COOLING DEVICE

专利摘要:
cooling device. an air conditioner (110) includes a refrigerant circuit (120) that connects an external circuit (111a) and a plurality of internal circuits (112a) connected in parallel. the air conditioner (110) includes a leak detection section (141) which detects leakage of a refrigerant from the internal circuits (112a), and a control section (142) which circulates the refrigerant to perform the refrigerant cycle. refrigeration when the leak detection section (141) detects refrigerant leakage such that the refrigerant in the internal circuits (112a) of the refrigerant circuit (120) is at low pressure. provision of the control section (142) in the air conditioner (110) can reduce internal circuit refrigerant leakage at low cost.
公开号:BR112015003481B1
申请号:R112015003481-0
申请日:2013-08-27
公开日:2021-08-24
发明作者:Ryuzaburo Yajima；Toshiyuki Kurihara
申请人:Daikin Industries, Ltd；
IPC主号:

专利说明:

TECHNICAL FIELD
[001] The present disclosure refers to a refrigeration device that includes a refrigeration circuit that performs the refrigeration cycle, especially for measures to prevent leakage of a refrigerant from the refrigeration circuit. PRIOR TECHNIQUE
[002]When a refrigerant circuit of an air conditioner, etc., leaks refrigerant into a room to increase the concentration of refrigerant in the room, the acute toxicity and flammability of the refrigerant can possibly cause accidental poisoning, combustion, suffocation, etc. In particular, when the refrigerant has a low global warming potential (GWP), which is an index that has lately received attention, the refrigerant is more flammable than a refrigerant with a high GWP, and can cause accidental events with a higher possibility. To avoid accidental events, IEC 60335-2-40 (special requirements for electric heat pumps, air conditioners and dehumidifiers) and the revised design of ISO5149 (cooling systems and heat pumps □ safety and environmental requirements) establish a permissible value of the amount of refrigerant filling the refrigerant circuit. The allowable value is set at a value at which the refrigerant concentration in the room does not exceed a limit, even if the total amount of refrigerant filling the refrigerant circuit leaks. In the event that the refrigerant concentration in the room exceeds the limit when the total amount of refrigerant filling the refrigerant circuit leaks, safety measures were required, for example, a refrigerant leak detector arranged in the room to provide an alarm when the leakage is detected, or a forced ventilation device arranged in the room.
[003]To properly select and take the security measures, it is required that the designers and operators have a high degree of specialization. The security measures described above increase the number and cost of installation processes. Under these circumstances, security measures are not always taken.
[004] As a solution to this problem, the air conditioner itself is provided with a mechanism to reduce refrigerant leakage. For example, Patent Document 1 discloses an air conditioner of this type. Patent Document 1 air conditioner includes an outdoor unit and an indoor unit. In the outdoor unit, the control valves are provided in a gas tube and a liquid tube connected to the indoor unit. When the air conditioner has detected refrigerant leakage in the room from the indoor unit, the control valve in the liquid pipe is closed to perform a cooling operation (a refrigerant collection operation). Therefore, the control valve stops the flow of refrigerant from the outdoor unit to the indoor unit, and the refrigerant in the indoor unit flows to the outdoor unit to be contained in an outdoor heat exchanger or a refrigerant regulator. After the refrigerant collection operation is performed for a predetermined period, the control valve on the gas pipe is closed to finish the operation. Therefore, the refrigerant in the indoor unit is collected in the outdoor unit, thus preventing refrigerant leakage into the room from the indoor unit.
[005]Among the refrigeration devices, a flexible cooling/heating air conditioner, which can simultaneously satisfy the cooling and heating requirements of the room was known as disclosed by Patent Document 2. The air conditioner includes a plurality of side units of use units arranged in different rooms so that some of the use side units perform the cooling operation, while the other use side units perform the heating operation. CITATION LIST PATENT DOCUMENTS
[006] [Patent Document 1] Unexamined Japanese Patent Publication No. H10-9692
[007] [Patent Document 2] Unexamined Japanese Patent Publication No. 2008-138954 SUMMARY OF THE INVENTION TECHNICAL PROBLEM
[008] The mechanism for reducing refrigerant leakage disclosed by Patent Document 1 disadvantageously increases the cost, because the control valves (stop valves) provided in the gas pipe and in the liquid pipe are expensive. As refrigerant leakage does not occur very often, it is not economical to use expensive control valves only to control refrigerant leakage.
[009] In view of the above, disclosure was obtained to reduce refrigerant leakage from a side circuit of low cost use.
[010] For the purpose described above, according to the present disclosure, a difference between a pressure in a side use circuit (3a-5a, 112a) (a refrigerant pressure) and a pressure in the side use space is reduced as much as possible to reduce the refrigerant leakage rate when refrigerant has leaked from the side usage circuit (3a-5a, 112a).
[011] Specifically, a first aspect of the present disclosure relates to a refrigeration device that includes: a refrigerant circuit (120) connecting a heating source side circuit (111a) having a compressor (121), a heat exchanger heating source side (123) and an expansion valve (124) and a use side circuit (112a) having a use side heat exchanger (125), and which performs the refrigeration cycle by reversibly circulating the refrigerant in it, a gas end of the utilization side circuit (112a) always communicating with the compressor (121). The refrigeration device further includes a leak detection section (141) which detects the leakage of refrigerant from the utilization side circuit (112a), and a control section (142) which circulates the refrigerant to carry out the refrigeration cycle. when the leak detection section (141) has detected the refrigerant leak such that the refrigerant in the use side circuit (112a) of the refrigerant circuit (120) is at low pressure.
[012] According to the first aspect of the present disclosure, for example, the leak detection section (141) detects refrigerant leakage when the refrigerant has leaked from a tube of the utilization side circuit (112a) into the side space of use in the refrigeration cycle carried out in such a way that the refrigerant in the use side circuit (112a) of the refrigerant circuit (120) is at high pressure (the use side heat exchanger (125) functions as a radiator). Then, the refrigerant is circulated to carry out the refrigeration cycle such that the refrigerant in the use side circuit (112a) of the refrigerant circuit (120) is at low pressure. This reduces the difference between the pressure of the refrigerant in the side use circuit (112a) and the pressure in the side use space, thus reducing the velocity of leakage of the refrigerant leaking from the side use circuit (112a). Therefore, the amount of leaked refrigerant is reduced to such a degree that the refrigerant can be sufficiently released from the use side space by natural ventilation from the use side space, and the increase in refrigerant concentration in the use side space can be reduced .
[013] In a second aspect of the present disclosure related to the first aspect of the present disclosure, the control section (142) circulates the refrigerant to perform the refrigeration cycle when the leak detection section (141) has detected the refrigerant leak such that the refrigerant in the use side circuit (112a) of the refrigerant circuit (120) is at a low pressure not lower than atmospheric pressure.
[014] According to the second aspect of the present disclosure, the refrigerant pressure in the use side circuit (112a) is controlled as being at atmospheric pressure, that is, the refrigerant pressure in the use side circuit (112a) is controlled as being greater than the pressure in the lateral space of use. Therefore, air in the side use space does not enter the side use circuit (112a) through a leak point in the side use circuit (112a) through which the refrigerant leaks (e.g. a hole formed in the tube by corrosion).
[015] In a third aspect of the present disclosure related to the first or second aspect of the present disclosure, the refrigerant circuit (120) includes a plurality of side-use circuits (112a) connected in parallel. The heat source side circuit (111a) has a single expansion valve (124) connected to the head of the utilization side circuits (112a). The control section (142) reduces the degree of opening of the expansion valve (124) of the heat source side circuit (111a) such that the refrigerant in the utilization side circuits (112a) is at low pressure.
[016] In the third aspect of the present disclosure, the refrigerant in the heating source side circuit (111a) of the refrigerant circuit (120) between the expansion valve (124) and a compressor suction side (121) is at low pressure . Therefore, the refrigerant in the entire use side circuit (112a) which includes a communication tube connecting the heat source side circuit (111a) and the use side circuit (112a) is at low pressure.
[017] According to a fourth aspect of the present disclosure related to the first or second aspect of the present disclosure, the refrigerant circuit (120) includes a plurality of side use circuits (112a). The side heating source circuit (111a) has branched heads connected to the heads of the side usage circuits (112a), and branched gas ends connected to the gas ends of the side usage circuits (112a), and the expansion valve ( 124) is provided in each plurality of tubes (1f) constituting the head parts of the heat source side circuit (111a). The control section (142) reduces the degree of opening of the expansion valve (124) which corresponds to the utilization side circuit (112a) to which the leak detection section (141) has detected the refrigerant leakage in such a way that the refrigerant in the utilization side circuit (112a) at which the leak detection section (141) has detected the refrigerant leak is at low pressure.
[018] In the fourth aspect of the present disclosure, among the plurality of side use circuits (112a), the refrigerant in the side use circuit (112a) from which the refrigerant has leaked is at low pressure.
[019] According to a fifth aspect of the present disclosure related to the third or fourth aspect of the present disclosure, the refrigerant circuit (120) has a pressure reduction mechanism (132) that reduces the pressure of the refrigerant, and includes a refrigerant tube. injection (131) that guides the circulating refrigerant portion to a suction side of the compressor (121) or an intermediate pressure chamber of the compressor (121). The control section (142) increases the speed of refrigerant flow in the injection tube (131) when the leak detection section (141) has detected the refrigerant leak.
[020] In the fifth aspect of the present disclosure, the flow velocity of the refrigerant in the injection tube (131) increases, thus reducing the temperature of the refrigerant released from the compressor (121).
[021] According to the sixth aspect of the present disclosure related to the third or fourth aspect of the present disclosure, the refrigerant device further includes a side use fan (116) supplying air, which exchanges heat with the refrigerant to the heat exchanger side of use (125). The control section (142) reduces the speed of air flow supplied by the use side fan (116) when the leak detection section (141) has detected the refrigerant leak.
[022] In the sixth aspect of the present disclosure, the air flow velocity supplied by the use side fan (116) is reduced, thus reducing the degree of superheat of the refrigerant sucked into the compressor (121). This reduces the temperature of the refrigerant released from the compressor (121).
[023] According to a seventh aspect of the present disclosure, a refrigerant circuit (10) connecting a heat source side circuit (2a) having a compressor (21) and a heat source side heat exchanger (22 ) and a plurality of use side circuits (3a, 4a, 5a) each having a use side heat exchanger (31, 41, 51) for air conditioning the use side space, the refrigerant circuit (10) being configured such that the use-side heat exchangers (31, 41, 51) independently perform a cooling operation and a heating operation, and a high pressure gaseous refrigerant released from the compressor (21) flows entirely into the exchanger source side heat exchanger (22) when all utilization side heat exchangers (31, 41, 51) perform the cooling operation. The refrigeration device according to the seventh aspect of the present disclosure further includes a leak detection section (17) which detects refrigerant leakage from the refrigerant circuit (10) in the side space of use, and a control section (18), which circulates the refrigerant to perform the refrigeration cycle when the leak detection section (17) has detected the refrigerant leak in such a way that the refrigerant in the usage side circuit (3a, 4a, 5a) of the circuit refrigerant (10) is at low pressure.
[024] In the seventh aspect of the present disclosure, for example, the leak detection section (17) detects refrigerant leakage when the refrigerant has leaked from a tube in the side space of use in the refrigeration cycle performed in such a way that the refrigerant in the use side circuit (3a, 4a, 5a) of the refrigerant circuit (10) is at high pressure (the use side heat exchangers (31, 41, 51) function as radiators). Then, the refrigerant is circulated to carry out the refrigeration cycle such that the refrigerant in the use side circuit (3a, 4a, 5a) of the refrigerant circuit (10) is at low pressure. This reduces the difference between the pressure of the refrigerant in the side use circuit (3a, 4a, 5a) and the pressure in the side use space, thus reducing the leakage rate of the refrigerant leaking from the side use circuit (3a, 4a, 5a). Therefore, the amount of leaked refrigerant is reduced to such a degree that the refrigerant can be sufficiently released from the use side space by natural ventilation of the use side space, and the increase in the concentration of refrigerant concentration in the use side space can be reduced.
[025] According to an eighth aspect of the present disclosure related to the seventh aspect of the present disclosure, the control section (18) circulates the refrigerant to carry out the refrigeration cycle when the leak detection section (17) has detected the leak of the refrigerant in such a way that the refrigerant in the usage side circuit (3a, 4a, 5a) of the refrigerant circuit (10) is at a low pressure not lower than atmospheric pressure.
[026] In the eighth aspect of the present disclosure, the pressure of the refrigerant in the lateral use circuit (3a, 4a, 5a) is controlled as being not less than atmospheric pressure, i.e., the pressure of the refrigerant in the lateral use circuit (3a , 4a, 5a) is controlled to be greater than the pressure in the lateral space of use. Thus, air in the side use space does not enter the side use circuit (3a, 4a, 5a) through a leak point in the side use circuit (112a) by means of refrigerant leaks (e.g. a formed orifice in the pipe by corrosion).
[027] According to a ninth aspect of the present disclosure related to the seventh or eighth aspect of the present disclosure, the control section (18) reduces the degree of opening of an expansion valve (23) for refrigerant evaporation in the heat exchanger heating source side (22) such that the refrigerant in the use side circuit (3a, 4a, 5a) is at low pressure.
[028] In the ninth aspect of the present disclosure, the refrigerant in the refrigerant circuit (10) between the expansion valve (23) of the heating source side circuit (2a) and the compressor suction side (21) is at low pressure . Thus, the refrigerant in the use side circuit (3a, 4a, 5a) which includes liquid tubes and gas tubes connecting the heat source side circuit (2a) and the use side circuits (3a, 4a, 5a) is at low pressure.
[029] According to the tenth aspect of the present disclosure related to the ninth aspect of the present disclosure, the cooling device further includes use side fans (3F, 4F, 5F) that supply air that exchanges heat with the refrigerant to the heat exchangers. use side heater (31, 41, 51), wherein the control section (18) reduces the air flow speed supplied by the use side fan (3F, 4F, 5F) when the leak detection section (17 ) has detected the refrigerant leak.
[030] In the tenth aspect of the present disclosure, the air flow velocity supplied by the use side fan (3F, 4F, 5F) is reduced, thus reducing the degree of superheat of the refrigerant sucked into the compressor (21). This reduces the temperature of the refrigerant released from the compressor (21).
[031] According to an eleventh aspect of the present disclosure relating to any one of the first to tenth aspects of the present disclosure, the refrigerant circuit (120) uses R32, R1234yf, R1234ze or R744 alone, or a refrigerant mixture containing R32, R1234yf , R1234ze or R744 as refrigerant.
[032] In the eleventh aspect of the present disclosure, R32, R1234yf, R1234ze or R744 alone, or a refrigerant mixture containing R32, R1234yf, R1234ze or R744 is used as the refrigerant. ADVANTAGES OF THE INVENTION
[033] According to the first aspect of the present disclosure, the refrigerant in the use side circuit (112a) is at low pressure when the refrigerant has leaked into the use side space. Thus, the difference between the pressure of the refrigerant in the side usage circuit (112a) and the pressure in the side usage space can be reduced as much as possible. According to the seventh aspect of the present disclosure, the pressure of the refrigerant in the side use circuits (3a, 4a, 5a) is at low pressure when the refrigerant has leaked into the side use space. Therefore, the difference between the pressure of the refrigerant in the lateral use circuits (3a, 4a, 5a) and the pressure in the lateral use space can be reduced as much as possible.
[034] According to the first and seventh aspects of the present disclosure, the difference between the pressure of the refrigerant in the side circuits of use (3a-5a, 112a) can be reduced when the refrigerant has leaked, thus reducing the leakage rate of the soda. Therefore, the refrigerant can be sufficiently discharged from the use side space by natural ventilation of the use side space, thus reducing the increase in refrigerant concentration in the use side space. Thus, the refrigerant concentration does not exceed the predetermined limit. Refrigerant leakage can be reduced at low cost because the refrigerant flow shutoff valve is no longer needed.
[035] According to the seventh aspect of the present disclosure, the refrigerant pressure in the side use circuits (3a, 4a, 5a) is at low pressure when refrigerant leakage was detected when the side use circuits (3a, 4a) perform the heating operation, and the utilization side circuit (5a) concurrently performs the cooling operation. Therefore, the utilization side circuit (5a) continues to perform the cooling operation. This can reduce refrigerant leakage while ensuring the comfort of the usage side circuit (5a) performing the cooling operation.
[036] According to the second aspect of the present disclosure, the pressure of the refrigerant in the side circuit of use (112a) is at a low pressure not lower than atmospheric pressure. Therefore, the pressure of the refrigerant in the lateral use circuit (112a) is not less than the pressure in the lateral use space. According to the eighth aspect of the present disclosure, the pressure of the refrigerant in the side usage circuits (3a, 4a, 5a) is at a low pressure not less than atmospheric pressure. Therefore, the refrigerant pressure in the side usage circuits (3a, 4a, 5a) is not less than atmospheric pressure. Thus, according to the second and eighth aspect of the present disclosure, the entry of air into the use side space in the use side circuits (3a-5a, 112a) by the refrigerant leak point can certainly be avoided.
[037] According to the third and fourth aspects of the present disclosure, the degree of opening of the expansion valve (124) of the heating source side circuit (111a) is reduced such that the refrigerant in the use side circuit ( 112a) is at low pressure, thus keeping the refrigerant in the side usage circuit (112a) at low pressure. This can safely reduce refrigerant leakage from the side usage circuit (112a).
[038] According to the fifth aspect of the present disclosure, the flow velocity of the refrigerant in the injection tube (131) is high, thus reducing the temperature of the refrigerant released from the compressor (121). In the present disclosure, the difference between the pressure of the refrigerant in the use side circuit (112a) and the pressure in the use side space is reduced as much as possible to reduce the rate of refrigerant leakage. Thus, the degree of opening of the expansion valve 124 of the side heat source circuit 111a tends to be less than the degree of opening in normal operation. This can lead to an abnormal increase in the temperature of the refrigerant released from the compressor (121) due to the increase in high pressure in the refrigeration cycle. The present disclosure can prevent such abnormal increase.
[039] In accordance with the sixth aspect of the present disclosure, the air flow velocity supplied by the use side fan (116) is reduced, thus reducing the degree of superheat of the refrigerant sucked into the compressor (121). This reduces the temperature of the released refrigerant. According to the tenth aspect of the present disclosure, the air flow velocity supplied by the side use fans (3F, 4F, 5F) is reduced, thus reducing the degree of superheat of the refrigerant sucked into the compressor (21). This can reduce the temperature of the released refrigerant.
[040] According to the sixth and tenth aspects of the present disclosure, the difference between the pressure of the refrigerant in the use side circuit (112a) and the pressure in the use side space is reduced as much as possible to reduce the leakage rate of the soda. Thus, the pressure of the refrigerant in the side usage circuits (3a-5a, 112a) tends to be lower than the pressure in normal operation. This can cause an abnormal increase in the degree of superheat of the refrigerant sucked into the compressor (21, 121) and in the temperature of the refrigerant released. Abnormal enlargement can be avoided according to the sixth and tenth aspects of the present disclosure.
[041] According to the ninth aspect of the present disclosure, the degree of opening of the expansion valve (23) of the heating source side circuit (2a) is reduced such that the refrigerant in the side usage circuits (3a, 4a, 5a) is at low pressure. Thus, the refrigerant in the side usage circuits (3a, 4a, 5a) can safely be kept at low pressure. This can safely reduce refrigerant leakage from the side usage circuits (3a, 4a, 5a).
[042] The refrigerants R32, R1234yf, R1234ze and R744 have a relatively low global warming potential (GWP) and are environmentally friendly refrigerants. Refrigerants R32, R1234yf and R1234ze exhibited flammability (slightly flammable refrigerants) and could possibly cause accidental combustion if they leak. R744 refrigerant has no flammability (flammable refrigerant) but may cause accidental suffocation if it leaks. However, according to the eleventh aspect of the present disclosure, accidental combustion and suffocation due to leakage of the environment-friendly refrigerants used. R32 is difluoromethane (HFC-32), R1234yf is 2,3,3,3-tetrafluoro-1-propene (HFO-1234yf), R1234ze is 1,3,3,3-tetrafluoro-1-propene (HFO-1234ze) and R744 is carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS
[043] [FIG. 1] FIG. 1 is a refrigerant circuit diagram showing a general configuration of an air conditioner of a first embodiment.
[044] [FIG. 2] FIG. 2 is a table showing the characteristics of refrigerants.
[045] [FIG. 3] FIG. 3 is a graph showing an R32 liquid refrigerant leak rate.
[046] [FIG. 4] FIG. 4 is a graph showing a leak rate of a gaseous refrigerant R32.
[047] [FIG. 5] FIG. 5 is a refrigerant circuit diagram showing a general configuration of an air conditioner of a second embodiment.
[048] [FIG. 6] FIG. 6 is a diagram of a refrigerant circuit of an air conditioner of a third embodiment.
[049] [FIG. 7] FIG. 7 is a refrigerant circuit diagram showing the flow of a refrigerant when the air conditioner of the third embodiment performs the general heating operation.
[050] [FIG. 8] FIG. 8 is a refrigerant circuit diagram showing the flow of refrigerant when the air conditioner of the third embodiment performs a general cooling operation.
[051] [FIG. 9] FIG. 9 is a refrigerant circuit diagram showing the flow of refrigerant when the air conditioner of the third embodiment performs a first simultaneous operation.
[052] [FIG. 10] FIG. 10 is a refrigerant circuit diagram showing the flow of refrigerant when the air conditioner of the third embodiment performs a second simultaneous operation.
[053] [FIG. 11] FIG. 11 is a refrigerant circuit diagram of an air conditioner of a fourth embodiment. DESCRIPTION OF ACHIEVEMENTS
[054] Embodiments of the present disclosure will be described in detail with reference to the drawings. The following and alternative embodiments are described as essentially preferable examples, and do not limit the scope of the present disclosure, applications, or its use.
[055] (First Achievement)
[056] The first realization of the present disclosure will be described below. An air conditioner (110) of the present embodiment constitutes a refrigeration device of the present disclosure.
[057] As shown in FIG. 1, the air conditioner (110) includes an outdoor unit (111) and a plurality of indoor units (112) (two indoor units in the present embodiment). The outdoor unit (111) and the indoor units (112) are connected to each other by means of a liquid communication tube (113) and a gas communication tube (114). In the air conditioner (110), a refrigerant circuit (120) is formed by an external circuit (111a) contained in the outdoor unit (111), internal circuits (112a) contained in the indoor units (112), the liquid communication tube (113) and the gas communication tube (114). The outdoor unit (111) constitutes a heating source unit, and the indoor units (112) constitute side use units. The external circuit (111a) constitutes a heat source side circuit, and the internal circuits (112a) constitute the use side circuits.
[058] The external circuit (111a) includes a compressor (121), a four-way switching valve (122), an external heating switch (123), an external expansion valve (124), and a heating switch subcooling (127). The outdoor unit (111) is provided with an external fan (115) to supply external air to the external heating switch (123). Each of the internal circuits (112a) includes an internal heat switch (125) and an internal expansion valve (126). Each of the indoor units (112) is provided with an indoor fan (116) to supply indoor air to the indoor heat switch (125). The external heat switch (123) constitutes a heat source side heat exchanger, and the internal heat switches (125) are use-side heat exchangers. The external fan (115) constitutes a heat source side fan, and the internal fans (116) constitute the use side fans.
[059] The refrigerant circuit (120) is a closed circuit and uses R32, R1234yf, R1234ze or R744 alone, or a refrigerant mixture containing R32, R1234yf, R1234ze or R744 as the refrigerant. R32 is difluoromethane (HFC-32), R1234yf is 2,3,3,3-tetrafluoro-1-propene (HFO-1234yf), R1234ze is 1,3,3,3-tetrafluoro-1-propene (HFO-1234ze) and R744 is carbon dioxide. The refrigerant circuit (120) is configured to reversibly circulate refrigerant to perform a refrigeration cycle.
[060] The compressor (121) has a release side connected to a first port of the four-way switching valve (122) through a release tube (101a), and a suction side connected to a second valve port four-way switching (122) via a suction tube (101b). A third port of the four-way switch valve (122) is connected to one end of the external heat switch (123) via an external gas pipe (101c), and a fourth port of the four-way switch valve (122 ) is connected to a gas shut-off valve (118) via an external gas pipe (101d). The other end of the external heating switch (123) is connected to a liquid shutoff valve (117) via an external liquid pipe (101e). The external liquid pipe (101e) is provided with the external expansion valve (124) and the subcool heating switch (127) arranged in this order from the side closest to the external heating switch (123). An injection tube (131) having an injection valve (132) is connected as a pressure reducing mechanism between the outer liquid tube (101e) and the suction tube (101b). The subcool heating switch (127) includes a high temperature passage (127a) connected to the outer liquid tube (101e), and a low temperature passage (127b) connected to the injection tube (131). In the subcool heating switch (127), liquid refrigerant reduced in pressure by the injection valve (132) flows in the low temperature passage (127b), and exchanges heating with a liquid refrigerant in the high temperature passage (127a ) to evaporate. The liquid refrigerant in the high temperature passage (127a) is sub-cooled.
[061] Each of the internal circuits (112a) includes an inner tube (102a) connected to the liquid shutoff valve (117) at one end (a liquid end), and connected to the gas shutoff valve (118) at other end (a gas end). The inner tube (102a) includes the inner expansion valve (126) and the inner heating switch (125) arranged in this order from the side closest to the liquid shutoff valve (117).
[062] The liquid communication pipe (113) is connected to the liquid shutoff valve (117) of the external circuit (111a) at one end, and is branched in two at the other end to be connected to the liquid shutoff valves (117) of the internal circuits (112a). The gas communication tube (114) is connected to the gas shutoff valve (118) of the external circuit (111a) at one end, and is branched in two at the other end to be connected to the gas shutoff valves (118) of the internal circuits (112a). Thus, the two internal circuits (112a) are connected to each other in parallel. In the refrigerant circuit (120) of the present embodiment, the gas shutoff valves (118) of the internal circuits (112a) (gas ends) communicate with the compressor (121).
[063] The compressor (121) is a hermetic or rotary roller compressor. The four-way switching valve (122) is switched between a first state (indicated by a dashed line in FIG. 1) where the first port communicates with the third port, and the second port communicates with the fourth port, and a second state (indicated by a solid line in FIG. 1) where the first port communicates with the fourth port, and the second port communicates with the third port. The external expansion valve (124) and the internal expansion valve (126) are thus called electrical expansion valves.
[064] The external heat switch (123) switches heat between the external air and the refrigerant. The external heat switch (123) will be described later. The internal heat switch (125) exchanges heat between the internal air and the refrigerant. The internal heat switch (125) is a so-called cross tube and wing heat switch that includes a round heat transfer tube.
[065] The air conditioner (110) includes a controller (140) to control the operation. The controller (140) includes a leak detection section (141) and a control section (142). Each of the internal circuits (112a) includes a pressure sensor (135) for sensing refrigerant pressure. In the present embodiment, the pressure sensor (135) is provided in the inner tube (102a) between the internal heating switch (125) and the gas shutoff valve (118).
[066] The leak detection section (141) detects refrigerant leakage based on a determination that refrigerant has leaked from the internal circuit (112a) when decreasing a value detected by the pressure sensor (135) by time of unit is not less than the predetermined value. When the leak detection section (141) has detected the refrigerant leak, the control section (142) circulates the refrigerant in the refrigerant circuit (120) to perform a refrigeration cycle such that the refrigerant in the internal circuits (112a ) is at low pressure. Specifically, the control section (142) circulates the refrigerant to perform the refrigeration cycle in which the external heating switch (123) functions as a condenser (a radiator), and the internal heating switch (125) functions as an evaporator. (an emergency operation). Details of the operation of the control section (142) will be described later. AIR CONDITIONER OPERATING MECHANISM
[067] The air conditioner (110) performs a cooling operation and a heating operation as normal operations, and an emergency operation in a switchable manner.
[068] In the cooling operation, the refrigerant circuit (120) performs the refrigeration cycle with the four-way switching valve (122) established in the first state. In this state, refrigerant flows from the compressor (121) to circulate through the external heating switch (123), the external expansion valve (124), the subcool heating switch (127), the internal expansion valves ( 126), and of the internal heating switches (125) in that order, and the external heating switch (123) functions as the condenser (the radiator), while the internal heating switch (125) functions as the evaporator. The external expansion valve (124) is fully open. The degree of opening of each of the internal expansion valves (126) is controlled such that the degree of superheat of the refrigerant flowing from the internal heating switch (125) (the degree of superheat of the refrigerant sucked into the compressor (121 )) matches the predetermined value. Specifically, in normal cooling operation, the refrigerant is reduced in pressure by the internal expansion valve (126) such that the refrigerant remaining between the internal expansion valve (126) and the suction side of the compressor (121) is at low pressure. In the external heating switch (123), the gaseous refrigerant dissipates heat in the external air to condense. In each of the internal heating switches (125), the liquid refrigerant absorbs heat from the indoor air to evaporate, thereby cooling the indoor air. Part of the liquid refrigerant condensed in the external heating switch (123) flows into the injection tube (131). The liquid refrigerant that has flowed into the injection tube (131) is reduced in pressure by the injection valve (132) and then flows to the low temperature passage (127b) of the subcool heating switch (127). In the subcool heating switch (127), the liquid refrigerant in the high temperature passage (127a) exchanges heat with the refrigerant in the low temperature passage (127b) to be subcooled, thus evaporating the refrigerant in the low passage temperature (127b). Evaporated refrigerant is injected into the suction tube (101b).
[069] In the heating operation, the refrigerant circuit (120) performs the refrigeration cycle with the four-way switching valve (122) established in the second state. In this state, refrigerant flows from the compressor (121) to circulate through the internal heating switches (125), the internal expansion valves (126), the subcool heating switch (127), the external expansion valve ( 124) and the external heating switch (123) in that order, and the internal heating switch (125) functions as the condenser (the radiator), while the external heating switch (123) functions as the evaporator. Each of the internal expansion valves (126) is fully open, or its degree of opening is controlled in accordance with heating performance. The degree of opening of the external expansion valve (124) is controlled such that the degree of superheat of the refrigerant flowing from the external heating switch (123) (the degree of superheat of the refrigerant sucked into the compressor (121)) matches the predetermined value. Specifically, in the heating operation, the external expansion valve (124) reduces the refrigerant pressure, and the refrigerant in all internal circuits (112a) is at high pressure. At the external heating switch (123), liquid refrigerant absorbs heat from the external air to evaporate. In the internal heating switches 125, the gaseous refrigerant dissipates heat in the indoor air to condense, thus heating the indoor air. The injection valve (132) is fully closed. EMERGENCY OPERATION
[070] Emergency operation is performed when the leak detection section (141) detects refrigerant leakage in the normal operation described above. This section describes the case where the leak detection section (141) detected the refrigerant leak while the heating operation is carried out.
[071] When a hole is formed in the inner circuit tube (112a) due to corrosion to leak the refrigerant through the hole in the heating operation, the value detected by the pressure sensor (135) abruptly reduces. Then, the leak detection section (141) detects the refrigerant leak. As the refrigerant in the internal circuits (112a) is at high pressure in the heating operation, there is a big difference between the pressure of the refrigerant in the internal circuits (112a) and the pressure in the room. Therefore, the refrigerant leakage rate increases, and the refrigerant is not released sufficiently to the outside of the room by natural room ventilation. As a result, the refrigerant concentration in the room exceeds the limit.
[072] In the present embodiment, emergency operation is performed when the leak detection section (141) has detected the refrigerant leak. In emergency operation, the refrigerant circulates in the refrigerant circuit (120) in the same direction as in the cooling operation. Specifically, the four-way switching valve (122) is set to the first state. Then, the inner expansion valves (126) are fully opened, and the degree of opening of the outer expansion valve (124) is reduced. That is, in emergency operation, the external expansion valve (124) reduces the refrigerant pressure to reduce the pressure in all internal circuits (112a). Therefore, the difference between the pressure of the refrigerant in the internal circuits (112a) and the pressure in the room is reduced, thus reducing the leakage rate of the refrigerant leaking from the internal circuits (112a).
[073] The degree of opening of the external expansion valve (124) is controlled in such a way that the refrigerant pressure in the internal circuits (112a) is reduced as much as possible within a range not less than atmospheric pressure. In emergency operation, the control section (142) reduces the air flow speed supplied by the internal fan (116). In addition, the control section (142) completely opens the injection valve (132) in emergency operation.
[074] The refrigerant leakage rate (kg/h) is described below. As shown in FIG. 3 and FIG. 4, the refrigerant leakage velocity (kg/h) increases as the size of the orifice through which the refrigerant leaks increases. The refrigerant leakage rate (kg/h) decreases as the refrigerant saturation temperature decreases, ie the refrigerant pressure decreases. In the internal circuits (112a), liquid refrigerant or gaseous refrigerant leaks, depending on a leak location through which the refrigerant leaks.
[075] When the orifice is formed by corrosion, which is the most frequent cause of refrigerant leakage, it is assumed that the orifice has a maximum diameter of 0.2 mm. As shown in FIG. 4, when gaseous refrigerant leaks from the 0.2 mm diameter orifice, the leak rate is 2.00 (kg/h) at a saturation temperature of 63 °C where the pressure is the highest in the range shown in FIG. 4. The pouring speed is 0.026 (kg/h) when the saturation temperature is -50 °C.
[076] Liquid refrigerant leaks at a higher leakage rate (kg/h) than gaseous refrigerant. As shown in FIG. 3, when the liquid refrigerant leaks from the 0.2 mm diameter orifice, the leakage velocity is 5.3 (kg/h) at the saturation temperature of 63 °C, and it is 0.32 (kg/h ) at a saturation temperature of -50 °C. Therefore, the pouring speed (kg/h) decreases considerably when the pressure is reduced to reduce the saturation temperature.
[077] In relation to the minimum ventilation by which the refrigerant concentration does not exceed the refrigerant concentration limit RCL = 0.061 (kg/m3) in the room established in the revised design of ISO5149, the minimum ventilation > 0.32 (kg/h ) / 0.061 (kg/m3) = 5.2(m3/h). It is assumed that the volume of the room in which the indoor unit of approximately 1 horsepower is arranged is 2.7 mx 2.7 mx 2.3 m = 16.7 m3, the minimum ventilation is 5.2 ( m3/h) / 16.7 m3 = 0.32 times/h. This is less than 0.5 times/h, which is the minimum ventilation set for Japanese homes. It was considered that ventilation performed at a frequency of approximately 0.32 times/h can be sufficiently performed by natural ventilation. Once the refrigerant pressure decreases, the refrigerant generally becomes gaseous refrigerant, and the leakage rate (kg/h) reduces further.
[078] As described above, emergency operation makes it possible to reduce the refrigerant pressure in the internal circuits (112a) to reduce the refrigerant leak rate (kg/h). This can prevent the refrigerant concentration in the room from exceeding the limit.
[079] When the leak detection section (141) has detected refrigerant leakage in the cooling operation, the control section (142) fully opens the internal expansion valves (126), and reduces the degree of opening of the valve expansion port (124) with the four-way switching valve (122) held in the first state, thus switching the cooling operation to the emergency operation. ADVANTAGES OF THE FIRST ACHIEVEMENT
[080] In the air conditioner (110) of the present embodiment, the refrigeration cycle is performed in such a way that the refrigerant in the internal circuits (112a) is at low pressure when refrigerant has leaked from the internal circuits (112a). This can reduce the difference between the refrigerant pressure in the internal circuits (112a) and the pressure in the room as much as possible. Therefore, the refrigerant leakage speed can be reduced. As a result, the refrigerant can be sufficiently released out of the room by natural room ventilation, thus reducing the increase in refrigerant concentration in the room. Thus, the refrigerant concentration in the room does not exceed the predetermined limit. Refrigerant leakage can be reduced at low cost because the refrigerant flow shutoff valve is no longer needed.
[081] According to the present embodiment, the refrigerant in the internal circuits (112a) is at a low pressure not less than atmospheric pressure. Therefore, the pressure of the refrigerant in the internal circuits (112a) is not less than the pressure in the room. This can safely prevent the internal air from entering the internal circuits (112a) through the refrigerant leak point.
[082] According to the present embodiment, in emergency operation, the degree of opening of the external expansion valve (124) is reduced rather than reducing the degree of opening of the internal expansion valve (126) such that the refrigerant in internal circuits (112a) is at low pressure. This can safely keep the refrigerant in all internal circuits (112a) at low pressure. Therefore, refrigerant leakage can safely be reduced irrespective of the position of the point in the internal circuits (112a) through which the refrigerant leaks.
[083] According to the present embodiment, the air flow velocity provided by the internal fan (116) is reduced in emergency operation. This can reduce the degree of superheat of the refrigerant sucked into the compressor (121), thus reducing the temperature of the refrigerant released from the compressor (121). In the present embodiment, the difference between the pressure of the refrigerant in the internal circuits (112a) and the pressure in the room is reduced as much as possible to reduce the rate of leakage of the refrigerant. Therefore, the refrigerant pressure in the internal circuits (112a) tends to be less than the refrigerant pressure in normal cooling operation. This can lead to an abnormal increase in the degree of superheat of the refrigerant sucked into the compressor (121) and the temperature of the refrigerant released from the compressor (121). The present embodiment can prevent such abnormal increase.
[084] According to the present embodiment, the injection valve (132) is fully open in emergency operation. Thus, part of the refrigerant that has passed through the external expansion valve (124) is injected into the suction tube (101b), and the flow velocity of the injected refrigerant is greater than the amount injected in normal cooling operation. This can safely reduce the temperature of the refrigerant released from the compressor (121). In the present embodiment, the difference between the pressure of the refrigerant in the internal circuits (112a) and the pressure in the room is reduced as much as possible to reduce the rate of leakage of the refrigerant. Thus, the degree of opening of the external expansion valve 124 tends to be less than the degree of opening in normal operation. This can lead to an abnormal increase in the temperature of the refrigerant released from the compressor (121) due to the increase in high pressure in the refrigeration cycle. The present embodiment can prevent such abnormal increase.
[085] As shown in FIG. 2, R32, R1234yf, R1234ze and R744 (not shown) refrigerants have a relatively low global warming potential (GWP) and are environment friendly refrigerants. R32, R1234yf and R1234ze refrigerants have flammability (slightly flammable refrigerants) and could possibly cause accidental combustion if they leak. R744 refrigerant has no flammability (a flammable refrigerant) but can cause accidental suffocation if it leaks. However, the present embodiment can safely prevent accidental combustion and suffocation even when environment-friendly refrigerants are used.
[086] In the present embodiment, it has been assumed that refrigerant does not leak into the room when refrigerant leaks from a part beyond the internal circuits (112a). Therefore, the leak detection section (141) of the present embodiment is configured to detect refrigerant leakage from the internal circuits (112a). In emergency operation in the present embodiment, the degree of opening of the external expansion valve (124) is reduced. Therefore, not only the refrigerant in the internal circuits (112a), but also the refrigerant in the liquid communication tube (113) and the gas communication tube (114) are at low pressure. Therefore, when the leak detection section (141) is configured to detect refrigerant leakage not only from the internal circuits (112a), but also from the communication tubes (13, 14), the refrigerant leakage from the communication tubes ( 13, 14) can also be reduced. SECOND ACHIEVEMENT
[087] A second embodiment of the present disclosure will be described below. An air conditioner (110) of the present embodiment includes a refrigerant circuit modified from the refrigerant circuit (120) of the first embodiment. The differences between the present embodiment and the first embodiment will be described below.
[088] In the external circuit (111a) of the present embodiment, one end of the external gas pipe (101d) connected to the fourth port of the four-way switching valve (122) is branched in two, and the two ends are connected to the valves stop gas (118), respectively. In the external circuit (111a), the two-leg tubes (101f) constitute one end of the external liquid tube (101e) (i.e., a liquid end of the external circuit (111a)). Each of the branch tubes (101f) is connected to the liquid shutoff valve (117). The external expansion valve (124) is provided in each of the branch tubes (101f).
[089] In the present embodiment, liquid communication (113) and two gas communication tubes (114) are provided. The liquid communication pipes (113) are connected to the liquid shut-off valve (117) of the external circuit (111a) and the liquid shut-off valve (117) of the internal circuit (112a), respectively. The gas communication pipes (114) are connected to the gas shutoff valve (118) of the external circuit (111a) and the gas shutoff valve (118) of the internal circuit (112a), respectively. Specifically, in the refrigerant circuit (120) of the present embodiment, the liquid end of the external circuit (111a) is branched in two (the same number as the number of the internal circuits (112a)) to be connected to the internal circuits (112a), and the gas end of the outer circuit (111a) is branched in two (the same number as the number of the inner circuits (112a)) to be connected to the inner circuits (112a). The external expansion valve (124) is provided in each of the internal circuits (112a).
[090] The external circuit (111a) of the present embodiment does not include the subcooling heating switch (127) and the injection tube (131). Each of the internal circuits (112a) does not include the internal expansion valve (126).
[091] The air conditioner (110) of the present embodiment performs the cooling operation and the heating operation as the normal operation, and the emergency operation in a switchable manner.
[092] In the cooling operation, the refrigerant circuit (120) performs the refrigeration cycle with the four-way switching valve (122) established in the first state. In this state, the cooler flows from the compressor (121) to cycle through the external heat switch (123), the external expansion valves (124), and the internal heat switch (125) in that order, and the external heat switch. (123) functions as a condenser (a radiator), while the internal heat switch (125) functions as an evaporator. The degree of opening of each of the external expansion valves (124) is controlled such that the degree of superheat of the refrigerant flowing from the internal heating switch (125) (the degree of superheat of the refrigerant sucking into the compressor ( 121)) matches the predetermined value. In the external heating switch (123), the gaseous refrigerant dissipates heat in the external air to condense. In each of the internal heating switches (125), the liquid refrigerant absorbs heat from the indoor air to evaporate, thereby cooling the indoor air.
[093] In the heating operation, the refrigerant circuit (120) performs the refrigeration cycle with the four-way switching valve (122) established in the second state. In this state, refrigerant flows from the compressor (121) to circulate through the internal heating switches (125), the external expansion valves (124), and the external heating switch (123) in that order, and the internal heating switch. (125) functions as the condenser (the radiator), while the external heating switch (123) functions as the evaporator. The degree of opening of each of the external expansion valves (124) is controlled such that the degree of superheat of the refrigerant that has flown from the external heating switch (123) (the degree of superheat of the refrigerant sucking into the compressor ( 121)) matches the predetermined value. In the external heating switch (123), the liquid refrigerant absorbs heat from the external air to evaporate. In each of the internal heating switches 125, the gaseous refrigerant dissipates heat in the indoor air to condense, thereby heating the indoor air.
[094] Emergency operation is performed when the leak detection section (141) has detected the refrigerant leak in the normal operation described above. This section describes the case where the leak detection section (141) detected refrigerant leakage in the heating operation.
[095] When refrigerant leaks from the internal circuits (112a) in the heating operation, the value detected by the pressure sensor (135) abruptly reduces. Then, the leak detection section (141) detects the refrigerant leak. In the heating operation, as in the first embodiment, the refrigerant in the internal circuits (112a) is at high pressure, and there is a big difference between the pressure of the refrigerant in the internal circuits (112a) and the pressure in the room. Thus, the refrigerant leakage rate increases, and the refrigerant is not sufficiently released out of the room by the room's natural ventilation alone. As a result, the refrigerant concentration in the room exceeds the limit.
[096] In the present embodiment, emergency operation is performed when the leak detection section (141) has detected the refrigerant leak. In emergency operation, the refrigerant in the refrigerant circuit (120) circulates in the same direction as the cooling operation. Specifically, the four-way switching valve (122) is set to the first state. Then, the degree of opening of the external expansion valve (124) that corresponds to the internal circuit (112a) from which the refrigerant has leaked is reduced. The degree of opening of the external expansion valve (124) which corresponds to the internal circuit (112a) from which the refrigerant has not leaked is fully opened. Specifically, in the emergency operation of the present embodiment, only the degree of opening of the external expansion valve (124) that corresponds to the internal circuit (112a) from which the refrigerant has leaked is reduced to reduce the refrigerant pressure. Therefore, the pressure of the refrigerant in the entire internal circuit (112a) from which it leaked is reduced. As a result, the leakage velocity of the refrigerant leaking from the internal circuit (112a) decreases.
[097] Also in the emergency operation of the present embodiment, the degree of opening of the external expansion valve (124) that corresponds to the internal circuit (112a) from which the refrigerant has leaked is controlled in such a way that the refrigerant pressure in the internal circuitry (112a) is reduced as much as possible within the range not less than atmospheric pressure. Furthermore, the flow velocity of the air supplied from the internal fan (116) corresponding to the internal circuit (112a) from which the refrigerant has leaked is reduced.
[098] As described above, also in the present embodiment, emergency operation is performed to reduce the refrigerant pressure in the internal circuit (112a) to reduce the refrigerant leakage rate (kg/h). This can prevent the refrigerant concentration in the room from exceeding the limit.
[099] When the leak detection section (141) has detected the refrigerant leak in the cooling operation, the control section (142) switches the cooling operation to emergency operation with the four-way switching valve ( 122) maintained in the first state. In emergency operation, the degree of opening of the external expansion valve (124) corresponding to the internal circuit (112a) from which the refrigerant has leaked is further reduced to further reduce the refrigerant pressure in the internal circuit (112a), while the degree of opening of the external expansion valve (124) which corresponds to the internal circuit (112a) from which the refrigerant has not leaked is maintained.
[0100] In the emergency operation of the present embodiment, only the degree of opening of the external expansion valve (124) that corresponds to the internal circuit (112a) from which the refrigerant has leaked is reduced. Therefore, as compared to the case where the opening degrees of all external expansion valves (124) are reduced, the abnormal increase in high pressure of the refrigeration cycle can be reduced. The other advantages and effects are the same as those of the first realization.
[0101] THIRD ACHIEVEMENT
[0102] A cooling device of the present embodiment is an air conditioner (1) that independently cools or heats rooms as a plurality of side spaces of use, as shown in FIG. 6. Specifically, the air conditioner (1) is a so-called flexibly cooling/heating air conditioner capable of performing the heating operation in one of the rooms, while performing the cooling operation in the other rooms..
[0103] The air conditioner (1) includes a refrigerant circuit (10) including a single outdoor unit (20), the first, second and third indoor units (30, 40, 50), and the first to third BS units ( 60, 70, 80) which are connected through tubes. BS units (60, 70, 80) are switching units. The refrigerant circuit (10) further includes a liquid pipe (11), a high pressure gas pipe (12) and a low pressure gas pipe (13). The refrigerant circuit (10) performs the vapor compression refrigeration cycle by circulating the refrigerant.
[0104] The refrigerant circuit (10) uses R32, R1234yf, R1234ze or R744 alone, or a refrigerant mixture containing R32, R1234yf, R1234ze or R744 as the refrigerant. R32 is difluoromethane (HFC-32), R1234yf is 2,3,3,3-tetrafluoro-1-propene (HFO-1234yf), R1234ze is 1,3,3,3-tetrafluoro-1-propene (HFO-1234ze) and R744 is carbon dioxide. OUTDOOR UNIT CONFIGURATION
[0105] The outdoor unit (20) constitutes a heat source side unit, and includes an external circuit (2a) as a heat source side circuit including a compressor (21), an external heat switch (22) as a heat source side heat exchanger, an external expansion valve (23), a first three-way valve (24), and a second three-way valve (25).
[0106] Each of the first three-way valve (24) and the second three-way valve (25) includes first through third ports. The first three-way valve (24) has the first port connected to a compressor release side (21), the second port connected to a gas side of the external heating switch (22), and the third port connected to a suction side of the compressor (21). The second three-way valve (25) has the first port connected to the compressor release side (21), the second port connected to the BS units (60, 70, 80) through the high pressure gas pipe (12), and the third port connected to the low pressure gas pipe (13) and the suction side of the compressor (21).
[0107] Each of the three-way valves (24, 25) is configured to perform switching between a state where the first port communicates with the second port, and the third port is closed (indicated by a solid line in FIG. 6), and a state where the second port communicates with the third port, and the first port is closed (indicated by a dashed line in FIG. 6). The three-way valves (24, 25) constitute a switching mechanism.
[0108] The external heating switch (22) includes an external fan (2F) as a heat source side fan, and has a liquid side connected to a liquid pipe (11). INDOOR UNIT CONFIGURATION
[0109] The first to third indoor units (30, 40, 50) include first to third internal circuits (3a, 4a, 5a) including first to third internal heating switches (31, 41, 51) and first to third internal expansion valves (32, 42, 52), respectively. The internal circuits (3a, 4a, 5a) are use side circuits. Internal heating switches (31, 41, 51) include internal fans (3F, 4F, 5F) as use side fans, and have liquid sides connected to the liquid tube (11). Internal expansion valves (32, 42, 52) are provided on the liquid sides of corresponding internal heating switches (31, 41, 51).
[0110] The indoor units (30, 40, 50) include pressure sensors (P1, P2, P3) to detect the refrigerant pressure on the gas sides of the first to third indoor heating switches (31, 41, 51). BS UNIT CONFIGURATION
[0111] Each of the BS units (60, 70, 80) includes a first branch tube (61, 71, 81) and a second branch tube (62, 72, 82), which are branches of the indoor unit (30 , 40, 50) and are connected to the gas side of the internal heating switch (31, 41, 51). An open/closed electromagnetic valve (SV-1, SV-2, SV-3, ...) is provided in each of the first branch tubes (61, 71, 81) and the second branch tubes (62, 72 , 82). The first branch tubes (61, 71, 81) are connected to the high pressure gas tube (12), and the second branch tubes (62, 72, 82) are connected to the low pressure gas tube (13) .
[0112] When the electromagnetic valve (SV1, SV-2, SV-3, ...) of the BS Unit (60, 70, 80) is open/closed, the refrigerant flow is switched such that the side of gas from the internal heating switch (31, 41, 51) corresponding to the electromagnetic valve (SV1, SV-2, SV-3, ...) is connected to the suction side or release side of the compressor (21). CONTROLLER CONFIGURATION
[0113] The air conditioner (1) includes a controller (16) to control the three-way valves (24, 25), the electromagnetic valves (SV-1, SV-2, SV-3, .), the compressor (21), etc. The controller (16) receives detection signals from the pressure sensors (P1, P2, P3) and includes a leak detection section (17) and a control section (18).
[0114] The leak detection section (17) detects refrigerant leakage based on a determination that refrigerant has leaked into the room when a decrease in the value detected by the pressure sensor (P1, P2, P3) per unit time is no less than the default value. When the leak detection section (17) has detected the refrigerant leak, the control section (18) circulates the refrigerant in the refrigerant circuit (10) to perform a refrigeration cycle so that the refrigerant in the internal circuits (3a, 4a, 5a) is at low pressure. Specifically, the control section (18) circulates the refrigerant to perform the refrigeration cycle in which the external heating switch (22) functions as the condenser (the radiator), and all internal heating switches (31, 41, 51 ) function as evaporators (the emergency operation). OPERATING MECHANISM
[0115] An operating mechanism of the air conditioner (1) will be described below. The air conditioner (1) can perform different operations according to the status of the three-way valves (24, 25) and the electromagnetic valves (SV-1, SV-2, SV-3, ...) of the BS units (60, 70, 80). Among these operations, representative operations will be described below. GENERAL HEATING OPERATION
[0116] In a general heating operation, all indoor units (30, 40, 50) perform room heating. As shown in FIG. 7, in the general heating operation, each of the three-way valves (24, 25) is set in the state where the first port communicates with the second port. In BS units (60, 70, 80), the first electromagnetic valve (SV-1), the third electromagnetic valve (SV-3) and the fifth electromagnetic valve (SV-5) are opened, and the second electromagnetic valve (SV-1) -2), the fourth solenoid valve (SV-4) and the sixth solenoid valve (SV-6) are closed. In FIG. 7 and in the other figures that show the other operating mechanisms, the closed electromagnetic valves are filled with black and the open electromagnetic valves are filled with white.
[0117] In general heating operation, the refrigeration cycle is performed, in which the external heating switch (22) acts as the evaporator, and the internal heating switches (31, 41, 51) function as condensers. In FIG. 7 and in the other figures showing the other operating mechanisms, the heating switches that act as condensers are dotted, and the heating switches that act as evaporators are filled with white. In this refrigeration cycle, the refrigerant released from the compressor (21) passes through the second three-way valve (25), flows through the high-pressure gas tube (12) and is split to flow in the first branch tubes (61, 71 , 81) of the BS units (60, 70, 80). Refrigerant that has passed through the BS units (60, 70, 80) flows towards the corresponding indoor units (30, 40, 50).
[0118] For example, when refrigerant flows in the first internal heating switch (31) of the first indoor unit (30), the refrigerant dissipates heat in the indoor air in the first internal heating switch (31) to condense. As a result, the room corresponding to the first indoor unit (30) is heated. Refrigerant condensed in the first internal heating switch (31) passes through the first internal expansion valve (32). The opening degree of the first internal expansion valve (32) is adjusted in accordance with the degree of subcooling of the refrigerant flowing from the first internal heating switch (31). In the second indoor unit (40) and in the third indoor unit (50), refrigerant flows in the same way from the first indoor unit (30) to heat the corresponding rooms.
[0119] The refrigerant flows from the indoor units (30, 40, 50) mix in the liquid pipe (11). The mixed refrigerant is reduced to low pressure once it has passed the external expansion valve (23), and flows into the external heating switch (22). In the external heating switch (22), the refrigerant absorbs heat from the external air to evaporate. Refrigerant evaporated in the external heating switch (22) passes through the first three-way valve (24), and then is sucked into the compressor (21) for further compression. GENERAL COOLING OPERATION
[0120] In a general cooling operation, all indoor units (30, 40, 50) perform room cooling. As shown in FIG. 8, the three-way valves (24, 25) are established in the state where the first port communicates with the second port in the general cooling operation. In BS units (60, 70, 80), the second solenoid valve (SV-2), the fourth solenoid valve (SV-4) and the sixth solenoid valve (SV-6) are opened, and the first solenoid valve (SV-2) -1), the third solenoid valve (SV-3) and the fifth solenoid valve (SV-5) are closed.
[0121] In general cooling operation, the refrigeration cycle is performed, in which the external heating switch (22) acts as a condenser, and the internal heating switches (31, 41, 51) function as evaporators. Specifically, refrigerant released from the compressor (21) passes through the first three-way valve (24) and flows into the external heating switch (22). Specifically, all the high-pressure gaseous refrigerant released from the compressor (21) does not flow in the high-pressure gas pipe (12), but only flows in the external heating switch (22). In the external heating switch (22), the refrigerant dissipates heat in the external air to condense. Refrigerant condensed in the external heating switch (22) passes through the fully open external expansion valve (23), flows through the liquid pipe (11) and is divided to flow in the indoor units (30, 40, 50).
[0122] For example, in the first indoor unit (30), the refrigerant is reduced to low pressure as it passes through the first internal expansion valve (32) and flows into the first internal heating switch (31). In the first internal heating switch (31), the refrigerant absorbs heat from the internal air to evaporate. As a result, the room corresponding to the first indoor unit (30) is cooled. The opening degree of the first internal expansion valve (32) is adjusted in accordance with the degree of superheat of the refrigerant flowing from the first internal heating switch (31). In the second indoor unit (40) and third indoor unit (50), the refrigerant flows in the same way from the first indoor unit (30) to cool the corresponding rooms. Refrigerant flows from the indoor units (30, 40, 50) pass through the second branch tubes (62, 72, 82) of the BS units (60, 70, 80), mix in the low pressure gas tube (13), and then are sucked into the compressor (21) for further compression. SIMULTANEOUS COOLING/HEATING OPERATION
[0123] The simultaneous heating/cooling operation is a concurrent operation, in which some of the indoor units heat the rooms, while the other indoor units cool the rooms. In simultaneous heating/cooling operation, the external heating switch (22) functions as an evaporator or condenser in accordance with the operating conditions. Among the indoor units (30, 40, 50), one or more indoor heating switches corresponding to one or more rooms in which heating is required function as condensers, while the rest of the indoor heating switches corresponding to rooms in which cooling is required function as an evaporator. In the following description, the external heating switch (22) functions as a condenser, at least one of the internal heating switches (31, 41, 51) functions as a condenser, and the rest of the internal heating switches function as evaporators. FIRST CONCOMITANT OPERATION
[0124] In a first simultaneous operation, the first indoor unit (30) and the second indoor unit (40) heat the rooms, while the third indoor unit (50) cools the room. As shown in FIG. 9, in this operation, the three-way valves (24, 25) are set in the state where the first port communicates with the second port. In BS units (60, 70, 80), the first electromagnetic valve (SV-1), the third electromagnetic valve (SV-3) and the sixth electromagnetic valve (SV-6) are opened, and the second electromagnetic valve (SV-6) -2), the fourth electromagnetic valve (SV-4) and the fifth electromagnetic valve (SV-5) are closed.
[0125] In the first concurrent operation, the refrigeration cycle is performed, in which the external heating switch (22), the first internal heating switch (31) and the second internal heating switch (41) function as capacitors, while the third internal heating switch (51) acts as an evaporator. Specifically, refrigerant released from the compressor (21) is split to flow into the first three-way valve (24) and the second three-way valve (25). Refrigerant passing through the first three-way valve (24) is condensed in the external heating switch (22), passes through the external expansion valve (23) open to the predetermined degree and flows through the liquid pipe (11).
[0126] The refrigerant that has passed the second three-way valve (25) flows through the high pressure gas pipe (12), and is divided to flow in the first BS unit (60) and the second BS unit (70). The refrigerant which has flown from the first BS unit (60) flows into the first internal heating switch (31). In the first internal heating switch (31), the refrigerant dissipates heat into the internal air to condense. As a result, the room corresponding to the first indoor unit (30) is heated. The refrigerant used in the first indoor unit (30) to heat the room flows in the liquid pipe (11). Likewise, the refrigerant that has flown from the second BS unit (70) is used in the second indoor unit (40) to heat the room, and then flows into the liquid pipe (11).
[0127] The refrigerant mixed in the liquid pipe (11) flows into the third indoor unit (50). Refrigerant is reduced to low pressure as it passes through the third internal expansion valve (52), and then flows into the third internal heating switch (51). In the third internal heating switch (51), the refrigerant absorbs heat from the internal air to evaporate. As a result, the room corresponding to the third indoor unit (50) is cooled. The refrigerant used in the third indoor unit (50) to cool the room passes through the third BS unit (80), flows through the low pressure gas pipe (13) and is sucked into the compressor (21) for further compression. SECOND CONCOMITANT OPERATION
[0128] In a second concurrent operation, the first indoor unit (30) heats the room, while the second indoor unit (40) and the third indoor unit (50) cool the rooms. As shown in FIG. 10, in this operation, the three-way valves (24, 25) are set in the state where the first port communicates with the second port. In BS units (60, 70, 80), the first electromagnetic valve (SV-1), the fourth electromagnetic valve (SV-4) and the sixth electromagnetic valve (SV-6) are opened, and the second electromagnetic valve (SV-6) -2), the third solenoid valve (SV-3) and the fifth solenoid valve (SV-5) are closed.
[0129] In the second concurrent operation, the refrigeration cycle is performed, in which the external heating switch (22) and the first internal heating switch (31) function as capacitors, while the second internal heating switch (41) and the third internal heating switch (51) function as evaporators. Specifically, refrigerant released from the compressor (21) is split to flow into the first three-way valve (24) and the second three-way valve (25). Refrigerant which has passed through the first three-way valve (24) is condensed in the external heating switch (22), passes through the external expansion valve (23) open to the predetermined degree and flows in the liquid pipe (11).
[0130] Refrigerant that has passed the second three-way valve (25) flows in the first indoor unit (30) through the high pressure gas pipe (12) and the first BS unit (60). In the first indoor unit (30), refrigerant is condensed in the first indoor heating switch (31) to heat the room. The refrigerant used in the first indoor unit (30) to heat the room flows in the liquid pipe (11).
[0131] The refrigerant mixed in the liquid pipe (11) is divided to flow in the second indoor unit (40) and the third indoor unit (50). In the second indoor unit (40), the refrigerant reduced in pressure by the second indoor expansion valve (42) evaporates in the second indoor heating switch (41) to cool the room. Likewise, in the third indoor unit (50), the refrigerant reduced in pressure by the third internal expansion valve (52) evaporates in the third indoor heating switch (51) to cool the room. The refrigerants used in the indoor units (40, 50) to cool rooms pass through the second BS unit (70) and the third BS unit (80), respectively, mix in the low pressure gas pipe (13) and are sucked into inside the compressor (21) for re-compression. In FIGS. 7-10, the external fan (2F) and the internal fans (3F, 4F, 5F) are not shown. EMERGENCY OPERATION
[0132] Emergency operation is performed when the leak detection section (17) has detected the refrigerant leak in the normal operation described above. This section describes the case where the leak detection section (17) detected the refrigerant leak in the general heating operation.
[0133] For example, when a hole is formed in the tube of the internal circuit (3a, 4a, 5a) due to corrosion to leak the refrigerant through the hole in the general heating operation, the value detected by the pressure sensor (P1, P2, P3) abruptly decreases. Then, the leak detection section (17) detects the refrigerant leak. As the refrigerant in the internal circuits (3a, 4a, 5a) is at high pressure in the general heating operation, for example, there is a big difference between the refrigerant pressure in the first internal circuit (3a) and the pressure in the room. Therefore, the refrigerant leakage rate increases, and the refrigerant is not sufficiently released out of the room by the room's natural ventilation. As a result, the refrigerant concentration in the room exceeds the limit.
[0134] In the present embodiment, the emergency operation is performed when the leakage detection section (17) has detected the refrigerant leak. In the emergency operation, the refrigerant circulates in the refrigerant circuit (10) in the same direction as in the general cooling operation. However, the internal expansion valves (32, 42, 52) are opened, and the degree of opening of the external expansion valve (23) is reduced. Specifically, in emergency operation, the refrigerant is reduced in pressure by the external expansion valve (23), and the refrigerant in all internal circuits (3a, 4a, 5a) is at low pressure. This reduces the difference between the pressure of the refrigerant in the internal circuits (3a, 4a, 5a) and the pressure in the room, thus reducing the leakage rate of the refrigerant that has leaked from the internal circuits (3a, 4a, 5a).
[0135] The degree of opening of the external expansion valve (23) is controlled in such a way that the pressure of the refrigerant in the internal circuits (3a, 4a, 5a) is reduced as much as possible within the range not less than the atmospheric pressure. In emergency operation, the control section (18) reduces the air flow velocity supplied by the internal fans (3F, 4F, 5F).
[0136] As described in the first embodiment, the refrigerant leak rate (kg/h) increases as the size of the orifice through which the refrigerant leaks increases. The refrigerant leakage velocity (kg/h) decreases as the refrigerant saturation temperature decreases, that is, as the refrigerant pressure decreases.
[0137] Therefore, when emergency operation is performed, the refrigerant pressure in the internal circuits (3a, 4a, 5a) is reduced to reduce the refrigerant leakage rate (kg/h). This can prevent the refrigerant concentration in the room from exceeding the limit. ADVANTAGES OF THE THIRD ACHIEVEMENT
[0138] In the air conditioner (1) of the present embodiment, the refrigeration cycle is carried out in such a way that the refrigerant in the internal circuits (3a, 4a, 5a) is at low pressure when the refrigerant has leaked into the room. This can reduce the difference between the refrigerant pressure in the internal circuits (3a, 4a, 5a) and the pressure in the room as much as possible. Therefore, the refrigerant leakage speed can be reduced. As a result, the refrigerant can be sufficiently released outside the room by the room's natural ventilation, thus reducing the increase in refrigerant concentration in the room. Thus, the refrigerant concentration in the room does not exceed the predetermined limit. Refrigerant leakage can be reduced at low cost because the refrigerant flow shutoff valve is no longer needed.
[0139] In the present embodiment, the cooling operation is performed in such a way that the refrigerant in all internal circuits (3a, 4a, 5a) is at low pressure when refrigerant leakage is detected when the indoor units (30, 40) ) perform the heating operation, and the indoor unit (50) concurrently performs the cooling operation. Therefore, the indoor unit (50) continues to perform the cooling operation. This can reduce refrigerant leakage while ensuring the comfort of the indoor unit (50) which performs the cooling operation.
[0140] In the present embodiment, the refrigerant in the internal circuits (3a, 4a, 5a) is at a low pressure not less than atmospheric pressure. Therefore, the refrigerant pressure in the internal circuits (3a, 4a, 5a) is not less than the pressure in the room. This can safely prevent the internal air from entering the internal circuits (3a, 4a, 5a) through the refrigerant leak point.
[0141] In the emergency operation of the present embodiment, the degree of opening of the external expansion valve (23) is reduced rather than reducing the degrees of opening of the internal expansion valve (32, 42, 52) such that the refrigerant in internal circuits (3a, 4a, 5a) is at low pressure. Therefore, the refrigerant in all internal circuits (3a, 4a, 5a) can safely be kept at low pressure. Thus, refrigerant leakage can safely be reduced irrespective of the point in the internal circuits (3a, 4a, 5a) through which the refrigerant leaks.
[0142] In the present embodiment, the air flow velocity provided by the internal fans (3F, 4F, 5F) is reduced in emergency operation. This can reduce the degree of superheat of the refrigerant sucked into the compressor (21), thus reducing the temperature of the refrigerant released from the compressor (21). In the present embodiment, the difference between the pressure of the refrigerant in the internal circuits (3a, 4a, 5a) and the pressure in the room is reduced as much as possible to reduce the rate of leakage of the refrigerant. Thus, the refrigerant pressure in the internal circuits (3a, 4a, 5a) tends to be lower than the pressure in normal cooling operation. This can lead to an abnormal increase in the degree of superheat of the refrigerant sucked into the compressor (21) and the temperature of the refrigerant released from the compressor (21). The present embodiment can prevent such abnormal increase.
[0143] As shown in FIG. 2, R32, R1234yf, R1234ze and R744 (not shown) refrigerants have a relatively low global warming potential (GWP) and are environment friendly. R32, R1234yf and R1234ze refrigerants have flammability (slightly flammable refrigerants), and could possibly cause accidental combustion if they leak. R744 refrigerant has no flammability (a flammable refrigerant) but can cause accidental suffocation if it leaks. However, the present embodiment can safely prevent combustion and accidental suffocation due to refrigerant leakage even when environment friendly refrigerants are used.
[0144] In the present embodiment, it is assumed that refrigerant does not leak into the room when refrigerant leaks from a part beyond the internal circuits (3a, 4a, 5a). Therefore, the leak detection section (17) of the present embodiment is configured to detect refrigerant leakage from the internal circuits (3a, 4a, 5a). In the emergency operation of the present embodiment, the degree of opening of the external expansion valve (23) is reduced. Thus, not only the refrigerant in the internal circuits (3a, 4a, 5a), but also the refrigerant in the communication pipes, such as the liquid pipe (11), etc., are at low pressure. Therefore, when the leak detection section (17) is configured to detect refrigerant leakage not only from the internal circuits (3a, 4a, 5a), but also from the liquid pipe (11), etc., refrigerant leakage from communication pipes such as liquid pipe (11), etc., can be reduced. FOURTH ACHIEVEMENT
[0145] The fourth embodiment of the present disclosure will be described in detail with reference to the drawings.
[0146] As shown in FIG. 11, an air conditioner (1) of the present embodiment is the same air conditioner of the third embodiment in addition to the liquid pipe (11), the high pressure gas pipe (12) and the low pressure gas pipe (13 ) of the third embodiment are replaced by two communication tubes (90, 91).
[0147] Specifically, an external unit (20) includes a compressor (21), an external heating switch (22) and a four-way switching valve (92). The four-way switching valve (92) is connected to a release side and a suction side of the compressor (21). One end of an external heat switch (22) is connected to a first main tube (93), and the other end of the external heat switch (22) is connected to a second main tube (94).
[0148] The first main tube (93) is connected to a first communication tube (90), and is provided with a check valve (CV) to allow refrigerant to flow from the first communication tube (90) to the first tube main (93). The second main tube (94) is connected to a second communication tube (91), and is provided with a check valve (CV) to allow refrigerant to flow from the second main tube (94) to the second communication tube (91). ).
[0149] The first communication tube (90) is connected to the second main tube (94) via a first branch tube (95). The first branch tube (95) is provided with a check valve (CV) to allow refrigerant to flow from the first communication tube (90) to the second main tube (94). The second communication tube (91) is connected to the first main tube (93) via a second branch tube (96). The second branch tube (96) is provided with a check valve (CV) to allow refrigerant to flow from the first main tube (93) to the second communication tube (91).
[0150] The first communication tube (90) and the second communication tube (91) are connected to a switching unit (97). Three indoor units (30, 40, 50) are connected to the switching unit (97). Although not shown, the switching unit (97) includes expansion valves, etc., and switches the flow of refrigerant in such a way that the three indoor units (30, 40, 50) can independently perform the cooling operation and the heating operation.
[0151] The air conditioner (1) includes a controller (16) similar to the air conditioner of the third embodiment. OPERATING MECHANISM
[0152] A general heating operation, a general cooling operation, a first concurrent operation and a second concurrent operation performed by the air conditioner (1) will be described below.
[0153] In the general heating operation, the refrigerant released from the compressor (21) passes through the first main tube (93), the second branch tube (96), the second communication tube (91) and the switching unit (97 ), and flows into the indoor unit to condense. Then, the refrigerant flows through the switching unit (97), the first communicating tube (90), the first branch tube (95) and the second main tube (94), evaporates in the external heating switch (22) and returns to compressor (21). Refrigerant circulation is repeated.
[0154] In general cooling operation, refrigerant released from the compressor (21) flows into the external heating switch (22) to condense. Then, the refrigerant passes through the second main tube (94), the second communication tube (91) and the switching unit (97), flows in the indoor unit, evaporates in the internal heating switch and returns to the compressor (21) through the switching unit (97), the first communication tube (90) and the first main tube (93). Refrigerant circulation is repeated.
[0155] In the first concomitant operation, for example, the first indoor unit (30) and the second indoor unit (40) heat the rooms, while the third indoor unit (50) cools the room. In the first concurrent operation, all the refrigerant released from the compressor (21) flows from the first main tube (93) to the second branch tube (96) and the second communication tube (91), it is divided by the switching unit (97) to flow in the first internal heating switch (31) and the second internal heating switch (41) to condense. Then, part of the condensed liquid refrigerant flows in the third internal heating switch (51) through the switching unit (97) to evaporate, while the remainder of the liquid refrigerant is reduced in pressure by the switching unit expansion valve (97) to be a two-phase refrigerant, and mixes with the evaporated refrigerant in the third internal heating switch (51). Then, the mixed low pressure refrigerant flows from the switching unit (97) to pass the first communication tube (90), the first branch tube (95) and the second main tube (94), flows into the external heating switch (22) to evaporate, and returns to the compressor (21). Refrigerant circulation is repeated.
[0156] In the second concomitant operation, for example, the first indoor unit (30) heats the room, while the second indoor unit (40) and the third indoor unit (50) cool the rooms. In the second concurrent operation, all of the refrigerant released from the compressor (21) flows into the external heating switch (22), and part of the refrigerant is condensed to be a two-phase high pressure refrigerant. The two-phase high pressure refrigerant passes through the second main tube (94) and the second communication tube (91), flows into the switching unit (97), and is divided into a high pressure gaseous refrigerant and a liquid refrigerant. high pressure in the switching unit (97). High pressure gaseous refrigerant flows into the first internal heating switch (31) to condense. The split high pressure liquid refrigerant mixes with the condensed liquid refrigerant in the first internal heating switch (31), and then flows in the second internal heating switch (41) and the third internal heating switch (51) to evaporate. Evaporated low pressure refrigerant flows through the switching unit (97), the first communication pipe (90) and the first main pipe (93) to return to the compressor (21). Refrigerant circulation is repeated..
[0157] Also in the present embodiment, as in the third embodiment, the emergency operation is performed when the leak detection section (17) has detected the refrigerant leak. In emergency operation, all indoor units perform the cooling operation. Although not shown, the opening degrees of the switch unit expansion valves (97) are reduced such that the refrigerant in all internal circuits (3a, 4a, 5a) is at low pressure. Although not shown, the airflow speed provided by the internal fans is also reduced. The other advantages and effects of the present realization are the same as those of the third realization.
[0158] ADVANTAGES OF THE FOURTH ACHIEVEMENT
[0159] In the air conditioner (1) of the present embodiment, the refrigeration cycle is carried out in such a way that the refrigerant in the internal circuits (3a, 4a, 5a) is at low pressure when the refrigerant leaks into the room. This can reduce the difference between the refrigerant pressure in the internal circuits (3a, 4a, 5a) and the pressure in the room as much as possible. Therefore, the refrigerant leakage speed can be reduced. As a result, the refrigerant can be sufficiently released outside the room by the room's natural ventilation, thus reducing the increase in refrigerant concentration in the room. Thus, the refrigerant concentration in the room does not exceed the predetermined limit. Refrigerant leakage can be reduced at low cost because the refrigerant flow shutoff valve is no longer needed. The other advantages are the same as those of the third achievement. OTHER ACHIEVEMENTS
[0160] The embodiments described above can be modified as follows.
[0161] For example, in the embodiments described above, the speed of air flow provided by the internal fan (116) may not be reduced in emergency operation. In the first embodiment, refrigerant may not be injected into the suction tube (101b) in emergency operation.
[0162] Needless to say, the refrigerant used in the realizations is not limited to the refrigerants described above.
[0163] In the emergency operation of the first embodiment, the degree of opening of the external expansion valve (124) is reduced such that the refrigerant in all internal circuits (112a) is at low pressure. Alternatively, for example, when the refrigerant leak location in the internal circuit (112a) is closer to the gas shutoff valve (118) than to the internal expansion valve (126), the external expansion valve (124) and the internal expansion valve (126) of the other internal circuit (112a) from which the refrigerant has not leaked can be fully opened, and only the degree of opening of the internal expansion valve (126) of the internal circuit (112a) to from which the refrigerant has leaked can be reduced. In this case, in the internal circuit (112a) from which the refrigerant has leaked, the refrigerant remaining in the internal circuit between the internal expansion valve (126) and the gas shut-off valve (118) is at low pressure. Therefore, the refrigerant leakage rate can be safely reduced.
[0164] The injection tube (131) connected to the suction tube (101b) in the first embodiment can communicate with an intermediate pressure chamber of the compressor (121). Also in this case, the temperature of the refrigerant released from the compressor (121) can be reduced.
[0165] The three indoor units (30, 40, 50) are used in the third and fourth embodiments. However, the number of indoor units is not limited to these. INDUSTRIAL APPLICABILITY
[0166] As described above, the present disclosure is useful for a refrigeration device that includes a refrigerant circuit, which performs a refrigeration cycle by circulating a refrigerant.
[0167] DESCRIPTION OF REFERENCE CHARACTERS
[0168] 1 Air conditioner (cooling device)
[0169] 2nd External circuit (heat source side circuit)
[0170] 10 Coolant circuit
[0171] 17 Leak detection unit
[0172] 18 Control Unit
[0173] 20 Outdoor unit (side heating source unit)
[0174] 21 Compressor
[0175] 22 External heating switch (heat source side heat exchanger)
[0176] 23 External expansion valve
[0177] 30, 40, 50 Indoor unit (lateral unit of use)
[0178] 31, 41, 51 Internal heating switch (use side heat exchanger)
[0179] 3rd, 4th, 5th Internal circuit (usage side circuit)
[0180] 3F, 4F, 5F Internal fan (use side fan)
[0181] 110 Air conditioner (cooling device)
[0182] 111a External circuit (heat source side circuit)
[0183] 112a Internal circuit (use side circuit)
[0184] 116 Internal fan (use side fan)
[0185] 120 Coolant circuit
[0186] 121 Compressor
[0187] 123 External heating switch (heat source side heat exchanger)
[0188] 124 External expansion valve (expansion valve)
[0189] 125 Internal heating switch (use side heat exchanger)
[0190] 131 Injection tube
[0191] 132 Injection valve (pressure reduction mechanism)
[0192] 141 Leak detection unit
[0193] 142 Controller

权利要求:
Claims (11)
[0001]
1. COOLING DEVICE, characterized in that it comprises: refrigerant circuit (120), which connects a heat source side circuit (111a) having a compressor (121), a heat source side heat exchanger (123) and a valve expansion (124) and a use side circuit (112a) having a use side heat exchanger (125), and performs a refrigeration cycle by reversibly circulating a refrigerant therein, a gas end of the use side circuit. (112a) always communicating with the compressor (121), wherein the refrigeration device further comprises a leak detection section (141) which detects refrigerant leakage from the utilization side circuit (112a), and a control section ( 142), which is configured to switch the refrigeration device, when the leak detection section (141) has detected the refrigerant leak, from an operation in which the heat exchanger The use-side heat exchanger (125) functions as a condenser for an operation in which the use-side heat exchanger (125) functions as an evaporator and the refrigerant in the use-side circuit (112a) is at low pressure.
[0002]
2. COOLING DEVICE according to claim 1, characterized in that the control section (142) circulates the refrigerant to carry out the refrigeration cycle when the leak detection section (141) has detected refrigerant leakage in such a way that the refrigerant in the use side circuit (112a) of the refrigerant circuit (120) is at a low pressure not lower than atmospheric pressure.
[0003]
3. COOLING DEVICE, according to any one of claims 1 or 2, characterized in that the refrigerant circuit (120) includes a plurality of side circuits of use (112a) connected in parallel, by the side circuit of the heating source (111a) having a single expansion valve (124) connected to the heads of the utilization side circuits (112a), and by the control section (142) to reduce the opening degree of the expansion valve (124) of the heat source side circuit (111a) in such a way that the refrigerant in the side usage circuits (112a) is at low pressure.
[0004]
4. COOLING DEVICE, according to any one of claims 1 or 2, characterized in that the refrigerant circuit (120) includes a plurality of side circuits for use (112a), the side heating source circuit (111a) has branched heads connected to the heads of the side use circuits (112a), and branched gas ends connected to the gas ends of the side use circuits (112a), by the expansion valve (124) being provided in each plurality of tubes (1f) constituting parts of heads of the heating source side circuit (111a), and by the control section (142) to reduce the opening degree of the expansion valve (124) corresponding to the utilization side circuit (112a) to which the leakage detection section (141) detected the refrigerant leak such that the refrigerant in the utilization side circuit (112a) to which the leak detection section (141) detected the refrigerant leak. generator is at low pressure.
[0005]
5. COOLING DEVICE, according to any one of claims 3 or 4, characterized in that the refrigerant circuit (120) has an injection tube (131) that includes a pressure reduction mechanism (132) reducing the pressure of the refrigerant, and part by directing the circulating refrigerant to a suction side of the compressor (121) or an intermediate pressure chamber of the compressor (121), and by the control section (142) to increase the flow velocity of the refrigerant in the injection tube (131) when the leak detection section (141) has detected the refrigerant leak.
[0006]
A REFRIGERATION DEVICE according to any one of claims 3 or 4, characterized in that it further comprises: side-use fan (116) supplying air, which exchanges heat for the refrigerant to the side-use heat exchanger (125), in which control section (142) reduces the air flow velocity supplied by the use side fan (116) when the leak detection section (141) has detected the refrigerant leak.
[0007]
7. COOLING DEVICE, characterized in that it comprises: refrigerant circuit (10) connecting a side heating source circuit (2a) having a compressor (21) and a heating source side heating exchanger (22) and a plurality of use side circuits (3a, 4a, 5a) each having a use side heat exchanger (31, 41, 51) for the air conditioning use side space, the refrigerant circuit (10) being configured in such a way that the use-side heat exchangers (31, 41, 51) independently perform a cooling operation and a heating operation, and the high-pressure gaseous refrigerant released from the compressor (21) flows entirely into the use-side heat exchanger. heating source (22) when all the use side heating exchangers (31, 41, 51) perform the cooling operation, wherein the cooling device further comprises a leak detection section (17) which detects refrigerant leakage from the refrigerant circuit (10) in the use side space, and a control section (18) which is configured to switch the refrigeration device when the refrigerant detection section leak (17) has detected the refrigerant leak, from an operation in which the use-side heat exchanger (31, 41, 51) functions as a condenser to an operation in which the use-side heat exchanger (31, 41) , 51) functions as an evaporator and the refrigerant in the side usage circuit (3a, 4a, 5a) is at low pressure.
[0008]
8. COOLING DEVICE, according to claim 7, characterized in that the control section (18) circulates the refrigerant to carry out the refrigeration cycle when the leak detection section (17) has detected the refrigerant leak in such a way that the refrigerant in the operating side circuit (3a, 4a, 5a) of the refrigerant circuit (10) is at a low pressure not lower than atmospheric pressure.
[0009]
9. COOLING DEVICE, according to any one of claims 7 or 8, characterized in that the control section (18) reduces the degree of opening of an expansion valve (23) to evaporate the refrigerant in the heat source side heat exchanger (22) such that the refrigerant in the side usage circuit (3a, 4a, 5a) is at low pressure.
[0010]
10. COOLING DEVICE according to claim 9, characterized in that it further comprises: side-use fans (3F, 4F, 5F) providing air that exchanges heat with the refrigerant to the side-use heat exchangers (31, 41 , 51), in which the control section (18) reduces the air flow velocity supplied by the use side fan (3F, 4F, 5F) when the leak detection section (17) has detected the refrigerant leak.
[0011]
11. COOLING DEVICE, according to any one of claims 1 to 10, characterized in that the refrigerant circuit (10, 120) uses R32, R1234yf, R1234ze or R744 alone, or a refrigerant mixture containing R32, R1234yf, R1234ze or R744 as refrigerant.

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EP2905563A1|2015-08-12|

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法律状态:
2018-11-21| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|

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2020-04-22| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|

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2021-08-03| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2021-08-24| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 27/08/2013, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

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申请号 | 申请日 | 专利标题

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JP2012-186620|2012-08-27|

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JP2012186620A|JP6079055B2|2012-02-06|2012-08-27|Refrigeration equipment|

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JP2012-189053|2012-08-29|

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JP2012189053A|JP6079061B2|2012-02-06|2012-08-29|Refrigeration equipment|

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PCT/JP2013/005056|WO2014034099A1|2012-08-27|2013-08-27|Refrigeration system|

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