JP3292588B2 - 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. 5 is an explanatory diagram at the time of the heat storage operation, and shows the start of heat storage (a), the time of heat storage (b), (c), (d), and the completion of heat storage (e). FIG. FIG. 8 shows (f), (g), and (h) during load operation, and is 8 in FIGS. 5 and 6.
Two operating states are shown.

At the start of heat storage, in FIG.
Numerals 0 and 11 are regenerators. 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. Reference numeral 12 denotes a refrigerator, for example, 17
C. cold water is sucked by the pump 13 and cooled, for example, at 2 ° C.
From the pipe 14 to the tank 9. When the water in the tank 11 is sucked, the water at 17 ° C. moves 9 → 10 → 11 by the connecting pipes 15 and 16. 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.
FIG. 5B shows a state in which, for example, about one hour has elapsed from the time of heat storage (a). That is, the heat storage tank is a stratified heat storage tank, but the temperature is 4 ° C./17° C. instead of 2 ° C./17° C. stratification.
FIG. 5 (c) shows a case where the temperature in the tank becomes approximately 4 ° C. during heat storage. Thereafter, the refrigerator performs an extreme throttle operation. And
After the heat storage is completed, as shown in FIG.
As shown in (e), the temperature becomes 2 ° C. and the operation of the refrigerator 12 is stopped.

During load operation FIG. 6 (f) shows a case where the load has been operated in the morning and a short time has elapsed. In this state, the three-way valve 17 is switched, and the cold water from the refrigerator 12
It does not flow to the four side, but flows to the three-way temperature control 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 the cold storage water is preferentially used while the cold storage water is stored at 2 ° C. 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. 6 (g) shows a case where the temperature of the heat storage tank 9 becomes higher than 2 ° C. during the load operation. In this case, 2
Refrigerator 12 that produces chilled water outlet temperature of 1 ° C
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. 6 (h) shows a case where the temperature of the heat storage tank further increases during the load operation. In this state, the operation of the load is stopped.

This system has a large heat storage density and is good, but basically has the following major problems. That is, at the time of heat storage, in the case of FIG.
Despite the high temperature, the cold water outlet temperature is as low as 2 ° C, and the evaporation temperature is as low as -1 ° C. That is, the performance of the refrigerator is significantly lower than that of a general system having a small heat storage density. Therefore, compared to a general 12 → 7 ° C system,
The cold water flow rate is reduced to one third and the heat storage density is tripled, but these advantages are offset by the disadvantage of lowering the evaporation temperature.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a cooling apparatus which operates without lowering the evaporation temperature of the refrigerator to improve the performance of the refrigerator. That is the task.

[0008]

In order to solve the above-mentioned problems, the present invention provides a cold fluid supply pipe for sending a low-temperature cold fluid not exceeding 4 ° C. to a load side, and directly or indirectly using the cold fluid supply pipe. A cold load to be cooled, a load fluid return pipe for returning the return fluid from the load, a cold storage device for storing the cold fluid connected to the cold fluid supply pipe and the load fluid return pipe, and cooling the cold fluid In a cooling device using a cold fluid having one or more refrigerators, the regenerator includes one or more low-temperature-side stratified-type heat storage tanks and two or more high-temperature-side stratified-type heat storage tanks. It has a cold storage circulation path for cooling the cold fluid of the tank by a refrigerator, a three-way valve is provided in a path connected to the refrigerator in the circulation path, and the three-way valve has a high-temperature side cold fluid of the temperature-stratified heat storage tank. Connect the path for each of the low-temperature side cold fluids While controlling the three-way valve so that the refrigerator obtains the minimum cold fluid outlet temperature at the outlet by adjusting the inflow amounts of the respective cold fluids of the high-temperature side and the low-temperature side cold fluid during the load operation, during rapid cold-storage operation in which it was decided to have the control unit only before Symbol hot side of the cooling fluid is controlled to flow.

[0009]

By configuring the cooling devices as described above, each of the cooling devices has an operation as will be described in detail in the next embodiment, and the above-mentioned problems are solved.

[0010]

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 a cooling device showing an example of the present invention. 1A to 1E show a heat storage operation, and FIGS. 2F to 2H 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 used as a hot water tank in winter. However, when only a cold load is applied, 9 and 10 may be integrated into two tanks, or 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. cold water sent from the heat storage tank 11 by the pump 13 is cooled by the refrigerator 12, cooled to, for example, 10 ° C., and 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, 4 ° C. cold water at the lower part of the heat storage tank 9 is cooled by the refrigerator 23
It returns to the upper part of the heat storage tank 9 via the direction valve 15 → 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. In addition, the size of the heat storage tank 9 is planned so that the refrigerator 23 is also stopped substantially at the same time as the stop. That is, when the temperature of the thermostat 25 becomes approximately 2 ° C., the refrigerator 23 automatically stops.

FIG. 2 (f) shows the operation of the load when the load is operated.
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 temperature control 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,
A signal for not performing the control is given to the controller 51, and a means for not performing the temperature control by the water temperature detector 52 after mixing is taken. Similarly, in the case of the heat storage diagram (b), when the temperature of the heat storage tank temperature detector 53 is 10 ° C. or more, for example, the three-way temperature control valve 22 is not operated.

That is, when controlling the temperature, the three-way regulating valve 22 operates so that the temperature of the chilled water after mixing becomes approximately 10 ° C., so that the chilled water flows from the bypass pipe 26 and the tank 1
The mixture is mixed with the cold water of 17 ° C. from 1 to reach 10 ° C., sent to the refrigerator 12, cooled to 4 ° C., and discharged to the heat storage tank 10. A communication pipe 27 is provided between the tank 10 and the tank 9, and 4 ° C. cold water moves from the tank 10 to the tank 9 by an amount of water flowing from the pipe 21. The 4 ° C. cold water is cooled by the refrigerator 23 to 2 ° C.
To the load side. 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 in which 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 1 shows an example of the performance. In the case of the 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) .

[0016]

[Table 1]

Embodiment 2 FIGS. 3 and 4 are explanatory views of a cooling device according to another embodiment of the present invention in use modes. FIG. 3 shows a rapid cold storage mode (a), a low temperature cold storage mode (b), and a cold heat recovery / thawing mode (c), and FIG. 4 shows a peak cut operation mode (d), a winter mode (e), and a winter mode ( f) is shown.

Rapid Cool Storage Mode FIG. 3A is an explanatory diagram in the case where water in the cool storage device of the present device is rapidly cooled. The heat storage tank 31 is a temperature stratified type heat storage tank, 32 is an ice water heat storage tank, and 33 is a cold storage tank for storing cold water at 0 ° C.
And 31 and 33 are cold storage tanks that always store cold water,
A valve 32 (not shown) is switched in the winter to be used as a hot water storage tank. 34 is a brine refrigerator. Reference numeral 35 denotes a brine piping loop which sends brine of, for example, 11 ° C. to a brine refrigerator 34 by a pump 36, cools the brine to 7 ° C., and sends it to an ice making heat exchanger 37 for heating. The brine is heated in the ice making heat exchanger by cold water flowing down from the upper part of the ice making heat exchanger. That is, in the rapid cooling mode (a), the three-way valve 38 is in the rapid cooling mode, and the cold water of, for example, 16 ° C. in the upper part of the tank 32 is pumped up by the pump 39 to heat the ice making heat exchanger 37.

By this cold storage, the temperature in the tank 32 is gradually cooled. Note that cold water at 17 ° C. returns to the tank 31 from the load via the pipes 40 → 41. And it returns to this tank 32 via the communication pipe 42. Furthermore, it flows into the tank 33 via the connecting pipe 43, and the tank 3
3. Raise the internal temperature. However, as will be described later, the temperature in the tank 33 is controlled so as not to exceed 2 ° C. Note the temperature in the tank 32 in this mode is lowered for example a temperature detector by a signal from the 44 controller 4 5 operates three-way valve 38
Is automatically switched to the next low-temperature cold storage mode (Fig. 3 (b)).
Becomes In the cold storage mode (b), the three-way valve 38 is switched, cold water at the bottom of the tank 32 is pumped up through the pipe 47, and is cooled by the ice making heat exchanger 37 by brine. After a short period of operation, the temperature in the tank 32 becomes low, and the heat transfer surface of the ice making heat exchanger 37 starts to accumulate ice.

At this time, the temperature of the cold water is about 0 ° C., and the inlet temperature of the ice making heat exchanger of the brine pipe loop 35 is, for example, −7.
° C, and is heated to the outlet temperature of -3 ° C by latent heat during freezing. When the ice transfer on the heat transfer surface of the ice making heat exchanger 37 reaches a certain thickness, the timer automatically switches to the next cold heat recovery / thaw mode (FIG. 3C). That is, the pump 38 and the brine refrigerator 34 are stopped, and the pump 49 is operated. Then, cold water of, for example, 17 ° C. is sent by the heat exchanger 50 to cool the brine. As a result, the temperature becomes, for example, 11 ° C., and is returned to the lower part of the tank 31. When operated in this state for a while, the brine is heated from 8 ° C to 12 ° C. Then, the cold water of 12 ° C. heats the ice-attached portion with an ice making heat exchanger, detaches the ice from its heat transfer surface, and drops it to the lower part. Then, the mode is returned to the mode of FIG.
The operation of setting the mode (c) again is repeated. As a result, ice chips are stored in the tank 32.

FIG. 4D shows a peak cut operation mode in which the brine refrigerator 34 and the pumps 36, 39 and 49 are stopped. 17 ° C load return water is pipe 40
→ Flow 41, then tank 31 → pipe 42 → tank 32 → pipe 43
→ tank 33 → pipe 54 → three-way automatic temperature control valve 55 → pump 5
The pump 56 supplies 2 ° C. cold water to the load. Note that during the operation time of the brine refrigerator 34, load prediction computer control is performed so that the temperature in the tank 33 does not become 2 ° C. or more in the evening when the load stops.

In winter mode, FIG. 4 (e) shows 2 ° C. as in summer.
It is an explanatory view of a winter mode in the case of sending. Since the tank 32 is used in communication with another hot water tank (not shown) by switching the valves, the valves 58 and 59 are closed. Then, the valve 60 is opened, and only two regenerators, the tank 31 and the tank 33, are provided. In this system, the water is cooled by the brine refrigerator 34 through the heat exchanger 50 to produce 2 ° C., and the pipe 61 supplies 2 ° C. cold water to the tank 33. FIG. 4F shows a case in which 4 ° C. is sent to the load in winter. Usually, the cooling load is small in winter, so 4 ° C is sent and the return temperature is set to 15 ° C. Even in this case, since the amount of water is large for the same load, there is little inconvenience that the load-side heat exchanger is too small.

[0023]

As described above, according to the present invention,
The following excellent effects can be obtained respectively. That is, in the case of FIGS. 1 and 2, when the heat storage is started, the control device 51 that controls the temperature after mixing of the three-way temperature control valve 22 to, for example, 10 ° C. is controlled so as not to operate. Since the water does not flow, cold water of 17 ° C. flows through the refrigerator 12, so that the refrigerator outlet temperature becomes, for example, 10 ° C. That is, the evaporating temperature of the refrigerator becomes, for example, 7 ° C., and the refrigerator COP has extremely high performance.

Also, in the embodiment of FIGS. 3 and 4, the three-way valve 38 for switching the flow path at the time of the rated operation for pumping the cold water from the bottom of the tank 32 is operated as shown in FIG. Until the controller 45 is operated, relatively high-temperature cold water flows down to the ice making heat exchanger. Therefore, the evaporation temperature of the brine refrigerator 34 becomes, for example, 4 ° C., and the refrigerator can be operated at high performance.

[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 diagram showing a load operation of the cooling device of FIG. 1;

FIG. 3 is an explanatory diagram for each operation mode of the cooling device of the present invention.

FIG. 4 is an explanatory view of another operation mode of the cooling device of FIG. 3;

FIG. 5 is an explanatory view showing a known cooling device during a heat storage operation.

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

[Explanation of symbols]

9, 19, 11: heat storage tank, 12, 23: refrigerator, 13,
20: pump, 14, 19, 21, 26, 27: piping,
15, 18, 22: three-way valve, 24: thermostat, 3
1, 32, 33: heat storage tank, 34: brine refrigerator, 3
5: brine piping loop, 36, 39, 49, 56: pump, 37, 50: heat exchanger, 38, 55: three-way valve, 4
0, 41, 42, 43, 54, 61: piping, 44, 5
2, 53: thermostat, 45, 51: controller, 5
8, 59, 60: Valve

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kaki Yoshida 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside Ebara Corporation (56) References JP-A-5-113234 (JP, A) JP Sho 64-23040 (JP, A) JP-A-5-5538 (JP, A) JP-A-2-89940 (JP, A) JP-A-3-75427 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) F24F 5/00

Claims (1)

(57) [Claims] 1. A cold fluid supply pipe for sending a cold fluid of a low temperature not exceeding 4 ° C. to a load side, a cold load directly or indirectly cooled by the cold fluid, and a return fluid from the load to be returned. A load fluid return pipe for connecting the cold fluid supply pipe and the load fluid return pipe with a cold storage device for storing a cold fluid, and a cold fluid cooling device having one or more refrigerators for cooling the cold fluid, The regenerator is composed of one or more low-temperature-side stratified-type heat storage tanks and two or more high-temperature-side stratified-type heat storage tanks, and has a regenerative circulation path for cooling a cold fluid in these heat storage tanks by a refrigerator. A three-way valve is provided in a path connected to the refrigerator in the circulation path, and a path for inflow of each of the high-temperature side cold fluid and the low-temperature side cold fluid of the temperature-stratified heat storage tank is connected to the three-way valve. The three-way valve is connected to the high temperature Adjusting the flow rate of each of the cold fluid temperature side of the cold fluid the refrigerator is controlled to obtain the minimum cold fluid outlet temperature at the outlet and, during rapid cold-storage operation only before Symbol hot side of the cooling fluid flows Cooling device having a control device for controlling the cooling device.