JPH0567867B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ice making method and apparatus for ice heat storage for air conditioning.

[Conventional technology and problems]

Ice production methods in ice storage air conditioning systems are broadly classified into indirect heat exchange methods and direct heat exchange methods. The indirect heat exchange method uses heat exchanger tubes (heat exchangers) for ice making, in which a low-temperature refrigerant (brine, Freon, etc.) is passed inside (outside) the heat exchanger tubes, and ice is generated outside (inside) the tubes. It's a method. The other direct heat exchange method is a method in which refrigerant gas is blown directly into water.

In the indirect method using heat exchanger tubes, when the liquid to be cooled is water, the ice that is generated grows by forming ice on the tube walls. In this case, since the thermal conductivity of ice is poor, there is a drawback that as the thickness of the ice increases, the growth rate of the ice becomes slower.
In order to promote ice growth, it is necessary to lower the refrigerant temperature as the thickness of the ice increases, which has the disadvantage of lowering the coefficient of performance (COP) of the refrigerator. Furthermore, the ice filling factor (IPF) in the aquarium cannot be increased very much, and is approximately 20 to 30% at most. Therefore, the heat storage efficiency is not much better than that of a normal heat storage water tank (cold water heat storage).

For this reason, although it is a heat exchanger tube method, a method of mixing an antifreeze such as ethylene glycol with the liquid to be cooled has recently been attracting attention as a method of preventing ice from forming on the tube wall. In this method, sheave-like ice is formed in the liquid to be cooled without forming ice on the heat transfer surface. Therefore, the ice filling factor (IPF) can be increased to 50-60%. However, as ice forms, the ethylene glycol concentration in the liquid to be cooled increases, so the refrigerant temperature must be gradually lowered to about -10 to -20°C. Therefore, there is a problem that the coefficient of performance (COP) of the refrigerator decreases. Furthermore, unless the heat exchanger tubes have smooth surfaces, such as those with a mirror finish, ice will form on the tube walls, which naturally makes the heat exchanger expensive.

On the other hand, in the direct heat exchange method, the refrigerant temperature can be used at a temperature close to 0° C., so the coefficient of performance of the refrigerator increases. In addition, since it does not have a metal heat transfer surface, there is no formation of ice blocks due to icing, and therefore the ice filling rate is 50 to 60.
%. However, water enters the refrigerant gas,
A problem arises in that fluorocarbons and water react to generate corrosive chlorine gas.

The present invention was made with the aim of developing a novel ice-making method and apparatus for heat storage to replace the conventional ice-making method having the above-mentioned problems.

[Structure of the invention]

The gist of the present invention, which aims to achieve the above object, is to take out a part of the water in the heat storage tank outside the tank, transfer this water as a water film, and keep the dew point temperature below -5°C and the humidity. The bulb is brought into direct contact with a flow of low-temperature, low-humidity air with a temperature of -1°C or less at or below atmospheric pressure, and this direct gas-liquid contact generates an ice layer on the surface of the water film flow, and then This method of making ice for heat storage consists of returning this fluid with a composite phase of water and ice to the heat storage water tank. In other words, unlike the conventional method of producing ice by exchanging heat between a refrigerant and water to be cooled, the present invention directly produces ice using low-temperature, low-humidity air and a water film flow at or below atmospheric pressure. By bringing the water into gas-liquid contact with This causes a thin layer of ice to form on the surface of the flow.

The equipment suitable for use in implementing this method includes a heat storage water tank, a gas-liquid contact device installed outside the water layer of the heat storage water tank, and a low-temperature, low-humidity air to be supplied to the gas-liquid contact device. A heat storage ice making device comprising an air treatment facility for heating the water, and a fluid path for returning a part of the water in the heat storage water tank to the heat storage water tank via a gas-liquid contact device. Overflow water is allowed to fall into the pipe from the opening to form a falling water film flow along the inner wall of the pipe, and at the same time, low-temperature, low-humidity air is supplied into the pipe from the lower end opening of the vertical pipe.Counterflow with the inner wall of the pipe as a wet wall The air treatment equipment consists of a compressor,
To provide an ice making device for heat storage in which an air tank equipped with a drain and an air cooler are installed in the order of air flow.

Equipment for producing low-temperature, low-humidity air includes, in addition to the above, known dehumidifiers using dehumidifiers and/or
Alternatively, equipment including a cooling dehumidifier or a combination thereof may be used.

The contents of the present invention will be specifically explained below with reference to embodiments of the drawings.

〔Example〕

FIG. 1 shows the entire heat storage ice making apparatus according to the method of the present invention, in which a gas-liquid contacting device 3 is installed above a small water tank 2 constituting a heat storage water tank 1 for air conditioning.

The gas-liquid contacting device 3 is comprised of a cylindrical shell 4 and a plurality of vertically arranged tubes 5 each having an open upper and lower end. More specifically, by partitioning the inside of the shell 4 by two horizontal partition plates 6 and 7, a water reservoir chamber 8, a heat insulation chamber 9, and a composite phase chamber 10 are constructed from above. The upper end of each tube 5 is located in the middle of the water reservoir chamber 8 above the partition plate 6, and the lower end of each tube 5 is positioned at the upper part of the composite phase chamber 10 below the partition plate 7. There is a heat insulating material 11 inside the heat insulating chamber 9.
(see FIG. 2, which will be described later).

A portion of the water in the heat storage tank is supplied to the water storage chamber 8 by a pump 12. A cooler 13 is installed in the water supply route, and when the temperature of the pumped water is high, the cooler 13
After pre-cooling to about 2 degrees Celsius, remove the water reservoir chamber 8.
send to. The water surface of the water sent here is pipe 5.
When the water reaches the upper end level, it flows into the pipe as overflow water. This state is shown in FIG. When water is supplied to the water reservoir chamber 8,
Water will flow down into the pipes from the upper end opening of each pipe 5, but if the amount of water is adjusted appropriately,
As shown in FIG. 2, a falling water film flow is formed along the inner wall of the tube 5.

On the other hand, each tube 5 whose lower end is open to the composite phase chamber 10 has a dew point temperature of -5 from the lower end opening.
It supplies low-temperature, low-humidity air with a wet bulb temperature of -1°C or lower. This is done by blowing air produced by an air treatment facility, which will be described later, into the composite phase chamber 10. The sump chamber 8 has an exhaust port 14 open to the atmosphere, so that the inside of each tube 5 whose upper end opens into the sump chamber 8 is under atmospheric pressure. Note that when the air is circulated through the exhaust port 14 to a compressor for air processing equipment to be described later, the pressure inside each pipe 5 may be lower than atmospheric pressure. As a result, the surface of the water film flowing down along the inner wall of the tube 5 is cooled by the low temperature air, and is evaporated into the low humidity air and further cooled by its latent heat of evaporation. As a result, a thin ice phase forms on the exposed surfaces of the water film that falls into the composite phase chamber 10. At that time, if the state in which the water film flow continues to flow down is maintained, the surface temperature of each tube 5 will not become lower than the water temperature.
Further, since the outer wall is insulated by the heat insulating material 11, ice formation on the inner wall of each tube 5 is prevented.

In this way, a fluid consisting of a composite phase of water and fine ice falls from the lower end opening of each tube 5, and this composite phase is collected in the composite phase chamber 10 in the shell. Thereafter, the slurry-like composite phase is returned to the heat storage water tank via the outlet 15.
As a result, the amount of fine ice floating in the heat storage water tank increases gradually, and ice for heat storage is made.

Wetting the inner wall of the pipe according to the invention (falling water film flow)
The countercurrent gas-liquid contact device has a dew point temperature of -5
It is necessary to continuously supply low-temperature, low-humidity air with a wet bulb temperature of -1°C or lower.

In order to produce this low-temperature, low-humidity air, as shown in FIG.
The air cooler 23 of the refrigerator unit can advantageously be manufactured with an air treatment installation arranged in the order of the air flow.

The compressor 20 takes in ambient air or takes in exhaust gas discharged from the gas-liquid contacting device 3 described above. This is then compressed and stored in the air tank 21. The pressure within this air tank 21 is maintained at a predetermined pressure, for example 6 atmospheres, by a pressure regulating valve 24. A drain trap 25 is attached to the air tank 21, and drain generated by compression is discharged from the tank. This compressed air is then cooled and further dehumidified by the air cooler 23 of the refrigerator unit, but before that, it is precooled to near ambient temperature by the air cooling radiator 22, thereby reducing the load on the refrigerator unit. can be reduced. The refrigerator unit is a normal unit that circulates refrigerant between an air cooler 23 as an evaporator and a condenser 26 to form a refrigeration cycle. The liquid refrigerant is condensed and radiated to cooling water or air, the liquid refrigerant is throttled by the expansion valve 28, and then expanded and evaporated by the air cooler 23, which is an evaporator, to remove heat from the air to be treated. By this heat removal, the air cooler 2
The compressed air passing through 3 is forcedly cooled. Along with this cooling, moisture in the air condenses.
The condensed moisture is separated as drain by the drain trap 29, and is further separated by the mist separator 30.
The accompanying mist is separated to produce low-temperature, low-humidity, high-pressure air. This low-temperature, low-humidity, high-pressure air is supplied to the composite phase chamber 10 of the gas-liquid contact device 3.
However, as mentioned above, this composite phase chamber 10 is at atmospheric pressure or below atmospheric pressure, so when it is injected here, it expands and becomes even colder, so that the dew point temperature as mentioned above is reached. The air is supplied into each tube 5 as low-temperature, low-humidity air that satisfies the requirement that the wet bulb temperature is -1°C or lower at -5°C or lower.

In addition, in the air treatment equipment described above, the compressed air in the air tank 21 (low humidity air of 6 atm after draining) is returned to 1 atm and the compressed air is returned to the air cooler 23.
Even when the air cooler 23 cools the dry bulb temperature to about 2°C, the wet bulb temperature is -5°C or lower.
It can create air at a temperature of 1 atm and below 1°C. Even if this air is supplied as it is to the composite phase chamber 10, the same ice making as described above can be achieved. In any case, it is not necessary to lower the refrigerant temperature to 0° C. or lower in the air cooler 23 in the refrigerator unit.

[Effect]

The present invention generates a thin layer of ice on the surface of the water film by bringing low-temperature, low-humidity air into direct contact with a continuous water film flow at or below atmospheric pressure. In addition to the cooling of the water film flow due to contact with the water film, the further cooling effect due to the removal of latent heat by water evaporation from the water film surface is utilized for ice formation. Therefore, since the surface of the water film flow is a heat exchange surface, problems such as ice formation on the heat transfer surface do not occur at all. In addition, fresh water can be used as is as the liquid to be cooled. The generated ice takes on a fine form, and by forced circulation of the liquid to be cooled, ice heat can be stored in a shear bed-like state in the heat storage water tank, and the ice filling rate can be increased to over 60%. By using a compressor and an air tank to compress the air and remove the drain, the refrigerant temperature in the air cooler of the refrigerator only needs to be 0℃ or higher, and the coefficient of performance of the refrigerator is significantly higher than that of conventional methods. Become. Furthermore, since the tube for forming a falling water film according to the present invention does not function as a heat transfer tube, there is no need to use an expensive mirror-finished tube.

[Brief explanation of the drawing]

FIG. 1 is an equipment layout system diagram showing an apparatus for carrying out the method of the present invention, and FIG. 2 is a schematic sectional view showing an enlarged part of the gas-liquid contacting device shown in FIG. 1. 1... Heat storage water tank, 3... Gas-liquid contact device, 4...
Shell, 5... Pipe with upper and lower ends open, 6, 7... Partition plate, 8... Chamber for water reservoir, 9... Chamber for heat insulation, 10... Chamber for composite phase, 11
...Insulation material, 12...Sump pump, 13...
Cooler, 14...Exhaust port, 15...Composite phase outlet, 20...Compressor, 21...Air tank, 22...Air cooling radiator, 23...Air cooler, 29...Drain trap, 30... Mist separator.

Claims (1)

[Claims] 1. A part of the water in the heat storage tank is taken out of the tank, and while this water is transferred as a water film, the dew point temperature is -5°C.
Hereafter, a flow of low-temperature, low-humidity air with a wet bulb temperature of -1°C or less is brought into direct contact at atmospheric pressure or below atmospheric pressure, and an ice layer is generated on the surface of the water film flow through this direct gas-liquid contact. A method for making ice for thermal storage, which comprises: 2. A heat storage water tank, a gas-liquid contact device installed outside the water layer of the heat storage water tank, and air processing equipment for producing low-temperature, low-humidity air to be supplied to the gas-liquid contact device;
A heat storage ice making device comprising a fluid path for returning part of the water in the heat storage water tank to the heat storage water tank via a gas-liquid contact device, and the gas-liquid contact device directs overflow water into the pipe from the upper end opening of the vertical pipe. from a countercurrent gas-liquid contact device in which the inner wall of the vertical pipe is a wetted wall, in which a falling water film flow is formed along the inner wall of the pipe, and low-temperature, low-humidity air is supplied into the pipe from the lower end opening of the vertical pipe. A heat storage ice making device characterized in that the air processing equipment includes a compressor, an air tank equipped with a drain, and an air cooler installed in the order of air flow.