. The discharge pipe (56b) of the first non-inverter compressor (11B) and the discharge pipe (56c) of the second non-inverter compressor (11C) are provided with check valves (CV1, CV2), respectively. Yes.

[0051] The high-pressure gas pipe (57) is connected to the first port (P1) of the first four-way selector valve (12).

The gas side end of the outdoor heat exchanger (15) is connected to the second port (P2) of the first four-way switching valve (12) by the outdoor first gas pipe (58a). A second gas side communication pipe (52) is connected to the third port (P3) of the first four-way selector valve (12) via the outdoor second gas pipe (58b). The fourth port (P4) of the first four-way selector valve (12) is connected to the second four-way selector valve (13).

[0052] The first port (P1) of the second four-way selector valve (13) is connected to the discharge pipe (56c) of the second non-inverter compressor (11C) by the auxiliary gas pipe (59) !, The The second port (P2) of the second four-way selector valve (13) is configured as a closed port. The third port (P3) of the second four-way selector valve (13) is connected to the fourth port (P4) of the first four-way selector valve (12) by a connecting pipe (60). The suction pipe (61c) of the second non-inverter compressor (11C) is connected to the fourth port (P4) of the second four-way selector valve (13). For the second four-way selector valve (13), the second port (P2) is a closed port, so a three-way selector valve can be used instead.

[0053] The first four-way selector valve (12) has a first port (P1) and a second port (P2) communicating with each other, and a third port

(P3) communicates with the 4th port (P4) in the first state (shown by the solid line in Fig. 1), the 1st port (P1) and the 3rd port (P3) communicate with the 2nd port (P2 ) And the 4th port (P4) can be switched to the 2nd state (state shown by the broken line in Fig. 1).

[0054] In the second four-way selector valve (13), the first port (P1) and the second port (P2) communicate with each other, and the third port (P3) and the fourth port (P4) communicate with each other. In the first state (shown by the solid line in Fig. 1), the first port (P1) communicates with the third port (P3), and the second port (P2) communicates with the fourth port (P4). It can be switched to the state 2 (the state indicated by the broken line in FIG. 1).

[0055] One end of an outdoor liquid pipe (62), which is a liquid line, is connected to the liquid side end of the outdoor heat exchanger (15). A receiver (17) for storing liquid refrigerant is provided in the middle of the outdoor liquid pipe (62), and the other end of the outdoor liquid pipe (62) is connected to a group of liquid side communication pipes (53, 54, 55). Connected to the liquid pipe (53).

[0056] The receiver (17) includes a first inflow pipe (63a) that allows the refrigerant to flow from the heat source side heat exchanger (15), and the refrigerant to the liquid side connection pipe (53, 54, 55). To the first outflow pipe (63b) that allows the outflow, the second inflow pipe (63c) that allows the inflow of refrigerant from the liquid side connection pipe (53, 54, 55), and the outdoor heat exchanger (15) It is connected to the heat source side heat exchanger (15) and the liquid side connecting pipes (53, 54, 55) via a second outlet pipe (63d) that allows the refrigerant to flow out.

[0057] The suction pipe (61a) of the inverter compressor (11A) is connected to the first gas side connecting pipe (51) via the low pressure gas pipe (64) of the first system side circuit (50A). . The suction pipe (61c) of the second non-inverter compressor (11C) is connected to the low pressure gas pipe (outdoor first 1) of the second system side circuit (50B) via the first and second four-way selector valves (12, 13). It is connected to the gas pipe (58a) or the outdoor second gas pipe (58b)). The suction pipe (61b) of the first non-inverter compressor (11B) is connected to the suction pipe (61a) of the inverter compressor (11A) or the second non-inverter compression via the third four-way switching valve (14). Connected to the suction pipe (61c) of the machine (11C)!

Specifically, the branch pipe (61d) is connected to the suction pipe (61a) of the inverter compressor (11A), and the branch pipe is connected to the suction pipe (61c) of the second non-inverter compressor (11C). (61e) is connected! Then, the branch pipe (61d) of the suction pipe (61a) of the inverter compressor (11A) is connected to the first port (P1) of the third four-way selector valve (14) via the check valve (CV3), The suction pipe (61b) of the first non-inverter compressor (11B) is connected to the second port (P2) of the third four-way selector valve (14), and the suction pipe of the second non-inverter compressor (11C) ( The branch pipe (61e) of 61c) is connected to the third port (P3) of the third four-way selector valve (14) via the check valve (CV4). The check valves (CV3, CV4) provided on the branch pipes (61d, 61e) allow only directional refrigerant flow to the third four-way selector valve (14) and prohibit refrigerant flow in the reverse direction. To do. The fourth port (P4) of the third four-way selector valve (14) is connected to a high pressure inlet pipe (not shown) for introducing the high pressure of the refrigerant circuit (50). [0059] In the third four-way selector valve (14), the first port (P1) and the second port (P2) communicate with each other, and the third port (P3) and the fourth port (P4) communicate with each other. (The state indicated by the solid line in Fig. 1), the second port (P1) and the fourth port (P4) communicate with each other, and the second port (P2) and the third port (P3) communicate with each other. It can be switched to the state (state shown by the broken line in Fig. 1).

[0060] The first gas side connecting pipe (51) and the second gas side connecting pipe (52) and the collecting liquid pipe (53) of the connecting liquid pipe (53, 54, 55) are connected to an outdoor unit ( 10) is extended to the outside, and in the outdoor unit (10), shut-off valves (18a, 18b, 18c) are provided correspondingly.

[0061] The outdoor liquid pipe (62) includes an auxiliary liquid pipe (65) (second outlet pipe (63d)) and a liquid branch pipe (66) (second inlet pipe ( 63c)) and are connected. The auxiliary liquid pipe (65) is provided with an outdoor expansion valve (19), which is an expansion mechanism, in which refrigerant mainly flows during heating. The auxiliary liquid pipe (65) has one end connected between the outdoor heat exchanger (15) and the receiver (17) (first inflow pipe (63a)) and the other end connected to the receiver (17) and the shut-off valve (18c). ). Between the connection point of the outdoor liquid pipe (62) with the auxiliary liquid pipe (65) on the outdoor heat exchange (15) side and the receiver (17), only the counter flow of refrigerant flows to the receiver (17). Allowable check valve (CV5) is provided.

[0062] The liquid branch pipe (66) is provided with a check valve (CV6) and a relief valve (117) in order from the closing valve (18c) side. The check valve (CV6) allows only the refrigerant flow toward the receiver (17) as well as the closing valve (18c) side force. The relief valve (117) opens automatically when the acting refrigerant pressure reaches a specified pressure (for example, 1.5 MPa), while the liquid branch pipe (66) is closed until the specified pressure is exceeded. It is something to hold. One end of the liquid branch pipe (66) is connected between the check valve (CV5) and the receiver (17), and the other end is a closing valve with the auxiliary liquid pipe (65) in the outdoor liquid pipe (62). It is connected between the connection point on the (18c) side and the shut-off valve (18c).

[0063] Further, the outdoor liquid pipe (62) is connected between the connection point on the closing valve (18c) side with the auxiliary liquid pipe (65) and the connection point on the closing valve (18c) side with the liquid branch pipe (66). A check valve (CV7) is provided in the space (first outlet pipe (63b)). This check valve (CV7) allows only the flow of refrigerant from the receiver (17) to the closing valve (18c).

[0064] Further, an inlet pipe is provided between the receiver (17) and the check valve (CV5) in the outdoor liquid pipe (62). One end of a hot gas binos tube (Π) is connected. The other end of the hot gas no-pass pipe (Π) is connected between the shutoff valve (18b) of the outdoor second gas pipe (58b) and the first four-way selector valve (12). A valve (SV1) is provided. The hot gas bypass pipe (71) and the solenoid valve (SV1) constitute the refrigerant return mechanism (5) according to the present invention! / Speak.

[0065] Further, the liquid branch pipe (66) is connected with a liquid injection pipe (67) having one end connected to a connection portion between the suction pipe (61a) and the low pressure gas pipe (64). . The other end of the liquid injection pipe (67) is connected between the check valve (CV6) and the relief knob (117). The liquid injection pipe (67) is provided with an electric expansion valve (67a) for adjusting the flow rate.

[0066] <Indoor unit>

The indoor unit (20) includes an indoor heat exchanger (air conditioning heat exchanger) (21) as a second usage side heat exchanger and an indoor expansion valve (22) as an expansion mechanism. A second gas side connecting pipe (52) is connected to the gas side of the indoor heat exchanger (21). On the other hand, the second branch liquid pipe (55) of the liquid side connecting pipe (53, 54, 55) is connected to the liquid side of the indoor heat exchanger (21) via the indoor expansion valve (22). The indoor heat exchange (21) is, for example, a cross-fin type fin 'and' tube heat exchanger, and an indoor fan (23) that is a use side fan is disposed in close proximity. The indoor expansion valve (22) is an electric expansion valve.

[0067] <Refrigerated unit>

The refrigeration unit (30) includes a refrigeration heat exchanger (31) that is a first use side heat exchanger, and a refrigeration expansion valve (32) that is an expansion mechanism. The liquid side of the refrigerated heat exchanger (31) is connected to the first branch liquid pipe (54) (54) (53, 54, 55) via the electromagnetic valve (SV2) and the refrigeration expansion valve (32). The refrigeration side first branch liquid pipe (54a)) is connected. This solenoid valve (SV2) is used to stop the flow of refrigerant during thermo-off (rest) operation. On the other hand, the gas side of the refrigeration heat exchanger (31) is connected to a refrigeration branch gas pipe (51a) branched from the first gas side connecting pipe (51).

[0068] The refrigerated heat exchanger (31) communicates with the suction side of the inverter compressor (11A), while the indoor heat exchanger (21) sucks the second non-inverter compressor (11C) during the cooling operation. It communicates with the side. The refrigerant pressure (evaporation pressure) of the refrigerated heat exchanger (31) is the same as that of the indoor heat exchanger (21). Lower than the medium pressure (evaporation pressure). Specifically, the refrigerant evaporation temperature of the refrigeration heat exchanger (31) is, for example, 10 ° C, and the refrigerant evaporation temperature of the indoor heat exchanger (21) is, for example, + 5 ° C. The refrigerant circuit (50) forms a circuit for evaporation at different temperatures.

[0069] The refrigeration expansion valve (32) is a temperature-sensitive expansion valve, and a temperature-sensitive cylinder is attached to the gas side of the refrigeration heat exchanger (31). Therefore, the opening degree of the refrigeration expansion valve (32) is adjusted based on the refrigerant temperature on the outlet side of the refrigeration heat exchanger (31). The refrigeration heat exchanger (31) is, for example, a fin-and-tube heat exchanger of a cross fin type, and a refrigeration fan (33) that is a cooling fan is arranged in close proximity! RU

[0070] <Refrigeration unit>

The refrigeration unit (40) includes a refrigeration heat exchanger (41) as a first use side heat exchanger, a refrigeration expansion valve (42) as an expansion mechanism, and a booster compressor (43) as a refrigeration compressor. Get ready! The liquid side of the refrigeration heat exchanger (41) is connected to the first branch liquid pipe (54) (54) (53) via the solenoid valve (SV3) and the refrigeration expansion valve (42). The freezing-side first branch liquid pipe (54b) is connected.

[0071] The gas side of the refrigeration heat exchanger (41) and the suction side of the booster compressor (43) are connected gas pipes.

(68) connected. A freezing side branch gas pipe (51b) branched from the first gas side connecting pipe (51) is connected to the discharge side of the booster compressor (43). The refrigeration branch gas pipe (51b) is provided with a check valve (CV8) and an oil separator (44). Between the oil separator ( ₄₄ ) and the connecting gas pipe (68), an oil return pipe (69) having a capillary tube (45) is connected.

[0072] In the booster compressor (43), the refrigerant evaporation temperature of the refrigeration heat exchanger (41) is refrigerated heat exchanger.

The refrigerant is compressed in two stages with the compression mechanism (11D) of the first system so as to be lower than the refrigerant evaporation temperature of (31). The refrigerant evaporation temperature of the refrigeration heat exchanger (41) is set to, for example, -35 ° C.

[0073] The refrigeration expansion valve (42) is a temperature-sensitive expansion valve, and a temperature-sensitive cylinder is attached to the gas side of the refrigeration heat exchanger (31). The refrigeration heat exchanger (41) is, for example, a cross-fin type fin-and-tube heat exchanger, and a refrigeration fan (46), which is a cooling fan, is disposed close to the refrigeration heat exchanger (41). [0074] Further, the connecting gas pipe (68) on the suction side of the booster compressor (43), and between the oil separator (44) and the check valve (CV8) in the refrigeration side branch gas pipe (51b) Is connected to a bypass pipe (70) having a check valve (CV9). The bypass pipe (70) is configured so that the refrigerant flows by bypassing the booster compressor (43) when the booster compressor (43) is stopped due to a failure or the like.

[0075] <Control system>

The refrigerant circuit (50) is provided with various sensors and various switches. The high pressure gas pipe (57) of the outdoor unit (10) is provided with a high pressure sensor (75) for detecting high pressure refrigerant pressure and a discharge temperature sensor (76) for detecting high pressure refrigerant temperature. . The discharge pipe (56c) of the second non-inverter compressor (11C) is provided with a discharge temperature sensor (77) for detecting the high-pressure refrigerant temperature. The discharge pipes (56a, 56b, 56c) of the inverter compressor (11A), the first non-inverter compressor (11B), and the second non-inverter compressor (11C) have high pressure refrigerant pressure, respectively. A pressure switch (78) for high-pressure protection is provided to open and stop the compressor (11A, 11B, 11C) when a predetermined value is reached.

[0076] Each suction pipe (61a, 61c) of the inverter compressor (11A) and the second non-inverter compressor (11C) includes a low pressure sensor (79, 80) for detecting a low pressure refrigerant pressure, and a low pressure refrigerant An intake temperature sensor (81, 82) for detecting the temperature is provided. The low-pressure pressure sensor (79) and the suction temperature sensor (81) on the inverter compressor (11A) side constitute the suction superheat degree detection means according to the present invention.

[0077] The outdoor heat exchanger (15) is provided with an outdoor heat exchange sensor (83) for detecting an evaporation temperature or a condensation temperature which is a refrigerant temperature in the outdoor heat exchanger (15). The outdoor unit (10) is provided with an outdoor air temperature sensor (84) for detecting the outdoor air temperature.

[0078] The indoor heat exchanger (21) is provided with an indoor heat exchange sensor (85) for detecting a condensation temperature or an evaporation temperature, which is a refrigerant temperature in the indoor heat exchanger (21), on the gas side. A gas temperature sensor (86) for detecting the gas refrigerant temperature is provided. The indoor unit (20) is provided with a room temperature sensor (87) for detecting the indoor air temperature.

[0079] In the refrigeration unit (30), the refrigeration for detecting the temperature inside the refrigerated showcase. A temperature sensor (88) is provided. The refrigeration unit (40) is provided with a refrigeration temperature sensor (89) for detecting the internal temperature of the refrigeration showcase. In addition, a pressure switch (90) for high pressure protection is provided on the discharge side of the booster compressor (43), which opens when the discharge refrigerant pressure reaches a predetermined value and stops the compressor (43).

[0080] Output signals of the various sensors and various switches are input to a controller (95) which is a control means. The controller (95) is configured to control the operation of the refrigerant circuit (50) and to switch and control eight types of operation modes to be described later. During operation, the controller (95) starts, stops, and controls the capacity of the inverter compressor (11A), and starts and stops the first non-inverter compressor (11B) and the second non-inverter compressor (11C). In addition, it controls the degree of opening of the outdoor expansion valve (19) and indoor expansion valve (22), switches the four-way switching valves (12, 13, 14), and electrically expands the liquid injection pipe (67). It also controls the opening of the valve (67a).

[0081] In addition, the controller (95) performs hot gas bypass pipes in the first heating and refrigeration operation to be described later.

Also performs open / close control for solenoid valve (SV1) in (71). Specifically, the refrigerant delivered from the compression mechanism (11D) is transferred from the indoor unit (20) as the second usage side unit to the refrigeration unit (30) and the refrigeration unit (40) as the first usage side unit. The following control is performed during the first heating and refrigeration operation in which a refrigerant circulation path is formed that circulates and returns to the compression mechanism (11D).

First, the controller (95) uses the detection value of the low pressure sensor (79) and the detection value of the suction temperature sensor (81) to use the refrigeration heat exchanger (31) as the first usage side heat exchanger. And the direction of the refrigeration heat exchange (41) to the suction side of the compression mechanism (11D) detects the degree of superheat of the refrigerant. Then, the controller (95) opens the solenoid valve (SV1) when the detected degree of superheat exceeds a predetermined value, and closes the solenoid valve (SV1) when the degree of superheat falls below a predetermined value.

[0083] The controller (95) uses the refrigeration heat exchanger (31) and the refrigeration heat exchanger (41), which are the first use side heat exchangers, to determine whether the refrigerant is in the superheat degree of the refrigerant sucked into the compression mechanism (11D). Judging whether there is a shortage or not. When the controller (95) determines that the refrigerant is insufficient in refrigeration heat exchange (31) and refrigeration heat exchange (41), the solenoid valve (SV1) is used to return the refrigerant in the receiver (17) to the circulation path. ).

[0084] Driving action Next, the operation performed by the refrigeration apparatus (1) will be described for each operation. In the first embodiment, eight types of operation modes can be set. Specifically, i) Cooling operation that only cools the indoor unit (20), Kuii> Refrigerating operation that only cools the refrigeration unit (30) and the refrigerator unit (40), Kui> Indoor The first cooling / freezing operation that simultaneously cools the unit (20) and the refrigeration unit (30) and the refrigeration unit (40), and iv> the cooling capacity of the indoor unit (20) is insufficient during the first cooling / freezing operation. The second cooling and refrigeration operation, which is the operation of the indoor unit (20), and the heating operation of the indoor unit (20), vi> the heating and refrigeration unit (30) and the refrigeration unit (40) ) Is cooled in the 100% heat recovery operation without using the outdoor heat exchanger (15), vii> in the first heating / freezing operation, when the heating capacity of the indoor unit (20) is excessive Viii> Performed when the heating capacity of the indoor unit (20) is insufficient in the first heating / freezing operation. The third heating and refrigeration operation is possible.

Hereinafter, the operation of each operation will be specifically described.

[0086] <Cooling operation>

This cooling operation is an operation in which only the indoor unit (20) is cooled. During this cooling operation, as shown in FIG. 2, the inverter compressor (11A) constitutes the first system compression mechanism (11D), and the first non-inverter compressor (11B) and the second non-inverter compressor ( 11C) constitutes the second compression mechanism (11E). Then, only the first non-inverter compressor (11B) and the second non-inverter compressor (11C) that are the second-system compression mechanism (11E) are driven.

[0087] As shown by the solid line in FIG. 2, the first four-way switching valve (12) and the second four-way switching valve (13) are each switched to the first state, and the third four-way switching valve (13). The switching valve (14) switches to the second state. Also, the outdoor expansion valve (19), the electric expansion valve (67a) of the liquid injection pipe (67), the solenoid valve (SV1) of the hot gas bypass pipe (71), and the solenoid valve (SV2) of the refrigeration unit (30) And the solenoid valve (SV3) of the refrigeration unit (40) is closed.

[0088] In this state, the first non-inverter compressor (11B) and the second non-inverter compressor

The refrigerant discharged from (11C) flows from the first four-way switching valve (12) through the outdoor first gas pipe (58a) to the outdoor heat exchanger (15) and condenses. The condensed liquid refrigerant flows through the outdoor liquid pipe (62), passes through the receiver (17), and the collecting liquid pipe (53) and the second branch liquid pipe (55) in the liquid side connecting pipe (53, 54, 55). It passes through the indoor expansion valve (22) through the indoor heat exchanger (21) and evaporates. The evaporated gas refrigerant passes through the first four-way switching valve (12) and the second four-way switching valve (13) from the second gas side communication pipe (52) and the outdoor second gas pipe (58b) to the second non-inverter. Flows through the suction pipe (61c) of the compressor (11C). Part of this low-pressure gas refrigerant returns to the second non-inverter compressor (11C), and the remaining gas refrigerant is diverted from the suction pipe (61c) to the branch pipe (61e) of the second non-inverter compressor (11C). Return to the first non-inverter compressor (11B) through the third four-way selector valve (14). As the refrigerant repeats the above circulation, the inside of the store is cooled.

[0089] In this operating state, the first non-inverter compressor (11B) and the second non-inverter compressor (11C) are started and stopped according to the indoor cooling load, and the indoor expansion valve (22) The degree of opening is controlled. Only one compressor (11B, 11C) can be operated.

[0090] <Refrigeration operation>

The refrigeration operation is an operation that only cools the refrigeration unit (30) and the refrigeration unit (40). During this refrigeration operation, as shown in Fig. 3, the inverter compressor (11A) and the first non-inverter compressor (11B) constitute the first system compression mechanism (11D), and the second non-inverter The compressor (11C) constitutes the second system compression mechanism (11E). The inverter compressor (11A) and the first non-inverter compressor (11B) as the first system compression mechanism (11D) are driven, and the booster compressor (43) is also driven, while the second non-inverter is driven. The compressor (11C) has stopped.

[0091] The first four-way switching valve (12), the second four-way switching valve (13), and the third four-way switching valve (14) are each in the first state as shown by the solid line in FIG. Switch to. Furthermore, the solenoid valve (SV2) of the refrigeration unit (30) and the solenoid valve (SV3) of the refrigeration unit (40) are opened, while the solenoid valve (SV1) of the hot gas bypass pipe (71) and the outdoor expansion valve (19) And the indoor expansion valve (22) is closed. Further, the electric expansion valve (67a) of the liquid injection pipe (67) is set to a predetermined opening so that a liquid refrigerant having a predetermined flow rate is set to be fully closed according to the operating state.

[0092] In this state, the refrigerant that has also discharged the power of the inverter compressor (11A) and the first non-inverter compressor (11B) passes through the outdoor first gas pipe (58a) from the first four-way switching valve (12). It flows to the heat exchanger (15) and condenses. The condensed liquid refrigerant flows through the outdoor liquid pipe (62), passes through the receiver (17), and passes through the collecting liquid pipe (53) of the liquid side communication pipe (53, 54, 55) to the refrigeration side first branch liquid pipe (54a). ) And divert to the first branch liquid pipe (54b) on the freezing side.

[0093] The liquid refrigerant flowing through the refrigeration-side first branch liquid pipe (54a) flows through the refrigeration expansion valve (32) to the refrigeration heat exchanger (31), evaporates, and flows through the refrigeration-side branch gas pipe (51a). . On the other hand, the liquid refrigerant flowing through the refrigeration-side first branch liquid pipe (54b) flows through the refrigeration expansion valve (42) to the refrigeration heat exchanger (41) and evaporates. The gas refrigerant evaporated in the refrigeration heat exchanger (41) is sucked and compressed by the booster compressor (43) and discharged to the refrigeration side branch gas pipe (51b).

[0094] The gas refrigerant evaporated in the refrigeration heat exchanger (31) and the gas refrigerant discharged from the booster compressor (43) are merged in the first gas side communication pipe (51), and the low-pressure gas pipe (64 ) To return to the inverter compressor (11A) and the first non-inverter compressor (11B). By repeating the above circulation of the refrigerant, the inside of the refrigerator showcase and the freezer showcase is cooled.

[0095] Since the refrigerant pressure in the refrigeration heat exchanger (41) is sucked by the booster compressor (43), the refrigerant pressure is lower than the refrigerant pressure in the refrigeration heat exchanger (31). As a result, for example, the refrigerant temperature (evaporation temperature) in the refrigeration heat exchanger (41) is 35 ° C, and the refrigerant temperature (evaporation temperature) in the refrigeration heat exchanger (31) is 10 ° C.

[0096] During this refrigeration operation, for example, based on the low-pressure refrigerant pressure (LP) detected by the low-pressure sensor (79), the first non-inverter compressor (11B) is started and stopped, the inverter compressor (11A) is started, Stop or perform capacity control and perform operation according to the refrigeration load.

[0097] For example, the control for increasing the capacity of the compression mechanism (11D) starts with the first non-inverter compressor.

The inverter compressor (11A) is driven with (11B) stopped. If the load further increases after the inverter compressor (11 A) has increased to the maximum capacity, the first non-inverter compressor (11B) is driven and at the same time the inverter compressor (11A) is reduced to the minimum capacity. Thereafter, when the load further increases, the capacity of the inverter compressor (11A) is increased while the first non-inverter compressor (11B) is started. In the compressor capacity reduction control, the reverse operation of this increase control is performed.

[0098] Further, the degree of superheat of the opening of the refrigeration expansion valve (32) and the refrigeration expansion valve (42) is controlled by a temperature sensing cylinder. This point is the same in the following operations.

[0099] <First cooling / freezing operation>

This first cooling / freezing operation is performed by the cooling / refrigeration unit (30) and the freezing unit of the indoor unit (20). This is an operation that simultaneously cools the knit (40). During this first cooling / freezing operation, as shown in FIG. 4, the inverter compressor (11A) and the first non-inverter compressor (11B) constitute the first system compression mechanism (11D), and the second The non-inverter compressor (11C) constitutes the second system compression mechanism (11E). The inverter compressor (11A), the first non-inverter compressor (11B) and the second non-inverter compressor (11C) are driven, and the booster compressor (43) is also driven.

[0100] The first four-way switching valve (12), the second four-way switching valve (13), and the third four-way switching valve (14) are each in the first state as shown by the solid line in FIG. Switch to. Furthermore, the solenoid valve (SV2) of the refrigeration unit (30) and the solenoid valve (SV3) of the refrigeration unit (40) are opened, while the solenoid valve (SV1) of the hot gas bypass pipe (71) and the outdoor expansion valve (19) Is closed. Also, the electric expansion valve (67a) of the liquid index pipe (67) is set to be fully closed or a predetermined flow rate of liquid refrigerant is allowed to flow to the suction side of the compression mechanism (11D) depending on the operating state. The predetermined opening is set.

[0101] In this state, the refrigerant discharged from the inverter compressor (11A), the first non-inverter compressor (11B), and the second non-inverter compressor (11C) is joined by the high-pressure gas pipe (57), 1 Condenses by flowing through the first gas pipe (58a) outside the four-way selector valve (12) to the outdoor heat exchanger (15). The condensed liquid refrigerant flows through the outdoor liquid pipe (62), and then flows through the receiver (17) to the collecting liquid pipe (53) of the liquid side connecting pipe (53, 54, 55).

[0102] A part of the liquid refrigerant flowing through the collecting liquid pipe (53) of the liquid side connecting pipe (53, 54, 55) is divided into the second branch liquid pipe (55), and the indoor expansion valve (22) It passes through the indoor heat exchanger (21) and evaporates. The evaporated gas refrigerant passes through the first four-way switching valve (12) and the second four-way switching valve (13) from the second gas side communication pipe (52) and the outdoor second gas pipe (58b). ) And return to the second non-inverter compressor (11C).

On the other hand, the liquid refrigerant flowing through the collecting liquid pipe (53) of the liquid side connecting pipe (53, 54, 55) is refrigerated side first branch liquid pipe (54a) and refrigeration side first branch liquid pipe (54b). ). The liquid refrigerant flowing through the refrigeration side first branch liquid pipe (54a) flows through the refrigeration expansion valve (32) to the refrigeration heat exchanger (31), evaporates, and flows through the refrigeration side branch gas pipe (51a). Further, the liquid refrigerant flowing through the refrigeration-side first branch liquid pipe (54b) flows through the refrigeration expansion valve (42) to the refrigeration heat exchanger (41) and evaporates. The gas refrigerant evaporated in the refrigeration heat exchanger (41) is sucked and compressed by the booster compressor (43), and the refrigeration side It is discharged into the branch gas pipe (51b).

[0104] The gas refrigerant evaporated in the refrigeration heat exchanger (31) and the gas refrigerant discharged from the booster compressor (43) merge in the first gas side connecting pipe (51), and the low-pressure gas pipe (64 ) To return to the inverter compressor (11A) and the first non-inverter compressor (11B).

[0105] By repeating the circulation of the refrigerant as described above, the inside of the store is cooled, and at the same time, the inside of the refrigerated showcase and the freezer showcase is cooled.

[0106] <Second cooling / freezing operation>

The second cooling / freezing operation is an operation when the cooling capacity of the indoor unit (20) is insufficient during the first cooling / refrigeration operation, and the first non-inverter compressor (11B) is switched to the air conditioning side. . As shown in FIG. 5, the setting during the second cooling / freezing operation is basically the same as that during the first cooling / freezing operation, but the third four-way selector valve (14) is switched to the second state. This is different from the first cooling / freezing operation.

Accordingly, during the second cooling / freezing operation, similarly to the first cooling / freezing operation, the inverter compressor (11A), the first non-inverter compressor (11B), and the second non-inverter compressor (11C ) Is condensed in the outdoor heat exchanger (15) and evaporated in the indoor heat exchanger (21), the refrigeration heat exchanger (31), and the refrigeration heat exchanger (41).

Then, the refrigerant evaporated in the indoor heat exchanger (21) returns to the first non-inverter compressor (11B) and the second non-inverter compressor (11C), and the refrigerated heat exchanger (31) and the refrigeration The refrigerant evaporated in the heat exchanger (41) returns to the inverter compressor (11A). The use of two compressors (11B, 11C) on the air conditioning side will compensate for the lack of cooling capacity.

[0109] <Heating operation>

This heating operation is an operation in which only the indoor unit (20) is heated. During this heating operation, as shown in FIG. 6, the inverter compressor (11A) constitutes the first system compression mechanism (11D), and the first non-inverter compressor (11B) and the second non-inverter compressor ( 11C) constitutes the second compression mechanism (11E). Then, only the first non-inverter compressor (11B) and the second non-inverter compressor (11C) that are the second-system compression mechanism (11E) are driven.

[0110] Further, as shown by the solid line in FIG. 6, the first four-way selector valve (12) switches to the second state, the second four-way selector valve (13) switches to the first state, The third four-way selector valve (14) is in the second state Switch. On the other hand, the electric expansion valve (67a) of the liquid injection pipe (67), the solenoid valve (SV1) of the hot gas bypass pipe (71), the solenoid valve (SV2) of the refrigeration unit (30), and the solenoid valve of the refrigeration unit (40) (SV3) is closed. Further, the indoor expansion valve (22) is set to fully open, and the outdoor expansion valve (19) is controlled to a predetermined opening.

[0111] In this state, the first non-inverter compressor (11B) and the second non-inverter compressor

The refrigerant discharged from (11C) flows from the first four-way selector valve (12) through the outdoor second gas pipe (58b) and the second gas side connecting pipe (52) to the indoor heat exchanger (21) and condenses. To do. The condensed liquid refrigerant flows through the second branch liquid pipe (55) force collecting liquid pipe (53) of the liquid side connecting pipe (53, 54, 55), and further passes through the liquid branch pipe (66) to the receiver ( It flows into 17). Thereafter, the liquid refrigerant flows through the outdoor expansion valve (19) of the auxiliary liquid pipe (65), flows through the outdoor heat exchanger (15), and evaporates. The evaporated gas refrigerant is also supplied to the suction pipe (61c) of the second non-inverter compressor (11C) through the first four-way switching valve (12) and the second four-way switching valve (13). ) And return to the first non-inverter compressor (11B) and the second non-inverter compressor (11C). This circulation is repeated to heat the room.

[0112] As with the cooling operation, the compressors (11B, 11C) can be operated alone.

[0113] <First heating and refrigeration operation>

The first heating / freezing operation is a 100% heat recovery operation in which the indoor unit (20) is heated and the refrigeration unit (30) and the refrigeration unit (40) are cooled without using the outdoor heat exchanger (15). In this first heating and refrigeration operation, as shown in FIG. 7, the inverter compressor (11A) and the first non-inverter compressor (11B) constitute the first system compression mechanism (11D), and the second non-refrigeration operation (11D). The inverter compressor (11C) constitutes the second system compression mechanism (11E). Then, the inverter compressor (11A) and the first non-inverter compressor (11B) are driven, and the booster compressor (43) is also driven. The second non-inverter compressor (11C) is stopped.

[0114] As shown by a solid line in FIG. 7, the first four-way switching valve (12) switches to the second state, and the second four-way switching valve (13) and the third four-way switching valve (14 ) Switches to the first state. Further, the solenoid valve (SV2) of the refrigeration unit (30) and the solenoid valve (SV3) of the refrigeration unit (40) are opened, while the outdoor expansion valve (19) is closed. Also, the solenoid valve (SV1) of the hot gas bypass pipe (71) detects the detected value of the low pressure sensor (79) and the detected value of the suction temperature sensor (81). Opening / closing control is performed based on the degree of superheat of the refrigerant flowing through the suction pipe (61a). Further, the opening degree of the electric expansion valve (67a) of the liquid index pipe (67) is controlled based on the degree of superheat and the detected value of the discharge temperature sensor (76).

[0115] In this state, the refrigerant discharged from the inverter compressor (11A) and the first non-inverter compressor (11B) flows from the first four-way selector valve (12) to the outdoor second gas pipe (58b) and the second It flows through the gas side communication pipe (52) and flows into the indoor heat exchanger (21) for condensation. The condensed liquid refrigerant is refrigerated from the second branch liquid pipe (55) of the liquid side communication pipe (53, 54, 55) to the first branch liquid pipe (54a) before the collecting liquid pipe (53). Shunt to the side first branch pipe (54b).

[0116] The liquid refrigerant flowing through the refrigeration-side first branch liquid pipe (54a) flows through the refrigeration expansion valve (32) to the refrigeration heat exchanger (31), evaporates, and flows through the refrigeration-side branch gas pipe (51a). . Further, the liquid refrigerant flowing through the refrigeration-side first branch liquid pipe (54b) flows through the refrigeration expansion valve (42) to the refrigeration heat exchanger (41) and evaporates. The gas refrigerant evaporated by the refrigeration heat exchange (41) is sucked and compressed by the booster compressor (43) and discharged to the refrigeration side branch gas pipe (51b).

[0117] The gas refrigerant evaporated in the refrigeration heat exchanger (31) and the gas refrigerant discharged from the booster compressor (43) are merged in the first gas side connecting pipe (51), and the low-pressure gas pipe (64 ) To return to the inverter compressor (11A) and the first non-inverter compressor (11B). By repeating the above circulation of the refrigerant, the inside of the store is heated, and at the same time, the inside of the refrigerated showcase and the freezer showcase is cooled. During this first heating and refrigeration operation, the cooling capacity (evaporation heat amount) between the refrigeration unit (30) and the refrigeration unit (40) balances with the heating capacity (condensation heat amount) of the indoor unit (20). Heat recovery is performed. Thus, in the first heating / freezing operation, the refrigerant sent out from the compression mechanism (11D) flows through the indoor unit (20), the refrigeration unit (30), and the refrigeration unit (40) and returns to the compression mechanism (11D). A refrigerant circulation path is formed. In this circulation path, the refrigerant condensed in the indoor unit (20) flows directly into the refrigeration unit (30) and the refrigeration unit (40) without returning to the outdoor unit (10).

[0118] During the first heating / freezing operation, the pressure of the hydraulic fluid side connecting pipe (53, 54, 55) is set too high so that the relief valve (117) is closed. ) May exceed a predetermined pressure (for example, 1.5 MPa), and the relief valve (117) may open. Even if the relief valve (117) is closed, refrigerant leaks. There is also a case. In such a case, the refrigerant in the circulation path flows from the collecting liquid pipe (53) through the liquid branch pipe (66) to the receiver (17), and the refrigerant in the circulation path decreases. As the refrigerant in the circulation path decreases, the refrigerant flow rate gradually decreases in the refrigeration heat exchanger (31) and the refrigeration heat exchanger (41), and the region through which the gas-liquid two-phase refrigerant flows decreases. As a result, the region where the single-phase gas refrigerant flows increases, so that the refrigerant flows out of the refrigeration heat exchanger (31) and the refrigeration heat exchanger (41) and is directed to the compression mechanism (11D). Become.

[0119] The controller (95) has a superheat degree of the refrigerant flowing through the suction pipe (61a) detected based on the detected value of the low pressure sensor (79) and the detected value of the suction temperature sensor (81) above a predetermined value. When it becomes, the solenoid valve (SV1) is opened. When the solenoid valve (SV1) opens, the high-pressure gas refrigerant discharged from the compressor mechanism (11D) is introduced into the receiver (17) through the hot gas no-pass pipe (71) as shown in FIG. 17) The internal pressure rises. As a result, the liquid coolant in the receiver (17) is forced out and returned from the collecting liquid pipe (53) to the circulation path. The circulation path force gas refrigerant is supplied to the receiver (17), but the liquid refrigerant is pushed out. As a result, the amount of refrigerant in the receiver (17) decreases and the amount of refrigerant in the circulation path increases. As a result, the refrigerant shortage in the refrigeration unit (30) and the refrigeration unit (40) can be prevented, and a decrease in the cooling capacity in the refrigeration unit (30) and the refrigeration unit (40) can be avoided.

[0120] When the liquid refrigerant in the receiver (17) is returned to the circulation path and the amount of refrigerant in the circulation path increases, the degree of superheat of the refrigerant flowing through the suction pipe (61a) gradually decreases. Go. Then, the controller (95) closes the solenoid valve (SV1) when the superheat degree of the refrigerant detected based on the detected value of the low pressure sensor (79) and the detected value of the suction temperature sensor (81) becomes less than a predetermined value. The

[0121] <Second heating / freezing operation>

The second heating / freezing operation is an operation performed when the heating capacity of the indoor unit (20) is excessive in the first heating / freezing operation. During this second heating and refrigeration operation, as shown in FIG. 9, the inverter compressor (11A) and the first non-inverter compressor (11B) constitute the first system compression mechanism (11D), and the second non-freezing operation is performed. The inverter compressor (11C) constitutes the second system compression mechanism (11E). Then, the inverter compressor (11A) and the first non-inverter compressor (11B) are driven, and the booster compressor (43) is also driven. Second non-inverter compressor (11C) stopped is doing.

[0122] In the second heating and refrigeration operation, the second four-way switching valve (13) is switched to the second state as shown by the solid line in FIG. It is the same as heating and refrigeration operation.

[0123] Therefore, a part of the refrigerant discharged from the inverter compressor (11A) and the first non-inverter compressor (11B) flows to the indoor heat exchanger (21) in the same manner as in the first heating and refrigeration operation. Condensate. The condensed liquid refrigerant flows from the second branch liquid pipe (55) of the liquid side connecting pipe (53, 54, 55) to the first branch liquid pipe (54) (first branch of the refrigeration side) before the collecting liquid pipe (53). It flows to the liquid pipe (54a) and the freezing side first branch liquid pipe (54b)).

[0124] On the other hand, the other refrigerant discharged from the inverter compressor (11A) and the first non-inverter compressor (11B) is the auxiliary gas pipe (59) force second four-way switching valve (13) and first four After passing through the path switching valve (12), it flows through the outdoor first gas pipe (58a) and condenses in the outdoor heat exchanger (15). The condensed liquid refrigerant passes through the receiver (17) when flowing through the outdoor liquid pipe (62), passes through the collecting liquid pipe (53) of the liquid side connecting pipe (53, 54, 55), and then enters the first branch liquid pipe. (54) The refrigerant flows into the refrigeration-side first branch liquid pipe (54a) and the refrigeration-side first branch liquid pipe (54b)) and merges with the refrigerant from the second branch liquid pipe (55).

Thereafter, the liquid refrigerant flowing through the refrigeration side first branch liquid pipe (54a) flows to the refrigeration heat exchanger (31) and evaporates, and flows through the refrigeration side branch gas pipe (51a). Further, the liquid refrigerant flowing through the refrigeration-side first branch liquid pipe (54b) flows into the refrigeration heat exchanger (41), evaporates, is sucked into the booster compressor (43) and compressed, and is then supplied to the refrigeration-side branch gas pipe. (51b). The gas refrigerant evaporated in the refrigeration heat exchanger (31) and the booster compressor (43) force merged in the first gas side connecting pipe (51), and the low pressure gas pipe (64) is connected. Return to the inverter compressor (11A) and the first non-inverter compressor (11B).

[0126] During the second heating / refrigeration operation, the refrigerant repeats the above circulation, whereby the interior of the store is heated and the interiors of the refrigerated showcase and the refrigerated showcase are cooled at the same time. At this time, the cooling capacity (evaporation heat amount) of the refrigeration unit (30) and the refrigeration unit (40) and the heating capacity (condensation heat amount) of the indoor unit (20) are not balanced, and excess condensation heat is transferred to the outdoor heat. It will be discharged outdoors by the exchanger (15).

[0127] <Third heating / freezing operation>

This third heating / freezing operation is the same as that of the first heating / refrigeration operation. This operation is performed when power is insufficient. In this third heating and refrigeration operation, as shown in FIG. 10, the inverter compressor (11A) and the first non-inverter compressor (11B) constitute the first system compression mechanism (11D), and the second non-inverter operation The compressor (11C) constitutes the second system compression mechanism (11E). The inverter compressor (11A), the first non-inverter compressor (11B), and the second non-inverter compressor (11C) are driven, and the booster compressor (43) is also driven.

[0128] In the third heating and refrigeration operation, the opening degree of the outdoor expansion valve (19) is controlled, the solenoid valve (SV1) is closed without being controlled to open and close, and the second non-inverter compressor (11C) is closed. Except for the fact that it is driven, the setting is the same as in the first heating and refrigeration operation.

[0129] Therefore, the refrigerant discharged from the inverter compressor (11A), the first non-inverter compressor (11B), and the second non-inverter compressor (11C) is the second gas as in the first heating / refrigeration operation. It flows to the indoor heat exchanger (21) through the side connecting pipe (52) and condenses. The condensed liquid refrigerant flows from the second branch liquid pipe (55) to the first branch liquid pipe (54) (the refrigeration side first branch liquid pipe (54a) and the refrigeration side of the liquid side communication liquid pipe (53, 54, 55). The first branch liquid pipe (54b)) and the collecting liquid pipe (53) are divided.

[0130] The liquid refrigerant flowing through the refrigeration side first branch liquid pipe (54a) flows to the refrigeration heat exchanger (31), evaporates, and flows through the refrigeration side branch gas pipe (51a). The liquid coolant flowing through the refrigeration-side first branch liquid pipe (54b) flows to the refrigeration heat exchanger (41), evaporates, is sucked into the booster compressor (43), is compressed, and the refrigeration-side branch gas pipe (51b). The gas refrigerant evaporated in the refrigeration heat exchanger (31) and the booster compressor (43) force The discharged gas refrigerant merges in the first gas side connecting pipe (51) and passes through the low-pressure gas pipe (64). Return to the inverter compressor (11A) and the first non-inverter compressor (11B).

[0131] On the other hand, after condensing in the indoor heat exchanger (21), the liquid refrigerant flowing through the collecting liquid pipe (53) flows through the liquid branch pipe (66) and flows into the receiver (17). It flows through the outdoor heat exchanger (15) via (19) and evaporates. The evaporated gas refrigerant flows through the outdoor first gas pipe (58a), passes through the first four-way switching valve (12) and the second four-way switching valve (13), and the suction pipe of the second non-inverter compressor (11C). (61c) and return to the second non-inverter compressor (11C).

[0132] During the third heating / freezing operation, the refrigerant repeatedly circulates, so that the inside of the store is heated, and at the same time, the interiors of the refrigerated showcase and the refrigerated showcase are cooled. At this time, The cooling capacity (evaporation heat amount) between the storage unit (30) and the refrigeration unit (40) and the heating capacity (condensation heat amount) of the indoor unit (20) are not balanced, and the lack of evaporative heat is exchanged with the outdoor heat exchanger (15). It ’s hard to get from.

[0133] Effect of Embodiment 1

In the first embodiment, the solenoid valve (SV1) of the hot gas bypass pipe (71) is used during the first heating / refrigeration operation in which the circulation path in which the refrigerant amount decreases when the refrigerant flows into the receiver (17) is formed. By opening the, the liquid refrigerant in the receiver (17) can be returned to the circulation path. When the liquid refrigerant in the receiver (17) is returned to the circulation path, the amount of refrigerant flowing through the indoor unit (20), the refrigeration unit (30), and the refrigeration unit (40), which are the use side units, increases. Therefore, by returning the liquid refrigerant in the receiver (17) to the circulation path by the refrigerant return mechanism (5) before the refrigerant runs short in each user side unit (20, 30, 40), each user side unit (20, 30 30 and 40) can prevent the refrigerant shortage.

[0134] In the first embodiment, the refrigeration heat exchanger (31) and the refrigeration heat exchanger (41) determine whether or not the refrigeration unit (30) and the refrigeration unit (40) run out of refrigerant! The hot gas bypass pipe based on the detected value of the low-pressure pressure sensor (79) and the detected value of the suction temperature sensor (81), focusing on the fact that it can be determined from the degree of superheat of the refrigerant going to the suction side of the compression mechanism (11D) (71) solenoid valve (SV1) is controlled. Accordingly, the liquid refrigerant in the receiver (17) can be returned to the circulation path at an appropriate timing before the refrigerant runs short in the refrigeration unit (30) and the refrigeration unit (40). A decrease in cooling capacity in the unit (40) can be reliably avoided.

<< Embodiment 2 of the Invention >>

Embodiment 2 of the present invention will be described. FIG. 11 shows a refrigerant circuit diagram of the refrigeration apparatus (1) according to the second embodiment. The refrigeration apparatus (1) of the second embodiment is different from the first embodiment in that the hot gas bypass pipe (71) and the solenoid valve (SV1) are not provided, and the second four-way that is a communication mechanism. The switching valve (13) constitutes the refrigerant return mechanism (5).

[0136] An operation for returning the liquid refrigerant in the receiver (17) to the circulation path in the first heating / freezing operation will be described. In the refrigeration apparatus (1) of the second embodiment, the controller (95) detects the suction pipe (61a) detected by the low pressure sensor (79) and the suction temperature sensor (81). ), The second four-way selector valve (13) is switched to the second state.

[0137] When the second four-way selector valve (13) is set to the second state, a part of the high-pressure gas refrigerant discharged from the compression mechanism (11D) is supplied to the auxiliary gas pipe (59). After passing through the four-way switching valve (13) and the first four-way switching valve (12), it flows through the outdoor first gas pipe (58a), and further flows from the outdoor heat exchanger (15) through the outdoor liquid pipe (62) to the receiver. Enter (17). At that time, the outdoor fan (16) remains stopped. As a result, the internal pressure of the receiver (17) rises and the liquid refrigerant in the receiver (17) is forced out and returned from the collecting liquid pipe (53) to the circulation path.

[0138] Note that the state in which the second four-way selector valve (13) is set to the second state in the first heating and refrigeration operation is the same operating state as the second heating and refrigeration operation of the first embodiment. However, the second heating and refrigeration operation of Embodiment 1 is an operation performed to reduce the heating capacity of the indoor unit (20), whereas the first heating and refrigeration operation of Embodiment 2 is performed by the receiver (17 This operation is to forcibly return the liquid cooling medium in parenthesis to the circulation path. In the second heating / freezing operation of the first embodiment, the outdoor fan (16) is driven to condense the refrigerant by the outdoor heat exchange (15), but in the first heating / refrigeration operation of the second embodiment, The outdoor heat exchanger (15) is only used as a flow path for introducing the high-pressure gas refrigerant discharged from the compression mechanism (11D) into the receiver (17). When the refrigerant condenses, the receiver (17) Since the liquid refrigerant is introduced and the amount of refrigerant in the receiver (17) is not easily reduced, the outdoor fan (16) is not driven.

[0139] In Embodiment 2, the outdoor heat exchanger (15) is used as a flow path for introducing a high-pressure gas refrigerant into the receiver (17), so that the discharge side of the receiver (17) and the compression mechanism (11D) The liquid refrigerant in the receiver (17) can be returned to the circulation path without providing a separate distribution path for connecting to the circulation path. This simplifies the configuration of the refrigeration apparatus (1).

<< Embodiment 3 of the Invention >>

Embodiment 3 of the present invention will be described. A refrigerant circuit diagram of the refrigeration apparatus (1) according to Embodiment 3 is shown in FIG. The refrigeration apparatus (1) of the third embodiment is provided with a hot gas bypass pipe (71) and a solenoid valve (SV1), and the point and the connection position of the liquid injection pipe (67) are the same as those of the first embodiment. Is different.

[0141] The liquid injection pipe (67) has one end at the connection between the suction pipe (61a) and the low pressure gas pipe (64). The other end of the outdoor liquid pipe (62) is connected between the connection point of the auxiliary liquid pipe (65) on the side of the shut-off valve (18c) and the receiver (17). The liquid injection pipe (67) is a communication pipe for communicating the receiver (17) to the suction side of the compression mechanism (11D), and constitutes a refrigerant return mechanism (5) together with the electric expansion valve (67a). ! / Speak.

[0142] The operation of returning the liquid refrigerant in the receiver (17) to the circulation path in the first heating / freezing operation will be described. In the refrigeration apparatus (1) of Embodiment 3, the controller (95) distributes the suction pipe (61a) detected based on the detection value of the low pressure sensor (79) and the detection value of the suction temperature sensor (81). When the superheat degree of the refrigerant to be reached exceeds a predetermined value, the electric expansion valve (67a) is opened. As a result, the receiver (17) communicates with the suction side of the compression mechanism (11D), so that the liquid refrigerant in the receiver (17) is forcibly sucked out by the compression mechanism (11D) and returned to the circulation path. It is.

[0143] In the refrigeration apparatus (1) of Embodiment 1 and Embodiment 2 described above, even if the electric expansion valve (67a) is opened in the first heating and refrigeration operation, the pressure in the collecting liquid pipe (53) is high. Therefore, the liquid refrigerant in the receiver (17) does not flow out of the receiver (17).

[0144] In Embodiment 3, when the liquid refrigerant in the receiver (17) is returned to the circulation path, the compression mechanism (11D) sucks the liquid refrigerant in the receiver (17), so that the compression mechanism (11D) Inhalation superheat is reduced. Therefore, the refrigerant can be returned to the circulation path to solve the shortage of refrigerant, and at the same time, the suction superheat degree can be suppressed and the input of the compression mechanism (11D) can be reduced.

[0145] << Other Embodiments >>

According to the above embodiment, the following configuration may be adopted.

In the above embodiment, the refrigerant return mechanism (5) is controlled based on the detected value of the controller (95) force low pressure sensor (79) and the detected value of the suction temperature sensor (81). The refrigerant return mechanism (5) may be controlled based on the detection values of the high pressure sensor (75) and the discharge temperature sensor (76). When the degree of superheat of the refrigerant discharged by the compression mechanism (11D) calculated based on the detected value of the high pressure sensor (75) and the detected value of the discharge temperature sensor (76) exceeds a predetermined value, the controller (95) (17) The liquid refrigerant inside is returned to the circulation path. The high pressure sensor (75) and the discharge temperature sensor (76) constitute discharge superheat degree detection means. [0147] Further, the controller (95) may control the refrigerant return mechanism (5) based on the detection value of the discharge temperature sensor (76) that detects the temperature of the refrigerant discharged by the compression mechanism (11D). Yo ... The controller (95) performs an operation of returning the liquid refrigerant in the receiver (17) to the circulation path when the detection value of the discharge temperature sensor (76) becomes a predetermined value or more. The discharge temperature sensor (76) constitutes discharge refrigerant temperature detection means.

[0148] Further, the controller (95) may control the refrigerant return mechanism (5) based on the opening degree of the electric expansion valve (67a) of the liquid injection pipe (67). When the opening degree of the electric expansion valve (67a) exceeds a predetermined opening degree (for example, 400 pulses or more in the case of an electric expansion valve with 480 pulses), the controller (95) sets the liquid refrigerant in the receiver (17). To return to the circulation path. When the opening of the electric expansion valve (67a) falls below a predetermined opening (for example, 350 pulses or less in the case of a 480 pulse electric expansion valve), the controller (95) End the operation to return the coolant to the circulation path.

[0149] The electric expansion valve (67a) has a detection value of the discharge temperature sensor (76), a detection value of the low pressure sensor (79), and a detection value of the suction temperature sensor (81). The opening degree is controlled based on the degree of superheat of the refrigerant in 61a). For example, the controller (95) may detect either the condition that the detected value of the discharge temperature sensor (76) is 90 ° C or higher, or the condition that the superheat degree of the refrigerant in the suction pipe (61a) is 5 ° C or higher. When is established, the opening of the electric expansion valve (67a) is increased.

[0150] Further, the controller (95) controls the refrigerant return mechanism (5) based on the degree of superheat at the outlet of the refrigeration heat exchanger (31) and the refrigeration heat exchanger (41) serving as an evaporator. Anyway! In this case, in order to detect the degree of superheat, a temperature sensor and a pressure sensor are provided at the outlet of the refrigeration heat exchanger (31) and the outlet of the refrigeration heat exchanger (41). For example, the controller (95) has a duration of 10 minutes at which the refrigerant superheat degree is 10 ° C or higher at either the outlet of the refrigeration heat exchanger (31) or the outlet of the refrigeration heat exchanger (41). If exceeded, the liquid refrigerant in the receiver (17) is returned to the circulation path. In addition, the controller (95) is in a state where the superheat of the refrigerant at the outlet is 7 ° C or less for an evaporator that has exceeded the duration of 10 minutes when the superheat of the refrigerant is 10 ° C or more. If the continuation time exceeds 1 minute, the operation of returning the liquid refrigerant in the receiver (17) to the circulation path is terminated. The refrigerant return mechanism (5) is controlled by all refrigeration units (30) and refrigeration units. It is not necessary to carry out based on the degree of superheat of the refrigerant at the outlet of the evaporator in the refrigeration unit (40). The unit at the outlet of the evaporator in a unit where liquid refrigerant is difficult to flow (for example, a unit placed at a high place). Based on the degree of superheat of the refrigerant!

[0151] Further, the controller (95) includes a refrigerant return mechanism based on the detection value of the high pressure sensor (75).

(5) may be controlled. In this case, since the high pressure of the refrigeration cycle varies depending on the temperature of the indoor space in which the indoor unit (20) is provided, the refrigerant return mechanism (5) has a function based on the saturation temperature at the pressure detected by the high pressure sensor (75). Take control. For example, the controller (95) returns the liquid refrigerant in the receiver (17) to the circulation path when the duration of the state where the difference between the saturation temperature and the temperature of the indoor space is 15 ° C or less exceeds 10 minutes. Perform the action. The controller (95) ends the operation of returning the liquid refrigerant in the receiver (17) to the circulation path when the duration of the state where the temperature difference is 15 ° C or more exceeds 1 minute.

[0152] Further, the controller (95) includes a refrigerant return mechanism based on the detection value of the low pressure sensor (79).

(5) may be controlled. For example, the controller (95) returns the liquid refrigerant in the receiver (17) to the circulation path if the duration of the state where the detection value of the low pressure sensor (79) is 0.15 MPa or less exceeds 10 minutes. Do. The controller (95) also transfers the liquid refrigerant in the receiver (17) to the circulation path when the detected value of the low pressure sensor (79) exceeds 0.2 MPa for more than 1 minute. End the return operation.

[0153] The controller (95) has a degree of superheat of the refrigerant from the refrigeration heat exchanger (31) and the refrigeration heat exchanger (41) to the suction side of the compressor mechanism (11D), and the compression mechanism (11D) discharges The temperature of the refrigerant discharged from the compression mechanism (11D), the opening of the electric expansion valve (67a) of the liquid injection pipe (67), the degree of refrigerant superheat at the outlet of the evaporator, and the high pressure sensor (75 ) And the detection value of the low-pressure sensor (79) may control the refrigerant return mechanism (5) based on a plurality of conditions. In this case, when any one of the conditions is satisfied, an operation of returning the liquid refrigerant in the receiver (17) to the circulation path is performed.

[0154] In addition, the controller (95) may perform an operation of returning the liquid refrigerant in the receiver (17) to the circulation path when the first heating / refrigeration operation for 100% heat recovery continues for 30 minutes or more. Good. When the outside air is at a low temperature (for example, 10 ° C or less), the receiver (17) is at a low pressure and liquid refrigerant tends to accumulate, so if the first heating / freezing operation continues for 20 minutes or more, the receiver The operation of returning the liquid refrigerant in (17) to the circulation path may be performed.

[0155] Further, the controller (95) may forcibly terminate the operation when the operation of returning the liquid refrigerant in the receiver (17) to the circulation path exceeds 10 minutes.

[0156] In the above embodiment, if liquid refrigerant is accumulated in the receiver (17) during the first heating / freezing operation (first operation mode) in which 100% heat recovery is performed, the controller (95) The operating state may be switched by temporarily setting the first four-way selector valve (12), which is a mechanism, to the second state. At that time, the indoor expansion valve (22) is closed at the same time. In this case, the conditions for switching the first four-way switching valve (12) to the second state are the same as those for performing the operation of returning the liquid refrigerant in the receiver (17) to the circulation path by the refrigerant return mechanism (5). It is. When the first four-way selector valve (12) is set to the second state, the second operation mode in which the refrigerant circulates in the same flow as in the refrigeration operation is set. However, unlike the freezing operation, the outdoor fan (16) remains stopped. As a result, the high-pressure gas refrigerant discharged from the compression mechanism (11D) flows into the receiver (17) through the outdoor heat exchanger (15). Then, the internal pressure of the receiver (17) rises and the liquid refrigerant in the receiver (17) is forced out and returned to the collecting liquid pipe (53) force refrigeration unit (30) and refrigeration unit (40). .

[0157] Further, the liquid branch pipe (66) of the above embodiment may be provided with an electromagnetic valve instead of the relief valve (117).

[0158] In the above embodiment, two indoor units (20), eight refrigeration units (30), and one refrigeration unit (40) are provided for one outdoor unit (10). Although an example has been explained, the number of units on the usage side (20, 30, 40) may be changed as long as 100% heat recovery operation is possible.

In the above embodiment, the example in which the compression mechanism (11D, 11E) is configured by three compressors (11A, 11B, 11C) has been described. However, the number of compressors can be changed as appropriate.

[0160] It should be noted that the above embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

Industrial applicability

[0161] As described above, the present invention is useful for a refrigeration apparatus having a plurality of utilization side heat exchangers and capable of performing 100% heat recovery operation between the utilization side heat exchangers ^^. .

Claims

The scope of the claims

[1] A heat source side unit (10) having a compression mechanism (11D, HE), a heat source side heat exchanger (15), and a receiver (17), and a first use side heat exchanger (31, 41) The first user side unit (30, 40) having the second user side unit (20) having the second user side heat exchanger (21) and each unit (10, 20, 30, 40) are connected. Gas side connecting pipe (51, 52) and liquid side connecting pipe (53, 54, 55) constituting the refrigerant circuit (50),

The gas side communication pipe (51, 52) is connected to the heat source side unit (10) and the first use side unit (30, 40); A second gas side communication pipe (52) connected to the heat source side unit (10) and the second usage side unit (20),

The liquid side communication pipe (53, 54, 55) is connected to the collecting liquid pipe (53) connected to the heat source side unit (10), and the collecting liquid pipe (53) is branched into the first usage side unit. A first branch liquid pipe (54) connected to (30, 40), and a second branch liquid pipe (55) branched from the collecting liquid pipe (53) and connected to the second usage side unit (20). )

In the refrigerant circuit (50), the refrigerant sent out by the compression mechanism (11D, 11E) flows from the second usage-side unit (20) to the first usage-side unit (30, 40), and the compression mechanism (11D , 11E), a refrigerant circulation path can be formed,

A refrigeration apparatus comprising a refrigerant return mechanism (5) for returning the liquid refrigerant in the receiver (17) to the circulation path.

[2] In claim 1,

The refrigerant return mechanism (5) includes an introduction pipe (71) for introducing the high-pressure refrigerant discharged from the compression mechanism (11D, 11E) force into the receiver (17), from the introduction pipe (71). The liquid refrigerant in the receiver (17) is returned to the circulation path through the collecting liquid pipe (53) by introducing the high-pressure refrigerant into the receiver (17) and pressurizing the receiver (17). The refrigeration equipment.

[3] In claim 1,

The refrigerant return mechanism (5) includes a communication pipe (67) for communicating the receiver (17) to the suction side of the compression mechanism (11D, 11E). The communication pipe (67) allows the receiver (17 ) The liquid refrigerant inside is sucked into the compression mechanism (11D, 11E) and returned to the circulation path. Refrigeration equipment.

[4] In claim 1,

The refrigerant return mechanism (5) includes a communication mechanism (13) for communicating the receiver (17) to the discharge side of the compression mechanism (11D, 11E) via the heat source side heat exchanger (15). The communication mechanism (13) connects the receiver (17) to the discharge side of the compression mechanism (11D, 11E), and the high-pressure refrigerant discharged by the compression mechanism (11D, 11E) is sent to the receiver (17). The refrigeration apparatus characterized in that the liquid refrigerant in the receiver (17) is returned to the circulation path through the collecting liquid pipe (53) by flowing in.

[5] In any one of claims 1 to 4,

Suction superheat degree detection means (79, 81) for detecting the degree of superheat of the refrigerant from the first use side heat exchanger (31, 41) to the suction side of the compression mechanism (11D, 11E);

A control means (5) for controlling the refrigerant return mechanism (5) to return the refrigerant in the receiver (17) to the circulation path when the detection value of the suction superheat degree detection means (79, 81) becomes a predetermined value or more. 95) and a refrigeration apparatus characterized by being beaten!

[6] In any one of claims 1 to 4,

A discharge superheat degree detection means (75, 76) for detecting the superheat degree of the refrigerant discharged by the compression mechanism (11D, 11E);

A control means (5) for controlling the refrigerant return mechanism (5) to return the refrigerant in the receiver (17) to the circulation path when the detection value of the discharge superheat degree detection means (75, 76) exceeds a predetermined value. 95) and a refrigeration apparatus characterized by being beaten!

[7] In any one of claims 1 to 4,

A discharge refrigerant temperature detection means (76) for detecting the temperature of the refrigerant discharged by the compression mechanism (11D, 11E);

A control means (95) for controlling the refrigerant return mechanism (5) to return the refrigerant in the receiver (17) to the circulation path when the detected value of the discharged refrigerant temperature detecting means (76) becomes a predetermined value or more. ).

[8] A heat source side unit (10) having a compression mechanism (11D, 11E), a heat source side heat exchanger (15), and a receiver (17), and a first use side heat exchanger (31, 41) A first usage unit (30, 40) having a first 2Gas side communication pipe (51) connecting the second usage side unit (20) with usage side heat exchange (21) and each unit (10, 20, 30, 40) to form the refrigerant circuit (50) , 52) and liquid side connecting piping (53, 54, 55),

In the refrigerant circuit (50), the refrigerant sent out by the compression mechanism (11D, 11E) flows from the second usage-side unit (20) through the first usage-side unit (30, 40) to the compression mechanism ( 11D, 1 1E), and the first use side unit (11D, 11E) after the refrigerant sent out from the heat source side heat exchange (15) flows into the receiver (17). 30, 40) is provided to switch the second operation mode to return to the compression mechanism (11D, 11E). (12)

The switching mechanism (12) switches from the first operation mode to the second operation mode, and the liquid refrigerant accumulated in the receiver (17) during the first operation mode passes through the collecting liquid pipe (53). A refrigeration system that is returned to the user side unit (30, 40).