JPH03244985A - Ice making device - Google Patents

Abstract

PURPOSE:To improve heat transfer performance and to simplify heat exchanger structure by a method wherein a heat transfer pipe forms a double pipe type heat exchanger, and an injection nozzle for water to be cooled is located in the heat transfer pipe of the heat exchanger. CONSTITUTION:Cooling fluid 6 of 0 deg.C or less is flowed in a high speed swirling state to a heat transfer pipe 1 and an outer shell pipe 2 of a double pipe type heat exchanger, and water 7 to be cooled is cooled through convection heat transfer of the cooling fluid 6. Meanwhile, the water 7 to be cooled is fed from the lower part of a heat accumulating tank 5 directly to a water feed pipe 3 in the heat transfer pipe 1 with the aid of a pump and uniformly injected through an injection nozzle 4 against the inner wall surface of the heat transfer pipe 1 to form a uniform water film 8 for cooling. Further, through a heat transfer promoting action produced through collision of injecting water with a wall surface, a convection heat transfer factor on the water film 8 side is increased. As a result, through improvement of the convection heat transfer factors of the cooling fluid 6 and the water 7 to be cooled, the water 7 to be cooled in a state of the water film 8 flows down through the heat transfer pipe 1 as the cooling fluid is effectively cooled by the cooling liquid 6 to produce water in an subcooling state. The subcooling state is ruptured through the impact action of injection water on the downstream side, and fluid ice 9 having temperature equivalent to the sensible heat of subcooling water is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ice making device for ice heat storage used for air conditioning and cooling of buildings, food storage, and the like.

(Conventional technology) An ice heat storage device operates a refrigerator using cheap late-night electricity at night to store ice making heat, and then melts the ice during the daytime when electricity costs are high to utilize the cold energy.It uses the latent heat of solidification of water. Because of its heat storage method, compared to the conventional ice heat storage device that uses the sensible heat of water,
Since heat storage tanks can be significantly downsized, they have recently become popular.

Conventionally, this type of ice-making equipment for ice heat storage has been designed to flow low-temperature refrigerant or antifreeze through one side of the ice-making heat exchanger tube (heat exchanger), and to flow water through the other side to directly form ice on the surface of the heat exchanger tube. The fixed ice-making method is widely adopted because the equipment cost is low, or the ice-making ability of this method decreases due to the increase in thermal resistance of the heat transfer surface as the ice layer grows. There were problems in that it was large in size and had poor thermal response during ice melting due to stuck ice, making it only possible to respond to sudden changes in heat load.

In response to this, a method of producing fluid ice has recently been proposed. For example, as shown in Figure 3, on page 77 of the November 17, 1986 issue of Nikkei Mechanical, there is - A falling water film method was proposed and became well known, in which the outside of the heat transfer tube of a tube heat exchanger is used as a refrigerant of fluorocarbon liquid, and water overflows and falls onto the vertical surface inside the heat transfer tube to make sherbet-like ice. Compared to the conventional fixed ice making method, there is no ice formation on the heat transfer tubes, so the ice making capacity (heat transfer resistance) does not deteriorate over time, and the water in the heat storage tank is High filling rate, good thermal response during ice melting,
It has the advantage of low equipment and operating costs.

(Problems to be Solved by the Invention) However, in this ice making device, the heat exchanger is a shell-and-tube system consisting of a large number of small-diameter heat transfer tubes, so the device cost is high, and the upper end of each heat transfer tube is the same. Since it was difficult to maintain the same level, there was a problem in that the overflow and fall of water became uneven and the cooling performance deteriorated.

In addition, since overflow water flows down by gravity, the flow rate of water is generally lower than in forced flow systems, which limits the convective heat transfer coefficient inside the pipes, resulting in a larger heat exchanger. there were.

The purpose of the present invention is to solve the above-mentioned problems by improving the heat transfer performance of ice making equipment and simplifying the heat exchanger structure.
The purpose is to provide a compact and inexpensive ice making device.

(Means for Solving the Problems) The present invention has the following configuration in order to achieve the above object. In other words, in an ice making device that produces fluid ice by passing a cooling fluid through the outside of a vertical heat exchanger tube and forming a film of falling water to be cooled on the inside of the tube, the heat exchanger tube is replaced with a double tube heat exchanger. This ice-making apparatus is characterized in that a cooling water injection nozzle is provided in the heat exchanger tube of the heat exchanger.

(Function) Since the present invention is configured as described above, the supercooled water can be effectively removed by the combination of the action of forming a uniform water film through uniform dispersion of the jet nozzle and the action of promoting heat transfer through the collision of the jet water with the wall surface. It is possible to carry out the manufacturing of

Furthermore, since the cooling fluid can be swirled at high speed between the heat transfer tubes and the outer shell tubes of the double tube heat exchanger, the convective heat transfer coefficient can be increased.

(Examples) Hereinafter, the present invention will be specifically described according to examples shown in the drawings.

FIG. 1 is a conceptual diagram showing the configuration of an ice making apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. 1.

The heat transfer tubes 1 of the vertical double-tube heat exchanger are required to have functions such as high thermal conductivity, airtightness, and corrosion resistance, so metal tubes such as stainless steel, copper, and aluminum are usually used.

On the other hand, the outer shell tube 2 of the heat exchanger, which is provided to cover the outer periphery of the heat exchanger tube 1, is required to have functions such as heat insulation, airtightness, and corrosion resistance, so it is usually made of the same material as the heat exchanger tube 1. Use a heat insulating material on its outer surface.

The upper end side of the heat exchanger tube 1 has a sealed structure, and the water supply pipe 3 within the heat exchanger tube 1 is provided with injection nozzles 4 in multiple stages.

The lower end side of the heat exchanger tube 1 has an open structure, and the heat storage tank 5 provided at the bottom is required to have functions such as water leakage, heat insulation, and corrosion resistance. Use the one that has been constructed.

The cooling fluid 6 that has been completed between the heat transfer tube 1 and the outer shell tube 2 of the heat exchanger is usually heat exchanged with the refrigerant of the refrigeration circuit (not shown in the diagram) using an antifreeze agent. Although the refrigerant is cooled to below 0°C and used for circulation, it is of course also possible to use the refrigerant in the direct refrigeration circuit.

The water to be cooled 7 supplied from the injection nozzle 4 forms a uniform water film 8 on the inner surface of the heat transfer tube 1, and is cooled by the cooling fluid 6 to produce fluid ice 9.

Note that, if necessary, an ice-making lubricant such as ethylene glycol is added to the water to be cooled 7 to adjust the water diameter and freezing (solidification) temperature.

Arrows in the figure indicate flows of the cooling fluid 6 and the water to be cooled 7.

Next, the operational functions of the present invention will be explained.

First, a cooling fluid 6 of 0°C or lower is flowed between the heat transfer tubes 1 and the outer shell tubes 2 of a double-tube heat exchanger in a high-speed swirling state, and the convection heat transfer of the cooling fluid 6 causes the water to be cooled 7 to flow. Perform cooling.

On the other hand, the water to be cooled 7 is directly sent from the lower part of the heat storage tank 5 to the water supply pipe 3 inside the heat exchanger tube 1 using a pump or the like, and is evenly injected from the injection nozzle 4 onto the inner wall surface of the heat exchanger tube 1 to form a uniform water film 8. Form and cool.

Furthermore, the water film 8 increases due to the heat transfer promotion effect caused by the collision of the jet water with the wall surface.
Make an increase in the convection heat transfer coefficient on the side.

As a result, by improving the convective heat transfer coefficient between the cooling fluid 6 and the water to be cooled 7, the water to be cooled 7 in the form of a water film 8 is effectively cooled by the cooling fluid 6 while flowing down inside the heat transfer tube 1 and passing through the heat transfer tube 1. The water becomes cooled, and the supercooled state is destroyed by the impact action of the water jetted on the downstream side, producing fluid ice 9 corresponding to the sensible heat of the supercooled water.

The water to be cooled 7 accompanied by the fluid ice 9 that has flowed down to the lower end side of the heat transfer tube 1 naturally falls into the heat storage tank 5, and heat is stored using the difference in specific gravity between the water to be cooled 7 and the fluid ice 9. Ice heat storage is performed in the upper part of tank 5.

In addition, in order to prevent ice from forming on the inner wall surface of the heat exchanger tubes 1 of the heat exchanger, the heat exchanger tubes 1 are coated with a fluororesin that is non-adhesive and water repellent.
Of course, it is also possible to coat the inner surface of the.

(Effects of the Invention) As explained above, the ice making device of the present invention has a structure in which an injection nozzle for water to be cooled is provided on the inner wall surface of the heat transfer tube of the vertical double-tube heat exchanger. 1) Since a uniform water film is formed using a double pipe heat exchanger and a water injection nozzle, the heat exchanger structure is simple and the equipment cost is low.

2) Inside the heat transfer tube due to the heat transfer promotion effect due to the collision of the nozzle jet water with the wall and the high speed swirling effect of the cooling fluid between the heat transfer tube and the outer shell tube of the double tube heat exchanger.

The external convection heat transfer coefficient increases, and as a result, the heat transfer area of the condenser converter decreases, making the device more compact.

In addition, since the heat exchanger tubes have a large diameter and the space between the ice making heat exchanger and the heat storage tank is open, there is no problem of blockage due to icing.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing the configuration of an ice making heat storage device showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the AA plane of FIG. 1, and FIG. 3 is a conceptual diagram showing the prior art. 1...Heat transfer tube 2...Outer shell tube 3...
Water supply pipe 4... Injection nozzle 5... Heat storage tank 6... Cooling fluid 7... Water to be cooled 9... Fluid ice 8... Water film

Claims (1)

[Claims] In an ice making device that produces fluid ice by passing a cooling fluid through the outside of a vertical heat exchanger tube and forming a film of falling water to be cooled on the inside of the tube, the heat exchanger tube is a double-tube heat exchanger. With,
An ice making device characterized in that a cooling water injection nozzle is provided in a heat transfer tube of the heat exchanger.