JP3015560B2 - Heat storage type cooling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a regenerative cooling system.

[0002]

2. Description of the Related Art In a regenerative cooling system disclosed in, for example, Japanese Patent Application Laid-Open No. 1-174864, the ratio of heat storage to the total cooling load during air-conditioning operation time is about 20% throughout the air-conditioning operation time, and the heat storage dependence rate is low. There was a problem that it was relatively small.

FIG. 15 shows a conventional embodiment.
The compressor 1, the condenser 2, the first decompression mechanism 3 for decompressing the refrigerant, the evaporator 4, and the accumulator 5 are connected to the main refrigerant circuit 2.
4, a heat storage tank 7 containing a heat storage medium is arranged. A heat storage heat exchanger 8 and a liquid supercooling heat exchanger 22 are provided inside the heat storage tank 7. The heat storage heat exchanger 8 is connected to the outlet side of the condenser 2 and the compressor 1. Mounted between the suction sides. A second throttle mechanism 19 is provided on the inlet side of the heat storage heat exchanger 8, and the liquid subcooling heat exchanger 22 includes the condenser 2 and the first pressure reducing mechanism 3.
It is arranged so as to bypass the main refrigerant circuit 24.

[0004] During the heat storage operation in which the regenerative cooling device having the above-described configuration operates at night, the switching devices 11 and 1 are operated.
When the compressor 2 is closed and the switchgear 10 is opened and the compressor 1 is operated, the high-temperature and high-pressure gas refrigerant from the compressor 1 radiates heat in the condenser 2, condensed and liquefied, and heat stored in the second decompression mechanism 19. After entering the tank circuit, it is adiabatically expanded by the second decompression mechanism 19, becomes a low-temperature liquid-gas two-phase fluid, and enters the heat storage tank heat exchanger 8,
The heat is taken from the heat storage medium 6, the gas itself evaporates and returns to the compressor 1 via the accumulator 5. By such an operation, heat of low temperature is stored by freezing the heat storage medium 6 or the like.

In the daytime, when the subcooling operation is performed by utilizing heat storage, the switching devices 10 and 12 in FIG. 15 are closed, the switching device 11 is opened, and the compressor 1 is operated. Of the high-temperature and high-pressure gas refrigerant radiates heat in the condenser 2,
The liquid itself is condensed and liquefied and sent to the liquid supercooling circuit 23,
The liquid refrigerant is further cooled by the heat storage medium 6 and is sent to the first decompression mechanism 3 as a supercooled liquid, where it is adiabatically expanded and becomes a low-temperature liquid-gas two-phase fluid and enters the evaporator 4. Here, cooling is performed by removing heat from the surroundings, and the refrigerant itself evaporates and gasifies, and returns to the compressor 1 via the accumulator 5. When the operation at this time is represented on a Mollier diagram, as shown in FIG. 16, the operation spreads laterally by the amount of supercooling enthalpy, the compressor input enthalpy (そ の ま ま ic) remains unchanged, and the evaporation enthalpy for cooling is △. It increases from ie1 to $ ie2.

In general cooling operation, when the switching devices 10 and 11 in FIG. 15 are closed and the switching device 12 is opened to operate the compressor 1, the high-pressure gas refrigerant from the compressor 1 passes through the condenser 2. The heat is condensed and liquefied, passes through the main circuit 24, and is sent to the first decompression mechanism 3, where it is adiabatically expanded to become a low-temperature liquid-gas two-phase liquid and enters the evaporator 4, where it takes heat from the surroundings. Cools itself, evaporates and gasifies itself, and accumulator 5
And returns to the compressor 1.

[0007]

In the conventional regenerative cooling system which performs each of the above-mentioned operations, the capacity in the subcooling operation of the liquid is smaller than that in the general cooling operation. Only big. However, during the liquid supercooling operation, since the amount of heat stored in the heat storage medium by the heat storage operation is used only by the liquid supercooling cooling operation, the heat storage utilization rate is △ io as shown in FIG. / △ ie
2, that is, about 0.2 to 0.3, and the heat storage utilization rate is substantially the same even under a light load. Therefore, even if the remaining heat storage amount is sufficient, since only the same ratio is used, when the load is reduced, the heat storage amount becomes excessive. This means that in the above-mentioned conventional regenerative refrigeration cycle apparatus, it is not possible to efficiently use heat storage for the size of the heat storage tank, and the economic effect of using nighttime power is insufficient even though it is called heat storage. However, in a society where power control in the daytime is not sufficient, problems remain.

The present invention has been developed in view of the above points, and a purpose thereof is to make more efficient use of the amount of heat stored in the heat storage medium by the heat storage operation during the midnight power hours. It is an object of the present invention to provide a regenerative cooling device capable of reducing power use time in the daytime and performing cooling and cooling more effectively at an inexpensive midnight power rate.

[0009]

A regenerative cooling device of the present invention is formed by connecting a compressor, a condenser, a first pressure reducing mechanism, and an evaporator with piping, and operating the compressor to evaporate the evaporator. A general cooling circuit for performing a general cooling operation for cooling with a heat exchanger, a refrigerant transfer device connected to the inlet side and the outlet side of the evaporator, a heat storage heat exchanger for performing heat exchange with the stored heat storage medium, and a second heat exchanger. A cooling circuit that is formed by connecting a pressure reducing mechanism to a pipe and that performs a cooling operation that cools by the evaporator by operating the refrigerant transport device. Of these, the base load corresponds to the load in the cooling operation using heat storage , and the variation corresponds to the load in the general cooling operation .
The remaining load corresponding to the load in the general cooling operation .

[0010]

[0011]

According to the above-described structure, the base load of the cooling load is covered by the heat storage, so that the substantially constant heat storage is always used, thereby facilitating the heat storage management.
Especially at a light load, the heat storage utilization rate can be increased.

[0012]

[Embodiment 1] Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a view showing a regenerative cooling device of the present invention. In the figure, 1 is a compressor, 2 is a condenser, 3 is a first decompression mechanism, 4 is an evaporator, 5 is an accumulator and is sequentially connected to 1 to 5,
A general cooling circuit is formed. Reference numeral 6 denotes a heat storage medium, for example, water stored in the heat storage tank 7.

Reference numeral 8 denotes a heat storage heat exchanger for exchanging heat with a heat storage medium. A second pressure reducing mechanism 19 is connected between the heat storage heat exchanger inlet 8a and the evaporator 4 inlet. For heat storage
A refrigerant gas pump cooling circuit is formed by connecting a refrigerant conveying means (refrigerant gas pump) 18 between the heat exchanger outlet 8b and the evaporator 4 outlet.

Reference numeral 9 denotes a heat storage bypass circuit, which connects the outlet of the first pressure reducing mechanism 3 to the heat storage heat exchanger inlet 8a. The compressor 1, the condenser 2, the first pressure reducing mechanism 3, and the heat storage The bypass circuit 9 for heat storage, the heat exchanger for heat storage, and the accumulator 5 are sequentially connected to form a heat storage circuit.

FIG. 2 is a circuit diagram showing an operation during a heat storage operation mainly in the midnight power time zone.
0, 11, 12 are closed, and the switching devices 13, 14, 15, 1
6 and 20, opening the refrigerant gas pump 18,
When the compressor 1 is operated, the high-temperature and high-pressure gas refrigerant from the compressor 1 radiates heat in the outdoor heat exchanger 2, condensed and liquefied, adiabatically expanded in the first decompression mechanism 3, and formed a low-temperature liquid-gas two-phase fluid. And enters the heat exchanger 8 for heat storage, deprives the heat storage medium of heat,
The gas itself evaporates and returns to the compressor 1 via the accumulator 5. By such an operation, heat of low temperature is stored by freezing the heat storage medium 6 or the like. FIG. 3 shows an operation state on the Mollier diagram of the refrigeration cycle at that time. In the figure, △ ic is the compressor enthalpy and △ ie is the evaporation enthalpy.

Further, when daytime cooling load is below a predetermined value, the row stomach the cooling operation by the heat storage use, closes the opening and closing device 10,14,16,20 as shown in FIG. 4, switchgear 1
When the refrigerant gas pump 18 is operated without opening the compressors 1, 12, 15, 17 without operating the compressor 1, the low-temperature, low-pressure gas refrigerant pressurized by the refrigerant gas pump 18 enters the heat exchanger 8 for heat storage, The medium is heated and condensed and liquefied, adiabatically expanded by the second decompression mechanism 19, becomes a low-temperature liquid-gas two-phase fluid, flows into the evaporator 4, where it takes heat from the surroundings to cool it. The gas itself vaporizes and returns to the refrigerant gas pump 18 again.

FIG. 5 shows a change in the Mollier diagram of the refrigeration cycle at this time. In the figure, △ igp is the refrigerant gas pump enthalpy, △ ic is the compressor enthalpy, and △ ie is the evaporation enthalpy. In this cooling operation, since the evaporating operation is performed at a pressure approximately equal to the condensing temperature, which is slightly lower than the condensing temperature, the same refrigerant amount can be forcibly circulated with an enthalpy much smaller than the enthalpy of the compressor 1, and compared with the compressor 1. Achieve high coefficient of performance (COP) driving. In addition, by setting the heat storage amount to a predetermined value or more, all the cooling loads can be performed by the cooling operation, and the time period of the peak load can be performed by the cooling operation.

When the cooling load in the daytime is equal to or more than a predetermined value, the switches 13, 14, 20 are closed and the switches 10, 11, 12, 15, 16, 17 are opened as shown in FIG. 1. When both of the refrigerant gas pumps 18 are operated, a combined operation is performed in which the general cooling operation and the cooling operation are simultaneously performed. At that time, the evaporator 4 is operated at the time when only the general cooling operation or only the cooling operation is performed. The flow of the refrigerant flows. The change on the Mollier diagram of the refrigeration cycle at this time is shown in FIG. 7, where Δic is the compressor enthalpy and Δic
c is general cooling side condensation enthalpy, Δicp is cooling side condensation enthalpy, Δigp is refrigerant liquid pump enthalpy, Δi
e is the enthalpy of evaporation.

In this refrigeration cycle, the ratio of the refrigerant circulation amount of the refrigerant gas pump to the refrigerant circulation amount of the compressor can be arbitrarily designed. Therefore, the ratio of the cooling operation to the total cooling load and the ratio of the general cooling operation can be arbitrarily set. However, actually, the heat storage operation performed at night is performed by the compressor 1 (the driving source of the general cooling operation).
And the cooling operation time in the daytime and the heat storage operation time in the nighttime are almost the same, so it is appropriate that the cooling capacity by the general cooling operation and the cooling operation by the cooling operation is almost equal. Also here
The larger the ratio of the cooling operation, the higher the heat storage dependency ratio and the smaller the power consumption of the regenerative cooling device during the same cooling load operation.

[0020] An example in FIG. 8 for cooling load to Q ₁ daytime cooling operation described above and general cooling operation load and nighttime heat storage operation load. Figure Q ₃ are thermal storage operation load, Q ₂ is allowed to cool operating load, Q ₁ -Q ₂ is generally cooling operation load. According to FIG. 8, Q of the area of the thermal storage operation daytime nighttime Q _{3 2}
Indicate that the area of the cooling operation load is almost equal, and the heat storage at night is used up during the day. Furthermore, among the cooling load Q _1, general cooling operation load so that cover only the amount of Q ₁ -Q _2. In other words, so that cover the remaining amount of the load financed by cooling operation load Q _2.

Embodiment 2 FIG. Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a diagram showing a regenerative cooling device of the present invention.
In the figure, 1 is a compressor, 2 is a condenser, 3 is a first pressure reducing mechanism, 4
Is an evaporator, and 5 is an accumulator, which is sequentially connected to 1 to 5 to form a general cooling circuit. Reference numeral 6 denotes a heat storage medium, for example, water stored in the heat storage tank 7.

Reference numeral 8 denotes a heat storage heat exchanger for exchanging heat with the heat storage medium. A refrigerant liquid pump 21 and a second pressure reducing mechanism 19 are provided between the heat storage heat exchanger inlet 8a and the evaporator 4 inlet. The refrigerant liquid pump cooling circuit is formed by connecting the heat storage heat exchanger outlet 8b and the evaporator 4 outlet in order. Reference numeral 9 denotes a heat storage bypass circuit, which connects the outlet of the first pressure reducing mechanism 3 and the heat storage heat exchanger inlet 8a. The compressor 1, the condenser 2, the first pressure reducing mechanism 3, and the heat storage bypass The circuit 9, the heat storage heat exchanger, and the accumulator 5 are sequentially connected to form a heat storage circuit.

FIG. 10 is a circuit diagram showing the operation during the heat storage operation mainly in the midnight power time zone.
0, 11, 12 are closed, and the switching devices 13, 14, 15, 1
6, the compressor 1 is stopped while the refrigerant liquid pump 21 is stopped.
Is operated, the high-temperature and high-pressure gas refrigerant from the compressor 1 radiates heat in the outdoor heat exchanger 2, condensed and liquefied, and adiabatically expanded in the first pressure reducing mechanism 3 to become a low-temperature liquid-gas two-phase fluid. The heat enters the heat exchanger 8 for heat storage, deprives the heat storage medium of heat, evaporates itself, and returns to the compressor 1 via the accumulator 5. By such an operation, heat of low temperature is stored by freezing the heat storage medium 6 or the like.

When the daytime cooling load is equal to or less than a predetermined value, when the cooling operation is performed by utilizing heat storage, the switching devices 10, 14, and 16 are closed as shown in FIG.
When the refrigerant liquid pump 21 is operated without opening the compressors 1, 12, 15 and 17 and the compressor 1 is not operated, the low-temperature, low-pressure supercooled refrigerant pressurized by the refrigerant liquid pump 21 is discharged by the second pressure reducing mechanism 19. It slightly expands adiabatically and enters the evaporator 4, where it takes heat from the surroundings to cool it, evaporates and gasifies itself, radiates heat in the heat storage heat exchanger, condenses and liquefies, and turns the refrigerant liquid pump 2
Return to 1.

FIG. 12 shows a change in the Mollier diagram of the refrigeration cycle at this time. In the figure, Δiep indicates the refrigerant liquid pump enthalpy, and Δie indicates the evaporation enthalpy. In this cooling operation, the evaporating operation is performed at almost the same pressure, which is slightly higher than the condensing pressure. Only the same amount of heat of condensation as the heat of vaporization for cooling needs to be released, and a high coefficient of performance (COP) of about 10 times that of a gas pump is achieved. Further, by making the heat storage amount over a predetermined value, together performed in cool operating all cooling load, it can also be carried out in cooling <br/> OPERATION time zone peak load.

When the cooling load in the daytime is equal to or greater than a predetermined value, the switches 13, 14 are closed and the switches 10, 11, 12, 15, 16, 17 are opened as shown in FIG. When both of the liquid pumps 21 are operated, the general cooling operation and the cooling operation are simultaneously performed. At that time, the evaporator 4 outputs the total refrigerant flow rate when only the general cooling operation or the cooling operation is performed. Become. The change on the Mollier diagram of the refrigeration cycle at this time is shown in FIG. 14, where Δic is the compressor enthalpy, △ icc is the general cooling-side condensation enthalpy, △ icp is the cooling-side condensation enthalpy, ｐie
p is the refrigerant liquid pump enthalpy, and Δie is the evaporation enthalpy.

In this refrigerant cycle, the ratio of the refrigerant circulation amount of the refrigerant liquid pump to the refrigerant circulation amount of the compressor can be arbitrarily set, so that the ratio of the cooling operation to the total cooling load and the general cooling operation can be arbitrarily set. However, actually, the heat storage operation performed at night uses the compressor 1 (the driving source of the general cooling operation), and since the cooling operation time in the daytime and the heat storage operation time in the night are almost the same, the cooling capacity of the general cooling operation and the cooling operation by the cooling operation is reduced. It is reasonable that they are approximately equal. Also, here, the larger the ratio of the cooling operation, the higher the heat storage dependency ratio and the smaller the power consumption of the heat storage type cooling device during the same cooling load operation.

[0028]

As described above, the regenerative cooling device according to the present invention is provided.
Has a compressor, a condenser, a first decompression mechanism, and an evaporator.
The pipe is formed and the compressor is operated to evaporate
A general cooling circuit that performs general cooling operation in which cooling
Connected to the inlet and outlet sides of the evaporator,
Storage heat exchanger for exchanging heat with the stored heat storage medium
And a second pressure reducing mechanism connected by piping.
The cooling device is operated to cool down by the evaporator.
A regenerative cooling device provided with a cooling circuit for performing cooling.
By the load response means, the base load of the total cooling load
Load by cooling operation using heat storage, and general cooling
By responding to the load by operation,
The remaining load will be used for general cooling operation.
Therefore, the amount of heat storage becomes almost constant, the amount of heat storage can be made almost constant, the management of the amount of heat storage becomes easy, and the heat storage can be used up. Is big. In addition, when the load is reduced due to cooling load fluctuation, the base load is covered by heat storage. As the load decreases, the ratio of the cooling operation to the total cooling load increases, and the coefficient of performance increases. Driving. On the other hand, when the load of the cooling load is compensated for by the heat storage, as the load decreases, the ratio of the cooling operation to the total cooling load decreases, and the operation becomes a low coefficient of performance. Avoid the situation.

[0029]

[Brief description of the drawings]

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

FIG. 2 is an operation diagram during a heat storage operation.

FIG. 3 is a Mollier chart during a heat storage operation.

FIG. 4 is an operation diagram during a cooling operation.

FIG. 5 is a Mollier chart during a cooling operation.

FIG. 6 shows an operation during a merge operation.

FIG. 7 is a Mollier chart during a merging operation.

FIG. 8 shows each operation and the cooling load at the time of the merging operation.

FIG. 9 is a cycle diagram of a regenerative cooling device according to a second embodiment of the present invention.

FIG. 10 is an operation diagram during a cold storage operation according to the second embodiment.

FIG. 11 is an operation diagram at the time of a cooling operation according to the second embodiment.

FIG. 12 is a Mollier chart during a cooling operation according to the second embodiment.

FIG. 13 is an operation diagram at the time of a merge operation in the second embodiment.

FIG. 14 is a Mollier chart at the time of a merge operation according to the second embodiment.

FIG. 15 is a cycle diagram of a conventional regenerative cooling device.

FIG. 16 is a Mollier chart during a conventional liquid subcooling operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 3 First decompression mechanism 4 Evaporator 6 Heat storage medium 7 Heat storage tank 8 Heat storage heat exchanger 8a Heat storage heat exchanger inlet 8b Heat storage heat exchanger outlet 9 Heat storage bypass circuit 10, 11, 12, 13, 14, 15, 16, 17, 2
0 Switchgear 18 Refrigerant gas pump 19 Second decompression mechanism 21 Refrigerant liquid pump 22 Liquid supercooling heat exchanger 23 Liquid subcooling circuit 24 Main refrigerant circuit

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroaki Hama 6-66, Tehira, Wakayama-shi Mitsubishi Electric Corporation Wakayama Works (72) Inventor Masami Imanishi 6-66, Tepa, Wakayama-shi Mitsubishi Electric In Wakayama Works, Ltd. (72) Inventor Kenzo Kurahashi 6-5-66, Tehira, Wakayama City Mitsubishi Electric Wakayama Works, Ltd. (56) References JP-A-2-33573 (JP, A) JP-A-3-3 191260 (JP, A) JP-A-1-174864 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F24F 5/00 102 Z F25B 1/00 321 C F25B 5/00 A

Claims (1)

(57) [Claims] 1. A general cooling circuit which is formed by connecting a compressor, a condenser, a first decompression mechanism, and an evaporator by piping, and performs a general cooling operation in which the compressor is operated to perform cooling by the evaporator. And a refrigerant transfer device connected to the inlet side and the outlet side of the evaporator, and formed by pipe connection of a refrigerant transfer device, a heat storage heat exchanger for exchanging heat with the stored heat storage medium, and a second pressure reducing mechanism. A regenerative cooling system comprising a cooling circuit for operating the apparatus and performing a cooling operation for cooling by the evaporator.
Cooling operation by loading load by cooling operation using heat storage and load change by general cooling operation
The remaining load corresponding to the load in
Regenerative cooling apparatus characterized by that.