WO2016038659A1

WO2016038659A1 - Refrigeration cycle apparatus

Info

Publication number: WO2016038659A1
Application number: PCT/JP2014/073666
Authority: WO
Inventors: 山下　浩司
Original assignee: 三菱電機株式会社
Priority date: 2014-09-08
Filing date: 2014-09-08
Publication date: 2016-03-17
Also published as: JPWO2016038659A1; EP3193089A1

Abstract

A refrigeration cycle apparatus is provided with a refrigeration cycle configured by connecting a compressor 10, a first heat exchanger 12, a throttle device 16, and a second heat exchanger 15 with refrigerant pipes and through which a refrigerant circulates. The refrigerant is a single refrigerant or a mixed refrigerant formed of a substance that causes a disproportionation reaction. The refrigerant pipes include a bend section 45. Either one of the first heat exchanger 12 or the second heat exchanger 15 acts as a condenser and the other one thereof acts as an evaporator. The bend section 45 is provided in either one of or both of a flow passage between the condenser and the throttle device and a flow passage between the throttle device and the evaporator. The bend radius R of the bend section 45 through which a liquid refrigerant or a two-phase refrigerant passes satisfies the following relationship: R ≥ (d/2) × [1 + {tan(π/36) + cosθ}]/[1 - {tan(π/36) + cosθ}], where θ (rad) denotes the angle formed between the center line of an inlet pipe configuring a refrigerant inlet side of the bend section 45 and the center line of an outlet pipe configuring a refrigerant outlet side of the bend section 45, R (mm) denotes the bend radius of the bend section 45, and d (mm) denotes the internal diameter of the inlet pipe of the bend section 45.

Description

Refrigeration cycle equipment

The present invention relates to a refrigeration cycle apparatus such as an air conditioner applied to, for example, a building multi-air conditioner.

In a refrigeration cycle apparatus that forms a refrigerant circuit that circulates refrigerant and performs air conditioning, such as a multi air conditioner for buildings, generally, R410A that is nonflammable, hydrogen and carbon such as propane that exhibits flammability A substance containing is used as a refrigerant. When these substances are released into the atmosphere, they have different lifetimes until they are decomposed in the atmosphere and changed to other substances. However, they are highly stable in the refrigeration cycle apparatus and have been used for a long period of several decades. It can be used as a refrigerant.

On the other hand, some substances containing hydrogen and carbon have poor stability in the refrigeration cycle apparatus and are difficult to use as refrigerants. These substances having poor stability include, for example, substances that cause a disproportionation reaction. Disproportionation is the property that substances of the same type react to change to another substance.

For example, when some strong energy is applied to the refrigerant in a state where the distance between adjacent substances such as a liquid state is very close, this energy causes a disproportionation reaction, and the adjacent substances react with each other, It changes to another substance. When the disproportionation reaction occurs, heat is generated and a rapid temperature rise occurs, so that the pressure may rise rapidly. For example, if a substance that causes a disproportionation reaction is used as a refrigerant in a refrigeration cycle device and is enclosed in a pipe such as copper, the pipe cannot withstand the pressure rise of the internal refrigerant, and the pipe will burst. May occur. As substances having such a disproportionation reaction, for example, 1,1,2-trifluoroethylene (HFO-1123), acetylene and the like are known.

There is also a thermal cycle system (refrigeration cycle apparatus) using 1,1,2-trifluoroethylene (HFO-1123) as a working medium for thermal cycle (for example, Patent Document 1).

International Publication No. 2012/157774 (3rd page, 12th page, FIG. 1 etc.)

In a refrigeration cycle apparatus such as a thermal cycle system described in Patent Document 1, it is described that 1,1,2-trifluoroethylene (HFO-1123) is used as a thermal cycle working medium. 1,1,2-trifluoroethylene (HFO-1123) is a substance having a disproportionation reaction. When used as a refrigerant as it is, in a place where there is a liquid state substance where the distance between adjacent substances such as liquid and two-phase is very close, the adjacent substances react with each other and change to another substance by some energy. In addition to not functioning as a refrigerant, there is a possibility that pipe rupture or the like may occur due to a sudden rise in pressure.

Therefore, in order to use as a refrigerant, there is a problem that it must be used so as not to cause this disproportionation reaction. Thus, a device for preventing this disproportionation reaction is required, but Patent Document 1 and the like do not describe any method for realizing an apparatus that does not cause the disproportionation reaction.

The present invention has been made to solve the above-described problem, and a refrigeration cycle that can safely use a substance having a property of causing a disproportionation reaction by reducing energy received from the outside of the refrigerant as a refrigerant. Get the device.

A refrigeration cycle apparatus according to the present invention comprises a refrigeration cycle in which a compressor, a first heat exchanger, a throttling device, and a second heat exchanger are connected by a refrigerant pipe and the refrigerant circulates. The refrigerant is a single refrigerant composed of a substance having a disproportionation reaction or a mixed refrigerant containing a substance having a disproportionation reaction, and the refrigerant pipe has a flow direction of the refrigerant in the refrigerant pipe. One of the first heat exchanger and the second heat exchanger that acts as a condenser and the other as an evaporator, and the bent portion includes a condenser and a throttle device. The bending radius R of the bending portion provided in one or both of the flow path between the flow path and the flow path between the expansion device and the evaporator and through which the liquid refrigerant or the two-phase refrigerant flows satisfies the following relationship: .
R ≧ (d / 2) × [1+ {tan (π / 36) + cos θ}] / [1- {tan (π / 36) + cos θ}]
θ (rad): Angle formed by the center line of the inlet pipe constituting the refrigerant inlet side of the bent portion and the center line of the outlet pipe constituting the refrigerant outlet side of the bent portion R (mm): Bending radius of the bent portion d ( mm): Inner diameter of bent pipe

In the refrigeration cycle apparatus of the present invention, a substance having a disproportionation reaction such as 1,1,2-trifluoroethylene (HFO-1123) causes a disproportionation reaction and cannot be used as a refrigerant. It is possible to prevent the occurrence of pipe rupture or the like and to use it safely as a refrigerant.

Schematic which shows the example of installation of the refrigerating-cycle apparatus which concerns on Embodiment 1 of this invention. FIG. 3 is a circuit configuration diagram showing an example of a circuit configuration of the refrigeration cycle apparatus according to Embodiment 1. The refrigerant circuit figure which shows the flow of the refrigerant | coolant at the time of the air_conditionaing | cooling operation mode of the refrigerating-cycle apparatus which concerns on Embodiment 1 of this invention. The refrigerant circuit figure which shows the flow of the refrigerant | coolant at the time of the heating operation mode of the refrigerating-cycle apparatus which concerns on Embodiment 1 of this invention. The expanded sectional view of the curved part in the refrigerating-cycle apparatus which concerns on Embodiment 1 of this invention. Explanatory drawing of the structure for relieving the collision energy of a refrigerant | coolant in the refrigerating-cycle apparatus which concerns on Embodiment 1 of this invention. The figure which showed the bending part in case the angle of the inlet pipe and outlet pipe of the bending part in the refrigerating-cycle apparatus which concerns on Embodiment 1 of this invention is (theta). The solubility diagram of the refrigeration oil of the refrigeration cycle apparatus which concerns on Embodiment 1 of this invention. The circuit diagram of the refrigerating-cycle apparatus which concerns on Embodiment 2 of this invention.

Hereinafter, a refrigeration cycle apparatus according to an embodiment of the invention will be described with reference to the drawings. Here, in FIG. 1 and the following drawings, the same reference numerals denote the same or corresponding parts, and are common to the whole text of the embodiments described below. And the form of the component represented by the whole specification is an illustration to the last, Comprising: It does not limit to the form described in the specification. In particular, the combination of the components is not limited to the combination in each embodiment, and the components described in the other embodiments can be applied to another embodiment. Further, when there is no need to particularly distinguish or identify a plurality of similar devices that are distinguished by subscripts, the subscripts may be omitted. In the drawings, the size relationship of each component may be different from the actual one. The level of temperature, pressure, etc. is not particularly determined in relation to absolute values, but is relatively determined in the state, operation, etc. of the system, apparatus, and the like.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating an installation example of a refrigeration cycle apparatus according to Embodiment 1 of the present invention. The refrigeration cycle apparatus shown in FIG. 1 can select either a cooling mode or a heating mode as an operation mode by configuring a refrigerant circuit that circulates refrigerant and using a refrigerant refrigeration cycle. Here, the refrigeration cycle apparatus of the present embodiment will be described by taking an air conditioning apparatus that performs air conditioning of the air-conditioning target space (indoor space 7) as an example.

In FIG. 1, the refrigeration cycle apparatus according to the present embodiment has one outdoor unit 1 that is a heat source unit and a plurality of indoor units 2. The outdoor unit 1 and the indoor unit 2 are connected by an extension pipe (refrigerant pipe) 4 that conducts the refrigerant, and the cold or warm heat generated by the outdoor unit 1 is delivered to the indoor unit 2.

The outdoor unit 1 is usually arranged in an outdoor space 6 that is a space outside a building 9 such as a building (for example, a rooftop), and supplies cold or hot heat to the indoor unit 2. The indoor unit 2 is disposed at a position where air whose temperature is adjusted can be supplied to the indoor space 7 which is a space inside the building 9 (for example, a living room). Supply air.

As shown in FIG. 1, in the refrigeration cycle apparatus according to the present embodiment, an outdoor unit 1 and each indoor unit 2 are connected to each other using two extension pipes 4.

In addition, in FIG. 1, although the case where the indoor unit 2 is a ceiling cassette type is shown as an example, it is not limited to this. Any type may be used as long as heating air or cooling air can be blown directly into the indoor space 7 by a duct or the like, such as a ceiling-embedded type or a ceiling-suspended type.

FIG. 1 shows an example in which the outdoor unit 1 is installed in the outdoor space 6, but the present invention is not limited to this. For example, the outdoor unit 1 may be installed in an enclosed space such as a machine room with a ventilation opening. Further, if the waste heat can be exhausted outside the building 9 by the exhaust duct, it may be installed inside the building 9. Furthermore, you may make it install in the inside of the building 9 using the water-cooled outdoor unit 1. FIG. No matter what place the outdoor unit 1 is installed, no particular problem occurs.

Further, the number of connected outdoor units 1 and indoor units 2 is not limited to the number shown in FIG. 1, but the number of units can be determined according to the building 9 in which the refrigeration cycle apparatus according to the present embodiment is installed. That's fine.

FIG. 2 is a circuit configuration diagram showing an example of a circuit configuration of the refrigeration cycle apparatus (hereinafter referred to as the refrigeration cycle apparatus 100) according to the first embodiment. Based on FIG. 2, the detailed structure of the refrigerating-cycle apparatus 100 is demonstrated. As shown in FIG. 2, the outdoor unit 1 and the indoor unit 2 are connected by an extension pipe (refrigerant pipe) 4 through which a refrigerant flows.

[Outdoor unit 1]
The outdoor unit 1 is mounted with a compressor 10, a first refrigerant flow switching device 11 such as a four-way valve, a heat source side heat exchanger 12, and an accumulator 19 connected in series by a refrigerant pipe.

The compressor 10 sucks refrigerant and compresses the refrigerant to a high temperature and high pressure state. For example, the compressor 10 may be composed of an inverter compressor capable of capacity control. The first refrigerant flow switching device 11 switches the refrigerant flow during the heating operation and the refrigerant flow during the cooling operation. The heat source side heat exchanger 12 functions as an evaporator during heating operation, and functions as a condenser (or radiator) during cooling operation. The heat source side heat exchanger 12 serving as the first heat exchanger performs heat exchange between air supplied from a blower (not shown) and the refrigerant, and evaporates or condenses the refrigerant. is there. The heat source side heat exchanger 12 acts as a condenser in the operation of cooling the indoor space 7. Moreover, in the case of the driving | operation which heats the indoor space 7, it acts as an evaporator. The accumulator 19 is provided on the suction side of the compressor 10 and stores excess refrigerant in the refrigerant circuit due to an operation mode change or the like.

The outdoor unit 1 includes a compressor 10, a first refrigerant flow switching device 11, a heat source side heat exchanger 12, an accumulator 19, a high pressure detection device 37, a low pressure detection device 38, and a control device 60. The compressor 10 has, for example, a low-pressure shell structure that has a compression chamber in a sealed container, the inside of the sealed container has a low-pressure refrigerant pressure atmosphere, and sucks and compresses the low-pressure refrigerant in the sealed container. Alternatively, a high-pressure shell structure is used in which the inside of the sealed container becomes a high-pressure refrigerant pressure atmosphere and the high-pressure refrigerant compressed in the compression chamber is discharged into the sealed container.

Further, the outdoor unit 1 includes a control device 60, and controls equipment based on detection information from various detection devices, instructions from a remote controller, and the like. For example, the driving frequency of the compressor 10, the rotation speed of the blower (including ON / OFF), the switching of the first refrigerant flow switching device 11 and the like are controlled, and each operation mode described later is executed. Here, the control device 60 of the present embodiment is configured by a microcomputer or the like having control arithmetic processing means such as a CPU (Central Processing Unit). In addition, the control device 60 has storage means (not shown), and has data in which a processing procedure related to control and the like is a program. Then, the control arithmetic processing means executes processing based on the program data to realize control.

[Indoor unit 2]
The indoor unit 2 is equipped with a load-side heat exchanger 15 serving as a second heat exchanger. The load side heat exchanger 15 is connected to the outdoor unit 1 by the extension pipe 4. The load-side heat exchanger 15 exchanges heat between air supplied from a blower (not shown) and a refrigerant, and generates heating air or cooling air to be supplied to the indoor space 7. . The load side heat exchanger 15 acts as a condenser in the case of an operation for heating the indoor space 7. In addition, the load side heat exchanger 15 acts as an evaporator in the operation of cooling the indoor space 7.

FIG. 2 shows an example in which four indoor units 2 are connected, and are illustrated as an indoor unit 2a, an indoor unit 2b, an indoor unit 2c, and an indoor unit 2d from the bottom of the page. Further, according to the indoor unit 2a to the indoor unit 2d, the load side heat exchanger 15 is also loaded from the lower side of the page with the load side heat exchanger 15a, the load side heat exchanger 15b, the load side heat exchanger 15c, and the load side heat exchange. It is shown as a container 15d. As in FIG. 1, the number of connected indoor units 2 is not limited to four as shown in FIG.

Each operation mode executed by the refrigeration cycle apparatus 100 will be described. The refrigeration cycle apparatus 100 determines the operation mode of the outdoor unit 1 to be either the cooling operation mode or the heating operation mode based on an instruction from each indoor unit 2. That is, the refrigeration cycle apparatus 100 can perform the same operation (cooling operation or heating operation) for all of the indoor units 2 and adjusts the indoor temperature. Note that each indoor unit 2 can be freely operated / stopped in both the cooling operation mode and the heating operation mode.

The operation mode executed by the refrigeration cycle apparatus 100 includes a cooling operation mode in which all the driven indoor units 2 perform a cooling operation (including a stop), and all of the driven indoor units 2 are in a heating operation. There is a heating operation mode for executing (including stopping). Below, each operation mode is demonstrated with the flow of a refrigerant | coolant.

[Cooling operation mode]
FIG. 3 is a refrigerant circuit diagram illustrating a refrigerant flow in the cooling operation mode of the refrigeration cycle apparatus according to Embodiment 1 of the present invention. In FIG. 3, the cooling operation mode will be described by taking as an example a case where a cooling load is generated in all the load-side heat exchangers 15. In FIG. 3, a pipe indicated by a thick line indicates a pipe through which the refrigerant flows, and a flow direction of the refrigerant is indicated by a solid line arrow.

In the cooling operation mode shown in FIG. 3, in the outdoor unit 1, the first refrigerant flow switching device 11 is switched so that the refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12. The low-temperature and low-pressure refrigerant is compressed by the compressor 10 and discharged as a high-temperature and high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12 via the first refrigerant flow switching device 11. The refrigerant that has flowed into the heat source side heat exchanger 12 is condensed and liquefied while dissipating heat to the outdoor air in the heat source side heat exchanger 12, becomes high-pressure liquid refrigerant, and flows out of the outdoor unit 1.

The high-pressure liquid refrigerant that has flowed out of the outdoor unit 1 passes through the extension pipe 4 and flows into each of the indoor units 2 (2a to 2d). The high-pressure liquid refrigerant that has flowed into the indoor unit 2 (2a to 2d) flows into the expansion device 16 (16a to 16d), and is throttled and decompressed by the expansion device 16 (16a to 16d). It becomes a phase refrigerant. The low-temperature and low-pressure two-phase refrigerant further flows into each of the load-side heat exchangers 15 (15a to 15d) acting as an evaporator, absorbs heat from the air circulating around the load-side heat exchanger 15, and It becomes a low-pressure gas refrigerant. The low-temperature and low-pressure gas refrigerant flows out of the indoor unit 2 (2a to 2d), flows into the outdoor unit 1 again through the extension pipe 4, passes through the first refrigerant flow switching device 11, and passes through the accumulator 19. Then, it is sucked into the compressor 10 again.

At this time, the opening degree (opening area) of the expansion devices 16a to 16d is determined based on the detected temperature of the load-side heat exchanger gas refrigerant temperature detection device 28 and the control device 60 of each outdoor unit 2 from the control device 60 of the outdoor unit 1 (FIG. It is controlled so that the temperature difference (superheat degree) between the evaporation temperature transmitted by communication to the target value (not shown) approaches the target value.

Note that when the cooling operation mode is executed, the operation is stopped because there is no need to flow the refrigerant to the load-side heat exchanger 15 (including the thermo-off) without the heat load. At this time, the expansion device 16 corresponding to the stopped indoor unit 2 is fully closed or set to a small opening at which the refrigerant does not flow.

[Heating operation mode]
FIG. 4 is a refrigerant circuit diagram illustrating a refrigerant flow when the refrigeration cycle apparatus according to Embodiment 1 of the present invention is in the heating operation mode. In FIG. 4, the heating operation mode will be described by taking as an example a case where a thermal load is generated in all the load side heat exchangers 15. In FIG. 4, a pipe indicated by a thick line indicates a pipe through which the refrigerant flows, and a flow direction of the refrigerant is indicated by a solid line arrow.

In the heating operation mode shown in FIG. 4, in the outdoor unit 1, the refrigerant discharged from the compressor 10 passes through the first refrigerant flow switching device 11 to the indoor unit 2 without passing through the heat source side heat exchanger 12. Switch to inflow. The low-temperature and low-pressure refrigerant is compressed by the compressor 10 and discharged as a high-temperature and high-pressure gas refrigerant, passes through the first refrigerant flow switching device 11, and flows out of the outdoor unit 1. The high-temperature and high-pressure gas refrigerant that has flowed out of the outdoor unit 1 flows into each of the indoor units 2 (2a to 2d) through the extension pipe 4.

The high-temperature and high-pressure gas refrigerant that has flowed into the indoor unit 2 (2a to 2d) flows into the load-side heat exchanger 15 (15a to 15d) and circulates around the load-side heat exchanger 15 (15a to 15d). It liquefies while radiating heat to the air, and becomes a high-temperature and high-pressure liquid refrigerant. The high-temperature and high-pressure liquid refrigerant that has flowed out of the load-side heat exchanger 15 (15a to 15d) flows into the expansion device 16 (16a to 16d), is throttled and decompressed by the expansion device 16 (16a to 16d), It becomes a low-pressure two-phase refrigerant and flows out of the indoor unit 2 (2a to 2d). The low-temperature and low-pressure two-phase refrigerant that has flowed out of the indoor unit 2 flows into the outdoor unit 1 again through the extension pipe 4.

At this time, the opening degree (opening area) of the expansion devices 16a to 16d is determined based on the condensation temperature transmitted from the control device 60 of the outdoor unit 1 to the control device (not shown) of each indoor unit 2 through communication and the load side heat. Control is performed so that the temperature difference (degree of supercooling) from the detected temperature of the exchanger liquid refrigerant temperature detecting device 27 approaches the target value.

The low-temperature and low-pressure two-phase refrigerant that has flowed into the outdoor unit 1 flows into the heat source side heat exchanger 12, absorbs heat from the air flowing around the heat source side heat exchanger 12, and evaporates to form a low-temperature and low-pressure gas refrigerant or low-temperature and low-pressure. It becomes a two-phase refrigerant with a large dryness. The low-temperature and low-pressure gas refrigerant or two-phase refrigerant is again sucked into the compressor 10 via the first refrigerant flow switching device 11 and the accumulator 19.

When the heating operation mode is executed, it is not necessary to flow the refrigerant to the load-side heat exchanger 15 (including the thermo-off) that has no heat load. However, in the heating operation mode, if the expansion device 16 corresponding to the load-side heat exchanger 15 without the heating load is fully closed or has a small opening at which the refrigerant does not flow, the load-side heat exchanger 15 that is not in operation is set inside. There is a possibility that the refrigerant is cooled and condensed by the ambient air, and the refrigerant accumulates, resulting in a shortage of refrigerant in the entire refrigerant circuit. Therefore, during heating operation, the opening degree (opening area) of the expansion device 16 corresponding to the load-side heat exchanger 15 having no heat load is set to a large opening degree such as full opening to prevent accumulation of refrigerant.

The first refrigerant flow switching device 11 generally uses a four-way valve. However, the first refrigerant flow switching device 11 is not limited to this, and uses a plurality of two-way flow switching valves and three-way flow switching valves. You may comprise so that a refrigerant | coolant may flow into this.

Moreover, although the case where the accumulator 19 which stores an excess refrigerant | coolant in the refrigerant circuit was provided was demonstrated here, when the extension piping 4 is short, when the number of indoor units 2 is one, etc., there is little excess refrigerant | coolant. Therefore, the accumulator 19 may not be provided.

As described above, in the refrigeration cycle apparatus 100, when the indoor unit 2 is performing the cooling operation, the heat source side heat exchanger 12 acts as a condenser, and the heat source side heat exchanger 12 has a high-temperature and high-pressure gas. The refrigerant flows in and condenses, liquefies through a two-phase region, and flows out as a high-temperature and high-pressure liquid refrigerant. Further, when the indoor unit 2 is performing the heating operation, the load side heat exchanger 15 (15a to 15d) acts as a condenser, and the load side heat exchanger 15 (15a to 15d) The refrigerant flows in and condenses, liquefies through a two-phase region, and flows out as a high-temperature and high-pressure liquid refrigerant.

[Type of refrigerant]
When using a substance that is normally used as a refrigerant, such as R32, R410A, etc., as a refrigerant used in the refrigeration cycle apparatus 100, devise to improve the stability of the refrigerant in the refrigerant circuit. Without any problem, it can be used normally. However, here, the refrigerant is composed of a substance that causes a disproportionation reaction such as 1,1,2-trifluoroethylene (HFO-1123) represented by C2H1F3 and having one double bond in the molecular structure. It is assumed that a single refrigerant or a mixed refrigerant obtained by mixing another substance with a substance that causes a disproportionation reaction is used. Note that the refrigerant used in this example is not limited to HFO-1123, and any material may be used as long as it has a property of causing a disproportionation reaction.

To produce a mixed refrigerant, as the material to be mixed to the material properties causing disproportionation reaction, for _example, represented by C ₃ H 2-tetrafluoropropene represented by _{_{F 4 (CF 3 CF = CH}} 2 HFO-1234yf which is 2,3,3,3-tetrafluoropropene, HFO-1234ze which is 1,3,3,3-tetrafluoro-1-propene represented by CF ₃ CH═CHF), or Difluoromethane (HFC-32) whose chemical formula is represented by CH ₂ F ₂ is used. However, the substance to be mixed with the substance having a disproportionation reaction is not limited thereto, and HC-290 (propane) or the like may be mixed, and the thermal performance that can be used as the refrigerant of the refrigeration cycle apparatus 100 is improved. Any substance may be used as long as it has a substance. In addition, the mixing ratio at that time may be any mixing ratio.

物質 Substances that cause a disproportionation reaction have the following problems if used as refrigerants. That is, when a strong substance is applied in a place where there is a liquid state where the distance between adjacent substances is very close, such as a liquid phase, two phases, etc., the adjacent substances react with each other and become different substances. It will change and will not function as a refrigerant. Not only that, there is a possibility of pipe rupture or the like due to a sudden rise in pressure due to heat generation. Therefore, in order to use a material having a disproportionation reaction as a refrigerant, a device that does not cause the disproportionation reaction in the liquid part or the two-phase part that is a mixed state of gas and liquid. Is required. Here, the collision energy when the refrigerant and the structure collide also causes a disproportionation reaction of the refrigerant. For this reason, if the components of the refrigerant circuit have a structure in which the collision energy is reduced, disproportionation reaction hardly occurs.

[Bent part 45]
In the cooling operation of FIG. 3, the heat source side heat exchanger 12 acts as a condenser, and liquid refrigerant flows from the outlet of the heat source side heat exchanger 12 to the inlet of the expansion device 16 (16a to 16d). In this portion, there are bent portions 45 (45a, 45b) that change the flow direction of the refrigerant in the refrigerant pipe.

FIG. 5 is an enlarged cross-sectional view of a bent portion in the refrigeration cycle apparatus according to Embodiment 1 of the present invention. In the bent portion 45, if the pipe inner diameter is d and the bend radius at the center of the pipe is R, the bend radius inside the pipe of the bend section 45 is Rd / 2, and the bend radius outside the pipe is R + d / 2. . In FIG. 5, the bent portion 45 includes an inlet pipe 46 on the refrigerant inlet side, an outlet pipe 47 on the refrigerant outlet side, and a bent pipe 48 between the inlet pipe 46 and the outlet pipe 47.

Here, the points O, A to F in FIG. 5 indicate the following positions.
Point O: Center of the bending radius R of the bent portion 45 Point A: Of the two intersections of the straight line 46b passing through the point O drawn in the normal direction perpendicular to the center line 46a of the inlet pipe 46 and the inner surface of the pipe, the point O Point B: Of the two intersections of the straight line 47b passing through the point O drawn in the normal direction orthogonal to the center line 47a of the outlet pipe 47 and the inner surface of the pipe, the one farther to the point O. Point C: the inlet pipe 46 Of the two intersections of the straight line 46b passing through the point O drawn in the normal direction perpendicular to the center line 46a and the inner surface of the pipe, the one near the point O Point D: Normal direction perpendicular to the center line 47a of the outlet pipe 47 Of the two intersections between the straight line 47b passing through the point O drawn on the inner surface of the pipe and the inner surface of the pipe, the one near the point O. Point E: The straight line along the inner surface away from the point O of the inlet pipe 46 and the point O Intersection with a straight line along the inner surface away from the point F: From a straight line connecting the point O and the point E and the point O of the pipe It is assumed that the points A, B, C, D, E, F, and O are all on the same plane.

Now, here, the collision energy when the refrigerant flows into the bent portion 45 and collides with the curved surface AFB, which is the opposite surface, is obtained by the equation (1).

[Equation 1]
Collision energy = Refrigerant mass x Refrigerant speed change = (Refrigerant mass flow rate x Unit time) x Refrigerant speed change (1)

The following explains the mitigation of this collision energy. The actual piping has a three-dimensional cylindrical shape, but here, description will be given within the two-dimensional cross section shown in FIG. Therefore, although the actual collision energy relaxation amount and the collision energy relaxation amount described below are slightly different, the tendency is the same, and there is no big problem even if they are handled in two dimensions.

5, the facing surface of the refrigerant flowing into the bent portion 45 from the inlet pipe 46 is a curved surface having a curvature (R + d / 2), and the impact energy of the refrigerant is dispersed and relaxed by the influence. At this time, the larger the bending radius R of the bent portion 45 (bent pipe 48), the larger the curvature of the facing surface, and the greater the amount of relaxation of the collision energy of the refrigerant. That is, as the bending radius R of the bent portion 45 is larger, the collision energy is reduced and the disproportionation reaction is less likely to occur. If the length of the line segment BE (R + d / 2) is larger than the portion where the refrigerant flowing in from the inlet pipe 46 collides, all of the refrigerant flowing in from the inlet pipe 46 is curved surface AF. Since it collides with -B, the collision energy of the refrigerant is reduced.

On the other hand, when (R + d / 2), which is the length of the line segment BE, is smaller than the portion where the refrigerant flowing in from the inlet pipe 46 collides, the refrigerant flowing in from the inlet pipe 46 hits the curved surface AFB. And a thing which collides with the exit pipe | tube 47 generate | occur | produce. Since the inner surface of the outlet pipe 47 faces the normal direction of the inner surface of the inlet pipe 46, the refrigerant that has flowed from the inlet pipe 46 collides with the inner face of the outlet pipe 47 at a right angle. become. For this reason, the collision energy between the refrigerant and the inner surface of the pipe is not alleviated, so that a large collision energy is generated and a disproportionation reaction of the refrigerant may occur. Therefore, in order to alleviate the collision energy of the refrigerant and prevent the refrigerant from causing a disproportionation reaction, it is necessary that all of the refrigerant flowing from the inlet pipe 46 collides with the curved surface AFB.

Now, when fluid is ejected into the space, it diffuses while spreading around, and the spreading angle at that time is generally about 5 degrees. Hereinafter, based on this spreading angle, a configuration for reducing the collision energy of the refrigerant will be examined.

FIG. 6 is an explanatory diagram of a configuration for reducing the collision energy of the refrigerant in the refrigeration cycle apparatus according to Embodiment 1 of the present invention.
The refrigerant flowing in from the inlet pipe 46 passes through a surface having a line segment AC as a cross section, spreads from there according to the spread angle of the jet, and then collides with the opposite surface. Only the outlet pipe 47 side is not in contact with the solid wall surface, and the distance traveled by the refrigerant is the length of the line segment OB, that is, (R + d / 2). Therefore, in order to cause all of the refrigerant flowing from the inlet pipe 46 to collide with the curved surface AFB, and to reduce the collision energy of the refrigerant, the equation (2) needs to be satisfied.

[Equation 2]
R + d / 2 ≧ d + (R + d / 2) × tan (5 × π / 180) (2)

If this is rewritten, equation (3) is obtained, and if this equation is established, the collision energy at the bent portion 45 of the refrigerant is alleviated and the refrigerant is less likely to be disproportionate.

For example, when the outer diameter of the inlet pipe 46 of the bent portion 45 is 1/4 inch (6.35 mm), the thickness of the pipe is about 0.6 mm, the inner diameter is 5.15 mm, and the bending radius is 3.0688 mm. If it is above, the disproportionation reaction of a refrigerant | coolant will become difficult to occur. Accordingly, when the outer diameter of the inlet tube 46 of the bent portion 45 is small, the same effect is obtained with a smaller bending radius. Therefore, when the outer diameter of the inlet tube 46 of the bent portion 45 is 1/4 inch or less, the bending radius is reduced. If it is set to 3.0688 mm or more, the disproportionation reaction of the refrigerant hardly occurs.

For example, when the outer diameter of the inlet pipe 46 of the bent portion 45 is 3/8 inch (9.52 mm), the thickness of the pipe is about 0.7 mm, the inner diameter is 8.12 mm, and the bending radius is 4 If it is at least 8385 mm, the disproportionation reaction of the refrigerant hardly occurs. Therefore, when the outer diameter of the inlet pipe 46 of the bent portion 45 is larger than ¼ inch and smaller than 3/8 inch, the disproportionation reaction of the refrigerant is difficult to occur when the bending radius is 4.8385 mm or larger.

For example, when the outer diameter of the inlet pipe 46 of the bent portion 45 is 1/2 inch (12.7 mm), the thickness of the pipe is about 0.8 mm, the inner diameter is 11.1 mm, and the bending radius is 6 If it is 6142 mm or more, disproportionation reaction of the refrigerant hardly occurs. Therefore, when the outer diameter of the inlet pipe 46 of the bent portion 45 is larger than 3/8 inch and not larger than 1/2 inch, the disproportionation reaction of the refrigerant is difficult to occur when the bending radius is set to 6.6142 mm or more.

For example, when the outer diameter of the inlet pipe 46 of the bent portion 45 is 5/8 inch (15.88 mm), the thickness of the pipe is about 0.9 mm, the inner diameter is 14.08 mm, and the bending radius is 8 If it is 3899 mm or more, the disproportionation reaction of the refrigerant hardly occurs. Therefore, when the outer diameter of the inlet pipe 46 of the bent portion 45 is larger than ½ inch and smaller than 5/8 inch, the disproportionation reaction of the refrigerant hardly occurs when the bending radius is 8.3899 mm or more.

For example, when the outer diameter of the inlet pipe 46 of the bent portion 45 is 3/4 inch (19.05 mm), the wall thickness of the pipe is about 1 mm, the inner diameter is 17.05 mm, and the bending radius is 10.15597 mm. If it is above, the disproportionation reaction of a refrigerant | coolant will become difficult to occur. Therefore, when the outer diameter of the inlet pipe 46 of the bent portion 45 is larger than 5/8 inch and not larger than 3/4 inch, the disproportionation reaction of the refrigerant does not easily occur when the bending radius is 10.15597 mm or larger.

For example, when the outer diameter of the inlet pipe 46 of the bent portion 45 is 7/8 inch (22.2 mm), the thickness of the pipe is about 1 to 1.2 mm, and the inner diameter is 19.8 to 20.2 mm. Thus, if the bending radius is set to 12.0367 mm or more calculated with respect to the larger dimension of 20.2 mm, the disproportionation reaction of the refrigerant does not easily occur. Therefore, when the outer diameter of the inlet pipe 46 of the bent portion 45 is larger than 3/4 inch and not larger than 7/8 inch, the disproportionation reaction of the refrigerant does not easily occur when the bending radius is 12.0367 mm or larger.

For example, when the outer diameter of the inlet pipe 46 of the bent portion 45 is 1 inch (25.4 mm), the thickness of the pipe is about 1 to 1.3 mm, and the inner diameter is 22.8 to 23.4 mm. If the bending radius is set to a value of 13.9435 mm or more calculated with respect to the larger dimension of 23.4 mm, the disproportionation reaction of the refrigerant does not easily occur. Therefore, when the outer diameter of the inlet pipe 46 of the bent portion 45 is larger than 7/8 inch and 1 inch or less, the disproportionation reaction of the refrigerant is difficult to occur when the bending radius is set to 13.9435 mm or more.

Now, FIG. 5 shows the case where the outlet pipe 47 of the bent portion 45 faces the normal direction of the inlet pipe 46, that is, the case where the angle between the inlet pipe 46 and the outlet pipe 47 is 90 degrees. Hereinafter, the collision energy when the angle between the inlet pipe 46 and the outlet pipe 47 is θ will be considered.

FIG. 7 is a diagram showing a bent portion when the angle between the inlet pipe and the outlet pipe of the bent portion in the refrigeration cycle apparatus according to Embodiment 1 of the present invention is θ.
In this case, in consideration of the inclination of the inlet pipe 46, all the refrigerant flowing from the inlet pipe 46 may collide with the curved surface AFB, and the expression (4), that is, the expression (5) ), The impact force is alleviated and refrigerant disproportionation is unlikely to occur. In addition, Formula (2) and Formula (3) have shown the case where (theta) is 90 degree | times in Formula (4) and Formula (5).

[Equation 4]
R + d / 2 ≧ d + (R + d / 2) × {tan (5 × π / 180) + cos θ} (4)

Note that the shape of the inlet pipe 46 of the bent portion 45, the portion including the curved surface AFB, and the shape of the outlet pipe 47 may be any shape. Although shown here as if it were a circular tube, a rectangular tube, an elliptical tube, and other shapes may be sufficient, and there exists the same effect.

Further, during the heating operation of FIG. 4, the load-side heat exchanger 15 (15a to 15d) functions as a condenser, and the expansion device 16 (16a) is provided from the outlet of the load-side heat exchanger 15 (15a to 15d). The liquid refrigerant flows to the inlets to 16d), and when the bent portion 45 of the pipe exists in this portion, the same effect can be obtained if the bent portion 45 has the same structure as described above. Further, in FIG. 4, the heat source side heat exchanger 12 acts as an evaporator, and two-phase in which liquid refrigerant and gas refrigerant are mixed from the outlet of the expansion device 16 (16a to 16d) to the evaporator inlet. When the refrigerant is flowing and the bent portion 45 of the pipe is present in the portion where the two-phase refrigerant flows, the same effect can be obtained if the bent portion 45 has the same structure as described above. In each operation mode, the same effect can be obtained if the bent portion 45 is also present in other portions where the liquid refrigerant or the two-phase refrigerant flows.

[Refrigerator oil]
The refrigerating machine oil filled in the refrigerant circuit is mainly composed of either polyol ester or polyvinyl ether, and a part of the refrigerating machine oil filled in the compressor 10 circulates in the refrigerant circuit together with the refrigerant. To do. Both the polyol ester and the polyvinyl ether are refrigerating machine oils having compatibility easily dissolved in a refrigerant having one double bond in the molecular structure. When this refrigerating machine oil and HFO 1123 as a refrigerant are mixed, HFO-1123 dissolves to some extent in refrigeration oil. As described above, if the bent portion 45 is configured as described above with respect to the refrigerant having the property of causing a disproportionation reaction, the collision energy of the refrigerant is reduced and the disproportionation of the refrigerant does not easily occur. Furthermore, when the refrigerating cycle is filled with highly compatible refrigerating machine oil, the refrigerant disproportionation reaction is less likely to occur than when the refrigerating machine oil with low compatibility or incompatible refrigerating machine oil is filled into the refrigerating cycle. Become.

FIG. 8 is a solubility diagram of refrigerating machine oil of the refrigeration cycle apparatus according to Embodiment 1 of the present invention. High solubility means that many refrigerants are dissolved in the refrigeration oil, and low solubility means that only a small amount of refrigerant is dissolved in the refrigeration oil. FIG. 8 shows the relationship between the solubility and the pressure for each of the refrigerant temperatures T1, T2, and T3. In FIG. 8, T1, T2, and T3 are different temperatures, and Equation (6) is established.

[Equation 6]
T1 <T2 <T3 (6)

As shown in FIG. 8, under the same pressure condition, the lower the refrigerant temperature, the higher the solubility, and under the same temperature condition, the higher the refrigerant pressure, the higher the solubility. When the refrigerant is dissolved in the refrigerating machine oil, the refrigerating machine oil molecules are present between the refrigerant molecules. That is, if the solubility of the refrigerant in the refrigerating machine oil is large, the refrigerating machine oil exists between molecules of many refrigerants. As described above, the refrigerant disproportionation reaction is a phenomenon in which molecules of adjacent refrigerants react with each other. Therefore, if a refrigerating machine oil that is compatible with the refrigerant is used, the refrigerant between the molecules of the refrigerant is used. Since the molecules of the refrigerating machine oil exist, the disproportionation reaction of the refrigerant hardly occurs. The refrigerating machine oil is not limited to this as long as it is compatible with the refrigerant, and another type of oil may be used.

In order to suppress the disproportionation reaction of the refrigerant, the greater the solubility of the refrigerant in the refrigerating machine oil, the greater the effect. Practically, if the solubility is 50 wt% (weight%) or more, many refrigerants are dissolved in the refrigerating machine oil, so that the disproportionation reaction can be suppressed.

Usually, in a building multi-air conditioner or the like, the condensation temperature, which is the temperature of the refrigerant in the condenser, is controlled by controlling the frequency of the compressor 10 and the rotational speed of a blower (not shown) attached to the heat source side heat exchanger 12. Control at about 50 ° C. Further, the expansion device 16 is controlled so that the degree of supercooling of the refrigerant at the outlet of the condenser is about 10 ° C. That is, if the condensation temperature is about 50 ° C., the refrigerant at the outlet of the condenser is controlled to about 40 ° C. and flows out of the condenser. Therefore, the refrigerant between the condenser and the expansion device 16 is in a saturated pressure state where the temperature is about 40 ° C. and the pressure is 50 ° C.

Considering the control performance (transient characteristics) of the expansion device 16, the refrigerant flowing between the condenser and the expansion device 16 is in a state where the temperature is between about 40-50 ° C. and the saturation pressure is 50 ° C. It has become. Therefore, if the solubility of the refrigerant in the refrigerating machine oil is high at these temperatures and pressures, the refrigerant disproportionation reaction hardly occurs. Practically, in the state where the refrigerant is at these temperatures and pressures, if the solubility of the refrigerant in the refrigerating machine oil is 50 wt% (weight%) or more, many refrigerants are dissolved in the refrigerating machine oil. The chemical reaction can hardly occur.

[Extended piping 4]
As described above, the refrigeration cycle apparatus 100 according to the present embodiment has several operation modes. In these operation modes, the refrigerant flows through the extension pipe 4 that connects the outdoor unit 1 and the indoor unit 2.

The high pressure detection device 37 and the low pressure detection device 38 are installed to control the refrigeration cycle high pressure and low pressure to target values, but may be temperature detection devices that detect a saturation temperature.

In general, the heat source side heat exchanger 12 and the load side heat exchangers 15a to 15d are provided with a blower, and in many cases, condensation or evaporation is promoted by blowing, but this is not restrictive. . For example, as the load side heat exchangers 15a to 15d, those such as panel heaters using radiation can be used, and as the heat source side heat exchanger 12, a water-cooled type that moves heat by water or antifreeze liquid is used. Things can also be used. Any heat exchanger having a structure capable of radiating or absorbing heat can be used.

In addition, the heat source side heat exchanger 12 or the load side heat exchangers 15a to 15d have fins 44 in order to improve the heat transfer performance, but sufficient heat transfer performance can be obtained by using only the heat transfer tube 43. May not have the fins 44.

In addition, here, the case where there are four load-side heat exchangers 15a to 15d has been described as an example, but any number may be connected. Further, a plurality of outdoor units 1 may be connected to constitute one refrigeration cycle.

In addition, although the explanation has been made by taking the cooling / heating switching type refrigeration cycle apparatus 100 in which the indoor unit 2 performs only the cooling operation or the heating operation as an example, the present invention is not limited to this. For example, the indoor unit 2 can arbitrarily select one of a cooling operation and a heating operation, and the entire system can perform a mixed operation of the indoor unit 2 that performs the cooling operation and the indoor unit 2 that performs the heating operation. The present invention can also be applied to a refrigeration cycle apparatus and has the same effect.

In addition, it can be applied to an air conditioner such as a room air conditioner, to which only one indoor unit 2 can be connected, a refrigeration apparatus to which a showcase or a unit cooler is connected, and any refrigeration cycle apparatus using a refrigeration cycle. The same effect is produced.

Embodiment 2. FIG.
A second embodiment of the present invention will be described with reference to the drawings. In the following, the second embodiment will be described focusing on the differences from the first embodiment. Note that the modification applied in the configuration part of the first embodiment is also applied to the same configuration part of the second embodiment.

FIG. 9 is a circuit diagram of the refrigeration cycle apparatus according to Embodiment 2 of the present invention.
A refrigeration cycle apparatus 100 shown in FIG. 9 includes a refrigerant circulation circuit A in which an outdoor unit 1 and a heat medium relay unit 3 as a relay are connected by an extension pipe 4 so that a refrigerant circulates. The refrigeration cycle apparatus 100 includes a heat medium circuit B in which the heat medium converter 3 and the indoor unit 2 are connected by a pipe (heat medium pipe) 5 and a heat medium such as water and brine circulates. . The heat medium relay unit 3 includes a load side heat exchanger 15a and a load side heat exchanger 15b that perform heat exchange between the refrigerant circulating in the refrigerant circuit A and the heat medium circulating in the heat medium circuit B.

The heat medium relay unit 3 is located separately from the outdoor unit 1 and the indoor unit 2, for example, a ceiling that is inside the building 9 but separate from the indoor space 7 as shown in FIG. 1. It is installed in a space such as the back (hereinafter simply referred to as space 8). The heat medium relay 3 can also be installed in a common space where there is an elevator or the like.

[Type of refrigerant]
In this refrigeration cycle apparatus 100, the same refrigerant as in the first embodiment can be used, and the same effect can be obtained.

The operation mode executed by the refrigeration cycle apparatus 100 includes a cooling only operation mode in which all the driven indoor units 2 execute a cooling operation and a heating operation in which all the driven indoor units 2 execute a heating operation. There is an operation mode. Further, there are a cooling main operation mode executed when the cooling load is larger and a heating main operation mode executed when the heating load is larger.

[Cooling operation mode]
In the cooling only operation mode, the high-temperature and high-pressure gas refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12 via the first refrigerant flow switching device 11 and dissipates heat to the surrounding air. It condenses and becomes high-pressure liquid refrigerant and flows out of the outdoor unit 1 through the check valve 13a. Then, it flows into the heat medium relay unit 3 through the extension pipe 4. The refrigerant flowing into the heat medium relay unit 3 passes through the opening / closing device 17a, expands in the expansion device 16a and the expansion device 16b, and becomes a low-temperature and low-pressure two-phase refrigerant. The two-phase refrigerant flows into each of the load side heat exchanger 15a and the load side heat exchanger 15b acting as an evaporator, absorbs heat from the heat medium circulating in the heat medium circuit B, and becomes a low-temperature and low-pressure gas refrigerant. . The gas refrigerant flows out of the heat medium relay unit 3 via the second refrigerant flow switching device 18a and the second refrigerant flow switching device 18b. Then, it flows into the outdoor unit 1 again through the extension pipe 4. The refrigerant flowing into the outdoor unit 1 passes through the check valve 13d and is sucked into the compressor 10 again via the first refrigerant flow switching device 11 and the accumulator 19.

In the heat medium circulation circuit B, the heat medium is cooled by the refrigerant in both the load side heat exchanger 15a and the load side heat exchanger 15b. The cooled heat medium flows through the pipe 5 by the pump 21a and the pump 21b. The heat medium flowing into the use side heat exchangers 26a to 26d through the second heat medium flow switching devices 23a to 23d absorbs heat from the indoor air. The indoor air is cooled to cool the indoor space 7. The refrigerant that has flowed out of the use side heat exchangers 26a to 26d flows into the heat medium flow control devices 25a to 25d, passes through the first heat medium flow switching devices 22a to 22d, and passes through the load side heat exchanger 15a and the load side. It flows into the heat exchanger 15b, is cooled, and is sucked into the pump 21a and the pump 21b again. Note that the heat medium flow control devices 25a to 25d corresponding to the use side heat exchangers 26a to 26d without heat load are fully closed. Further, the heat medium flow control devices 25a to 25d corresponding to the use side heat exchangers 26a to 26d having the heat load adjust the opening degree to adjust the heat load in the use side heat exchangers 26a to 26d.

[Heating operation mode]
In the heating only operation mode, the high-temperature and high-pressure gas refrigerant discharged from the compressor 10 flows out of the outdoor unit 1 through the first refrigerant flow switching device 11 and the first connection pipe 4a and the check valve 13b. To do. Then, the refrigerant that has flowed out of the outdoor unit 1 flows into the heat medium relay unit 3 through the extension pipe 4. The refrigerant that has flowed into the heat medium relay unit 3 flows into the load-side heat exchanger 15a and the load-side heat exchanger 15b through the second refrigerant flow switching device 18a and the second refrigerant flow switching device 18b, respectively. The heat is radiated to the heat medium circulating in the heat medium circuit B, and becomes a high-pressure liquid refrigerant. The high-pressure liquid refrigerant expands in the expansion device 16a and the expansion device 16b to become a low-temperature and low-pressure two-phase refrigerant, and flows out of the heat medium converter 3 through the opening / closing device 17b.

Then, the refrigerant that has flowed out of the heat medium relay unit 3 flows into the outdoor unit 1 again through the extension pipe 4. The refrigerant flowing into the outdoor unit 1 passes through the second connection pipe 4b and the check valve 13c, flows into the heat source side heat exchanger 12 acting as an evaporator, absorbs heat from the surrounding air, and is a low-temperature and low-pressure gas refrigerant. It becomes. The gas refrigerant is again sucked into the compressor 10 via the first refrigerant flow switching device 11 and the accumulator 19. Note that the operation of the heat medium in the heat medium circuit B is the same as in the cooling only operation mode. In the heating only operation mode, the heat medium is heated by the refrigerant in the load-side heat exchanger 15a and the load-side heat exchanger 15b, and is radiated to the indoor air in the use-side heat exchanger 26a and the use-side heat exchanger 26b. The indoor space 7 is heated.

[Cooling operation mode]
In the cooling main operation mode, the high-temperature and high-pressure gas refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12 via the first refrigerant flow switching device 11 and radiates and condenses to the surrounding air. Then, it becomes a two-phase refrigerant and flows out of the outdoor unit 1 through the check valve 13a. Then, the refrigerant that has flowed out of the outdoor unit 1 flows into the heat medium relay unit 3 through the extension pipe 4. The refrigerant flowing into the heat medium relay unit 3 flows into the load-side heat exchanger 15b acting as a condenser through the second refrigerant flow switching device 18b, and dissipates heat to the heat medium circulating in the heat medium circuit B. And high pressure liquid refrigerant.

The high-pressure liquid refrigerant expands in the expansion device 16b and becomes a low-temperature and low-pressure two-phase refrigerant. The two-phase refrigerant flows into the load-side heat exchanger 15a acting as an evaporator through the expansion device 16a, absorbs heat from the heat medium circulating in the heat medium circuit B, and becomes a low-pressure gas refrigerant. It flows out of the heat medium relay unit 3 through the path switching device 18a. Then, it flows again into the outdoor unit 1 through the refrigerant h that has flowed out of the heat medium relay unit 3 and the extension pipe 4. The refrigerant flowing into the outdoor unit 1 passes through the check valve 13d and is sucked into the compressor 10 again via the first refrigerant flow switching device 11 and the accumulator 19.

In the heat medium circulation circuit B, the heat of the refrigerant is transmitted to the heat medium by the load side heat exchanger 15b. The heated heat medium flows in the pipe 5 by the pump 21b. The heat medium that has flowed into the use side heat exchangers 26a to 26d for which heating is requested by operating the first heat medium flow switching devices 22a to 22d and the second heat medium flow switching devices 23a to 23d radiates heat to the indoor air. To do. The indoor air is heated to heat the indoor space 7. On the other hand, the cold heat of the refrigerant is transmitted to the heat medium in the load side heat exchanger 15a.

And the cooled heat medium flows in the pipe 5 by the pump 21a. The heat medium that has flowed into the use side heat exchangers 26a to 26d for which cooling is requested by operating the first heat medium flow switching devices 22a to 22d and the second heat medium flow switching devices 23a to 23d absorbs heat from the indoor air. To do. The indoor air is cooled to cool the indoor space 7. Note that the heat medium flow control devices 25a to 25d corresponding to the use side heat exchangers 26a to 26d without heat load are fully closed. Further, the heat medium flow control devices 25a to 25d corresponding to the use side heat exchangers 26a to 26d having the heat load adjust the opening degree to adjust the heat load in the use side heat exchangers 26a to 26d.

[Heating main operation mode]
In the heating main operation mode, the high-temperature and high-pressure gas refrigerant discharged from the compressor 10 passes through the first refrigerant flow switching device 11, passes through the first connection pipe 4 a and the check valve 13 b, and then the outdoor unit 1. Spill from. Then, the refrigerant that has flowed out of the outdoor unit 1 flows into the heat medium relay unit 3 through the extension pipe 4. The refrigerant flowing into the heat medium relay unit 3 flows into the load-side heat exchanger 15b acting as a condenser through the second refrigerant flow switching device 18b, and dissipates heat to the heat medium circulating in the heat medium circuit B. And high pressure liquid refrigerant. The high-pressure liquid refrigerant expands in the expansion device 16b and becomes a low-temperature and low-pressure two-phase refrigerant. The two-phase refrigerant flows into the load-side heat exchanger 15a acting as an evaporator via the expansion device 16a, absorbs heat from the heat medium circulating in the heat medium circuit B, and passes through the second refrigerant flow switching device 18a. And flows out of the heat medium relay unit 3.

Then, it flows into the outdoor unit 1 again through the extension pipe 4. The refrigerant flowing into the outdoor unit 1 flows into the heat source side heat exchanger 12 acting as an evaporator through the second connection pipe 4b and the check valve 13c, absorbs heat from the surrounding air, and is a low-temperature and low-pressure gas. Becomes a refrigerant. The gas refrigerant is again sucked into the compressor 10 via the first refrigerant flow switching device 11 and the accumulator 19. The operation of the heat medium in the heat medium circuit B, the first heat medium flow switching devices 22a to 22d, the second heat medium flow switching devices 23a to 23d, the heat medium flow control devices 25a to 25d, and the use side The operations of the heat exchangers 26a to 26d are the same as those in the cooling main operation mode.

[Bent part 45]
In FIG. 9, in the cooling only operation mode or the cooling main operation mode in which the heat source side heat exchanger 12 acts as a condenser, the liquid refrigerant or the two-phase refrigerant from the condenser outlet to the inlet of the expansion device 16 flows. A bent portion 45a, a bent portion 45b, and a bent portion 45c are provided. If these are configured so as to satisfy the formula (3) or the formula (5) described in the first embodiment, the collision energy of the refrigerant is alleviated and the disproportionation of the refrigerant does not easily occur. Further, in the heating only operation mode or the heating main operation mode in which the heat source side heat exchanger 12 acts as an evaporator, liquid refrigerant and gas refrigerant are mixed from the outlet of the expansion device 16 (16a to 16d) to the evaporator inlet. When the two-phase refrigerant is flowing and the bent portion 45 of the pipe is present in the portion through which the two-phase refrigerant flows, the same effect can be obtained if the bent portion 45 has the same structure as described above. Further, in each operation mode, in the other part where the liquid refrigerant or the two-phase refrigerant flows, if the bent portion 45 exists, the same effect can be obtained if the structure is the same.

[Extended piping 4 and piping 5]
In each operation mode in the present embodiment, the refrigerant flows through the extension pipe 4 connecting the outdoor unit 1 and the heat medium converter 3, and water is supplied to the pipe 5 connecting the heat medium converter 3 and the indoor unit 2. Heat medium such as antifreeze is flowing.

When the heating load and the cooling load are mixedly generated in the use side heat exchanger 26, the first heat medium flow switching device 22 corresponding to the use side heat exchanger 26 performing the heating operation and The second heat medium flow switching device 23 is switched to a flow path connected to the load side heat exchanger 15b for heating. Further, the first heat medium flow switching device 22 and the second heat medium flow switching device 23 corresponding to the use side heat exchanger 26 performing the cooling operation are connected to the cooling load side heat exchanger 15a. Switch to the flow path. For this reason, in each indoor unit 2, heating operation and cooling operation can be performed freely.

The first heat medium flow switching device 22 and the second heat medium flow switching device 23 are those that can switch a three-way flow path such as a three-way valve, and those that open and close a two-way flow path such as an on-off valve. What is necessary is just to switch a flow path, such as combining two. In addition, the first heat medium can be obtained by combining two things such as a stepping motor drive type mixing valve that can change the flow rate of the three-way flow path and two things that can change the flow rate of the two-way flow path such as an electronic expansion valve. The flow path switching device 22 and the second heat medium flow path switching device 23 may be used.

Further, the heat medium flow control device 25 may be installed together with a bypass pipe that bypasses the use side heat exchanger 26 as a control valve having a three-way flow path other than the two-way valve. Further, the heat medium flow control device 25 may be a stepping motor drive type that can control the flow rate flowing through the flow path, and may be a two-way valve or a device in which one end of the three-way valve is closed. Further, as the heat medium flow control device 25, a device that opens and closes a two-way flow path such as an open / close valve may be used, and the average flow rate may be controlled by repeating ON / OFF.

Further, the first refrigerant flow switching device 11 and the second refrigerant flow switching device 18 are shown as if they were four-way valves. However, the present invention is not limited to this, but a two-way flow switching valve, a three-way flow switching A plurality of valves may be used so that the refrigerant flows in the same manner.

Further, it goes without saying that the same holds true even when only one use-side heat exchanger 26 and one heat medium flow control device 25 are connected, and the same applies to the load-side heat exchanger 15 and the expansion device 16. Of course, there is no problem even if multiple moving objects are installed. Furthermore, although the case where the heat medium flow control device 25 is built in the heat medium converter 3 has been described as an example, the heat medium flow control device 25 is not limited thereto, and may be built in the indoor unit 2. 3 and the indoor unit 2 may be configured separately.

Further, if one or both of the heat medium flow switching device 22 and the heat medium flow switching device 23 have a function of adjusting the flow rate of the heat medium, the heat medium flow control device 25 may not be provided. .

As the heat medium, for example, brine (antifreeze), water, a mixed solution of brine and water, a mixed solution of an additive having a high anticorrosive effect against water, or the like can be used. Therefore, in the refrigeration cycle apparatus 100, even if the heat medium leaks into the indoor space 7 through the indoor unit 2, a highly safe heat medium is used, which contributes to an improvement in safety. Become.

In general, the heat source side heat exchanger 12 and the use side heat exchangers 26a to 26d are provided with a blower, and in many cases, condensation or evaporation is promoted by blowing, but this is not restrictive. . For example, as the use side heat exchangers 26a to 26d, a panel heater using radiation can be used. Moreover, as the heat source side heat exchanger 12, a water-cooled type that moves heat by water or antifreeze can also be used. Any structure that can dissipate or absorb heat can be used.

In addition, here, the case where there are four use-side heat exchangers 26a to 26d has been described as an example, but any number may be connected. Further, a plurality of outdoor units 1 may be connected to constitute one refrigeration cycle.

In addition, the case where there are two load-

side heat exchangers

15a and 15b has been described as an example, but of course, the present invention is not limited to this, and if the heat medium can be cooled and heated, it can be installed in any number. May be.

Further, a plate-type heat exchanger is generally used as the load-side heat exchanger 15. However, the load-side heat exchanger 15 is not limited to a plate type, but can be any type that can exchange heat between the refrigerant and the heat medium. It may be a thing.

Also, the number of pumps 21a and 21b is not limited to one, and a plurality of small capacity pumps may be arranged in parallel.

In addition, the compressor 10, the four-way valve (first refrigerant flow switching device) 11, and the heat source side heat exchanger 12 are accommodated in the outdoor unit 1, and the use side heat exchanger is configured to exchange heat between the air in the air-conditioning target space and the refrigerant. 26 is accommodated in the indoor unit 2, the load-side heat exchanger 15 and the expansion device 16 are accommodated in the heat medium converter 3, and the outdoor unit 1 and the heat medium converter 3 are connected by the extension pipe 4 to form a refrigerant. Is circulated, and the heat medium is circulated by connecting the indoor unit 2 and the heat medium converter 3 with a set of two pipes 5 each, and the load-side heat exchanger 15 exchanges heat between the refrigerant and the heat medium. The system to be performed has been described by way of an example of a system that can perform a mixed operation of the indoor unit 2 that performs the cooling operation and the indoor unit 2 that performs the heating operation, but is not limited thereto. For example, the outdoor unit 1 and the heat medium relay unit 3 described in the first embodiment can be combined and applied to a system that performs only a cooling operation or a heating operation in the indoor unit 2 and has the same effect.

1 Heat source unit (outdoor unit), 2, 2a, 2b, 2c, 2d indoor unit, 3 heat medium converter (repeater), 4 extension piping, 4a first connection piping, 4b second connection piping, 5 piping (heat Medium piping), 6 outdoor space, 7 indoor space, 8 outdoor space such as the back of the ceiling and indoor space, 9 building, etc. 10 compressor, 11 first refrigerant flow switching device (four-way valve) 12 heat source side heat exchanger (first heat exchanger), 13a, 13b, 13c, 13d check valve, 15, 15a, 15b, 15c, 15d load side heat exchanger (second heat exchanger), 16, 16a, 16b, 16c, 16d throttle device, 17a, 17b opening / closing device, 18, 18a, 18b second refrigerant flow switching device, 19 accumulator, 21a, 21b pump, 22, 22a, 22b, 22c, 22d 1 Heat medium flow switching device, 23, 23a, 23b, 23c, 23d Second heat medium flow switching device, 25, 25a, 25b, 25c, 25d Heat medium flow control device, 26, 26a, 26b, 26c, 26d Use side heat exchanger, 27 Load side heat exchanger liquid refrigerant temperature detection device, 28 Load side heat exchanger gas refrigerant temperature detection device, 37 High pressure detection device, 38 Low pressure detection device, 43 Heat transfer tube, 45a, 45b, 45c Bend Part, 46 inlet pipe, 47 outlet pipe, 49 flow path, 60 control device, 100 refrigeration cycle device, A refrigerant circulation circuit, B heat medium circulation circuit.

Claims

The compressor, the first heat exchanger, the expansion device, and the second heat exchanger are connected by a refrigerant pipe, and include a refrigeration cycle in which the refrigerant circulates.
The refrigerant is a single refrigerant composed of a substance having a disproportionation reaction or a mixed refrigerant containing a substance having a disproportionation reaction,
The refrigerant pipe has a bent portion that changes a flow direction of the refrigerant in the refrigerant pipe,
Of the first heat exchanger and the second heat exchanger, one acts as a condenser and the other acts as an evaporator,
The bent portion is provided in one or both of a flow path between the condenser and the expansion device, a flow path between the expansion device and the evaporator,
A refrigeration cycle apparatus in which a bending radius R of the bent portion through which a liquid refrigerant or a two-phase refrigerant flows satisfies the following relationship.

R ≧ (d / 2) × [1+ {tan (π / 36) + cos θ}] / [1- {tan (π / 36) + cos θ}]
θ (rad): angle formed by the center line of the inlet pipe constituting the refrigerant inlet side of the bent portion and the center line of the outlet pipe constituting the refrigerant outlet side of the bent portion R (mm): bending of the bent portion Radius d (mm): Inner diameter of the inlet pipe of the bent portion
The refrigeration cycle apparatus according to claim 1, wherein the angle θ is 90 degrees.
The refrigeration cycle apparatus according to claim 1 or 2, wherein an outer diameter of the inlet pipe of the bent portion is ¼ inch or less, and a bending radius of the bent portion is 3.0688 mm or more.
The refrigeration according to claim 1 or 2, wherein an outer diameter of the inlet pipe of the bent portion is larger than 1/4 inch and not larger than 3/8 inch, and a bending radius of the bent portion is not less than 4.8385 mm. Cycle equipment.
The refrigeration according to claim 1 or 2, wherein an outer diameter of the inlet pipe of the bent portion is larger than 3/8 inch and smaller than 1/2 inch, and a bending radius of the bent portion is 6.6142 mm or more. Cycle equipment.
The refrigeration according to claim 1 or 2, wherein an outer diameter of the inlet pipe of the bent portion is larger than ½ inch and not larger than 5/8 inch, and a bending radius of the bent portion is not less than 8.3899 mm. Cycle equipment.
The refrigeration according to claim 1 or 2, wherein an outer diameter of the inlet pipe of the bent portion is larger than 5/8 inch and 3/4 inch or less, and a bending radius of the bent portion is 10.15597 mm or more. Cycle equipment.
The refrigeration according to claim 1 or 2, wherein an outer diameter of the inlet pipe of the bent portion is larger than 3/4 inch and 7/8 inch or less, and a bending radius of the bent portion is 12.0367 mm or more. Cycle equipment.
3. The refrigeration cycle apparatus according to claim 1, wherein an outer diameter of the inlet pipe of the bent portion is larger than 7/8 inch and equal to or smaller than 1 inch, and a bending radius of the bent portion is equal to or larger than 13.9435 mm. .
The refrigerating machine oil filled in the refrigerating cycle has a solubility in the refrigerating machine oil of 50% by weight or more in a state where the temperature of the refrigerant is 50 ° C. and the pressure of the refrigerant is a saturation pressure of 50 ° C. The refrigeration cycle apparatus according to any one of claims 1 to 9.
The refrigerating machine oil filled in the refrigerating cycle has a solubility of 50% by weight or more of the refrigerant in the refrigerating machine oil in a state where the temperature of the refrigerant is 40 ° C. and the pressure of the refrigerant is a saturation pressure of 50 ° C. The refrigeration cycle apparatus according to any one of claims 1 to 9.
An outdoor unit that houses one of the first heat exchanger or the second heat exchanger, and an indoor unit that houses the other of the first heat exchanger or the second heat exchanger. The refrigeration cycle apparatus according to any one of claims 1 to 11.
An outdoor unit that houses one of the first heat exchanger or the second heat exchanger, and the other of the first heat exchanger or the second heat exchanger, the outdoor unit and the room The refrigeration cycle apparatus according to any one of claims 1 to 11, further comprising a repeater that is separate from the machine and can be installed at a position separated from the machine.
The refrigeration cycle apparatus according to claim 13, wherein the first heat exchanger or the second heat exchanger housed in the relay is a heat exchanger that exchanges heat between the refrigerant and the heat medium.
The first heat exchanger or the second heat exchanger housed in the outdoor unit is a heat exchanger that exchanges heat between the refrigerant and the heat medium. The refrigeration cycle apparatus according to item.
The refrigeration according to any one of claims 12 to 15, wherein one or a plurality of the outdoor units and one or a plurality of the indoor units are provided, and the temperature-controlled air in each indoor unit can be supplied indoors. Cycle equipment.
The apparatus further comprises a refrigerant flow switching device for switching a flow path of the refrigerant, wherein one of the first heat exchanger and the second heat exchanger acts as a condenser, and the first heat exchanger and the second heat exchanger A first operation mode in which the other of the heat exchangers acts as an evaporator, and one of the first heat exchanger and the second heat exchanger acts as an evaporator, and the first heat exchanger The refrigeration cycle apparatus according to any one of claims 1 to 16, further comprising: a second operation mode in which the other of the second heat exchangers acts as a condenser.
The refrigeration cycle apparatus according to any one of claims 1 to 17, wherein the substance that causes the disproportionation reaction is 1,1,2-trifluoroethylene.