JP4922843B2 - Cooling system - Google Patents

Description

  The present invention relates to a cooling device for cooling and storing a liquid object to be cooled, such as milk, in a cooling container.

In a conventional cooling device, as described in Patent Document 1, for example, an object to be cooled is put into a cooling container, and the object to be cooled in the cooling container is cooled by using a refrigerant refrigeration cycle.
Japanese Patent No. 2860352

  By the way, as in the cooling device described in Patent Document 1, when warm milk (to be cooled) immediately after milking is put into a milk tank (cooling container), low-temperature milk stored in the milk tank is put in The temperature rises due to the warm milk produced. Therefore, the storage temperature of the milk in the milk tank greatly fluctuates, for example, when the milk immediately after milking is input. Moreover, in the cooling apparatus of patent document 1, the temperature of the to-be-cooled object in a cooling container cannot be made into a suitable temperature accurately.

  The problem to be solved is that the temperature of the object to be cooled stored in the cooling container varies greatly at the time of charging the object to be cooled, and the storage temperature in the cooling container is accurately adjusted to an appropriate temperature. This is a point that cannot be done.

In the cooling device of the present invention, at least the first compressor (2), the first radiator (3), the first throttle means (4), and the first evaporator (6) are connected in an annular shape so that the refrigerant circulates. One refrigeration cycle (1);
A second refrigeration cycle (21) in which refrigerant is circulated by connecting at least the second compressor (22), the second radiator (23), the second throttle means (24) and the second evaporator (26) in an annular shape; ,
A cooling container (8) for storing an object to be cooled;
An ice heat storage device (28) that uses water as a heat storage material to perform cold storage by freezing the water;
And a hot water storage tank (41a, 41b) for storing hot water.
And the to-be-cooled object stored in the cooling container is cooled using the evaporating action of the refrigerant in the first evaporator, and the water is heated by the heat radiation of the refrigerant in the first radiator to store the hot water in the hot water storage tank. And the water in the ice heat storage device is made by using the refrigerant evaporating action in the second evaporator, and the water is heated by the heat radiation of the refrigerant in the second radiator to be stored in the hot water storage tank. And after cooling the object to be cooled before being put into the cooling container by the latent heat of ice made in the ice heat storage device, the object to be cooled is thrown into the cooling container, and The hot water in the hot water storage tank can be supplied to the cooling container.

An internal heat exchanger (29) for exchanging heat between the refrigerant flowing through the circuit from the second radiator to the second throttle means and the refrigerant flowing through the circuit from the second evaporator to the second compressor is provided, In some cases, the refrigerant flowing through the second refrigeration cycle is carbon dioxide, and the refrigerant is in a gas-liquid two-phase state at the outlet of the second evaporator.
Furthermore, the object to be cooled may be a liquid such as milk.
In some cases, a plurality of hot water storage tanks are provided.

  The first radiator is a component of the first water heat exchanger (7). In the first water heat exchanger, heat can be exchanged with water led out from the lower part of the hot water storage tank. The vessel is a component of the second water heat exchanger (27), and in this second water heat exchanger, heat exchange is possible with water derived from the lower part of the hot water storage tank. The second water heat exchanger is provided in parallel, and the water derived from the lower part of the hot water storage tank flows through the first water heat exchanger or the second water heat exchanger and is heated by the heat radiation of the radiator. In some cases, it is configured to return to the upper part of the hot water storage tank after it has become hot water.

  According to the present invention, the water in the ice heat storage device is circulated in the heat exchanger that cools the object to be cooled before being charged into the cooling container so that the object to be cooled is cooled and then charged into the cooling container. Because it is configured, it is possible to cool the object to be cooled before charging using the latent heat of ice stored in the ice heat storage device, and the time required to cool the object to be cooled in the cooling container to a predetermined temperature As well as the temperature rise of the object to be cooled in the cooling container due to charging. In addition, since ice can be stored in the ice heat storage device in advance before charging, cold capacity can be stored with a freezer having a small capacity (cooling capacity). And since cooling of the to-be-cooled object in a cooling container is performed by the heat absorption in a 1st evaporator, the independent cool-in operation can be performed and the quality of to-be-cooled object can be maintained. Since there are a plurality of cooling means, that is, a first refrigeration cycle for cooling the object to be cooled in the cooling container and a second refrigeration cycle for cooling the object to be cooled before charging, trouble occurs in one of the cooling means. Even if it is a case, it can cool by the other cooling means. As a result, the reliability of cooling is improved. Furthermore, since the hot water is boiled due to the exhaust heat generated when making ice in the ice heat storage device or cooling the object to be cooled in the cooling container, the energy for hot water supply can be reduced.

  In addition, an internal heat exchanger for exchanging heat between the refrigerant flowing through the circuit from the second radiator to the second throttle means and the refrigerant flowing through the circuit from the second evaporator to the second compressor is provided. When the refrigerant flowing through the cycle is carbon dioxide and this refrigerant is in a gas-liquid two-phase state at the outlet of the second evaporator, the second state is obtained by setting the refrigerant state at the outlet of the second evaporator to a wet state. Oil retention inside the evaporator can be reduced, and return of the liquid refrigerant to the second compressor can be suppressed by the internal heat exchanger.

  The first radiator is a component of the first water heat exchanger. In the first water heat exchanger, heat can be exchanged with water derived from the lower part of the hot water storage tank. It is a component part of 2 water heat exchangers, In this 2nd water heat exchanger, heat exchange is possible with the water derived | led-out from the lower part of the hot water storage tank, This 1st water heat exchanger and 2nd water heat exchanger The water led out from the lower part of the hot water storage tank flows through the first water heat exchanger or the second water heat exchanger and is heated by heat radiation of the radiator to become hot water. , May be configured to return to the top of the hot water storage tank. In such a case, the hot water storage tank can be shared by the first water heat exchanger and the second water heat exchanger, and the operating efficiency of the hot water storage tank is improved. Moreover, since the low temperature water led out from the lower part of the hot water storage tank is guided to each water heat exchanger, the heat exchange efficiency is improved.

  The purpose of reducing the temperature fluctuation of the object to be cooled stored in the cooling container at the time of charging the object to be cooled, making the storage temperature in the cooling container suitable temperature accurately and reducing the energy consumption. After cooling the object to be cooled before being charged into the cooling container with the latent heat of ice produced in the ice heat storage device by the endothermic heat in the evaporator of the second refrigeration cycle, The object to be cooled is cooled by absorbing heat in the evaporator of the first refrigeration cycle, and hot water is generated by exhaust heat generated when ice is made in the ice heat storage device or when the object to be cooled in the cooling container is cooled. Realized by boiling.

  Next, an embodiment of the cooling device according to the present invention will be described with reference to FIG. FIG. 1 is a circuit diagram of a cooling device according to an embodiment of the present invention.

  The first refrigeration cycle 1 of the cooling device is closed by sequentially connecting a first compressor 2, a first radiator 3, a first expansion valve 4 as a first throttling means, and a first evaporator 6 in an annular manner through a refrigerant pipe. It is configured to form a circuit. The first radiator 3 is a component of the first water heat exchanger 7, and in the water heat exchanger 7, the refrigerant of the first radiator 3 can exchange heat with water flowing through the hot water storage circuit 12 a of the hot water supply device 11. is there. Moreover, the 1st evaporator 6 is provided in the milk tank 8 which is a cooling container, and cools the milk which is a to-be-cooled object. That is, the milk tank 8 or the milk in the milk tank 8 is directly cooled by the first evaporator 6, so that a highly accurate cold operation can be performed.

  The milk tank 8 is provided with a stirrer 13 for stirring the object to be cooled. A milk supply pipe (cooled object supply pipe) 14 and a cleaning liquid supply pipe 16 from the milking line are connected to the upper part of the milk tank 8. A milk extraction pipe 17 is connected to the lower part of the milk tank 8. The milk take-out pipe 17 is provided with two on-off valves 18, 18 from which a washing liquid return pipe 19 branches.

  In the second refrigeration cycle 21 of the cooling device, the second compressor 22, the second radiator 23, the second expansion valve 24 as the second throttle means, and the second evaporator 26 are sequentially connected by a refrigerant pipe to form a closed circuit. It is configured to make. The second radiator 23 is a component of the second water heat exchanger 27, and in the water heat exchanger 27, the refrigerant of the second radiator 23 can exchange heat with water flowing through the hot water storage circuit 12 b of the hot water supply device 11. is there. The second evaporator 26 cools the water in the ice heat storage device 28 to make ice. That is, the outer periphery of the pipe of the second evaporator 26 is iced. Furthermore, an internal heat exchanger 29 for exchanging heat between the refrigerant flowing through the circuit from the second radiator 23 to the second expansion valve 24 and the refrigerant flowing through the circuit from the second evaporator 26 to the second compressor 22 is provided. It has been.

  The third refrigeration cycle 31 of the cooling device includes a third compressor 32, a third radiator 33, a third expansion valve 34 as a third throttle means, and a third evaporator 36, which are sequentially connected by a refrigerant pipe to form a closed circuit. It is configured to make. The third radiator 33 is a component of the third water heat exchanger 37, and in the water heat exchanger 37, the refrigerant of the third radiator 33 exchanges heat with water flowing through the second hot water storage circuit 39 of the hot water supply device 11. Is possible. Further, the third evaporator 36 can exchange heat with the outside air by blowing air from the blower 38.

  Each refrigeration cycle 1, 21, 31 contains carbon dioxide as a refrigerant. Since the refrigerant pressure on the high pressure side of the refrigeration cycle such as the inside of the radiators 3, 23, 33 exceeds the critical pressure, the refrigeration cycle becomes a transcritical cycle. Further, as the lubricating oil of the compressors 2, 22, and 32, for example, mineral oil (mineral oil), alkylbenzene oil, ether oil, ester oil, PAG (polyalkylene glycol), POE (polyol ether) and the like are used.

  At the outlet of the second evaporator 26 of the second refrigeration cycle 21, the refrigerant is in a gas-liquid two-phase state. As described above, since the refrigerant at the outlet of the second evaporator 26 is in a wet state, the retention of oil in the second evaporator 26 can be reduced. The gas-liquid two-phase refrigerant flowing out of the second evaporator 26 is vaporized by exchanging heat with the refrigerant on the high-pressure side in the internal heat exchanger 29, and the liquid to the second compressor 22 is discharged. The return of the refrigerant is suppressed.

  The hot water supply device 11 includes three hot water storage tanks 41a, 41b, and 41c, and water supply pipes 42 are connected to the lower portions of the respective hot water storage tanks 41a, 41b, and 41c through water supply valves 43 and pressure reducing valves 44, respectively. Has been. This water supply valve 43 is normally open, and when hot water is used, city water decompressed by the pressure reducing valve 44 is supplied into the hot water supply device 11 in order to compensate for the amount of water corresponding to the amount used.

  In addition, the inlet side end of the hot water storage circuit 12 is branched to the lower portions of the first hot water storage tank 41a and the second hot water storage tank 41b, and is connected via shut-off valves 46a and 46b, respectively. Low temperature water can be taken out. On the other hand, the outlet side of the hot water storage circuit 12 is branched into two flow paths 12a and 12b, and the first hot water storage tank 41a and the flow rate adjusting valves 48a and 48b and the water heat exchangers 7 and 27 are respectively branched through the pumps 47a and 47b. It is connected to the upper part of the second hot water storage tank 41b. When the pumps 47a and 47b are operated, water is sucked from the lower portions of the first hot water storage tank 41a and the second hot water storage tank 41b, and the water is heat-exchanged and heated by the water heat exchangers 7 and 27. It returns to the upper part of 41a and the 2nd hot water storage tank 41b. In this way, the hot water storage circuits 12, 12a, 12b are configured to return the water from the lower part of the hot water storage tanks 41a, 41b to the upper part of the hot water storage tanks 41a, 41b through the water heat exchangers 7, 27. .

  As described above, the first hot water storage tank 41a and the second hot water storage tank 41b are provided in parallel, and the water flowing through the water heat exchangers 7 and 27 can flow into both the hot water storage tanks 41a and 41b. Moreover, the 1st water heat exchanger 7 and the 2nd water heat exchanger 27 are provided in parallel, and the water of the hot water storage tanks 41a and 41b can flow to both the water heat exchangers 7 and 27. Therefore, the hot water storage tanks 41a and 41b can be used for the water flowing through both the water heat exchangers 7 and 27.

  Further, drain pipes 52a and 52b having drain valves 51a and 51b are connected to the first hot water storage tank 41a and the second hot water storage tank 41b. By opening the drain valves 51a and 51b, excess water in the hot water storage tanks 41a and 41b can be discharged.

  Further, the inlet side end portion of the second hot water storage circuit 39 is connected to the lower portion of the third hot water storage tank 41c. The second hot water storage circuit 39 is provided with a pump 47c and a water heat exchanger 37 from the inlet side end portion toward the outlet side, and the outlet side end portion is connected to the upper portion of the third hot water storage tank 41c. When the pump 47c is operated, water is sucked from the lower part of the third hot water storage tank 41c, and this water is heated by exchanging heat with the water heat exchanger 37 and returned to the upper part of the third hot water storage tank 41c. The second hot water storage circuit 39 is not provided with a shutoff valve.

  The branch pipes 61a, 61b, 61c on the inflow side of the hot water supply pipe for taking out hot water are connected to the upper portions of the hot water storage tanks 41a, 41b, 41c, respectively. The first branch pipe 61a and the second branch pipe 61b connected to the first hot water storage tank 41a and the second hot water storage tank 41b are provided with shutoff valves 60a and 60b. The third branch pipe 61c connected to the third hot water storage tank 41c is not provided with a shutoff valve. The branch pipes 61a, 61b, 61c merge to form a single hot water supply main pipe 62. On the outflow side of the hot water main pipe 62, the branch washing pipe 63a, the milk tank washing branch pipe 63b, It branches off to the branch pipe 63c for other uses.

  The end of the milk tank cleaning branch pipe 63 b is connected to an automatic cleaning machine 66 through an on-off valve 64. A water supply pipe 67 and a detergent supply pipe 68 for supplying detergents and disinfectants are connected to the automatic washing machine 66. A cleaning pump 71 for sucking the cleaning liquid is connected to the lower part of the automatic cleaning machine 66 through a cleaning liquid suction pipe 72. The cleaning liquid discharged from the cleaning pump 71 is supplied to the milk tank 8 through the above-described cleaning liquid supply pipe 16. Then, the cleaning liquid after cleaning the milk tank 8 returns to the cleaning pump 71 via the above-described cleaning liquid return pipe 19. The cleaning liquid return pipe 19 includes a shut-off valve 73 and an end thereof is connected to the cleaning liquid suction pipe 72. A cleaning drain pipe 76 having a drain valve 74 is connected to the cleaning liquid suction pipe 72.

  The ice heat storage device 28 stores water and is cooled by the second evaporator 26 to produce ice. In order to stir the water in the ice heat storage device 28, a blower 81 is provided as a stirring device that sucks air from the upper part of the ice heat storage device 28 and blows it out from the lower part of the ice heat storage device 28. A pump 82 for sucking low-temperature water from the lower part of the ice heat storage device 28 is provided, and this pump 82 discharges the sucked cold water to the cold water circulation circuit 83. The end of the cold water circulation circuit 83 is connected to the upper part of the ice heat storage device 28. In this manner, the cold water of the ice heat storage device 28 circulates in the chilled water circulation circuit 83, and the chilled water circulation circuit 83 is provided with the heat exchanger 84, and the chilled water circulation circuit 83 is provided in the heat exchanger 84. The cold water and the milk in the feeding pipe 14 are subjected to heat exchange, the temperature of the milk in the feeding pipe 14 is lowered, and this low temperature milk is poured into the milk tank 8.

  Various sensors are attached to the cooling device, and typical sensors related to the present invention include a temperature sensor T1 to be cooled for measuring the temperature of milk in the milk tank 8, and hot water storage tanks 41a, 41b, 41c. There are upper temperature sensors T2, T3, T4 for measuring the upper hot water storage temperature, and lower temperature sensors T6, T7, T8 for measuring the lower water storage temperature of the hot water storage tanks 41a, 41b, 41c.

Next, in the cooling device configured in this way, explanation will be given when milk is stored in the milk tank 8.
First, in the case where there is a margin in the power consumption of the factory, or in an inexpensive time zone such as an electricity bill, the second refrigeration cycle 21 is operated, and the water in the ice heat storage device 28 is supplied to the second evaporator. Cool at 26 and make ice. During the operation of the second refrigeration cycle 21, the temperature of the second radiator 23 becomes high. However, if this heat is released to the outside, heat energy is wasted, so the heat of the refrigerant flowing through the second radiator 23 is lost. In the water heat exchanger 27, heat is exchanged with the water flowing through the hot water storage circuit 12b, and the hot water, that is, hot water is stored in the first hot water storage tank 41a and the second hot water storage tank 41b.

  And when warm milk is sent from a milking line etc., the pump 82 is operated and the cold water which became low temperature by the latent heat of the ice in the ice heat storage apparatus 28 is sent to the heat exchanger 84. This heat exchanger 84 exchanges heat with the cold water from the ice heat storage device 28 and the milk that has been sent to lower the temperature of the milk. This low-temperature milk is put into the milk tank 8. Therefore, the temperature of the milk stored in the milk tank 8 can be prevented from greatly fluctuating.

  In the milk tank 8, a control device (not shown) operates the first refrigeration cycle 1 so that the detected value of the to-be-cooled object temperature sensor T1 that detects the temperature of the milk in the milk tank 8 becomes the set temperature. That is, when the temperature of the milk in the milk tank 8 is higher than the set temperature, the first refrigeration cycle 1 is operated, and the temperature of the milk in the milk tank 8 is lowered by heat absorption in the first evaporator 6. . And the milk which became the suitable temperature in the milk tank 8 is carried out from the milk extraction pipe | tube 17 as needed suitably. During the operation of the first refrigeration cycle 1, the temperature of the first radiator 3 increases. However, if this heat is released to the outside, heat energy is wasted, so the heat of the refrigerant flowing through the first radiator 3 is reduced. In the water heat exchanger 7, heat is exchanged with water flowing through the hot water storage circuit 12a, and hot water, that is, hot water, is stored in the first hot water storage tank 41a and the second hot water storage tank 41b.

  The third refrigeration cycle 31 is for storing hot water almost always in the third hot water storage tank 41c. When the third refrigeration cycle 31 is operated, the heat of the high-temperature refrigerant flowing through the third radiator 33 is The water heat exchanger 37 exchanges heat with the water flowing through the second hot water storage circuit 39, and stores the hot water, that is, hot water, in the third hot water storage tank 41c.

When washing the milk tank 8, all the milk in the milk tank 8 is taken out from the milk take-out pipe 17 to empty the milk tank 8. The hot water from the hot water storage tanks 41a, 41b, 41c is guided to the automatic washing machine 66 through the branch pipes 61a, 61b, 61c, the hot water supply main pipe 62, and the milk tank cleaning branch pipe 63b, and the water from the water supply pipe 67 is supplied. The mixture is brought to an appropriate temperature, and a detergent, a disinfectant, and the like from the detergent supply pipe 68 are mixed, and the washing pump 71 flows into the milk tank 8 to perform washing. After washing, washing liquid, rinse water, and the like are discharged outside from the washing drain pipe 76 and the milk extraction pipe 17. When performing such cleaning, when the total amount of hot water stored in the hot water storage tanks 41a, 41b, 41c is insufficient, the third compressor 32 is operated to fill the third hot water storage tank 41c with hot water in advance. Is. Further, by using carbon dioxide (CO ₂ ) as a refrigerant in the refrigeration cycle, the hot water temperature in the hot water storage tank can be easily raised to 85 ° C. to 95 ° C., and the sterilizing effect due to this hot water is expected. It can be done.
The hot water in the hot water storage tanks 41a, 41b and 41c is also used for pipeline cleaning devices and other applications.

As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example, A various change is performed within the range of the summary of this invention described in the claim. It is possible. Examples of modifications of the present invention are illustrated below.
(1) The third refrigeration cycle 31 is not necessarily provided.
(2) Although a plurality of hot water storage tanks 41a, 41b, and 41c are provided, it is not always necessary to provide a plurality of hot water storage tanks 41a, 41b, and 41c.

(3) In the embodiment, the object to be cooled is milk, but other liquids other than milk and food are also possible.

  The latent heat of ice created in the ice storage device by absorbing heat in the evaporator of the second refrigeration cycle cools the object to be cooled before being put into the cooling container, and then puts it into the cooling container. The object to be cooled is cooled by absorbing heat in the evaporator of the first refrigeration cycle, and the hot water is boiled by exhaust heat generated when making ice in the ice heat storage device or cooling the object to be cooled in the cooling container. ing. Therefore, at the time of charging the object to be cooled, the temperature variation of the object to be cooled stored in the cooling container is reduced, the storage temperature in the cooling container is accurately adjusted to the appropriate temperature, and the energy consumption is reduced. be able to. Therefore, it is optimal to apply it to a cooling device in which maintaining the quality of an object to be cooled such as food is important.

FIG. 1 is a circuit diagram of a cooling device according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st refrigeration cycle 2 1st compressor 3 1st heat radiator 4 1st expansion valve (1st throttle means)
6 First evaporator 7 First water heat exchanger 8 Milk tank (cooling container)
21 2nd refrigeration cycle 22 2nd compressor 23 2nd radiator 24 2nd expansion valve (2nd throttle means)
26 second evaporator 27 second water heat exchanger 28 ice heat storage device 29 internal heat exchanger 41a first hot water tank 41b second hot water tank

Claims (5)

A first refrigeration cycle in which the refrigerant circulates by connecting at least the first compressor, the first radiator, the first throttling means, and the first evaporator in an annular shape;
A second refrigeration cycle in which the refrigerant circulates by connecting at least the second compressor, the second radiator, the second throttle means, and the second evaporator in an annular shape;
A cooling container for storing an object to be cooled;
An ice heat storage device that uses water as a heat storage material to perform cold storage by freezing the water;
A hot water storage tank for storing hot water,
The object to be cooled stored in the cooling container is cooled using the evaporating action of the refrigerant in the first evaporator, the water is heated by the heat radiation of the refrigerant in the first radiator, and the water is stored in the hot water storage tank. It is configured to store hot water, and the water in the ice heat storage device is made by using the refrigerant evaporating action in the second evaporator, and the water is heated by the heat radiation of the refrigerant in the second radiator. It is configured to store in the hot water storage tank,
After cooling the object to be cooled before being charged into the cooling container by the latent heat of ice produced in the ice heat storage device, the object to be cooled is charged into the cooling container, and the hot water storage tank A cooling device characterized in that hot water can be supplied to the cooling container. An internal heat exchanger is provided for exchanging heat between the refrigerant flowing through the circuit from the second radiator to the second throttle means and the refrigerant flowing through the circuit from the second evaporator to the second compressor;
The cooling device according to claim 1, wherein the refrigerant flowing through the second refrigeration cycle is carbon dioxide, and the refrigerant is in a gas-liquid two-phase state at the outlet of the second evaporator. The cooling apparatus according to claim 1 or 2, wherein the object to be cooled is a liquid such as milk. 4. The cooling device according to claim 1, wherein a plurality of the hot water storage tanks are provided. The first radiator is a component of a first water heat exchanger, and in the first water heat exchanger, heat exchange is possible with water derived from the lower part of the hot water storage tank,
The second radiator is a component of the second water heat exchanger, and in the second water heat exchanger, heat exchange is possible with water derived from the lower part of the hot water storage tank,
The first water heat exchanger and the second water heat exchanger are provided in parallel,
The water led out from the lower part of the hot water storage tank flows through the first water heat exchanger or the second water heat exchanger and is heated by heat radiation of the radiator to become hot water, and then enters the upper part of the hot water storage tank. 5. The cooling device according to claim 1, wherein the cooling device is configured to return.

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