JP2019027601A - Refrigerant circuit device - Google Patents

Abstract

To provide a refrigerant circuit device capable of improving thermal efficiency of a refrigerant and supplying hot water with a higher temperature.SOLUTION: A refrigerant circuit device includes: a compressor 1 for compressing a refrigerant; a hot water condenser 2 for exchanging heat between the refrigerant compressed by the compressor 1 and water to generate hot water; and a gas-liquid heat exchanger 3 that has an inner pipe 3a and an outer pipe 3b and in which the refrigerant that has passed through the hot water condenser 2 is introduced to the inner pipe 3a. The refrigerant circuit device also includes: a supercooling heat exchanger 4 for supercooling the refrigerant that has passed through the inner pipe 3a; an expansion valve 5 for decompressing the refrigerant that has passed through the supercooling heat exchanger 4; and a cold water evaporator 6 for exchanging heat between the refrigerant decompressed by the expansion valve 5 and water to generate cold water. The refrigerant that has passed through the cold water evaporator 6 is introduced to the outer pipe 3b to undergo heat exchange with the refrigerant passing through the inner pipe 3a, and then is introduced to the compressor 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a refrigerant circuit device that generates cold water and hot water.

  There has been proposed an apparatus for simultaneously taking out cold water and hot water by utilizing the condensation heat and evaporation heat of the refrigeration cycle. For example, Patent Document 1 discloses that a refrigerant circuit is configured by connecting a compressor, plate-type heat exchangers for hot water and cold water, and an expansion valve in order to generate cold water and hot water at the same time. Yes. By providing an adjustment valve for adjusting the suction pressure of the compressor in the refrigerant return pipe of the compressor, overload of the compressor is prevented and high temperature hot water is obtained.

JP 2003-176963 A

  In Patent Document 1 described above, the refrigerant returning to the compressor is throttled by the suction pressure adjusting valve to limit the refrigerant circulation amount of the refrigeration cycle, so that the cooling capacity and the heating capacity can be reduced and the temperature of the hot water can be increased. However, there was a problem that it was difficult to obtain the amount of heat (the amount of hot water).

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a refrigerant circuit device that can improve the thermal efficiency of the refrigerant and supply a sufficient amount of hot water at a higher temperature. It is to provide.

  A refrigerant circuit device that simultaneously obtains hot water and cold water, a compressor (1) that compresses the refrigerant, and a hot water condenser (2) that exchanges heat between the refrigerant compressed by the compressor and water to form hot water A gas-liquid heat exchanger (3) having a first flow path and a second flow path, into which the refrigerant that has passed through the hot water condenser is introduced into the first flow path, and the first flow path A supercooling heat exchanger (4) that supercools the refrigerant that has passed through the flow path, an expansion valve (5) that decompresses the refrigerant that has passed through the supercooling heat exchanger (4), and the pressure reduced by the expansion valve A chilled water evaporator (6) that exchanges heat between the refrigerant and water to produce chilled water, and the refrigerant that has passed through the chilled water evaporator is introduced into the second flow path and is supplied to the first flow path. The heat exchange with the refrigerant passing through the passage is then introduced into the compressor 1.

  In the present invention, a hot water condenser, a gas-liquid heat exchanger, and a supercooling heat exchanger are arranged in series on the high-pressure side of the refrigerant circuit, so that the sensible heat energy and condensation of the high-temperature gas refrigerant are achieved in the hot water condenser. The latent heat energy can be utilized, and a sufficient amount of water can be obtained with warmer hot water.

FIG. 1 is a flowchart showing the configuration of a refrigerant circuit according to an embodiment of the present invention. FIG. 2 is a ph diagram of the refrigerant circuit of the present embodiment. FIG. 3 is a graph showing the relationship between enthalpy and temperature.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Description of Configuration of this Embodiment]
FIG. 1 is an explanatory diagram showing a configuration of a refrigerant circuit device according to an embodiment of the present invention. As shown in FIG. 1, the refrigerant circuit device according to the present embodiment includes a compressor 1, a hot water condenser 2, a gas-liquid heat exchanger 3, a supercooling heat exchanger 4, an expansion valve 5, A cold water evaporator 6, an accumulator 7, a fan 8 (blower) for air-cooling the supercooling heat exchanger 4, a temperature sensor 9, a pressure sensor 10, and a controller 11 are provided.

  The compressor 1 compresses the refrigerant gas, discharges the compressed refrigerant gas, and supplies the compressed refrigerant gas to the refrigerant-side flow path 2a of the hot water condenser 2 via the pipe L1. As the pressure increases, the temperature of the refrigerant increases accordingly. Therefore, the compressed refrigerant gas is output in a high temperature and high pressure state.

  The hot water condenser 2 is, for example, a plate heat exchanger. High-temperature and high-pressure refrigerant gas protruding from the compressor 1 is supplied to the refrigerant-side flow path 2 a of the hot water condenser 2. Water is supplied to the water-side channel 2b by a pump (not shown) via the water pipes 21 and 22. Heat is exchanged between the refrigerant gas and water to obtain hot water. Refrigerant gas starts to condense and begins to condense into a gas-liquid mixed state, and is supplied to the gas-liquid heat exchanger 3 via the pipe L2. In the refrigerant side flow path 2a and the water side flow path 2b of the hot water condenser 2, the flow direction of the fluid is opposite.

  As an example, the gas-liquid heat exchanger 3 is a double-tube heat exchanger, and has a double-tube structure including an inner tube 3a (first flow path) and an outer tube 3b (second flow path). Is made. A high-pressure refrigerant pipe (L2) is connected to the inner pipe 3a, and a high-pressure refrigerant (gas-liquid mixed refrigerant) output from the hot water condenser 2 is supplied. A low-pressure refrigerant pipe (L5) is connected to the outer pipe 3b. A low-pressure gas refrigerant output from a cold water evaporator 6 to be described later is supplied.

  By performing heat exchange between the refrigerants flowing through the inner pipe 3a and the outer pipe 3b, the gas-liquid mixed refrigerant supplied from the pipe L2 is changed to a liquid state and output to the pipe L3. The temperature of the low-temperature gas refrigerant supplied from the pipe L5 is raised. The pipe L3 is connected to the supercooling heat exchanger 4.

  As an example, the supercooling heat exchanger 4 is a fin-and-tube heat exchanger and includes a fan 8 (blower). The fan 8 is driven to exchange heat between the outside air and the refrigerant, and the amount of air blown is controlled to control the degree of supercooling of the liquid refrigerant. The output of the supercooling heat exchanger 4 is connected to the expansion valve 5 via a pipe L4.

  The fan 8 is a fan that generates an external air current, and controls the degree of supercooling of the liquid refrigerant by changing the number of rotations under the control of the controller 11. Specifically, based on the pressure data detected by the pressure sensor 10 installed in the pipe L1, when the refrigerant pressure output from the compressor 1 exceeds a predetermined value, the rotational speed of the fan 8 is increased. Increase air volume and increase heat exchange. As a result, the degree of supercooling increases. In other words, control is performed to increase the rotational speed when the pressure is high and to decrease it when the pressure is low. As a specific control method, stepwise step control or PID control can be used.

  The expansion valve 5 reduces the pressure of the refrigerant and expands the refrigerant. As an example, an electronic expansion valve that controls the degree of superheat is used. The expansion valve 5 is connected to the controller 11 and controls the valve opening so that the degree of superheat of the gas refrigerant detected by the temperature sensor 9 provided at the outlet of the cold water evaporator 6 becomes a predetermined value.

  The cold water evaporator 6 is, for example, a plate heat exchanger. A low-temperature gas-liquid mixed refrigerant output from the expansion valve 5 is supplied to the refrigerant-side flow path 6 a of the cold water evaporator 6. Water is supplied to the water side channel 6b by a pump (not shown) via the water pipes 23 and 24. Heat is exchanged between the low-temperature gas refrigerant and water to obtain cold water. In the refrigerant-side flow path 6a and the water-side flow path 6b of the cold water evaporator 6, the flow direction of the fluid is opposite.

  The low-temperature gas-liquid mixed refrigerant evaporates into a gas state, and is supplied to the outer pipe 3b of the gas-liquid heat exchanger 3 via the pipe L5. As described above, since the high-temperature refrigerant is supplied to the inner tube 3a of the gas-liquid heat exchanger 3, heat exchange is performed between them. That is, the temperature of the gas refrigerant supplied to the outer pipe 3b of the gas-liquid heat exchanger 3 rises and is supplied to the accumulator 7 via the pipe L6.

  When the liquid refrigerant is introduced, the accumulator 7 converts the refrigerant into a gas refrigerant and supplies it to the compressor 1 via the pipe L7. In the present embodiment, the accumulator 7 is provided. However, the accumulator 7 is not necessarily provided.

  The temperature sensor 9 is installed in the pipe L5 immediately after the outlet of the cold water evaporator 6, and detects the temperature of the gas refrigerant output from the cold water evaporator 6. The detected temperature data is output to the controller 11. The controller 11 controls the opening degree of the expansion valve 5 so that the degree of superheat of the refrigerant at the outlet of the cold water evaporator 6 becomes a specified value from the temperature detected by the temperature sensor 9. That is, when the degree of superheat is high, the valve opening is increased, and when the degree of superheat is low, the valve opening is reduced.

  The pressure sensor 10 is installed in the pipe L <b> 1 immediately after the outlet of the compressor 1, and detects the pressure of the gas refrigerant output from the compressor 1. The detected pressure data is output to the controller 11. The controller 11 controls the rotation speed of the fan 8 based on the pressure of the gas refrigerant. That is, when the pressure is high, the rotational speed is increased, and when the pressure is low, the rotational speed is decreased.

[Description of action]
Next, the operation of the refrigerant circuit according to the present embodiment configured as described above will be described. The high-temperature and high-pressure gas refrigerant compressed by the compressor 1 is supplied to the refrigerant-side flow path 2a of the hot water condenser 2. On the other hand, water is supplied to the water side channel 2b via the water pipe 21. Heat exchange is performed between the gas refrigerant and water, and the temperature of the water rises to become warm water, which is output to the outside from the water pipe 22. That is, hot water can be obtained. At this time, as will be described later, hot water having a temperature higher than that in the prior art can be obtained.

  On the other hand, the refrigerant flowing through the refrigerant side flow path 2a releases sensible heat energy by heat exchange, and the temperature decreases. Further, when the temperature falls to the condensation temperature, condensation (liquefaction) of the refrigerant starts. In the vicinity of the outlet of the refrigerant side channel 2a, latent heat energy is released, and most of the refrigerant condenses. That is, the refrigerant output from the refrigerant side flow path 2a of the hot water condenser 2 is in a gas-liquid mixed state.

  Next, the refrigerant in the gas-liquid mixed state is introduced into the inner tube 3a of the gas-liquid heat exchanger 3, and heat is exchanged with the refrigerant flowing through the outer tube 3b. For this reason, the refrigerant flowing through the inner pipe 3a is further deprived of latent heat energy and becomes liquid refrigerant in the vicinity of the outlet.

  The liquid refrigerant output from the inner pipe 3a of the gas-liquid heat exchanger 3 is introduced into the supercooling heat exchanger 4 via the pipe L3. In the supercooling heat exchanger 4, the liquid refrigerant is cooled by the air supplied by the fan 8, and the sensible heat energy of the liquid refrigerant is taken away, so that the temperature of the refrigerant decreases. That is, the degree of supercooling increases.

  Thereafter, the liquid refrigerant having an increased degree of supercooling is introduced into the expansion valve 5, and the liquid refrigerant is depressurized by passing through the expansion valve 5 at an appropriate opening, so that the refrigerant becomes a low-temperature and low-pressure gas-liquid mixed refrigerant. .

  Thereafter, the low-temperature and low-pressure gas-liquid mixed refrigerant is introduced into the refrigerant-side flow path 6 a of the cold water evaporator 6. Heat exchange with water introduced into the water-side flow path 6b evaporates and vaporizes the refrigerant. The water flowing through the water side channel 6b is cooled and output as cold water. That is, cold water can be obtained.

  Further, as described above, the controller 11 controls the opening degree of the expansion valve 5 based on the degree of superheat detected by the temperature sensor 9 so that the degree of superheat of the refrigerant becomes a specified value.

  The gas refrigerant output from the cold water evaporator 6 is introduced into the outer tube 3b of the gas-liquid heat exchanger 3, and heat exchange is performed with the gas-liquid mixed refrigerant flowing through the inner tube 3a. The gas refrigerant flowing through the outer tube 3b rises in temperature, further increases in superheat, and is output from the gas-liquid heat exchanger 3 as a gas refrigerant with high superheat. Thereafter, the gas refrigerant is introduced from the suction pipe of the compressor 1 via the accumulator 7 and is compressed and circulated again.

[Description of heat absorption and release of refrigerant]
FIG. 2 is a ph diagram with the horizontal axis representing enthalpy and the vertical axis representing pressure. A curve 31 shown in FIG. 2 is a saturated liquid line, and a curve 32 is a saturated vapor line. Hereinafter, the refrigerant flow will be described in association with the refrigerant circuit shown in FIG. 1 and the ph diagram shown in FIG. 2.

  When the gas refrigerant is compressed by the compressor 1 at the point p1 shown in FIG. 2, the pressure and temperature rise due to adiabatic compression and reach the point p2. That is, the symbol Q3 indicates the amount of enthalpy change (increase) by the compressor 1. By passing the gas refrigerant that has reached the point p2 through the hot water condenser 2, the gas refrigerant is cooled. When the gas refrigerant is cooled, it releases the sensible heat energy (I) of the gas refrigerant.

  Thereafter, when the point p3 is reached, the refrigerant starts to condense (liquefy) and release latent heat energy (II). When the point p4 is reached, the gas-liquid mixed refrigerant is output from the hot water condenser 2 and introduced into the inner pipe 3a (first flow path) of the gas-liquid heat exchanger 3. The latent heat energy of the refrigerant passing through the inner pipe of the gas-liquid heat exchanger 3 is released to the refrigerant flowing through the outer pipe 3b. When all the refrigerant passing through the inner pipe 3a is liquefied to become liquid refrigerant, sensible heat energy (III) of the liquid refrigerant is released.

  When the point p5 is reached, the liquid refrigerant is supplied to the supercooling heat exchanger 4 and is cooled by the fan 8, and is supercooled and reaches the point p6. That is, P1 shown in FIG. 2 shows the amount of enthalpy change (decrease) by the hot water condenser 2, P2 shows the amount of enthalpy change (decrease) by the gas-liquid heat exchanger 3, and P3 is the supercooling heat exchanger. 4 indicates the amount of enthalpy change (decrease).

  When passing through the expansion valve 5, the pressure of the refrigerant decreases and vaporizes at a point p <b> 7 to become a gas-liquid mixed refrigerant. Furthermore, by passing through the cold water evaporator 6, the refrigerant evaporates and takes away latent heat energy. At this time, cold water is obtained in the evaporator 6 for cold water. The gas refrigerant that has passed through the cold water evaporator 6 is introduced into the outer tube 3b (second flow path) of the gas-liquid heat exchanger at the point p8, so that the degree of superheat increases and then reaches the point p1. That is, the symbol Q1 indicates the amount of enthalpy change (increase) by the cold water evaporator 6, and the symbol Q2 indicates the amount of enthalpy change (increase) by the gas-liquid heat exchanger 3. Thereafter, the above processing is repeated.

  In this embodiment, the gas-liquid heat exchanger 3 is provided in the subsequent stage of the hot water condenser 2, and the temperature of the gas refrigerant flowing through the outer pipe 3b is increased by the gas-liquid heat exchanger 3. That is, a temperature rise occurs between points p8 to p1 in FIG. Therefore, the temperature of the gas refrigerant output from the compressor 1 can be increased as compared with the conventional case. In the case where the gas-liquid heat exchanger 3 is not provided, since the compressor 1 compresses without increasing the temperature from the point p8, it is introduced into the hot water condenser 2 in the state of the point p11. Therefore, the efficiency of heat exchange in the hot water condenser 2 is lowered, and high temperature hot water cannot be obtained. On the other hand, in the present embodiment, the gas-liquid heat exchanger 3 is provided at the subsequent stage of the hot water condenser 2, and the temperature of the refrigerant introduced into the compressor 1 is increased by the gas-liquid heat exchanger 3, The refrigerant gas temperature output from the compressor 1 can be made higher.

  The above-described three energies of sensible heat energy (I), latent heat energy (II), and sensible heat energy (III) are illustrated in FIG. When compared in terms of temperature, (I)> (II)> (III), and when compared in terms of energy, (I) ≧ (II) and (I)> (III).

[Description of effects]
In this embodiment, the hot water condenser 2, the gas-liquid heat exchanger 3, and the supercooling heat exchanger 4 are provided on the high pressure side of the refrigerant circuit, and the refrigerant is passed in this order. With this configuration, in the hot water condenser 2, the sensible heat energy (I) and the latent heat energy (II) can be directly used as thermal energy for generating hot water.

Here, in the refrigerant circuit which does not provide the gas-liquid heat exchanger 3 and the supercooling heat exchanger 4 as in the prior art, as shown in “Prior Art” in FIG. It seems that all the energy (I) to (III) above can be used and the efficiency is good. However, even with the same amount of energy, the temperature zone is lower than that of the “present invention”, and high-temperature hot water cannot be taken out. That is, in this embodiment, since the refrigerant is passed through the hot water condenser 2, the gas-liquid heat exchanger 3, and the supercooling heat exchanger 4 in this order, the heat in the temperature range shown in “present invention” in FIG. It becomes possible to obtain hotter hot water.
Furthermore, since there is no suction pressure adjusting valve described in Patent Document 1, the amount of refrigerant circulation is not suppressed, a sufficient amount of heat can be obtained at a high temperature, and as a result, a sufficient amount of water can be obtained.

More specifically, in the above-described conventional technology, even if a high-temperature gas refrigerant is put into the inlet side of the refrigerant side flow path of the heat exchanger that generates hot water, all the refrigerant is liquefied on the outlet side (I and II). Further, the refrigerant is cooled and becomes supercooled (III), so that the temperature of the refrigerant is lowered. However, if the flow path is opposed to the water-side flow path, heat is exchanged with the refrigerant whose temperature has been lowered. A large temperature difference cannot be taken between the water side and the water side, resulting in poor heat exchange efficiency, resulting in difficulty in obtaining high-temperature hot water.
On the other hand, in the present invention, the gas-liquid heat exchanger 3 and the supercooling heat exchanger 4 are provided in the subsequent stage of the hot water condenser 2, thereby entering the gas-liquid mixed refrigerant and the water-side flow path 2b before being supercooled. Since heat exchange is performed with water (I and II), the temperature difference is increased, the heat exchange efficiency is improved, and high-temperature hot water can be obtained as a result.

  Further, in the gas-liquid heat exchanger 3, the heat energy ((II) and (III)) of the substantially condensed refrigerant in the inner tube 3a is exchanged with the suction refrigerant of the compressor 1 to increase the degree of superheat of the refrigerant. In particular, the temperature of the gas refrigerant output from the compressor 1 increases. That is, latent heat energy (II) and sensible heat energy (III) can be converted to sensible heat energy (I). As a result, hot hot water can be taken out. For example, high-temperature water at 65 ° C. can be obtained.

  Further, since the supercooling heat exchanger 4 is arranged at the subsequent stage of the gas-liquid heat exchanger 3 and the degree of supercooling of the liquid refrigerant is increased, the cooling capacity in the cold water evaporator 6 can be improved.

  Further, the temperature sensor 9 is installed, and the expansion valve 5 controls the opening degree of the expansion valve 5 so that the degree of superheat of the gas refrigerant exiting the cold water evaporator 6 becomes a predetermined value, so that the gas-liquid heat exchanger The temperature of the gas refrigerant introduced into the outer pipe 3b of the third can be stably raised. For this reason, the superheat degree of the refrigerant introduced into the compressor 1 can be sufficiently obtained, and the output temperature of the compressor 1 can be increased.

  Further, the gas-liquid heat exchanger 3 and the supercooling heat exchanger 4 can ensure the degree of supercooling of the refrigerant, and can suppress the entire refrigerant from being condensed (liquefied) in the hot water condenser 2.

  Furthermore, in the hot water condenser 2 and the cold water evaporator 6, the direction in which the refrigerant flows and the direction in which the water flows are opposite, so that the efficiency of heat exchange can be improved.

  Furthermore, since the degree of supercooling of the liquid refrigerant is increased by the supercooling heat exchanger 4, even if the temperature of the gas refrigerant output from the compressor 1 is high, the refrigerant can be sufficiently cooled and supplied to the expansion valve 5. become. Furthermore, the capacity | capacitance of the evaporator 6 for cold water can be raised with the sensible heat energy which increased the degree of supercooling. Further, since the rotation speed of the fan 8 is controlled based on the pressure of the discharge gas refrigerant output from the compressor 1 and the supercooling is controlled, the temperature of the suction gas refrigerant can be lowered and output from the compressor 1. It is possible to prevent the temperature of the discharged gas refrigerant from rising abnormally.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser for warm water 2a Refrigerant side flow path 2b Water side flow path 3 Gas-liquid heat exchanger 3a Inner pipe 3b Outer pipe 4 Supercooling heat exchanger 5 Expansion valve 6 Cold water evaporator 6a Refrigerant side flow path 6b Water side flow path 7 Accumulator 8 Fan 9 Temperature sensor 10 Pressure sensor 11 Controller 21, 22, 23, 24 Water piping

Claims (4)

A refrigerant circuit device for simultaneously obtaining hot water and cold water,
A compressor that compresses the refrigerant; a hot water condenser that exchanges heat between the refrigerant compressed by the compressor and water to form hot water;
A gas-liquid heat exchanger having a first flow path and a second flow path, into which the refrigerant that has passed through the hot water condenser is introduced into the first flow path;
A supercooling heat exchanger that supercools the refrigerant that has passed through the first flow path;
An expansion valve that depressurizes the refrigerant that has passed through the supercooling heat exchanger;
A cold water evaporator that exchanges heat with the refrigerant decompressed by the expansion valve to form cold water;
Have
The refrigerant that has passed through the cold water evaporator is introduced into the second flow path, heat-exchanged with the refrigerant that passes through the first flow path, and then introduced into the compressor 1. Refrigerant circuit device. The refrigerant circuit device according to claim 1, wherein at least one of the hot water condenser and the cold water evaporator has a flow direction of the refrigerant and a flow direction of the water opposite to each other. A temperature sensor that detects the temperature of the refrigerant that has passed through the cold water evaporator;
The opening degree of the expansion valve is controlled so that the degree of superheat of the refrigerant that has passed through the cold water evaporator becomes a predetermined value based on the detected temperature of the refrigerant. The refrigerant circuit device according to 1. A pressure sensor that detects the pressure of the refrigerant that is output from the compressor, and a blower that air-cools the refrigerant that passes through the supercooling heat exchanger,
The refrigerant circuit device according to any one of claims 1 to 3, wherein an air flow rate of the blower is controlled based on the detected refrigerant pressure.

Images