JP2019086208A - Refrigeration cycle device - Google Patents

Abstract

To provide a refrigeration cycle device which improves heat exchange efficiency of an internal heat exchanger during a heating operation while suppressing power consumption during a defrosting operation by reducing pressure loss of a high pressure side refrigerant, and which can perform an operation with high energy saving properties.SOLUTION: A refrigeration cycle device includes an internal heat exchanger 13 in which a high pressure side refrigerant supplied to decompression means 14 from a heat radiator 12 and a low pressure side refrigerant which has absorbed heat in an evaporator 15 exchange heat. A high pressure side pipe 1 in which the high pressure side refrigerant flows and a low pressure side pipe 2 in which the low pressure side refrigerant flows are closely attached with each other, and the refrigeration cycle device includes at least one or more bent parts in which the relationship between a bending radius RH of the high pressure side pipe 1 and a bending radius RL of the low pressure side pipe is RH<RL. Thereby, the heat exchange amount in the internal heat exchanger 13 is improved, energy consumption efficiency during a heating operation is improved, and compressor power during a defrosting operation can be suppressed. Thus, energy saving properties of the refrigeration cycle device can be improved.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a refrigeration cycle apparatus provided with an internal heat exchanger.

  Conventionally, an internal heat exchanger is provided in this type of refrigeration cycle apparatus (see, for example, Patent Document 1).

  As shown in FIGS. 8 (a) and 8 (b), the low pressure side pipe 102 in which the low pressure side refrigerant flowing out of the evaporator flows and the high pressure side pipe 101 in which the high pressure side refrigerant flowing out of the radiator flows It is characterized in that the refrigerant and the high pressure side refrigerant are integrated so as to be able to exchange heat.

JP, 2014-181870, A

  However, in the internal heat exchanger 100 of Patent Document 1, the internal heat exchanger is configured by making the internal diameter of the high pressure side pipe 101 smaller than the internal diameter of the low pressure side pipe 102 and making the high pressure side pipe 101 an internally grooved pipe. Although the heat exchange efficiency of 100 is enhanced, the pressure loss in the high pressure side flow path tends to be large due to the above configuration.

  In particular, in the defrosting operation in a forward cycle in which the refrigerant is annularly flowed in the order of the compressor 11, the radiator 12, the pressure reducing means 14, and the evaporator 15, the pressure in the high pressure side pipe 101 As the loss increases, the differential pressure between the high pressure side and the low pressure side increases, and the power consumption of the compressor 11 increases, and the evaporation pressure also decreases, leading to an increase in the defrosting operation time, and the defrosting operation time It had the subject that energy saving performance fell.

  Further, refrigerant and lubricating oil, which are absorbed by the evaporator 15 and gasified, flow into the low pressure side pipe 102 of the internal heat exchanger 100. Here, when a poorly soluble oil is used as the lubricating oil, the solubility of carbon dioxide decreases in the low pressure side region, and a phenomenon occurs in which the refrigerant and the lubricating oil are separated.

  Thereby, in the configuration of the conventional internal heat exchanger 100, since the lubricating oil adheres to the heat transfer surface of the low pressure side pipe 101, the lubricating oil inhibits the heat exchange and the heat exchange efficiency is lowered. I had a problem.

  The present invention solves the above-mentioned conventional problems and improves the heat exchange efficiency of the internal heat exchanger during heating operation while suppressing power consumption during defrosting operation by reducing the pressure loss of the high-pressure side refrigerant, An object of the present invention is to provide a refrigeration cycle apparatus capable of performing an operation with high energy saving performance.

  In order to achieve the above object, the refrigeration cycle of the present invention comprises a compressor, a radiator, a pressure reducing means, an evaporator, and a high pressure side refrigerant supplied from the radiator to the pressure reducing means and the evaporator And an internal heat exchanger that exchanges heat with the low pressure side refrigerant absorbed in the heat source, and the refrigerant is allowed to flow in the order of the compressor, the radiator, the pressure reducing means, and the evaporator to melt the frost of the evaporator In the internal heat exchanger, the high pressure side pipe in which the high pressure side refrigerant flows and the low pressure side pipe in which the low pressure side refrigerant flows are in close contact with each other, and the high pressure side pipe and the low pressure side pipe Is characterized in that at least one or more bent portions are provided, and RH <RL when the bending radius of the high pressure side piping is RH and the bending radius of the low pressure side piping is RL. is there.

  As a result, the pressure loss of the high pressure side refrigerant is reduced, and the differential pressure between the high pressure side and the low pressure side at the time of defrosting is reduced, so that the compressor power can be reduced. Moreover, the evaporation pressure is increased, and the defrosting time can be shortened, so that the energy saving property of the equipment at the time of the defrosting operation is improved.

  In addition, since the amount of lubricating oil adhering to the heat transfer surface of the low-pressure side pipe decreases, the amount of heat exchange at the bending portion increases, and the energy saving property of the equipment at the time of operation is improved.

  According to the present invention, the refrigeration cycle apparatus improves the heat exchange efficiency of the internal heat exchanger during the heating operation while suppressing the power consumption during the defrosting operation by reducing the pressure loss of the high pressure side refrigerant, thereby saving energy It is possible to provide a refrigeration cycle apparatus capable of performing high operation.

A perspective view of an internal heat exchanger according to Embodiment 1 of the present invention Top view of the internal heat exchanger shown in FIG. 1 (A) A-A sectional view of FIG. 2 (b) An enlarged view of a portion A of FIG. 3 (a) Top view of another internal heat exchanger according to Embodiment 1 of the present invention Circuit configuration of the refrigeration cycle apparatus according to the first embodiment of the present invention (A) Perspective view of another internal heat exchanger according to the first embodiment of the present invention (b) Top view of the internal heat exchanger shown in FIG. 6 (a) (A) BB sectional drawing of FIG.6 (b) (b) The B section enlarged view of FIG. 7 (a) (A) A schematic view of a conventional internal heat exchanger (b) XX cross-sectional view of FIG. 8 (a)

  According to a first aspect of the present invention, there is provided a compressor, a radiator, a pressure reducing means, an evaporator, a high pressure side refrigerant supplied from the radiator to the pressure reducing means, and a low pressure side refrigerant absorbed by the evaporator. An internal heat exchanger for exchanging heat, and having a defrosting operation mode for melting the frost of the evaporator by flowing a refrigerant in the order of the compressor, the radiator, the pressure reducing means, and the evaporator; In the internal heat exchanger, the high pressure side pipe in which the high pressure side refrigerant flows and the low pressure side pipe in which the low pressure side refrigerant flows are in close contact with each other, and the high pressure side pipe and the low pressure side pipe are in at least one place. It is a refrigeration cycle apparatus characterized in that a bent portion is provided, and RH <RL, where the bending radius of the high pressure side pipe is RH and the bending radius of the low pressure side pipe is RL.

  As a result, the flow path length of the high pressure side pipe is shortened and the pressure loss of the high pressure side refrigerant is reduced, as compared with the case where the bending R of the high pressure side pipe and the bending R of the low pressure side pipe are the same. Therefore, the high and low pressure difference at the time of defrosting is reduced, and the compressor power can be reduced. Moreover, since the evaporation pressure is increased and the defrosting time is shortened, the energy saving property of the apparatus is improved.

  In addition, in the bending portion of the internal heat exchanger, centrifugal force acts on the gas refrigerant flowing into the low pressure side piping and the lubricating oil, but larger centrifugal force is generated on the lubricating oil having a higher density than the gas refrigerant. Since it acts, the lubricating oil which inhibits heat transfer is pushed to the outer peripheral side of the low pressure side piping. As a result, the amount of lubricating oil on the heat transfer surface on the low pressure side decreases, so the amount of heat exchange at the bending portion increases, and the energy saving property of the device can be improved.

  In the second invention, particularly in the first invention, at least a part of the low pressure side pipe is formed in a substantially circular shape, and in the horizontal direction, the high pressure side pipe is located inward from the axial center of the low pressure side pipe The refrigeration cycle apparatus is characterized in that it is in close contact with the low pressure side pipe on the side.

  Thereby, the centrifugal effect acts on the low-temperature low-pressure gas refrigerant flowing in the low-pressure side pipe and the lubricating oil, and the lubricating oil having a density higher than that of the gas refrigerant flows on the outer peripheral side in the pipe.

  Therefore, at least a part of the low pressure side pipe is formed in a substantially circular shape, and in the horizontal direction, the high pressure side pipe is in close contact with the low pressure side pipe on the inner side with respect to the axial center of the low pressure side pipe With this configuration, the amount of lubricating oil adhering to the heat transfer surface on the low pressure side is reduced, and heat exchange is promoted, so that the amount of internal heat exchange is increased, and the energy saving property of the device is further improved.

  According to a third aspect of the invention, in the refrigeration system according to the first aspect of the invention, particularly, the high pressure side pipe is in close contact with the low pressure side pipe at a lower side than the axial center of the low pressure side pipe in the vertical direction. It is a cycle device.

  Thereby, the inner surface on the vertically lower side of the low pressure side pipe becomes the heat transfer surface of the refrigerant. Here, gravity acts on the refrigerant, and the liquid component of the refrigerant tends to stagnate vertically below the low pressure side pipe. Therefore, the liquid component of the refrigerant is more easily heated, the amount of internal heat exchange is increased, and the energy saving property of the device is improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited by the embodiment.

Embodiment 1
FIG. 5 shows a circuit configuration of a hot water supply apparatus including the refrigeration cycle apparatus 10 according to the first embodiment of the present invention.

  In FIG. 5, the refrigeration cycle apparatus 10 is configured such that a compressor 11, a radiator 12, a pressure reducing means 14, and an evaporator 15 are annularly connected by refrigerant pipes in order. The internal heat exchanger 13 comprises a high pressure side pipe 1 and a low pressure side pipe 2, the high pressure side pipe 1 is connected between the radiator 12 and the pressure reducing means 14, and the low pressure side pipe 2 is compressed with the evaporator 15 It is connected between the machine 11 and forms a part of the refrigeration cycle apparatus 10.

  In the refrigeration cycle apparatus 10, carbon dioxide as a refrigerant and polyalkylene glycol oil (PAG oil) which is a sparingly soluble oil as a lubricating oil for the compressor 11 are enclosed. It is known that PAG oil has an area incompatible with carbon dioxide in a temperature range of 31 ° C. or less, and the carbon dioxide solubility in PAG oil decreases especially as the pressure becomes low. The viscosity of PAG oil at 40 ° C. is preferably 5 to 300 cST.

  The structure of the internal heat exchanger 13 in Embodiment 1 of this invention is shown in FIG. 1-FIG. 3 (a) (b). In the internal heat exchanger 13, the high pressure side pipe 1 and the low pressure side pipe 2 are in close contact with each other at the pipe outer peripheral surface, and the pipe contact portion is joined by brazing material or solder to promote heat transfer. It is done. Here, the internal heat exchanger 13 is formed by being helically bent over substantially the entire area such that the relationship between the bending radius RH of the high pressure side pipe 1 and the bending radius RL of the low pressure side pipe 2 becomes RH <RL. ing.

  Further, in FIG. 5, the hot water storage apparatus 20 controls the hot water mixing valve that supplies hot water to the hot water storage tank 21 for storing hot water boiled by the refrigeration cycle apparatus 10 and the hot water supply terminal (not shown) such as a shower. And 24. FIG.

  The operation and action of the water heater provided with the refrigeration cycle device configured as described above will be described below.

  First, an operation at the time of heating operation for heating warm water in the radiator 12 will be described.

  During the heating operation, the high temperature and high pressure refrigerant discharged from the compressor 11 exchanges heat with water in the radiator 12 and radiates heat. The heated water is supplied to the hot water storage tank 21 and used for a shower or the like. The high pressure refrigerant leaving the radiator 12 flows into the high pressure side pipe 1 of the internal heat exchanger 13 and radiates heat to the low pressure side refrigerant flowing through the low pressure side pipe 2.

  The refrigerant leaving the high pressure side pipe 1 of the internal heat exchanger 13 is depressurized by the depressurizing means 14 to be a low temperature / low pressure gas-liquid two-phase state. The low-temperature and low-pressure refrigerant absorbs heat from the atmosphere in the evaporator 15 and is gasified to flow into the low-pressure pipe 2, and the high-pressure refrigerant flowing in the high-pressure pipe 1 in the low-pressure pipe 2 of the internal heat exchanger 13. The heat is absorbed further to be in the superheated state, and it is sucked into the compressor 11.

  By repeating this operation, the refrigeration cycle apparatus 10 performs a heating operation of water. During operation, the lubricating oil flowing out of the compressor 11 together with the refrigerant is circulating in the refrigeration cycle apparatus 10, and the low pressure refrigerant and the lubricating oil flowing into the low pressure side pipe 2 are separated into the refrigerant rich layer and the oil rich layer. It is flowing.

  Next, when frost adheres to the evaporator 15 by the heating operation, an operation of the defrosting operation for melting and removing the frost will be described.

  If the heating operation is performed in a state where the outside air temperature is low, the evaporator 15 is frosted, and the heat absorption capacity of the evaporator 15 is significantly reduced. Then, in order to melt and remove the frost adhering to the evaporator 15, a refrigerant | coolant is circulated and defrost operation is performed. The order in which the refrigerant flows at the time of the defrosting operation is the same as at the time of the heating operation, and is therefore omitted.

  During the defrosting operation, the pressure reduction amount in the pressure reducing means 14 is reduced, and the pressure of the refrigerant discharged from the compressor 11 is suppressed. Furthermore, in the radiator 12, the amount of heat released from the refrigerant is suppressed as much as possible, and the medium temperature / medium pressure refrigerant is supplied to the evaporator 15 through the pressure reducing means 14. Thus, by raising the temperature of the refrigerant flowing through the evaporator 15, the frost adhering to the evaporator 15 is melted. The refrigerant that has dissipated heat in the evaporator 15 to melt the frost is drawn into the compressor 11. By repeating this operation, the defrosting operation is performed until the frost adhering to the evaporator 15 is melted.

  Here, according to the first embodiment of the present invention, as shown in FIG. 2, the internal heat exchanger 13 has the relationship between the bending radius RH of the high pressure side pipe 1 and the bending radius RL of the low pressure side pipe 2 as RH. In order to achieve <RL, a helical shape is formed over substantially the entire area. As a result, the flow path length of the high pressure side pipe 1 becomes short, and the pressure loss of the high pressure side refrigerant decreases, as compared with the case where the bending R of the high pressure side pipe 1 and the low pressure side pipe 2 are synchronized. Therefore, the difference in high and low pressure at the time of defrosting is reduced, and the power of the compressor can be reduced. Further, the evaporation pressure is increased and the defrosting time is shortened.

  In addition, in the bent portion of the internal heat exchanger 13, the centrifugal force as shown in the equation (1) acts on the gas refrigerant flowing into the low pressure side pipe 2 and the lubricating oil.

  In equation (1), m is mass, v is velocity, and r is radius of gyration.

  Here, the density of the refrigerant in the low pressure side pipe 2 is, for example, 115.7 kg / m 3 when flowing in with a saturated gas at a pressure of 4 MPa. On the other hand, the density of the lubricating oil is 1015 kg / m 3 at a temperature of 280 K, although it slightly varies depending on the additives. In the low pressure side piping, the low pressure, low temperature refrigerant and lubricating oil flow separately into the refrigerant rich layer and the oil rich layer.

  As shown in FIGS. 3A and 3B, the high pressure side pipe 1 is in close contact with the low pressure side pipe 2 inward in the horizontal direction from the axial center of the low pressure side pipe 2. The substantially whole area of the low pressure side pipe 2 is bent in a spiral shape.

  In the bending portion, a large centrifugal effect acts on the lubricating oil having a larger density than the refrigerant, so the lubricating oil that inhibits the heat transfer flows on the outer peripheral side of the low pressure side pipe 2. As a result, the amount of adhesion of the lubricating oil on the heat transfer surface on the low pressure side is reduced, so the amount of heat exchange in the bending portion is increased, and the energy saving property of the device is improved. In addition, if at least a part of the high-pressure side pipe 1 and the low-pressure side pipe 2 is formed in a substantially circular shape even if it is not substantially the entire area, the effect is obtained at that portion.

  As described above, the refrigeration cycle apparatus equipped with the internal heat exchanger in the present embodiment can improve the energy consumption efficiency related to the operation of the refrigeration cycle apparatus in both the heating operation and the defrosting operation.

  In the embodiment, the internal heat exchanger in which substantially the entire area is bent in a spiral shape is described as an example, but as shown in FIG. 4, the internal heat exchanger in which at least one or more points are bent The same effect can be obtained.

  Furthermore, as shown in FIGS. 6 (a) and 6 (b) and FIGS. 7 (a) and 7 (b), this bending process is vertical to the central axis of the internal heat exchanger 13 helically bent over substantially the entire area, and The directions are substantially the same, and the high pressure side pipe 1 is in close contact with the low pressure side pipe 2 on the vertically lower side than the central axis of the low pressure side pipe 2. In addition, if at least a part of the high-pressure side pipe 1 is in close contact with the low-pressure side pipe 2 at the lower side of the axial center of the low-pressure side pipe 2 in the vertical direction Has its effect.

  During heating operation of the refrigeration cycle apparatus 10 at extremely low outside air temperature, the two-phase refrigerant absorbed by the evaporator 15 can not be completely gasified due to the insufficient capacity of the evaporator, and the internal heat exchanger 13 in two-phase state. May flow into the low pressure side piping 2 of the

  According to the bending process over the entire area of the pipe, as shown in FIG. 7, the inner surface on the vertically lower side of the low pressure side pipe becomes the heat transfer surface of the refrigerant. Here, since the gravity acts on the refrigerant, the liquid component of the refrigerant tends to stagnate vertically below the low pressure side pipe. Therefore, the liquid component of the refrigerant is more easily heated, so the amount of internal heat exchange is increased, and the energy saving property of the device is improved.

  As described above, the refrigeration cycle apparatus equipped with the internal heat exchanger in the present embodiment can further improve the energy consumption efficiency of the refrigeration cycle apparatus during heating operation.

  As mentioned above, since the refrigeration cycle apparatus concerning this invention can improve energy consumption efficiency, it can be applied to the use of energy saving improvement improvement, such as an air conditioning apparatus, a heat pump type hot water heater, and a heater.

DESCRIPTION OF SYMBOLS 1 High pressure side piping 2 Low pressure side piping 10 Refrigerating cycle device 11 Compressor 12 Radiator 13 Internal heat exchanger 14 Decompression means 15 Evaporator 20 Hot water storage device 21 Hot water storage tank 24 Hot water supply mixing valve

Claims (3)

A compressor, a radiator, pressure reducing means, an evaporator,
Said compressor, said radiator, said pressure reducing means, comprising: an internal heat exchanger for exchanging heat between the high pressure side refrigerant supplied from the radiator to the pressure reducing means and the low pressure side refrigerant absorbed by the evaporator And a defrosting operation mode for flowing the refrigerant in the order of the evaporator to melt the frost of the evaporator;
In the internal heat exchanger, the high pressure side pipe in which the high pressure side refrigerant flows and the low pressure side pipe in which the low pressure side refrigerant flows are in close contact with each other,
The high pressure side pipe and the low pressure side pipe are provided with at least one bent portion,
Assuming that the bending radius of the high pressure side piping is RH and the bending radius of the low pressure side piping is RL,
A refrigeration cycle apparatus characterized in that RH <RL. The low pressure side piping is at least partially formed in a substantially circular shape, and the high pressure side piping is in close contact with the low pressure side piping inward in the horizontal direction from the axial center of the low pressure side piping. The refrigeration cycle apparatus according to claim 1, wherein The refrigeration cycle apparatus according to claim 1, wherein the high pressure side pipe is in close contact with the low pressure side pipe at a lower side than an axial center of the low pressure side pipe in the vertical direction.

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