JPH02118348A - Regional cooling system - Google Patents

Abstract

PURPOSE:To make uniform supplying of cold heat to a group of buildings within a certain region by a method wherein the rate of ice in ice water flowing in an ice water transferring pipe is specified to keep a frictional resistance with the pipe at its superior condition, a particle diameter of ice is less than 1/2 of a diameter of the ice water transporting pipe to keep a better mixed condition of ice and water. CONSTITUTION:Ice particles made and crushed by a harvest ice making machine 11 are stored once in an ice accumulating tank 12, mixed with water and supplied to some buildings 1a to 1d through a cold heat supplying pipe CS under operation of a pump P. The ice particles are sent to heat exchangers installed at each of the floors or each of the rooms and supplied for a cooling operation. Either cold water with ice particles melted or hot water is collected from each of the buildings 1a to 1d to a water return pipe CR, returned back to a harvest ice making machine 11 and reused as ice making operation. In case the rate of ice particles is 5 to 20%, at each of the buildings 1a to 1d, an effective cooling can be carried out during a normal required cooling time (about ten hours) in a severe summer season. As the ice particles having diameters larger than 1/2 of the diameter of the pipe CS are flowed, a mixed condition of the ice particles and water becomes non-uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a district cooling system, and particularly to a district cooling system in which an ice water conveying system is economically applied.

(Prior art) Conventionally, cooling systems for buildings and residences have been equipped with cold heat generation devices and heat storage devices for each building and each residence, and from these devices, fan coils installed on each floor or in each room have been installed. The so-called door-to-door system, in which cold heat is sent to a heat exchanger such as a unit, was the mainstream.

On the other hand, in recent years, the above-mentioned cold energy is stored in the form of ice blocks, ice particles, or liquid ice in the form of sherbet, and this cold energy is extracted in the form of cold water, water mixed with ice chips, liquid ice, etc., and sent to the above-mentioned heat exchanger. Cooling systems that effectively utilize the latent heat of ice are attracting attention.

FIG. 3 shows an example of a general building cooling system in which a cooling system that utilizes the latent heat of ice is applied to the above-mentioned door-to-door system.

That is, an ice making machine and an ice heat storage tank 2 are installed on the roof of a building 1, and ice is made and stored using nighttime electricity. This is taken out as cold water, water mixed with ice chips, etc., and sent to the heat exchanger 3 installed on each floor or room of the building 1, and the hot water after heat exchange is returned to the ice maker or ice storage tank 2 for ice making, etc. It is intended to be reused as

(Problem to be solved by the invention) By the way, with the recent redevelopment of large cities, there has been a tendency for various government offices and buildings belonging to the same capital group to be concentrated in a certain area.
There is a growing need to develop a so-called large-scale district cooling system that cools these concentrated buildings using a single cooling system.

If the cooling load of such a large area is to be handled with chilled water, extremely thick pipes will be required, and in many cases, the equipment cost of this pipe alone accounts for about 20% of the entire district cooling system.

Therefore, the cooling system that utilizes the latent heat of ice is attracting attention, and in particular, the latent heat of ice is used not only during heat storage but also when extracting cold heat, increasing the amount of cold heat per unit flow rate, and as a result, the piping diameter Attention is being focused on so-called ice water conveyance systems that can reduce the size of ice.

However, this ice water conveyance system has so far only been adopted in a door-to-door system for each building as shown in Figure 3, and it remains unclear what specific conditions must be met to apply it to a district cooling system. This is a matter of concern.

The present invention has been made in view of the above points, and its purpose is to find specific conditions under which an ice water conveyance system can be economically applied to a district cooling system, and to provide a regional cooling system under these conditions. The purpose is to propose a cooling method.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides: - an area where ice water is transported from at least one ice heat storage means concentrated at a location to a group of buildings in a specific area; It is a cooling system, and is characterized in that the proportion of ice in the ice water is 5 to 20%, and the particle size of the ice is 1/2 or less of the diameter of the pipe for conveying the ice water.

(Function) In the present invention, ice water is transported to a group of buildings in a specific area from at least one ice heat storage means installed in a concentrated manner at one appropriate location in the specific area, and The building group will be cooled.

The thawed cold water or hot water after cooling is collected again in the ice water heat storage means and reused for preparing ice water to be transported to the building group, or for making ice using nighttime electricity or the like.

In the present invention, the mixing ratio of ice in the ice water conveyed from the ice heat storage means to the building group is 5 to 20%.

In other words, if it is less than 5%, the ice will melt immediately after being removed from the ice heat storage means, and the water will reach the buildings, making it meaningless to apply the ice water conveyance system. This is because the frictional resistance between the piping and the piping equipment increases, and various complications arise in terms of piping equipment.

Further, in the present invention, the particle size of the ice is set to 1/2 or less of the diameter of the pipe for conveying ice water. This is because if the particle size exceeds 1/2, ice and water will separate, making it impossible to maintain an optimal mixed state.

Note that the lower limit of the ice particle size is not particularly limited, and sherbet-like fine particles such as liquid ice can also be used.

In the present invention, by mixing such ice particles with ice at the above-mentioned mixing ratio and transporting the mixture to buildings, the operating cost and equipment cost are lower than when transporting cold water. This results in a significant reduction and the ice-water conveyance system can be applied economically in district cooling systems.

(Example) Fig. 1 is an explanatory diagram showing an example of the district cooling system according to the present invention. The air conditioner is cooled by ice water conveyed from one ice heat storage means 10.

The ice heat storage means 10 is composed of a harvest ice maker ALL having the function of producing thin plate ice and crushing it into ice cubes, and an ice storage tank 12.

This ice heat storage means 10 may be provided inside a building constructed in the above region, or within any one of the buildings 18 to 1d above, or may be buried underground.

The crushed ice grains made by the harvest ice maker 11 are
The ice is temporarily stored in the ice storage tank 12, mixed with water, and supplied by the pump P to the buildings 1a to 1d via the cold heat supply pipe C8.

The heat is then sent to heat exchangers provided on each floor or in each room of these buildings 18 to 1d, and is used for cooling.

The cold water or hot water in which the ice particles have melted in this manner is collected from each of the buildings 1a to 1d into the water return pipe CR, returned to the harvest ice maker 11, and reused for ice making.

Although not shown, a portion is sent to the ice storage tank 12, mixed with ice particles as described above, and used for preparing ice water.

In the above manner, a cooling experiment was conducted by flowing ice grains having a particle size of 1/2 or less of the diameter of the cold heat supply pipe C8 in a stepwise increase from 5% to the flow rate in the pipe C8. For comparison, a cooling experiment was conducted by flowing only cold water through the cold heat supply pipe C8.

As a result, it was confirmed that the ice particles did not separate from the water and flowed through the pipe C8 while maintaining a good mixed state.

It was also revealed that even when the proportion of ice particles was varied from 5 to 20%, there was no significant change in frictional resistance compared to the case of using only cold water.

If the proportion of ice particles is 5 to 20%, then buildings 1a to
It has also become clear that in any case of 1d, effective cooling can be performed during the normal cooling time (about 10 hours) during the height of summer.

In addition, when ice particles with a particle size larger than 1/2 of the diameter of pipe C8 were poured, the mixture of ice particles and water became uneven, and some of the ice particles became clogged in the middle of pipe C8, causing buildings 1a to 1. 1d could not be uniformly and effectively cooled during the above period.

Figures 2 (A) and (B) show the cold supply pipe C8 and the water return pipe CR.
Fig. 2(A) shows an example of the cooling system according to the present invention, and Fig. 2(B) shows an example of a case where the pipe is buried underground together with other water and sewage pipes W, electricity, telephone lines, etc. as a so-called common ditch. For comparison, this is an example of a cooling system that extracts cold heat using only cold water.

In the cooling system according to the present invention shown in FIG. 2(A), the cooling system shown in FIG.
) The diameters of the cold heat supply pipe C8 and the water return pipe CR are smaller than those of the cooling system in which cold water is extracted only using cold water, making it possible to significantly reduce piping costs. In a concrete trial calculation, the proportion of ice is 2
It has become clear that when the amount is reduced to about 0%, the piping cost can be reduced by about 60%.

Furthermore, it has been confirmed that the cross-sectional area of the common groove 100 is also reduced, and the construction cost thereof can also be reduced.

Furthermore, in the cooling system according to the present invention, as the flow rate in the cold heat supply pipe C8 and the water return pipe CR decreases, the conveying power becomes about 115 compared to the cooling system that extracts cold heat only by using cold water.
It was confirmed that running costs can also be significantly reduced.

In addition, in the cooling system according to the present invention shown in FIG. 1, when the ice making operation by the harvest ice maker 11 was performed using nighttime electricity, it was found that the ice maker 11 had a high coefficient of performance regarding ice production, and By using it in combination with the ice tank 12, the running cost for ice making could be reduced to about 1/3 of that in the case of the individual cooling system for the buildings 1a to 1d.

(Effects of the Invention) According to the cooling system according to the present invention detailed above, the following effects can be achieved.

(1) The ratio of ice in the ice water flowing through the ice water conveying pipe is 5 to 5.
By setting it to 20%, it is possible to maintain good frictional resistance with the piping, and it is also possible to provide good cooling and heat supply to buildings in the area.

(2) By setting the ice particle size to 1/2 or less of the diameter of the pipe for transporting ice water, it is possible to maintain a good mixing state of ice and water, and to uniformly supply cold and heat to the buildings in the area.

(3) With (1) and (2) above, each of the buildings in the area can be uniformly cooled for a long time.

(4) Since the latent heat of ice is utilized, the flow rate in the ice water conveyance piping and the return water piping after cold heat extraction can be reduced, resulting in a significant reduction in conveyance power and running costs.

(5) The diameter of ice water conveyance piping and water return piping can also be made smaller.
Piping costs can be significantly reduced.

(6) As a result of (5) above, the cross-sectional area of the common ditch with other water and sewage pipes, electricity/telephone lines, etc. is also reduced, and construction costs can be significantly reduced.

(7) Running costs for ice making can be significantly reduced by using low-cost nighttime electricity to make ice.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing an example of the cooling system according to the present invention, and Figures 2 (A) and (B) are the cooling system using only the common groove (Figure 2 (A)) and cold water in the cooling system according to the present invention. FIG. 3 is a diagram illustrating a cross-sectional state of the common groove (FIG. 2(B)) in a cooling system in which air is taken out, and FIG. 3 is a diagram showing a conventional cooling system. 1a to 1d... Building 10... Ice heat storage means C8... Cold heat supply pipe CR... Water return pipe

Claims (1)

[Claims] from at least one ice heat storage means concentrated in one place;
This is a district cooling system in which ice water is transported to a group of buildings in a specific area, and the ratio of ice in the ice water is 5 to 20%, and the particle size of the ice is 1/1 of the diameter of the pipe for transporting the ice water. A district cooling system characterized by a temperature of 2 or less.