JP2005076911A - Refrigeration cycle system, and method for film formation on refrigerant piping interior - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the performance of a refrigeration cycle system by reducing pressure loss in refrigerant piping. <P>SOLUTION: The refrigeration cycle system 1 includes a compressor 14 for compressing a refrigerant, a condenser 20 for condensing the compressed refrigerant, decompressing means 30 for decompressing the condensed refrigerant, and an evaporator 28 for evaporating the decompressed refrigerant back to the compressor 14, and has a film 42 including at least either a surfactant or a repellent formed on inner surfaces 40 of the refrigerant piping 33a to 33f where the refrigerant flows. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a refrigeration cycle apparatus, and more particularly to a technique for reducing fluid friction in refrigerant piping.

  The refrigeration cycle apparatus compresses the refrigerant with a compressor, dissipates the heat of the compressed refrigerant into the atmosphere, for example, into the atmosphere to condense the refrigerant, decompresses the condensed refrigerant with the decompression unit, and decompresses the refrigerant. The secondary refrigerant such as water or air is cooled by evaporating the water with an evaporator.

  In such a refrigeration cycle apparatus, it has been proposed to reduce energy consumption and the like in order to improve the coefficient of performance (COP) of the refrigeration cycle (see, for example, Patent Document 1). According to this, in order to prevent the water cooled by the evaporator from freezing on the inner surface of the pipe and increasing the pressure loss in the pipe, the water separation of the inner surface of the water flow pipe is improved to prevent freezing. I am doing so.

JP 2001-66081 A

  However, in the prior art described in Patent Document 1, no consideration is given to reducing the pressure loss of the refrigerant pipe of the refrigeration cycle. That is, for example, in the case of a refrigeration cycle of a building air conditioner, a refrigerant pipe that connects an outdoor unit installed on the roof of a building and an indoor unit installed indoors is provided. It will be relatively long. Therefore, there is a problem that the pressure loss of the refrigerant pipe increases and the COP performance of the refrigeration cycle decreases.

  The subject of this invention is reducing the pressure loss of refrigerant | coolant piping and improving the performance of a refrigerating-cycle apparatus.

  The gist of the present invention is to basically reduce the fluid friction resistance on the inner surface of the refrigerant pipe to reduce the pressure loss of the refrigerant pipe. Specifically, since the refrigerant pipe is manufactured by molding copper or the like, the inner surface is generally relatively rough, so when the refrigerant flows through the refrigerant pipe, the inner surface of the refrigerant pipe Fluid friction resistance is generated between the refrigerant and the refrigerant. Therefore, when the pipe length of the refrigerant pipe becomes relatively long, the fluid friction force acting on the refrigerant becomes large, and the pressure loss increases due to the fluid friction force.

  Therefore, in order to solve the above problem, a film including at least one of a surfactant or a water repellent is formed on the inner surface of the refrigerant pipe. As a result, the refrigerant in the refrigerant pipe flows in contact with the film containing the surfactant or the water repellent agent, so that the fluid frictional force is reduced and the pressure loss in the refrigerant pipe can be reduced.

  In this case, the refrigerant pipe on which the film is formed is preferably a refrigerant pipe that connects the condenser and the evaporator, and a refrigerant pipe that connects the evaporator and the compressor.

  As a method of forming such a film on the inner surface of the refrigerant pipe, at least one of a surfactant or a water repellent is added to the refrigerant flowing through the refrigerant pipe constituting the refrigeration cycle and circulated. It is preferable to form a film containing at least one of a surfactant or a water repellent film on the inner surface. That is, since a part of the refrigerating machine oil adheres to the inner surface of the refrigerant pipe, the added surfactant or water repellent is mixed with the refrigerating machine oil attached to the inner surface of the refrigerant pipe, and the surfactant or water repellent is mixed. A film containing the agent is formed. According to this method, a film can be easily formed even with an existing refrigeration cycle apparatus.

  Instead of the above film, a configuration may be adopted in which a plurality of dents are formed on the inner surface of the refrigerant pipe. In this case, it is preferable that the corner formed by the inner surface of the refrigerant pipe and the side surface of the recess is an angle larger than 90 degrees and smaller than 180 degrees. As a result, the refrigerant flowing near the surface of the refrigerant pipe flows into the plurality of recesses, thereby generating a plurality of vortices having different speeds and sizes and forming a so-called turbulent flow layer on the inner surface of the refrigerant pipe. Therefore, the main flow of the refrigerant flowing through the refrigerant pipe flows through the turbulent flow layer without directly contacting the inner surface of the refrigerant pipe. As a result, since fluids of main flow and turbulent flow are brought into contact with each other, fluid frictional resistance acting on the main flow refrigerant is reduced.

  Various forms such as forming a convex portion can be considered for the inner surface of the refrigerant pipe, but in short, any shape that forms a turbulent flow layer on the inner surface of the refrigerant pipe is not limited to the concave portion. That's fine.

  ADVANTAGE OF THE INVENTION According to this invention, the pressure loss of refrigerant | coolant piping can be reduced and the performance of a refrigeration cycle apparatus can be improved.

  (Embodiment 1) A first embodiment of a refrigeration cycle apparatus to which the present invention is applied will be described with reference to FIGS. The present embodiment is an example in which the pressure loss of the refrigerant pipe is reduced by forming a surfactant film on the inner surface of the refrigerant pipe of the building air conditioning equipment. FIG. 1 is a system diagram of a refrigeration cycle apparatus to which the present invention is applied, FIG. 2 is a sectional view in the radial direction of a refrigerant pipe, and FIG. 3 is a diagram for explaining the pressure loss and capacity ratio of the refrigerant pipe. .

  As shown in FIG. 1, a refrigeration cycle apparatus 1 for a building air-conditioning facility includes an outdoor unit 10 installed on the roof of a building, an indoor unit 12 installed indoors, and the like. The outdoor unit 10 is a compressor 14 that compresses gas refrigerant to a high pressure, acts as a condenser during cooling operation, dissipates the heat of the gas refrigerant to the atmosphere, condenses the refrigerant, and acts as an evaporator during heating operation. A heat exchanger 20 that dissipates the heat of evaporation of the refrigerant to the atmosphere, a throttle mechanism 24 that functions as a decompression unit during heating operation, and the like are provided.

  The indoor unit 12 is a throttle mechanism 30 that acts as a decompression unit during cooling operation, and acts as an evaporator during cooling operation to radiate the heat of evaporation of the liquid refrigerant to the atmosphere, and acts as a condenser during heating operation to compress the compressed gas. A heat exchanger 28 for condensing the refrigerant by dissipating the heat of the refrigerant to the atmosphere is provided. In addition, a blower 22 that blows air or the like to the heat exchanger 20, and a blower 32 that blows a secondary refrigerant such as air to the heat exchanger 28 are provided. Further, a gas-liquid separator 16 that removes liquid components from the gas refrigerant introduced into the compressor 14, a liquid tank 26 that adjusts the amount of liquid refrigerant flowing between the heat exchanger 20 and the indoor unit, cooling operation and heating. A four-way switching valve 18 for switching operation is provided.

  In the refrigeration cycle apparatus of the building air conditioning equipment configured as described above, the refrigerant pipes 33d and 33e are provided so as to be connected to the outdoor unit 12 installed indoors from the outdoor unit 10 installed on the roof of the building. The piping lengths of the refrigerant pipings 33d and 33e are relatively long, for example, exceeding 100 m. Therefore, as shown in FIG. 3, since the pressure loss exceeds 0.4 MPa, for example, the capacity ratio of the refrigeration cycle apparatus, that is, the COP performance is reduced to about 60%. In this regard, in the present embodiment, the pressure loss of the refrigerant pipes 33d and 33e is reduced by forming a surfactant film on the inner surfaces of the refrigerant pipes 33d and 33e.

  Here, a method for reducing pressure loss will be described using the refrigerant pipe 33e as an example. As shown in FIG. 2, since the refrigerant pipe 33e is manufactured by molding copper or the like, the inner surface 40 of the refrigerant pipe 33e is generally relatively rough. Therefore, when the refrigerant flows through the refrigerant pipe 33e, a fluid friction force is generated between the inner surface 40 of the refrigerant pipe 33e and the refrigerant. In the building air-conditioning equipment, the refrigerant pipe 33e is relatively long, so that the fluid frictional force acting on the refrigerant flowing through the refrigerant pipe 33e increases and pressure loss occurs. Therefore, in the present embodiment, a film 42 containing a surfactant is formed on the inner surface 40 of the refrigerant pipe 33e. As a result, the refrigerant in the refrigerant pipe 33e flows in contact with the film 42 containing the surfactant, so that the fluid friction resistance is reduced, and the pressure loss in the refrigerant pipe 33e can be reduced.

  According to the present embodiment, as shown in FIG. 3, the pressure loss of the refrigerant pipe 33e can be reduced from 0.4 MPa to 0.2 MPa at a portion where the pipe length is, for example, 150 m. As a result, the capacity ratio of the refrigeration cycle apparatus can be improved from 60% to 80%, for example, and energy saving can be achieved.

  In this case, the film may contain a water repellent. In short, any film that can form a smoother film 42 than the inner surface 40 of the refrigerant pipe 33e may be used. However, the one that does not deteriorate the refrigerant or refrigerating machine oil is selected. Moreover, although the example which forms the film | membrane 42 mainly on the inner surface of the refrigerant | coolant piping 33d and 33e from which piping length becomes comparatively long was demonstrated, the film | membrane 42 should just be suitably formed in the film | membrane 42 in all the refrigerant | coolant piping 33a-33f.

  The refrigerant pipe 33a is the compressor 14 and the four-way switching valve 18, the refrigerant pipe 33b is the four-way switching valve 18 and the heat exchanger 20, the refrigerant pipe 33c is the heat exchanger 20 and the liquid tank 26, and the refrigerant pipe 33d is the liquid tank 26. The heat exchanger 28 and the refrigerant pipe 33e connect the heat exchanger 28 and the four-way switching valve 18, the refrigerant pipe 33f connects the four-way switching valve 18 and the gas-liquid separator 16, and the refrigerant pipe 33g connects the gas-liquid separator 16 and the compressor 14. Is.

  Further, when the film 42 is formed on the refrigerant piping of an existing building air conditioner, the operation is complicated because it involves movement or change of the equipment configuration. Therefore, at least one of a surfactant or a water repellent is added to the refrigerant flowing through the refrigerant pipes 33a to 33f and circulated. That is, since a part of the refrigerating machine oil adheres to the inner surface of the refrigerant pipe 33e through which the gaseous refrigerant flows, the surfactant or the water repellent added to the refrigerant is the inner surface of the refrigerant pipe 33e. By mixing with the refrigerating machine oil adhering to the film, a film 42 containing a surfactant or a water repellent is formed. According to this method, the membrane 42 can be easily formed even with an existing refrigeration cycle apparatus.

  (Embodiment 2) A second embodiment of a refrigeration cycle apparatus to which the present invention is applied will be described with reference to FIGS. This embodiment is different from the first embodiment in that a plurality of dents 44 and 46 are formed instead of forming the layer 42 containing the surfactant on the inner surfaces of the refrigerant pipes 33a to 33f. . FIG. 4 is a front view of the inner surface of the refrigerant pipe 33a, and FIG. 5 is a sectional view in the axial direction of the refrigerant pipe 33a.

  As shown in FIG. 4, the inner surface 40 of the refrigerant pipe 33a is processed into a dimple shape similar to the surface shape of a golf ball. For example, a plurality of recesses 44 and a plurality of recesses 46 are arranged on the inner surface 40 of the refrigerant pipe 33a. The recess 44 is formed in a circular shape and is recessed in the thickness direction of the refrigerant pipe 33a. A corner 50 is formed by the side surface 48 and the inner surface 40 of the recess, and the formed angle (θ) is an obtuse angle larger than 90 degrees and smaller than 180 degrees. Further, the recessed portion 46 is formed in a circular shape having a diameter smaller than that of the recessed portion 44, and is recessed in the thickness direction of the refrigerant pipe 33 a similarly to the recessed portion 44.

  According to the present embodiment, the refrigerant flowing near the surface of the refrigerant pipe 33a flows into the plurality of recesses 44, 46, thereby generating a plurality of vortices having different speeds and sizes, and the inner surface of the refrigerant pipe 33a. A so-called turbulent layer is formed. Therefore, the main flow of the refrigerant flowing through the refrigerant pipe 33a flows through the turbulent layer without directly contacting the inner surface 40. As a result, since fluids such as a main flow and a turbulent layer are brought into contact with each other, the fluid frictional resistance acting on the main flow refrigerant is reduced.

  Moreover, various aspects can be considered about the inner surface 40 of the refrigerant | coolant piping 33a. For example, as shown in FIG. 6, a plurality of convex portions 52 may be formed. Also in this case, the angle formed by the side surface 53 and the inner surface 40 of the convex portion 52 is set to be larger than 90 degrees and smaller than 180 degrees. As a result, a recess is substantially formed between the convex portions 52, and as a result of the refrigerant flowing into the recess, a turbulent flow layer is formed on the inner surface of the coolant pipe 33a, so the fluid friction resistance can be reduced. . In addition, if the recessed part 44 is formed in the inner surface of the refrigerant | coolant piping 33a, compared with the case where the convex part 52 is formed, there exists an advantage that the flow path of a refrigerant | coolant can be ensured large.

  Further, in FIG. 4, an example in which two different types of dent portions 44 and dent portions 46 are arranged has been described so that the refrigerant pipe 33a can be easily formed, but a plurality of types of dent portions are formed. It may be. In short, the shape may be such that a turbulent layer is formed on the inner surface of the refrigerant pipe 33a.

  As described above, the refrigeration cycle apparatus according to the present invention has been described based on the embodiment. However, for example, as shown in FIG. The multi-air conditioner includes a plurality of indoor units 12 having the same configuration. Each indoor unit 12 is connected to the refrigerant pipes 33a and 33d via the refrigerant pipes 56 and 58. In such a multi-air conditioner, since the pipe length of the refrigerant pipe becomes relatively long, the pressure loss of the refrigerant pipe also increases. In this respect, if the present invention is applied, the pressure loss can be reduced, so that the COP performance of the refrigeration cycle can be prevented from being lowered. Therefore, since a pump having a large driving force is not necessary, the refrigeration cycle apparatus can be reduced in size, and the equipment cost can be reduced.

  Further, the present invention can be applied to an ice heat storage type air conditioner, a so-called cooling / heating simultaneous type air conditioner or refrigerator that simultaneously performs cooling and heating in a refrigeration cycle.

  In order to reduce the fluid friction resistance in the refrigerant pipe, it is conceivable to increase the pipe diameter to reduce the speed of the flowing refrigerant. However, increasing the pipe diameter causes problems such as an increase in the required amount of refrigerant, an increase in the size of the refrigerant pipe, an increase in the material cost of the refrigerant pipe, a deterioration in the workability of the refrigerant pipe, the environment, costs, and workability. To do. In this regard, according to the present invention, the fluid friction resistance can be reduced without increasing the pipe diameter of the refrigerant pipe.

It is a systematic diagram of the refrigerating cycle device of one embodiment of the present invention. It is sectional drawing of the radial direction of the refrigerant | coolant piping of one Embodiment of this invention. It is a diagram which shows the pressure loss and capability ratio of one Embodiment of this invention. It is a front view of refrigerant | coolant piping of other embodiment of this invention. It is sectional drawing of the axial direction of the refrigerant | coolant piping of other embodiment of this invention. It is sectional drawing of the axial direction of the refrigerant | coolant piping of other embodiment of this invention. It is a systematic diagram of a multi air conditioner to which the present invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigeration cycle apparatus 14 Compressor 20 Heat exchanger 24, 30 Throttle mechanism 28 Heat exchanger 33a-33f Refrigerant piping 42 Membrane

Claims (5)

  A compressor that compresses the refrigerant; a condenser that condenses the compressed refrigerant; a decompression unit that decompresses the condensed refrigerant; and an evaporator that evaporates the decompressed refrigerant and returns it to the compressor. The refrigeration cycle apparatus comprising: a refrigeration cycle apparatus, wherein a film containing at least one of a surfactant and a water repellent is formed on an inner surface of a refrigerant pipe through which the refrigerant flows.   The refrigerant pipe on which the film is formed is at least one of a refrigerant pipe connecting the condenser and the evaporator and a refrigerant pipe connecting the evaporator and the compressor. The refrigeration cycle apparatus according to 1.   By adding and circulating at least one of a surfactant or a water repellent to the refrigerant flowing through the refrigerant pipe constituting the refrigeration cycle, at least a film of the surfactant or water repellent is formed on the inner surface of the refrigerant pipe. A method of forming a film on the inner surface of a refrigerant pipe, comprising forming a film including one of them.   A compressor that compresses the refrigerant; a condenser that condenses the compressed refrigerant; a decompression unit that decompresses the condensed refrigerant; and an evaporator that evaporates the decompressed refrigerant and returns it to the compressor. The refrigeration cycle apparatus comprising the refrigeration cycle apparatus, wherein a plurality of recesses are formed on the inner surface of the refrigerant pipe. 5. The refrigeration cycle apparatus according to claim 4, wherein a corner formed by an inner surface of the refrigerant pipe and a side surface of the recess is an angle greater than 90 degrees and smaller than 180 degrees.

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