JP2004069226A - Low-temperature chilled water supply system with ice storage - Google Patents

Abstract

A low-temperature cold water at about 0 ° C. to 1.5 ° C. is stably taken out of an ice heat storage tank and supplied to a heat load side. Provide a chilled water supply system capable of energy saving operation.
A return water tank is disposed adjacent to the ice heat storage tank, all of the return water from the heat load is introduced into the return water tank, and a part of the cold water is introduced from the ice heat storage tank into the return water tank, and is returned to the return water tank. To produce low-temperature deicing water, and the low-temperature deicing water is introduced into the ice storage tank through the low-temperature deicing water introduction circuit by the deicing pump. The return water tank is a tank separated from the ice heat storage tank or a tank integrally connected to the ice heat storage tank, and is partially partitioned from the ice heat storage tank by a partition wall. Energy saving operation can be performed by controlling the flow rate and start / stop of the ice melting pump.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ice heat storage system, and more particularly to a low-temperature chilled water supply system for stably removing low-temperature chilled water at 0 ° C. to 1.5 ° C. from an ice heat storage tank.
[0002]
[Prior art]
Ice heat storage systems that store cold heat in the form of latent heat and use it as a cold heat source for air conditioning, etc., are already widely used.
A. An ice making device is provided in the middle of a chilled water supply circuit that pumps cold water from an ice heat storage tank with a chilled water pump, sends it out to a heat load, and transfers return water from the heat load to the ice heat storage tank. A single-circuit system that is being introduced,
B. A cold water supply circuit that pumps out cold water from the ice heat storage tank with a cold water pump and sends it to the heat load, and transfers return water from the heat load to the ice heat storage tank, and pumps low-temperature water from the ice heat storage tank with the ice making pump. There is known a parallel circuit type system including an ice introduction circuit for sending the produced ice to an ice making device and introducing the produced ice into an ice heat storage tank.
[0003]
The latter system is shown in, for example, FIG.
Japanese Patent Application Laid-Open No. 7-91693 "Ice heat storage system and operating method thereof" includes a method of stably supplying low-temperature chilled water by adjusting a water amount and a temperature by adding a bypass line to a single-circuit system. Has been described.
[0004]
The system shown in FIG. 4 is a conventional parallel-circuit type cold water supply system 60 described in Japanese Patent Application Laid-Open No. 1-147234, and includes an ice heat storage tank 1 for storing cold heat as ice, and an ice heat storage tank 1. A cold water supply circuit 61 for pumping out cold water by a cold water pump 5 and sending the cold water to a heat load 8 such as an air conditioner and transferring return water from the heat load 8 to the ice heat storage tank 1; An ice introduction circuit 62 for pumping out the ice by the ice making pump 7 to the ice making device 6 and introducing the produced ice to the ice heat storage tank 1 is included. In the middle of the circuit, thermometers 9 and 10 and a flow meter 12 are arranged.
However, if the return water (return water) from the load side is directly returned to the ice heat storage tank as in this system, if the temperature of the return water is high, the temperature of the cold water sent from the ice heat storage tank to the heat load side And the cooling efficiency decreases.
Also, the amount of inflow returning from the load side to the ice heat storage tank is difficult to adjust because it depends on the load.
[0005]
[Problems to be solved by the invention]
A main object of the present invention is to stably take out low-temperature cold water of about 0 ° C. to 1.5 ° C. from an ice heat storage tank and supply it to a heat load side.
Another object of the present invention is to provide a chilled water supply system that enables energy-saving operation.
[0006]
[Means for Solving the Problems]
The above-described object of the present invention is to provide an ice heat storage tank for storing cold heat as ice, and to pump out cold water from the ice heat storage tank with a cold water pump to send it to a heat load and return water from the heat load to the ice heat storage tank. A low-temperature chilled water supply circuit that includes a chilled water supply circuit for transferring ice water from the ice heat storage tank and an ice introduction circuit for pumping ice water from the ice heat storage tank with an ice making pump, sending the ice water to an ice making device, and introducing the produced ice into the ice heat storage tank. The system, wherein a return water tank is disposed adjacent to the ice heat storage tank, all of the return water from the heat load is introduced into the return water tank, and some cold water from the ice heat storage tank is introduced into the return water tank. This is achieved by a low-temperature chilled water supply system in which low-temperature thawing water is produced in the return tank, and the low-temperature thawing water is introduced into the ice heat storage tank through a low-temperature thawing water introduction circuit by an thawing pump. You.
[0007]
[Action]
According to the present invention, the following effects can be obtained.
(1) Since the return water from the load side and the cold water taken out from the ice heat storage tank are mixed in the return water tank and then returned to the ice heat storage tank, the temperature of the water returned to the ice heat storage tank becomes lower than before. As a result, the temperature of the chilled water taken out from the ice heat storage tank can be stably taken out at about 0 ° C. to 1.5 ° C. (2) Since the difference in utilization temperature on the load side can be increased, the amount of chilled water supplied to the load side Can be reduced, the piping system can be reduced, and energy can be saved.
(3) By adjusting the flow rate of the ice melting pump so that the return water temperature from the load side becomes the set temperature, the temperature of the cold water taken out of the ice heat storage tank is stabilized at about 0 ° C. to 1.5 ° C. (4) Energy saving can be achieved by applying the control of the number of pumps and / or the control of the number of revolutions by an inverter to the flow rate adjustment of the defrosting pump. ]
(5) When the load on the load side is very small, the de-icing pump can be stopped and the return water from the load side can be returned directly to the ice heat storage tank. When the supply temperature to the load side exceeds the set value or when the amount of water supplied to the load side exceeds the setting, the thaw pump is forcibly started to reduce the power consumption of the thaw pump. Energy saving.
[0010]
The return water tank may be a tank separated from the ice heat storage tank, and may be configured to receive a part of cold water supply from the ice heat storage tank through a communication pipe.
Alternatively, the return water tank may be a tank integrally connected to the ice heat storage tank, and may be configured such that the space from the ice heat storage tank is partially partitioned by a partition.
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a low-temperature chilled water supply system 20 according to a first embodiment of the present invention, in which an ice heat storage tank 1 for storing cold heat as ice and cold water from the ice heat storage tank 1 are pumped out by a chilled water pump 5 to generate a heat load. 8, a chilled water supply circuit 21 for transferring the return water from the heat load to the ice storage tank 1, and chilled water from the ice storage tank 1 drawn by the ice making pump 7 and sent to the ice making device (ice making machine) 6. And an ice introduction circuit 22 for introducing the ice produced there into the ice heat storage tank 1. In the middle of the circuit, thermometers 9, 10, 11 and a flow meter 12 are arranged.
[0012]
As a first aspect of the present invention, the return water tank 24 adjacent to the ice heat storage tank 1 is arranged as an independent tank separated from the ice heat storage tank 1. The return water tank 24 is connected to a return pipe from the heat load of the cold water supply circuit 21, a communication pipe 3 connecting the ice heat storage tank 1, and a low-temperature deicing water introduction circuit 23 connected to the ice melting pump 4. .
All of the return water from the heat load is introduced into the return water tank 24, and a part of the cold water from the ice heat storage tank 1 is introduced into the return water tank 24 through the communication pipe 3, and the low-temperature deicing water is produced in the return water tank 24. It is supposed to be. The produced low-temperature thawing water is introduced into the ice heat storage tank 1 by the thawing pump 4 through the low-temperature thawing water introduction circuit 23.
[0013]
Thus, since the return water from the load side and the cold water taken out of the ice heat storage tank are mixed in the return water tank and then returned to the ice heat storage tank, the temperature of the water returned to the ice heat storage tank is lower than before, As a result, the temperature of the cold water taken out from the ice heat storage tank can be stably taken out at about 0 ° C. to 1.5 ° C. and taken out.
In addition, since the difference in use temperature on the load side can be increased, the amount of chilled water supplied to the load side can be reduced, the piping system can be reduced, and energy can be saved.
[0014]
Further, by adjusting the flow rate of the ice melting pump 4 so that the return water temperature from the load side becomes the set temperature, the temperature of the cold water taken out from the ice heat storage tank is stabilized at about 0 ° C. to 1.5 ° C. It is possible to take out the fuel and to reduce the power consumption of the thawing pump 4 to save energy.
If the control of the number of pumps and / or the control of the number of rotations by an inverter is applied to the flow rate adjustment of the thawing pump 4, energy can be saved.
When the load on the load side is very small, the ice melting pump 4 is stopped, and the return water from the load side can be returned directly to the ice heat storage tank 1. If the thaw pump 4 is forcibly started only when the amount of water supplied to the load exceeds the set value or when the detected temperature exceeds the set value, the power consumption of the thaw pump 4 can be reduced. Energy saving.
[0015]
FIGS. 3A and 3B show the results of an experiment comparing the cold water temperature taken out by the low-temperature cold water supply system according to the present invention (FIG. 3A) with the cold water temperature taken out by the conventional system shown in FIG. 4 (FIG. 3B). This shows that the system of the present invention can supply cold water of 1.5 ° C. or less for a longer time than before.
[0016]
FIG. 2 shows a low-temperature chilled water supply system 40 according to a second embodiment of the present invention. As in the first embodiment, an ice heat storage tank 1 for storing cold heat as ice, a chilled water supply circuit 41, It includes an introduction circuit 42 and a low-temperature deicing water introduction circuit 43. In the middle of the circuit, thermometers 9, 10, 11 and a flow meter 12 are arranged.
As a feature of this embodiment, the return water tank is a return water tank 44 integrally connected to the ice heat storage tank 1, and is partially separated from the ice heat storage tank 1 by the partition wall 14.
[0017]
All of the return water from the heat load is introduced into the return water tank 44, and a part of the cold water from the ice heat storage tank 1 is introduced into the return water tank 44 through the communication part 45, and the low-temperature deicing water is produced in the return water tank 44. It is supposed to be. The produced low-temperature thawing water is introduced into the ice heat storage tank 1 by the thawing pump 4 through the low-temperature thawing water introduction circuit 43. However, if the thawing pump 4 is stopped in accordance with the above-described situation, a part of the return water flows directly into the ice heat storage tank 1 through the communication portion 45, and energy can be saved.
[0018]
Also in this embodiment, since the return water from the load side and the cold water taken out from the ice heat storage tank are mixed in the return water tank and then returned to the ice heat storage tank, the temperature of the water returned to the ice heat storage tank is lower than before. As a result, the temperature of the cold water taken out from the ice heat storage tank can be stably taken out at about 0 ° C. to 1.5 ° C. and taken out.
[0019]
【The invention's effect】
As described above in detail, according to the low-temperature chilled water supply system of the present invention, the temperature of the water returned to the ice heat storage tank is lower than before, and as a result, the temperature of the chilled water taken out from the ice heat storage tank is reduced to 0 ° C to 1 ° C. The technical effect is extremely remarkable. For example, it can be taken out stably at about 0.5 ° C., and furthermore, by controlling the operating condition of the pump, energy saving operation becomes possible.
[Brief description of the drawings]
FIG. 1 is a circuit diagram illustrating a low-temperature chilled water supply system according to the present invention.
FIG. 2 is a circuit diagram illustrating a low-temperature chilled water supply system according to another embodiment of the present invention.
FIG. 3 is a graph showing a comparison between a cold water removal temperature according to the present invention and a conventional one.
FIG. 4 is a circuit diagram illustrating a conventional chilled water supply system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ice heat storage tank 3 Communication pipe 4 Ice melting pump 5 Cold water pump 6 Ice making device 7 Ice making pump 8 Heat load 14 Partition wall 20, 40 Cold water supply system 21, 41 Cold water supply circuit 22, 42 Ice introduction circuit 23, 43 Water for low temperature defrosting Introduction circuits 24, 44 Return water tank 45 Communication section

Claims (5)

An ice heat storage tank for storing cold heat as ice, a cold water supply circuit for pumping cold water from the ice heat storage tank with a cold water pump, sending the cold water to the heat load, and transferring return water from the heat load to the ice heat storage tank, An ice introduction circuit that pumps out cold water from the ice heat storage tank with an ice making pump and sends it to an ice making device, and introduces the produced ice into the ice heat storage tank,
A return water tank is located adjacent to the ice heat storage tank,
All of the return water from the heat load is introduced into the return water tank, and a part of cold water is introduced from the ice heat storage tank into the return water tank, and low-temperature deicing water is produced in the return water tank. A low-temperature chilled water supply system using ice heat storage, wherein the low-temperature ice is supplied to the ice heat storage tank through a low-temperature deicing water introduction circuit by an ice melting pump. The low-temperature chilled water supply system according to claim 1, wherein the return water tank is a tank separated from the ice heat storage tank, and receives a part of the chilled water from the ice heat storage tank through a communication pipe. 2. The low-temperature chilled water supply system according to claim 1, wherein the return water tank is a tank integrally connected to the ice heat storage tank, and is partially partitioned from the ice heat storage tank by a partition. The low-temperature chilled water supply system according to any one of claims 1 to 3, wherein the flow rate of the thawing pump is adjusted so that the outlet temperature of the thawing pump becomes a set temperature. The low-temperature chilled water supply system according to any one of claims 1 to 4, wherein when the load on the load side is very small, the deicing pump is stopped, and return water from the load side is directly returned to the ice heat storage tank.

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