KR100562565B1 - flooded evaporator in chiller - Google Patents

Abstract

The present invention is installed by mixing the lower heat exchanger tube installed inside the shell and the expansion heat exchanger having a different diameter so as to increase the heat transfer efficiency of the liquid-type evaporator, or by mixing the raw heat exchanger tube and the other heat exchanger modified the shape of the inner and outer peripheral surfaces The present invention relates to a fully-loaded evaporator of a refrigerator which increases the total heat transfer coefficient between cold water and liquid refrigerant, or reduces pump power required for cold water circulation or uses them in combination.

The full-sized evaporator of the refrigerator according to the present invention is connected to the condenser by the lower side thereof through an expansion tube, and the upper side thereof is connected to the compressor by a cylindrical shell, and cold water flows in one direction to evaporate the liquid refrigerant inside the shell. In a fully-loaded evaporator of a refrigerator in which a plurality of lower heat transfer tubes provided at a lower portion of the refrigerator and a cold water flow in a different direction and an upper heat transfer tube provided at an upper portion of the lower heat transfer tube are installed in parallel, the upper heat transfer tubes have different diameters from the lower heat transfer tubes. It is characterized in that it is formed by any one or more of reducing the required power of the cold water pump or increase the efficiency by applying a raw heat pipe on the top.

   Refrigerator, Heat pipe, Evaporator, Full liquid type, Shell and tube

Description

    Float evaporator in chiller             

1 is a schematic configuration diagram of a refrigerator including a general liquid evaporator.

Figure 2 is a schematic cross-sectional view of a conventional fully liquid evaporator.

Figure 3 is a block diagram showing an embodiment of a refrigerator according to the present invention.

FIG. 4 is a schematic cross-sectional view of the fully liquid evaporator of FIG. 3. FIG.

Figure 5 is a block diagram showing another embodiment of the refrigerator according to the present invention.

6 is a schematic cross-sectional view of the evaporator of FIG.

* Description of the symbols for the main parts of the drawings *

10: freezer 20: compressor

30: condenser 40: evaporator

42: shell 44: expansion tube

45: orifice 46: liquid refrigerant

70: lower heat pipe 71: upper heat pipe

100: heat transfer unit 110: ridge

120: pupil 122: pupil entrance

160a, 160b: upper heat pipe

The present invention relates to a full-sized evaporator of a refrigerator, and more particularly, to install a mixture of the lower heat pipe and the upper heat pipe having a different diameter so as to increase the heat transfer efficiency of the full-body evaporator mainly used in the freezer. Or a combination of raw heat pipes with different shape of inner and outer peripheral surfaces to increase the total heat transfer coefficient between cold water and liquid refrigerant, or to reduce the pump power required for cold water circulation or to use them together. will be.

Hereinafter, the term “heat transfer tube” without a special modifier refers to a heat transfer promotion tube as a relative concept of a raw heat transfer tube.

A refrigerator using a cooling cycle is an air conditioner that liquefies a compressed refrigerant gas, and then vaporizes a liquid refrigerant to perform a cooling action by vaporization heat absorbed, and is widely used throughout society.

In particular, since a large-capacity cooling system is required for a central cooling device such as a large building, a so-called turbo cooler for condensing a refrigerant using a cooling tower is generally used.

On the other hand, the evaporator of a large refrigeration plant is usually used a shell-and-tube full-sized heat exchanger in which the refrigerant is boiled on the outside and the cold water circulates inside the heat exchange with the refrigerant.

As shown in FIG. 1 and FIG. 2, the conventional refrigerator 10 has a refrigerant gas compressed at high temperature and high pressure in a compressor 20 by heat exchange with cooling water flowing into a condenser 30 and circulating. Liquefied

The liquefied refrigerant 46 changes to low pressure through the orifice 45 of the expansion tube 44 and then flows into the shell 42 of the evaporator 40.

The low pressure liquid refrigerant 46 introduced into the shell 42 of the evaporator 40 exchanges heat with cold water (not shown) flowing into the heat transfer tubes 70 and 71.

That is, the heat transfer pipe 70 is installed in the shell 42 so as to be immersed in the liquid refrigerant 46, and the liquid refrigerant 46 is vaporized while being heat-exchanged with the cold water in the heat transfer tube 70.

In this case, the plurality of heat transfer tubes 71 installed in a plurality of cold water to flow in different directions in the shell 42 generally have various conditions such as diameter and shape.

The evaporated refrigerant is introduced into the compressor 20.

Accordingly, the cooled cold water cools the air in an air conditioning unit (not shown). At this time, the cooled air is blown to a blower (not shown) and supplied to each room through a duct (not shown). Thereby cooling the building.

On the other hand, the heat transfer amount (Q) from the cold water to the liquid refrigerant (46) can be expressed as the product of the total heat transfer coefficient (U), the cross-sectional area (A) and the temperature difference (ΔT) (Q = U × A × ΔT), generally If the number of heat transfer tubes 70 and 71 is large, the cross-sectional area A increases and the heat transfer amount Q increases.

However, as the number increases, the material cost increases and the flow velocity in the heat pipe decreases, thereby reducing the total heat transfer coefficient (U).

In general, to increase the heat transfer performance inside the heat transfer tubes (70, 71) is to make an uneven inside, which increases the pressure loss also increases the power required for cold water circulation.

Nevertheless, the heat transfer tubes 71 on the cold water outlet side have a small temperature difference with the refrigerant and sometimes do not wet the refrigerant, or do not sufficiently perform the performance due to the air bubbles generated from the bottom.

As a result, in the case of the cold water line on the outlet side, there is a problem of wasting power consumption by requiring only the required power for cold water circulation in a state in which the effect of improving the heat transfer performance is not largely obtained.

The present invention has been made to solve the above problems, by mixing a plurality of lower heat pipes provided in the inner lower portion of the shell and the upper heat pipes provided in the upper in different types to increase the efficiency per unit material ratio or to cold water circulation It is an object of the present invention to provide a freezer evaporator of a refrigerator, which reduces the required power and ultimately increases the overall efficiency.

In order to solve the above problems, the full-sized evaporator of the refrigerator according to the present invention is connected to a condenser and a lower side thereof through an expansion tube, and an upper side of the freezer evaporates liquid refrigerant inside the shell. In the liquid-type evaporator of a refrigerator, in which cold water flows in one direction and a plurality of lower heat pipes provided in the lower part of the shell and cold water flows in the other direction and an upper heat pipe provided in the upper part of the lower heat pipes are installed in parallel, The heat transfer pipe may be formed of any one or more of different diameters from the lower heat transfer pipe to reduce the required power of the cold water pump or increase efficiency by applying a raw heat transfer pipe to the upper portion.

Hereinafter, with reference to the accompanying drawings, the configuration of the present invention will be described in more detail.

Figure 3 is a block diagram showing an embodiment of a refrigerator according to the present invention, Figure 4 is a schematic cross-sectional view showing a fully-packed evaporator of FIG.

And, Figure 5 is a block diagram showing another embodiment of the refrigerator according to the present invention, Figure 6 is a cross-sectional view schematically showing the evaporator of FIG.

The same or similar components as in the prior art will be denoted by the same reference numerals or the same reference numerals.

As shown in Figure 3 to 6, the fully-loaded evaporator of the refrigerator according to the present invention through the expansion pipe 44 of the lower side is connected to the condenser 30 and the upper side of the cylindrical type is connected to the compressor 20 In order to evaporate the shell 42 and the liquid refrigerant 46 inside the shell 42, a plurality of lower heat transfer tubes 70 provided in the lower portion inside the shell 42 and flowing cold water (not shown) in one direction; In the fully-loaded evaporator 40 of the refrigerator 10 in which cold water flows in the other direction and the upper heat transfer tubes 160a and 160b provided in the upper portion of the lower heat transfer tube 70 are installed in parallel, the upper heat transfer tubes 160a and 160b) is an expansion heat pipe having a different diameter from the lower heat pipe 70, or by using a raw heat pipe having little or no degree of processing, thereby maintaining heat transfer performance and reducing the required pump power or reducing the number of heat pipes required. It is characterized by being.

As shown in Figure 3 and 5, the refrigerator 10 according to the present invention, as is known, the refrigerant gas compressed at a high temperature and high pressure in the compressor (20) is introduced into the condenser (30) It is formed to liquefy by heat exchange with the circulating cooling water.

As shown in FIGS. 4 and 6, an expansion tube 44 is connected to the lower portion of the shell 42 so that the liquefied refrigerant 46 flows into the shell 42 of the evaporator 40. An orifice 45 is formed in the expansion tube 44 to convert the liquid refrigerant 46 to low pressure.

In addition, the low pressure liquid refrigerant 46 introduced into the shell 42 of the evaporator 40 exchanges heat with cold water of the heat transfer pipe 70 inserted into the lower portion of the shell 42 and is inserted into the upper portion of the other type. Cold water flows through the heat transfer tubes 160a and 160b to form heat exchange with the liquid refrigerant 46.

On the other hand, the cold water circulation system in the shell 42 may be variously adopted in two or more passes depending on the number of passes (pass) based on the purpose or capacity.

In addition, the total heat transfer coefficient of the lower heat transfer pipe 70 and the upper heat transfer pipes 160a and 160b may be classified into an inner heat transfer coefficient and an outer heat transfer coefficient.

The median heat transfer coefficient is primarily proportional to the flow rate for a given tube-side configuration.

As described above, the heat transfer amount Q may be expressed by the following formula (1) as a product of the total heat transfer coefficient (U), the cross-sectional area (A), and the temperature difference (ΔT).

[Calculation 1]

Q = U × A × ΔT

Hereinafter, preferred embodiments of the present invention having the above configuration will be described in detail.

As shown in FIGS. 3 and 4, an expansion tube 44 having an orifice 45 is connected to the lower portion of the shell 42.

In addition, a plurality of lower heat transfer tubes 70 are installed in the lower portion of the shell 42, and an expansion heat transfer tube that is an upper heat transfer tube 160a having a different diameter from the lower heat transfer tube 70 is provided at an upper portion of the lower heat transfer tube 70. do.

At this time, the lower heat transfer pipe 70 and the upper heat transfer pipe 160a of the other form are all installed to be immersed in the liquid refrigerant 46.

Cold water (冷 水, not shown) is formed in the interior of the expansion heat pipe, which is the lower heat pipe 70 and the upper heat pipe 160a.

On the other hand, the upper heat pipe (160a) uses a tube thicker than the diameter of the lower heat pipe (70).

Making the diameter of the upper heat pipe 160a larger than the diameter of the lower heat pipe 70 may reduce the pressure loss in the upper heat pipe with less contribution to the heat transfer performance, or may reduce the required pump power or contribute to the heat transfer performance at the same pump power. This is to increase the heat transfer performance of the lower heat transfer tube 70 to increase the overall heat transfer efficiency.

It is preferable that the diameter of the upper heat exchanger tube 160a be 1.1 to 10 times the diameter of the lower heat exchanger tube 70.

When the diameter of the upper heat pipe 160a is less than 1.1 times the diameter of the lower heat pipe 70, the effect of reducing the pressure loss desired by the present invention is hardly obtained, and in the case of 10 times or more, the upper heat pipe 160a If the number of times is too small, the flow rate is too small, if the number of the upper heat pipe 160a is too small the area is too small, the heat transfer performance is greatly reduced.

At this time, it is preferable that the number of the upper heat pipe (160a) so that the internal flow rate is from 0.9 m / s to 3.6 m / s.

       In the present exemplary embodiment, the plurality of heat transfer tubes positioned at the upper portion do not have to be the upper heat transfer tube 160a having a diameter larger than that of the lower heat transfer tube 70, some of which are the upper heat transfer tube 160a and some of the same diameter as the lower heat transfer tube 70. May be used.

In addition, the sizes of the plurality of heat pipes may all vary.

5 and 6, another embodiment of the upper heat transfer tube according to the present invention is as follows.

5 and 6 are provided with lower heat transfer tubes 70 processed to promote a plurality of heat transfers, and a plurality of upper heat transfer tubes 160b on top of the lower heat transfer tubes 70. The heat transfer pipe () is provided in parallel with the lower heat transfer pipe (70), and the lower heat transfer pipe (70) and the upper heat transfer pipe (160b) are installed so as to be immersed in the liquid refrigerant 46 in the shell 42 shown in FIGS. 3 and 4. Same as).

Here, the processing of the heat transfer tube can be largely divided into the inside and the outside.

Inner processing increases the heat transfer area by increasing the heat transfer area by increasing the turbulence by disturbing the flow by making irregularities on the wall, and outer processing also increases the heat transfer area and at the same time creates an optimum shape that can boil well. The heat transfer efficiency is to increase.

The upper heat pipe is preferably an upper heat pipe 160b with little or no degree of processing.

In addition, the upper heat transfer tube 160b preferably has an average roughness of 0.1 mm or less on the surface.

Here, the roughness described above refers to the height of the surface unevenness of the raw heat pipe 160b.

At this time, the processing degree of the upper heat pipe (160b) is less or little to reduce the pressure loss in the upper heat pipe with less contribution to the heat transfer performance can reduce the required pump power or contribute to the heat transfer performance at the same pump power In order to increase the heat transfer performance of the large lower heat transfer tube 70, and as a result, to increase the overall heat transfer efficiency, when the average roughness of the surface of the raw heat transfer tube (160b) is 0.1mm or more, the desired pressure loss reduction effect is not obtained.

The lower heat transfer tube 70 is preferably provided with a heat transfer part 100 on the inner and outer circumferential surface, the heat transfer part 100 is a plurality of ridges 110 protruding a predetermined height on the inner circumferential surface of the lower heat transfer tube 70, The lower heat transfer pipe 70 is composed of a pupil 120 or other boiling acceleration shape that is an elliptical shape of upper and lower light from the outer circumferential surface to the low surface.

In another embodiment, the upper heat pipe (160a) larger than the diameter of the lower heat pipe 70 is installed in the shell 42 or the same diameter but the degree of processing is less or mixed with the raw heat pipe (160b) shell ( 42) may be provided at the top.

In the present invention, the number of upper heat transfer tubes 160a and 160b installed in the evaporator 40 is 10 to 2000, and the flow rates of the cold water inside the lower heat transfer tubes 70 and the upper heat transfer tubes 160a and 160b are within 3.6 kPa. Do.

On the other hand, cold water flows into the upper heat pipes 160a and 160b and the lower heat pipes 70 in the shell 42 to vaporize the liquid refrigerant 46 filled in a portion of the shell 42 as is known. Omit the description.

As described above, according to the fully-loaded evaporator of the freezer according to the present invention, the diameter of the upper heat pipe provided together with the shell in the shell is larger than the lower heat pipe, or the processed heat pipe between the cold water and the liquid refrigerant inside the heat pipe is used. It is possible to maximize the thermal efficiency of the evaporator by reducing the overall pressure loss and increasing the inner heat transfer coefficient of the lower heat pipe, which contributes to the heat transfer.

In addition, since the pump power for circulating cold water is low, the total heat transfer coefficient of the heat pipe is increased, thereby reducing the equipment cost.

Claims (6)

delete delete The lower side is connected to the condenser 33 through the expansion pipe 44 and the upper side is connected to the compressor 20 and the cylindrical shell 42 and the liquid refrigerant 46 inside the shell 42 to evaporate In order to flow the cold water in one direction and a plurality of lower heat pipes 70 provided in the lower portion of the inside of the shell 42, the cold water flows in the other direction and the upper heat pipes provided in the upper portion of the lower heat pipes 70 in parallel In the fully-loaded evaporator of the refrigerator installed The upper heat pipe is characterized in that the raw heat pipe 160b having an average roughness of 0 to 0.1mm on the surface to reduce the pump power required by reducing the pressure loss in the upper heat pipe with less contribution to the heat transfer performance. Full evaporator of the freezer. delete The method of claim 3, wherein The lower heat transfer tube (70) is a full-load evaporator of the refrigerator, characterized in that provided with a heat transfer part 100 on the inner, outer peripheral surface.        The method of claim 5, The heat transfer part 100 includes a plurality of ridges 110 protruding a predetermined height from an inner circumferential surface of the lower heat transfer pipe 70; Full-load evaporator of the freezer, characterized in that consisting of the pupil 120 of the elliptical shape of the upper and lower light from the outer peripheral surface of the lower heat transfer pipe (70) to the lower surface.

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