JP4765727B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a refrigeration apparatus mainly used as a heating means of a heat pump type hot water supply apparatus.

2. Description of the Related Art Conventionally, as a refrigeration apparatus for a heat pump type hot water supply apparatus, one composed of a compression refrigeration circuit is widely used. These refrigeration apparatuses are provided with a bypass circuit from the discharge side pipe line of the compressor to the inlet side of the air heat exchanger when performing defrost operation for defrosting, and the hot gas discharged from the compressor is supplied to the air. The type that defrosts by flowing in the heat exchanger, and the opening of the expansion valve is made larger than in normal operation without providing a bypass circuit, and hot gas discharged from the compressor is flowed to the air heat exchanger in the positive cycle. There is a defrosting type, and the latter type has a simple cycle configuration and low cost. (For example, refer to Patent Document 1).
JP 2001-82802 A

  However, the type of defrosting by flowing hot gas through the air heat exchanger in the positive cycle increases the flow rate of the hot gas flowing through the water heat exchanger because the opening of the expansion valve is larger than that during normal operation. There is a tendency to increase the noise during defrosting.

  The subject of this invention is providing the freezing apparatus which suppresses the noise at the time of a defrost by the type which flows a hot gas to an air heat exchanger by a positive cycle, and defrosts.

  The refrigeration apparatus according to the first aspect of the invention uses CO2 as a refrigerant and includes a water heat exchanger. In the water heat exchanger, heat exchange is performed between a refrigerant pipe through which refrigerant gas flows and a water pipe through which water flows. The refrigerant tube is branched into a plurality of refrigerant thin tubes.

The refrigeration apparatus according to the first invention includes a compressor, an expansion valve, an air heat exchanger, a water heat exchanger, and a control unit. In the water heat exchanger, heat exchange is performed between a refrigerant pipe through which refrigerant gas flows and a water pipe through which water flows. The control unit controls the opening degree of the expansion valve. In addition, the compressor, the refrigerant pipe, the expansion valve, and the air heat exchanger are connected in an annular shape by a refrigerant pipe to form a compression refrigeration circuit using CO2 as a refrigerant. The refrigerant tube is branched into a plurality of refrigerant thin tubes. When the predetermined condition is satisfied, the control unit performs a defrost operation in which the hot gas discharged from the compressor is caused to flow to the air heat exchanger in a positive cycle. During the defrost operation, the maximum speed of the refrigerant flowing through the plurality of refrigerant thin tubes is 4 m / s or less.

  In this refrigeration apparatus, the flow rate of the refrigerant passing through the refrigerant thin tube is 4 m / s or less at which the refrigerant flow noise is suppressed, so that an increase in the flow noise when hot gas passes through the water heat exchanger is suppressed. Is done.

A refrigeration apparatus according to a second aspect of the present invention is the refrigeration apparatus according to the first aspect of the present invention, wherein the sum of the refrigerant passage cross-sectional areas of the plurality of refrigerant thin tubes is larger than the refrigerant passage cross-sectional area of the refrigerant pipe.

  In this refrigeration apparatus, the flow rate of the refrigerant decreases in the water heat exchanger. For this reason, the distribution | circulation sound of the refrigerant | coolant which flows through a water heat exchanger is reduced.

A refrigeration apparatus according to a third aspect of the present invention is the refrigeration apparatus according to the first aspect of the present invention , wherein the control unit fully opens the expansion valve during the defrost operation and causes the refrigerant to flow.

  Here, when the expansion valve is fully opened, the flow rate of the refrigerant flowing through the refrigerant thin tube becomes faster than that during normal operation, and there is almost no heat exchange in the water heat exchanger. For this reason, a high-temperature refrigerant | coolant goes to an air heat exchanger quickly, and defrost performance improves. In addition, since the refrigerant is divided by the plurality of refrigerant thin tubes, the circulation sound of the refrigerant is lower than before.

A refrigeration apparatus according to a fourth aspect of the present invention is the refrigeration apparatus according to the first aspect of the present invention, further comprising a fan that applies air to the air heat exchanger to promote heat exchange and a fan chamber that houses the fan. A water heat exchanger is disposed in the fan chamber.

  Here, the noise of the refrigerant flowing through the refrigerant thin tube is eliminated by the fan rotation sound in the fan chamber. For this reason, the unpleasant circulation sound of a refrigerant is canceled.

A refrigeration apparatus according to a fifth aspect of the present invention is the refrigeration apparatus according to the first aspect of the present invention, wherein the refrigerant thin tube is wound so as to be in close contact with the outer periphery of the water tube.

  Here, since heat exchange between the refrigerant thin tube and the water tube is promoted, the heating capacity in the water heat exchanger is improved.

In the refrigeration apparatus according to the first invention or the second invention , the flow rate of the refrigerant decreases in the water heat exchanger. For this reason, the distribution | circulation sound of the refrigerant | coolant which flows through a water heat exchanger is reduced.

In the refrigeration apparatus according to the third invention, the high-temperature refrigerant quickly turns to the air heat exchanger, and the defrost performance is improved. In addition, since the refrigerant is divided by a plurality of refrigerant thin tubes, the circulation sound of the refrigerant is lower than before.

In the refrigeration apparatus according to the fourth aspect of the invention, the noise of the refrigerant flowing through the refrigerant thin tube is eliminated by the fan rotation sound in the fan chamber. For this reason, the unpleasant circulation sound of a refrigerant is canceled.

In the refrigeration apparatus according to the fifth aspect of the invention, since the refrigerant thin tube is wound so as to be in close contact with the outer periphery of the water tube, heat exchange between the refrigerant thin tube and the water tube is promoted, and the heating capacity in the water heat exchanger is improved. .

<Configuration of heat pump hot water supply device>
A system of a heat pump hot water supply apparatus including a refrigeration apparatus according to an embodiment of the present invention is shown in FIG. The heat pump type hot water supply apparatus 1 includes a refrigeration apparatus 2 and a hot water storage apparatus 3. The refrigeration apparatus 2 includes a compressor 21, a refrigerant pipe 22 a in the water heat exchanger 22, an expansion valve 23 as a decompression unit, and an air heat exchanger 24 that are annularly connected by a refrigerant pipe 25. 20

  Further, the refrigeration circuit 20 is provided with a gas heat exchanger 26 for heat exchange between the high-pressure and high-temperature refrigerant coming out of the water heat exchanger 22 and the low-pressure and low-temperature refrigerant coming out of the air heat exchanger 24. ing. Specifically, heat exchange is performed between the refrigerant passage connecting the water heat exchanger 22 and the expansion valve 23 and the refrigerant passage connecting the air heat exchanger and the compressor 21.

  The hot water storage device 3 includes a water circulation circuit 30 in which a hot water storage tank 31, a water pipe 22 b in the water heat exchanger 22, and a water circulation pump 32 are annularly connected by a water pipe 35.

  The refrigeration apparatus 2 includes an outside air temperature sensor 8 that detects the outside air temperature at the installation location, a discharge pipe temperature sensor 9 that detects the discharge pipe temperature of the compressor 21, and a temperature sensor 10 that detects the temperature of the air heat exchanger 24. The detection signals of these sensors are input to the microcomputer 6 (control unit).

  The water circulation amount is controlled by the water circulation pump 32 so that the temperature of the water heated by the water heat exchanger 22 becomes 85 ° C. The microcomputer 6 controls the opening degree of the expansion valve 23 in order to ensure the refrigerant temperature necessary for obtaining 85 ° C. water.

<Structure of refrigeration equipment>
FIG. 2 is a cross-sectional view showing the internal structure of the refrigeration apparatus 2. In FIG. 2, the right compartment of the heat insulation wall 2c is the machine room 2a, and the left compartment of the heat insulation wall 2c is the fan room 2b. A compressor 21 and an expansion valve 23 are arranged in the machine room 2a.

  In the fan chamber 2b, a fan 27 is disposed in front of the fan chamber 2b in a front view in FIG. A motor that drives the fan 27 is disposed behind the fan 27 in a state of being fixed to the motor support base 28. A water heat exchanger 22 is disposed below the fan chamber 2b with a heat insulating wall 2d interposed therebetween. In the water heat exchanger 22, heat exchange is performed between the refrigerant flowing through the refrigerant pipe 22a (see FIG. 1) and the water flowing through the water pipe 22b (see FIG. 1).

  In FIG. 2, the air heat exchanger 24 is disposed along the left side wall and the back wall of the fan chamber 2b, and the right end of the air heat exchanger 24 extends to the center of the machine chamber 2a. The control box 4 is disposed so as to straddle the upper part of the machine room 2a and the upper part of the fan room 2b. The control box 4 incorporates a control device 5 equipped with a microcomputer 6 (see FIG. 4) and an inverter 7 (see FIG. 4).

<Structure of water heat exchanger>
FIG. 3 is a piping diagram of the water heat exchanger 22. The refrigerant tube 22a is composed of three refrigerant thin tubes 221 to 223, and is spirally wound around the outer periphery of the water tube 22b so as not to contact each other. The inner diameter (3 mm) of the refrigerant thin tubes 221 to 223 is smaller than the inner diameter of the refrigerant pipe 25, but the sum of the refrigerant passage cross-sectional areas of the three refrigerant thin tubes 221 to 223 is larger than the refrigerant passage cross-sectional area of the refrigerant pipe 25. The water pipe 22b is arranged in a hairpin shape with the refrigerant thin tubes 221 to 223 wound around the outer periphery. The refrigerant that has flowed into the water heat exchanger 22 from the refrigerant pipe 25 is divided into approximately three equal parts by the refrigerant thin tubes 221 to 223 and circulates. For this reason, the amount of heat exchange increases. Moreover, the thing which wound three refrigerant | coolant thin tubes 221-223 around the water pipe 22b has a slower flow velocity compared with what wound only one or two, and the circulation sound of a refrigerant | coolant is reduced. Furthermore, since the water heat exchanger 22 is disposed below the fan chamber 2 b, the circulation sound of the refrigerant flowing through the refrigerant thin tubes 221 to 223 during normal operation is eliminated by the rotation sound of the fan 27, so that there is almost no problem. .

<Operation control of refrigeration equipment>
FIG. 4 is a control block diagram of the refrigeration apparatus 2. The microcomputer 6 sets the target discharge pipe temperature at the target discharge pipe temperature setting unit 62 based on detection signals from the outside air temperature sensor 8 and the temperature sensor 10 of the air heat exchanger 24. The microcomputer 6 controls the opening of the expansion valve 23 via the expansion valve opening controller 63 so that the discharge pipe temperature detected by the discharge pipe temperature sensor 9 approaches the target discharge pipe temperature. Data necessary for setting the target discharge pipe temperature is stored in the target discharge pipe temperature setting unit 62 in advance.

  Further, the microcomputer 6 compresses via the inverter control unit 64 in consideration of the influence of the outside air temperature on the cooking capacity of the refrigeration apparatus 2 and further considering that the hot water supply load changes according to the time zone of the day. The operating frequency of the machine 21 is controlled. For example, in a time zone in which the outside air temperature is low and the hot water supply load is large, the operating frequency of the compressor 21 is increased by ignoring the efficiency in order to prevent hot water shortage. On the other hand, in the time zone when the outside air temperature is high and the hot water supply load is small, the operating frequency of the compressor 21 is set to a high efficiency point.

  When the hot water supply load is large, the microcomputer 6 controls the operation of the compressor 21 so that the discharge pipe temperature does not exceed 120 ° C. for the purpose of protecting the compressor 21. Actually, when the discharge pipe temperature is 120 ° C., the internal temperature of the compressor 21 reaches 140 ° C. to 145 ° C. When the internal temperature further rises and exceeds 150 ° C., the magnet inside the compressor 21 The magnetic force of the oil drops and oil deterioration occurs, leading to failure. Therefore, in this embodiment, the upper limit of the discharge pipe temperature is set to 120 ° C.

  However, when the outside air temperature t1 is −20 ° C. or less, the compressor 21 is likely to be overloaded. Therefore, as a further safety measure, the correction value of the detection value of the discharge pipe temperature sensor 9 is increased, and the actual discharge pipe temperature is reduced. Before reaching 120 ° C., the detection value of the discharge pipe temperature sensor 9 needs to be 120 ° C. Therefore, the correction amount when the outside air temperature t1 is −20 ° C. or less is obtained experimentally and stored in the second correction means 61b of the temperature correction unit 61 of the microcomputer 6.

  In the temperature range of the outside air temperature t1> −20 ° C., the correction is made by the first correcting means 61a.

<Defrost operation control>
When the outlet temperature of the air heat exchanger 24 decreases to −5 ° C. during normal operation, the defrosting operation is started. The defrosting operation of the present embodiment is of a type in which the hot gas discharged from the compressor 21 is defrosted by flowing it through the air heat exchanger 24 in a positive cycle. During the defrosting operation, the water circulation pump 32 is operated. And the opening degree of the expansion valve 23 is made larger than that during normal operation. Here, the opening degree of the expansion valve 23 during the defrost operation is fully opened. Accordingly, the amount of heat released from the hot gas discharged from the compressor 21 by the water heat exchanger 22 is reduced, and the temperature drop due to the decompression at the expansion valve 23 is also reduced. Therefore, the hot gas discharged from the compressor 21 reaches the air heat exchanger 24 without greatly lowering the temperature, and defrosts the air heat exchanger.

  In normal operation, the density of the hot gas discharged from the compressor 21 is small, and when the heat is radiated in the water heat exchanger 22, the density gradually increases and the flow rate becomes slow. On the other hand, in the defrost operation, since the heat is hardly dissipated in the water heat exchanger 22, the density is small and the flow rate is fast. For this reason, there was a tendency for the flow noise when hot gas passes through the water heat exchanger 22 to increase. However, in the present embodiment, the refrigerant pipe 22a in the water heat exchanger 22 is divided into three branches of the refrigerant thin pipes 221, 222, and 223, and the flow rate of the refrigerant passing through the single refrigerant thin pipe is slowed down. The distribution sound is suppressed. In the present embodiment, the flow rate of the refrigerant passing through the refrigerant thin tube is about 2 m / s in the case of three branches, and about 3 m / s in the case of two branches, both of which are 4 m / s or less.

<Features>
(1)
The refrigeration apparatus 2 includes a compression refrigeration circuit 20 using CO2 as a refrigerant, and includes a water heat exchanger 22. In the compression refrigeration circuit 20, the compressor 21, the refrigerant pipe 22 a of the water heat exchanger 22, the expansion valve 23, and the air heat exchanger 24 are annularly connected by a refrigerant pipe 25. In the water heat exchanger 22, heat exchange is performed between the refrigerant pipe 22a through which the refrigerant gas flows and the water pipe 22b through which water flows. Since the refrigerant pipe 22a is branched into a plurality of refrigerant thin tubes 221 to 223, the refrigerant is divided into three refrigerant thin tubes. The sum total of the refrigerant passage sectional areas of the plurality of refrigerant thin tubes 221 to 223 is larger than the refrigerant passage sectional area of the refrigerant pipe. For this reason, the flow rate of the refrigerant in the water heat exchanger 22 decreases (specifically, 4 m / s or less), and the circulation sound of the refrigerant flowing through the water heat exchanger 22 is reduced.

(2)
The refrigeration apparatus 2 further includes a control unit 6 that controls the opening degree of the expansion valve 23. The control unit 6 causes the refrigerant to flow by fully opening the expansion valve 23 during the defrost operation. By fully opening the expansion valve 23, the flow rate of the refrigerant flowing through the refrigerant thin tubes 221 to 223 becomes faster than that during normal operation, and there is almost no heat exchange in the water heat exchanger. For this reason, the high-temperature refrigerant quickly moves to the air heat exchanger 24, and the defrost performance is improved. In addition, since the refrigerant is divided by the three refrigerant tubes, the circulation sound of the refrigerant is lower than before.

(3)
The refrigeration apparatus 2 further includes a fan chamber 2b. The fan chamber 2b houses a fan 27 that applies air to the air heat exchanger 24 to promote heat exchange. A water heat exchanger 22 is disposed in the fan chamber 2b. For this reason, the passage sound of the refrigerant passing through the refrigerant thin tubes 221 to 223 is eliminated by the sound of the fan 27.

(4)
In the refrigeration apparatus 2, since the refrigerant thin tubes 221 to 223 are wound so as to be in close contact with the outer periphery of the water tube 22b, heat exchange between the refrigerant thin tubes 221 to 223 and the water tube 22b is promoted, and the heating capacity is improved.

  As described above, according to the present invention, the refrigerant flow noise during normal operation and defrost operation is reduced, which is useful for a refrigeration apparatus of a heat pump hot water supply apparatus.

The system of the heat pump type hot water supply apparatus containing the freezing apparatus which concerns on one Embodiment of this invention. Sectional drawing which shows the internal structure of the freezing apparatus. Internal piping diagram of the water heat exchanger of the refrigeration system The block diagram of the control apparatus of the freezing apparatus.

DESCRIPTION OF SYMBOLS 1 Heat pump type hot water supply apparatus 2 Refrigeration apparatus 2a Fan chamber 6 Microcomputer (control part)
20 Compression Refrigeration Circuit 21 Compressor 22 Water Heat Exchanger 22a Refrigerant Tube 22b Water Tube 23 Expansion Valve 24 Air Heat Exchanger 25 Refrigerant Pipe 27 Fan 35 Water Pipe 221 Refrigerant Narrow Tube 222 Refrigerant Narrow Tube 223 Refrigerant Narrow Tube

Claims (5)

Hydrothermal heat exchange between the compressor (21), the expansion valve (23), the air heat exchanger (24), the refrigerant pipe (22a) through which the refrigerant gas flows and the water pipe (22b) through which water flows. A controller (6) for controlling the opening degree of the exchanger (22) and the expansion valve (23) , the compressor (21), the refrigerant pipe (22a), the expansion valve (23) and the air; A heat exchanger (24) is annularly connected by a refrigerant pipe (25) to form a compression refrigeration circuit (20) using CO2 as a refrigerant ,
The refrigerant pipe (22a) is branched into a plurality of refrigerant thin tubes (221 to 223),
The control unit (6) performs a defrost operation for flowing hot gas discharged from the compressor (21) to the air heat exchanger (24) in a positive cycle when a predetermined condition is established,
During the defrost operation, the maximum speed of the refrigerant flowing through the plurality of refrigerant thin tubes (221 to 223) is 4 m / s or less.
Refrigeration equipment (2). A sum of refrigerant passage cross-sectional areas of the plurality of refrigerant thin tubes (221 to 223) is larger than a refrigerant passage cross-sectional area of the refrigerant pipe (25);
The refrigeration apparatus (2) according to claim 1. The controller (6) circulates the refrigerant by fully opening the expansion valve (23) during the defrost operation.
The refrigeration apparatus (2) according to claim 1. A fan (27) that applies air to the air heat exchanger (24) to promote heat exchange; and a fan chamber (2b) that houses the fan (27),
The water heat exchanger (22) is disposed in the fan chamber (2b).
The refrigeration apparatus (2) according to claim 1. The refrigerant thin tubes (221 to 223) are wound so as to be in close contact with the outer periphery of the water tube (22b).
The refrigeration apparatus (2) according to claim 1.

Images