JP3251766B2 - Cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device using a cooling fluid, and more particularly to a cooling device for district cooling.

[0002]

2. Description of the Related Art A known cooling device will be described with reference to FIGS. FIG. 10 is an explanatory diagram at the time of the heat storage operation, and shows the start of the heat storage (a), the heat storage (b), (c), (d), and the completion of the heat storage (e), and FIG. 11 illustrates the load operation. It is a figure and shows (f), (g), (h) at the time of load operation, and shows a total of eight operation states. At the start of heat storage In FIG. 10A, reference numerals 9, 10, and 11 denote heat storage tanks.

In this case, the number of tanks is three, but even if there are three or more tanks, there may be one or two tanks depending on the system. 1
2 is a refrigerator that draws in cold water of, for example, 17 ° C. from the heat storage tank 11 with the pump 13 and cools it,
From the tank 9. When the water in the tank 11 is sucked, the water at 17 ° C. is changed from 9 to 10 by the connecting pipes 15 and 16.
→ Move to 11. At this time, since the density of water becomes maximum at 4 ° C., the 2 ° C. cold water flowing from 14 is mixed in the heat storage tank, and the 2 ° C. cold water layer is not formed. Figure 10 during heat storage
(B) shows a state where, for example, about one hour has elapsed from FIG. 10 (a) during heat storage. That is, the heat storage tank is a stratified type heat storage tank, but is not a 2 ° C./17° C. stratification but a 4 ° C./17° C. stratification.
FIG. 10 (c) shows a case where the temperature in the tank is approximately 4 ° C. during heat storage. Thereafter, the refrigerator performs an extreme throttle operation. And
When the heat storage is completed, as shown in FIG.
As shown at 0 (e), the temperature of the refrigerator 12 becomes 2 ° C., and the operation of the refrigerator 12 is stopped.

[0004] At the time of load operation FIG. 11 (f) is a diagram when the load is operated in the morning and a short time has passed. In this state, the three-way valve 17 is switched, and the cold water from the refrigerator 12 does not flow to the pipe 14 side, but flows to the three-way temperature adjustment valve 18 side. The three-way temperature control valve 18 is supplied with cold water from the heat storage tank 9 via the pipe 19, so that while the cold water of 2 ° C. is stored in the heat storage tank, the cold water of the heat storage tank is preferentially used, and Pump 20 supplies 2 ° C. cold water. Also, for example, cold water of 17 ° C. is returned from the load to the heat storage tank 11 via the pipe 21. FIG. 11 (g) shows the case where the temperature of the heat storage tank 9 becomes higher than 2 ° C. during the load operation. In this case, 2
Refrigerator 1 that produces cold water outlet temperature of 1 ° C
2 is operated in full, and the three-way valve 22 mixes, for example, 4 ° C. cold water to supply 2 ° C. cold water.
Similarly, FIG. 11H shows a case where the temperature of the heat storage tank is further increased during the load operation. In this state, the operation of the load is stopped.

Although this system is a good system having a large heat storage density, there are basically the following two problems. First
The problem is that, at the start of heat storage, as shown in FIG. 10 (a), cold water having a low density of 2 ° C. flows into the cold water portion of 4 ° C. from the lower part, so that the piston does not flow out due to the exothermicity. Loss occurs. Therefore, all inside the tank is 2 ℃
In order to satisfy the condition, as shown in FIG. 10D, the refrigerator 12 is forced to perform “extremely low load operation” for cooling the chilled water from 3 ° C. to 2 ° C., for example. In the case of a centrifugal chiller usually used for district cooling, the chiller cop in Table 1 is used.
As shown in the column, for example, the refrigerator cop drops to 1.5. In order to avoid this low load operation, the chilled water temperature becomes zero.
It will be below ℃ and freeze.

[0006]

[Table 1]

A second problem is that, in the present system, even when the load is low, a large refrigerator must be operated when there is a load. That is, at the time of load operation, in the case of FIG.
The can supply cold water, when the load return water is returned, because the direction of cold water 4 ° C. than 2 ℃ cold water density is large, the tube 1 9 as load operation FIG 11 (g) Since the temperature of the cold water is close to 4 ° C., in order to maintain the temperature of the supply cold water at 2 ° C., it is necessary to operate the large refrigerator 12 to produce cold water at 1 ° C. even when the load is small. In addition, when the load is small, the throttle operation is performed, and the three-way temperature control valve 2 is used.
The cold water in the tank 9 and the cold water in the tank 11 are mixed by, for example, 3 ° C., and the mixed water is sent to the refrigerator 12 by the pump 13 to produce 1 ° C. cold water. That is, mixed exergy loss occurs in the three-way control valve 22, and
The refrigerator 12 performs an extreme throttle operation, and the cop decreases.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an efficient cooling device which eliminates extremely low load operation even during heat storage and load operation. And

[0009]

According to the present invention, there is provided a cold fluid supply pipe for sending a cold fluid to a load side, a cold load directly or indirectly cooled by the cold fluid, a load fluid return pipe for returning the return fluid from the load, connected to the cold fluid supply pipe and a load fluid return pipe
Storage device for storing cold fluid and cooling fluid 1
In the cooling device according to the cold fluid chromatic and stand above the refrigerator, the cold storage device has a single tank or more and the low-temperature side temperature stratified storage tank and 2 tank or the hot side temperature stratified storage tank, which
These heat storage tanks are connected by a path, and the cold fluid in the heat storage tanks is connected.
High temperature cool storage circulation path for cooling the freezer, the cold
To cool the cooling fluid accumulated on the side temperature stratified storage tank to a temperature of more 4 ° C. or less by the refrigerator, the cold fluid to be sent to the cold fluid supply pipe directly or through the蓄<br/> thermal bath And a supply path. In the above, the high-temperature cold storage circulation path and the cold fluid supply path may be partially shared by time.

[0010] In the cooling device, refrigerator, the high
A refrigerator that cools the cold fluid in the warm-side temperature stratified heat storage tank to a certain temperature of 4 ° C. or more, and a refrigeration machine that further cools the cold fluid stored in the low- temperature stratified heat storage tank to a certain temperature of 4 ° C. or less And two refrigerators.

Further, the refrigerator is constituted by one compression refrigerator, and the evaporator of the compression refrigerator has water chambers on both side surfaces.
Tube coil, and flows through the tube coil.
When cooling the temperature of the temperature-stratified heat storage tank to a certain temperature of 4 ° C. or more.
Is configured such that the flow rate of the cold fluid flowing through the tube coil is lower than when the cold fluid stored in the temperature-stratified heat storage tank is further cooled to a certain temperature of 4 ° C. or less.
And the compression refrigerator cools the cold fluid in the temperature-stratified heat storage tank to a certain temperature of 4 ° C. or more.
The high-temperature side evaporator and the cold stored in the temperature-stratified heat storage tank.
Low temperature evaporation to further cool the fluid to a certain temperature below 4 ° C
It can be configured with a container .

[0012]

By configuring the cooling device as described above, each device has an operation as will be described in detail in the next embodiment, and a system which solves the above-mentioned problems can be obtained.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to the drawings, but the present invention is not limited to these. Embodiment 1 FIGS. 1 and 2 are explanatory views of the configuration and operation of an example of a cooling device of the present invention. (A) to (e) of FIG. 1 show a heat storage operation, and (f) to (g) of FIG. 2 show a load operation.

At the start of heat storage (a) in FIG. 1, the cold / hot water tank is composed of three tanks 9, 10, and 11. Tank 10
Is designed to be used as a hot water tank in winter, but when only a cold load is applied, 9 and 10 may be integrated into two tanks.
Conversely, three or more tanks may be used. Reference numeral 12 denotes a main refrigerator, which is operated at full load mainly by current control.
That is, 17 ° C. sent from the heat storage tank 11 by the pump 13
Of cold water is cooled by the refrigerator 12, for example, 10
C. and is discharged to the heat storage tank 10. Reference numeral 23 denotes a low-temperature refrigerator that cools 4 ° C. cold water to 2 ° C. During nighttime heat storage, the cold water at 4 ° C. below the heat storage tank 9 is cooled by the refrigerator 23 and returns to the upper part of the heat storage tank 9 via the three-way valve 15 → the pipe 14.

FIG. 1 (b) shows the temperature distribution of the heat storage tank after a certain time has elapsed from (a). As shown in FIG. 1B, both the tanks 9 and 10 have a temperature stratified temperature distribution.
When the state shown in FIG. 1D is reached after the heat storage shown in FIG. 1C, the cold water inlet temperature to the refrigerator 12 becomes 10 ° C. and the outlet temperature becomes about 4 ° C. And cold water temperature 4 ℃
When the heat storage is completed, the temperature becomes 4 ° C. as shown in FIG. 1 (e). For example, the thermostat 24 installed above the water in the tank 11 operates, and the refrigerator 12 stops. At this time, the size of the heat storage tank 9 is planned so that the refrigerator 23 is stopped almost at the same time. That is, when the temperature of the thermostat 25 becomes approximately 2 ° C., the refrigerator 23 automatically stops.

At the time of load operation, FIG.
It is a flow sheet in the case where the return cold water from the load returns to the tank 11 via the return pipe 21. At this time, for example, the three-way adjustment valve 22 operates in conjunction with the operation of the pump 20.
When the load is not operating, the three-way adjustment valve does not operate, and no cold water flows through the bypass pipe 26. That is, since the three-way regulating valve 22 operates so that the temperature of the chilled water after mixing becomes approximately 10 ° C., the chilled water flows from the bypass pipe 26 and is mixed with the chilled water of 17 ° C. from the tank 11 to become 10 ° C. 12
And cooled to 4 ° C. and discharged to the heat storage tank 10. There is a connecting pipe 27 between the tank 10 and the tank 9,
4 ° C. from tank 10 to tank 9 by the amount of water flowing in from pipe 21
Cold water moves. The cold water of 4 ° C. is cooled by the refrigerator 23 to become 2 ° C. and supplied to the load side by the pump 20 via the three-way valve 15. When the pump 20 is operated in a state where the refrigerator is operated, the three-way valve is switched, and the cold water from the refrigerator outlet is supplied to the load side.

FIG. 2 (g) shows a case where the refrigerators 12 and 23 are stopped for peak cutting during load operation. In this case, the three-way valve 15 is switched, and the cold water at 2 ° C. in the upper part of the tank is supplied to the load. At the time of load operation, FIG. 2H shows an operation state after the peak. The water temperature in the tank 9 is all 4 ° C.
Table 2 shows an example of the performance. In the case of heat storage (b) in the table, the evaporating temperature of the refrigerator 12 is increased to 7 ° C., and as a result, the total cop including the low-temperature refrigerator and the pump power is increased. In addition, all the refrigerators can be stopped at the time of the peak cut as in the load operation (g).

[0018]

[Table 2]

Embodiment 2 FIGS. 3 and 4 are explanatory views of the structure and operation of another example of the cooling device of the present invention. 3 (a) to 3 (e) show the heat storage operation, and FIGS. 4 (f) to 4 (h) show the load operation. Here, the heat storage is assumed to be up to 4 ° C. This is a case where the machine 23 is operated. In this method, peak cut cannot be performed, but c is always high.
Can be driven in op. Table 3 shows an example of the performance.

[0020]

[Table 3]

Embodiment 3 FIGS. 5 and 6 are explanatory views of the structure and operation of another example of the cooling device of the present invention. FIGS. 5 (a) to 5 (e) show the heat storage operation and FIGS. 6 (f) to 6 (h) show the load operation. Here, the installed capacity of the chilled water primary piping is slightly increased, and instead, the refrigerator is used. This is an embodiment that solves the above-mentioned problem with one device. The number of passes in the water-side passage of the evaporator of the refrigerator 12 can be switched, for example, “5 passes⇔1 pass”.

FIG. 7 shows a detailed view of the refrigerator 12. In FIG. 7, reference numeral 28 denotes a cold water inlet pipe. The chilled water line of the evaporator 29 of this refrigerator is provided with automatic valves 30, 31, 32, and 33, so that five passes and one pass can be automatically switched. That is, in the 5-pass mode, the automatic valves 30, 31, 32, and 33 are closed. Therefore, the cold water flows through the inlet pipe 28 → water chamber 34 → tube 35 → water chamber 36 → tube → water chamber 37 → tube → water chamber 38 → tube → water chamber 39 → tube → water chamber 40 → cold water outlet pipe 41.
That is, when the flow rate is small, the number of passes is increased to make the flow velocity in the tube an appropriate value. When the flow rate is large, open the automatic valves 30, 31, 32, 33
Can be switched to pass. That is, the cold water is introduced into the water chambers 34, 37, and 39 from the inlet pipe 28, and flows through the tubes to the outlet pipes 41 from the water chambers 36, 38, and 40, respectively. That is, since it is one pass, a large flow rate can be supplied to the tube. In FIG. 7, reference numeral 42 denotes a compressor; 43, a condenser;
4 is an expansion device.

At the start of heat storage (a) in FIG. 5, the refrigerator 12 is in the 5-pass mode. Cold water of 17 ° C. is supplied to the refrigerator 12 and cooled to 2 ° C. In some cases, it may be cooled to 4 ° C. Then, cold water is stored in the tank 9 through the switching valve 15 and the communication pipe 14. FIG. 5B shows a state where heat is stored to some extent. During heat storage, the state of FIG. 5 (c) is a state in which the temperature in the tank is all 4 ° C. For example, in this state, the thermostat 45 operates,
The automatic valves 30, 31, 32, and 33 in FIG. 7 are opened, and a one-pass mode is set. At the same time, a large flow rate mode is set such that the rotation speed of the pump 13 is increased. The pump 13 may be composed of two units, a small flow high head pump and a large flow low head, and the pump to be operated may be selected. 4 in this mode
5C is cooled to 2 ° C, but the heat storage tank operates as a mixed-type heat storage tank, and when the heat storage is completed, the entire tank becomes 2 ° C as shown in Fig. 5 (e).
The thermostat 46 operates in the state where
2 stops.

FIGS. 6 (f) to 6 (h) are explanatory diagrams of the operation when the load pump 20 is operated and there is a load. For example, as shown in FIG.
The refrigerator 12 is operated in a 5-pass mode. That is, 15 ° C
It becomes a large temperature difference (small flow rate) mode in which the cold water is cooled to 1 ° C. Generally, since the load capacity is larger than the capacity of the refrigerator, the cold water of 1 ° C. from the refrigerator is mixed with the cold water from the heat storage tank 9 by the three-way regulating valve and is sent to the load side at 2 ° C. In this system, unlike the conventional system, even when the temperature in the heat storage tank becomes 4 ° C. or lower, the cop value becomes high as shown in the right-side refrigerator cop column in FIG. 5D during heat storage. That is, FIG.
Compared with (b), the capacity is hardly reduced, so that no extreme throttle operation is performed, and therefore, the cop reduction value is also small. Also,
At the time of load operation, the amount of water flowing through the bypass pipe 26 is smaller than that of the conventional method, so that the cop is less reduced even when the load is reduced. Table 4 shows an example of the performance.

[0025]

[Table 4]

Embodiment 4 FIGS. 8 and 9 are explanatory views of another embodiment according to the present invention.
FIG. 8 is an explanatory diagram showing the two-temperature cooling mode, and reference numeral 45 denotes a brine refrigerator. The brine refrigerator 45 has two evaporators, a low-temperature evaporator 29 and a high-temperature evaporator 29 '. Then, the cold water of, for example, 17 ° C. in the upper portion of the tank 11 is sent to the high-temperature side evaporator 29 ′ by the pump 13 and cooled, and reaches 11 ° C. and flows into the lower portion of the tank 11. The evaporation temperature of the high-temperature side evaporator is, for example, 8 ° C. Tank 10
The water at 0 ° C. is sent to the ice maker 46 by the pump 13 ′, flows down the heat transfer surface of the ice maker, is cooled by the internal brine, and partially freezes on the heat transfer surface.

The brine in the ice maker 46 is pump 47
Is sent to the low-temperature side evaporator 29 to be cooled, for example, -3 ° C.
To -7 ° C. At this time, the evaporation temperature of the low-temperature side evaporator is, for example, −10 ° C. FIG. 9 is an explanatory diagram showing the cold heat recovery and defrosting mode. In this mode, the refrigerator normally stops. The pump 13 'is stopped and the pump 48 is operated,
The brine is heated by the heat exchanger 49. for that reason,
The ice adhering to the ice maker 46 is thawed and becomes ice pieces, and falls into the lower tank.

[0028]

As described above, according to the present invention,
The following excellent effects can be obtained respectively. (1) In the case of FIGS. 1 and 2, when the heat storage is completed. In FIG. 1 (e), when the temperature in the heat storage tank becomes almost 4 ° C. by the signal of the temperature detector 24, the refrigerator 12 is stopped. That is, the heat storage tank 1
0 and 11 always operate as a temperature stratified heat storage tank. 3 and 4, the refrigerator 12 is similarly stopped by the operation of the temperature detector 24. In this case, including tank 9 17 →
Operates as a 4 ° C temperature stratified thermal storage tank. In the case of FIGS. 5 and 6, when the heat is stored, when the state of FIG. 5C is reached, the refrigerator 12 becomes one pass by the temperature detector 45 and the controller 45 ', and the amount of water sent to the refrigerator 12 increases. As a result, even if the temperature in the heat storage tank becomes 4 ° C. or less and the temperature at the refrigerator inlet decreases, the extreme “refrigerator throttle operation” does not occur.

As a result, the performance of the refrigerator remains at 2 ° C.
Of cold water can be stored in the heat storage tank. Fig. 5 during heat storage
After (c), the heat storage tank is of a mixed type, but since the amount of water is large, a decrease in heat storage efficiency is small. 8 and 9, since the tank 11 always operates as a temperature stratification type of 4 ° C. or higher, the efficiency of the heat storage tank 11 can be maintained high. Also, since the heat storage tank 10 always operates at a temperature of 4 ° C. or less,
It is not necessary to consider that the density is inverted at ° C. An optimal design for a heat storage tank of 4 ° C. or less may be performed.

(2) Further, in the present apparatus, even when the load is operated, the refrigerator does not perform an extreme throttle operation. Figure 1
In the case of No. 4, since a small refrigerator is provided, even when the load is small, the refrigerator does not perform an extreme throttle operation.
In addition, in the case of FIGS. 5 and 6, the throttle operation is not performed even in the case of FIGS. 6 (f) to 6 (h) during the load operation, so that even if the load decreases, the extreme throttle operation does not occur. In addition, in the case of FIGS. 8 and 9 , since the refrigerator is always operated at full load regardless of the load, the performance of the refrigerator does not decrease when the load is small.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of a cooling device according to the present invention during a heat storage operation.

FIG. 2 is an explanatory view showing a load operation in FIG. 1;

FIG. 3 is an explanatory view showing a heat storage operation in another example of the cooling device of the present invention.

FIG. 4 is an explanatory diagram showing a state during a load operation in FIG. 3;

FIG. 5 is an explanatory diagram showing a heat storage operation in another example of the cooling device of the present invention.

FIG. 6 is an explanatory diagram showing a state during a load operation in FIG. 5;

FIG. 7 is an enlarged configuration diagram of the refrigerator used in FIG.

FIG. 8 is an explanatory diagram of a temperature cooling mode of another example of the cooling device of the present invention.

FIG. 9 is an explanatory diagram of the cold heat recovery / thaw mode of FIG. 8;

FIG. 10 is an explanatory view showing a known cooling device during a heat storage operation.

FIG. 11 is an explanatory diagram showing a state during a load operation in FIG. 10;

[Explanation of symbols]

9, 10, 11: heat storage tank, 12, 23: refrigerator, 13,
20: pump, 14, 19, 21, 26, 27: piping,
15, 18, 22: three-way valve, 24, 25: thermostat, 28: cold water inlet pipe, 29: evaporator, 30, 31, 3,
2, 33: automatic valve, 34, 36, 37, 38, 39, 4
0: water chamber, 35: tube, 41: cold water outlet pipe, 42:
Compressor, 43: condenser, 44: expansion device, 45: brine refrigerator, 46: ice machine, 47, 48: pump, 49:
Heat exchanger,

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kaki Yoshida 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside Ebara Corporation (56) References JP-A 64-23040 (JP, A) JP-A Hei 5-5539 (JP, A) Actually open Hei 3-3-10076 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F24F 5/00

Claims (4)

(57) [Claims] A cold fluid supply pipe for sending a cold fluid to a load side ;
A cold load directly or indirectly cooled by the cold fluid, a load fluid return pipe for returning the return fluid from the load, and a connection to the cold fluid supply pipe and the load fluid return pipe.
In the cooling device according to the cold fluid chromatic and one or more of the refrigerator for cooling the cold storage device and a cold fluid to the reservoir of cold fluid that, the cold storage apparatus, 1 tank or cold side temperature stratified storage tank and 2 tank and a more upper temperature stratified storage tank, which
These heat storage tanks are connected by a path, and the cold fluid in the heat storage tanks is connected.
High temperature cool storage circulation path for cooling the freezer, the cold
To cool the cooling fluid accumulated on the side temperature stratified storage tank to a temperature of more 4 ° C. or less by the refrigerator, the cold fluid to be sent to the cold fluid supply pipe directly or through the蓄<br/> thermal bath A cooling device having a supply path. 2. The refrigerator according to claim 1 , wherein the refrigerator cools the cold fluid in the high-temperature-side stratified-type thermal storage tank to a certain temperature of 4 ° C. or more, and cools the cold fluid stored in the low-temperature-side stratified-type thermal storage tank. And a refrigerator that cools down to a certain temperature of 4 ° C or less .
Cooling apparatus according to claim 1, characterized in that it comprises a refrigerator. 3. The refrigerator according to claim 1, wherein the refrigerator comprises one compression refrigerator, and the evaporator of the compression refrigerator has water chambers on both sides.
A cold coil that flows through the tube coil.
Is configured to be able to increase or decrease the flow rate of the fluid, when cooling the temperature stratified storage tank to 4 ° C. above a certain temperature, the flow rate of the cold fluid flowing in the tube coil, in front Symbol temperature stratified storage tank 2. The cooling device according to claim 1, wherein the cooling device is configured to reduce the amount of the stored cold fluid to a value lower than a certain temperature of 4 [deg.] C. or less. Wherein said refrigerator is configured with a single compressor refrigerator, hot side of the compressor refrigerator, cools the cold fluid <br/> the temperature stratified storage tank to 4 ° C. above a certain temperature 2. The cooling device according to claim 1, further comprising: an evaporator; and a low-temperature side evaporator that further cools the cold fluid stored in the temperature-stratified heat storage tank to a certain temperature of 4 ° C. or less.