WO2017110677A1 - Heat exchanger and cooling tower - Google Patents

Abstract

Provided are a cooling tower involving condensation and a heat exchanger used for the same which are capable of improving heat exchanging performance while reducing the amount of water to be used. The cooling tower is provided with: a heat exchanger which includes a plurality of parallel flow paths arranged at an inclination angle that enables a fluid for refrigeration to circulate in the gravity direction or that enables a condensed fluid to circulate by gravity utilization; a fan which performs perflation such that air passes through the heat exchanger; a spraying nozzle which sprays water drops in the form of fine particles to the heat exchanger; and a pipe which is connected to the heat exchanger.

Description

Heat exchanger and cooling tower

The present invention relates to a heat exchanger and a cooling tower, and more particularly to a cooling tower with condensation and a heat exchanger used therefor.

The cooling tower realized more efficient cooling by blowing air to the cooling water and causing heat exchange using latent heat between the water and air. The invention of the hermetic cooling tower not only solves the problem of contamination of cooling water, but also enables cooling of refrigerants other than water. As seen in Patent Document 1, the closed cooling tower has a heat exchange pipe in the cooling tower that is installed horizontally and meandering the pipe to increase the surface area in contact with the outside air and water spray and improve the heat exchange performance. Had gone.

Such a method is suitable for cooling the refrigerant without condensation, but cooling the refrigerant with condensation causes a decrease in heat transfer coefficient and increases the pressure loss of the system. It was unsuitable. In the hermetic cooling tower of Patent Document 2, the heat exchanger is installed with an inclination so that the plate fins descend along the ventilation direction without meandering the pipes constituting the heat exchanger. A method of sprinkling water from the top of the vessel to the heat exchanger has been proposed. By adopting such a method, it is possible to circulate the condensed refrigerant in the cooling tower by using gravity, so that improvement of heat transfer coefficient and reduction of pressure loss are expected.

Microfilm of Japanese Utility Model Application Sho 62-78944 (Japanese Utility Model Application Publication No. 63-190764) Microfilm of Japanese Utility Model No. 60-86562 (Japanese Utility Model Application No. 61-204173)

However, the cooling tower described above has the following problems. When water is sprayed from above on a heat exchanger having an inclination as in Patent Document 2, an extra amount of water is required to spray the entire heat exchanger. In addition, the upper part of the heat exchanger has an excessive amount of sprinkling, making it impossible to efficiently use latent heat. In addition, a water circulation system for watering is indispensable. When tap water is used for the watering, components such as calcium, magnesium, and silica contained in the tap water are condensed and crystallized to form a scale. Not only does the heat transfer rate significantly decrease due to scale generation, but frequent maintenance and filter installation are required. In addition, there are cases in which chemical substances that are harmful to the human body are used to remove silica.

An object of the present invention is to provide a cooling tower with condensation and a heat exchanger used therefor that can improve heat exchange performance while reducing the amount of water used.

In order to achieve the above object, the heat exchanger according to the present invention is a plurality of parallel flow paths in which fine droplets are sprayed, and the fluid to be cooled is in the direction of gravity or the fluid after condensation is gravity. It includes a plurality of parallel flow paths installed at an inclination that can be circulated by use.

The cooling tower according to the present invention includes a plurality of parallel flow paths that are installed in an inclined direction in which a fluid to be cooled is circulated in the direction of gravity or the condensed fluid can be circulated using gravity. A heat exchanger, a fan that blows air so that air passes through the heat exchanger, a spray nozzle that sprays particulate droplets onto the heat exchanger, and a pipe connected to the heat exchanger. .

According to the present invention, sprayed droplets can be efficiently vaporized on or near the surfaces of a plurality of parallel flow paths of a heat exchanger, and the fluid to be cooled is condensed while reducing the amount of water used. The heat exchange performance can be improved.

(A) is a general-view figure for demonstrating the cooling tower by embodiment of the highest concept, (b) is a general-view figure of the heat exchanger used for this cooling tower. It is a general-view figure for demonstrating the cooling tower of 1st Embodiment of this invention. It is a general-view figure of the heat exchanger used for the cooling tower of FIG. It is a conceptual diagram which shows the air volume distribution near the heat exchanger by the fan of the cooling tower of embodiment of this invention. It is a conceptual diagram which shows the positional relationship of the fan which comprises the cooling tower of embodiment of this invention, a heat exchanger, and a spray nozzle. (A) is a figure which shows the flow rate distribution of the spray nozzle which fits the appearance in the case of one inlet flow path of a heat exchanger, and an inlet flow path position, (b) is the case where there are multiple inlet flow paths of a heat exchanger. It is a figure which shows the flow volume distribution of the spray nozzle which fits the general view and inlet flow path position. It is a general-view figure for demonstrating the cooling system of the server room using the cooling tower of embodiment of this invention. It is a general-view figure for demonstrating the heat exchanger used for the cooling tower of 2nd Embodiment of this invention. It is a general-view figure for demonstrating the heat exchanger used for the cooling tower of 3rd Embodiment of this invention. It is a general-view figure for demonstrating the heat exchanger used for the cooling tower of 4th Embodiment of this invention. It is a general-view figure for demonstrating the heat exchanger used for the cooling tower of 5th Embodiment of this invention. It is a graph which shows the measurement result of the thermal resistance value by the change of wet-bulb temperature at the time of cooling using the heat exchanger of embodiment of this invention.

Preferred embodiments of the present invention will be described in detail with reference to the drawings.

Before describing specific embodiments, a cooling tower according to an embodiment of the highest concept of the present invention and a heat exchanger used for the cooling tower will be described. FIG. 1A is an overview diagram for explaining a cooling tower according to an embodiment of the highest concept, and FIG. 1B is an overview diagram of a heat exchanger used in the cooling tower.

1A includes a fan 109 that blows air, a heat exchanger 105, and a spray nozzle 106 that sprays particulate droplets onto the heat exchanger 105. As shown in FIG. 1B, the heat exchanger 105 in FIG. 1A is a plurality of parallel flow paths 103 in which fine droplets are sprayed, and the fluid to be cooled is in the gravity direction or condensed. It includes a plurality of parallel flow paths 103 installed at an inclination that allows subsequent fluid to circulate by gravity.

The sprayed particulate droplets can be efficiently vaporized on or near the surfaces of a plurality of parallel flow paths of the heat exchanger 105, and the fluid to be cooled is condensed while reducing the amount of water used. The heat exchange performance can be improved. The heat exchange performance of the heat exchanger 105 can be improved, and the cooling tower 100 with improved heat exchange performance can be realized. Hereinafter, more specific embodiments of the present invention will be described.

[First Embodiment]
First, the cooling tower according to the first embodiment of the present invention and the heat exchanger used therefor will be described. FIG. 2 is an overview for explaining the cooling tower of the first embodiment of the present invention.

[Description of structure]
The cooling tower of the first embodiment of the present invention is a hermetic cooling tower. 2 includes a fan 9 that blows air, a heat exchanger 5, and a spray nozzle 6 that sprays water droplets of fine particles as an example of fine particle droplets onto the heat exchanger 5. . Further, the closed cooling tower 20 includes pipes 12 a and 12 b connected to the heat exchanger 5. Further, the hermetic cooling tower 20 of FIG. 2 includes a pressure gauge 7, a flow rate adjusting valve 8, a pump 10, and a water storage tank 11.

The fan 9 is installed in the upper part of the casing 13 of the hermetic cooling tower 20 and blows air so that the air flows out of the upper part of the hermetic cooling tower 20 through the heat exchanger 5. The air blowing direction with respect to the heat exchanger 5 in the hermetic cooling tower 20 is directed from the spray nozzle 6 toward the plurality of parallel flow paths to be cooled from the side where the water droplets of fine particles are sprayed. More specifically, air is blown to the heat exchanger 5 along the direction of the arrow in FIG. 2 from the outside to the inside of the closed cooling tower 20.

The spray nozzle 6 sprays water droplets of fine particles on the heat exchanger 5. The spray nozzle 6 is installed with an inclination with respect to the heat exchanger 5 so that the spray distribution amount of the spray nozzle 6 is proportional to the fan airflow gradient. In particular, the spray nozzle 6 is installed so as to spray water droplets of fine particles onto the heat exchanger 5 obliquely downward from the outer upper portion of the heat exchanger 5.

The heat exchanger 5 includes a plurality of parallel flow paths that are installed in an inclined direction in which the refrigerant to be cooled is circulated in the direction of gravity or the condensed refrigerant can be circulated by using gravity. Hereinafter, a plurality of parallel flow paths of the heat exchanger 5 will be referred to as a plurality of flow paths. FIG. 2 shows a case where the heat exchanger 5 is installed so that a plurality of flow paths of the heat exchanger 5 are parallel to the direction of gravity as an example of the installation form. In FIG. 2, the case where the heat exchanger 5 is installed on both surfaces of the hermetic cooling tower 20 is shown. Corresponding to the double-sided installation of the heat exchanger 5, a spray nozzle 6, a pressure gauge 7, a flow rate adjusting valve 8 and a pump 10 are installed.

FIG. 3 is an overview of the heat exchanger 5 used in the cooling tower of FIG. As shown in FIG. 3, the heat exchanger 5 is provided in the inlet passage 1 through which the refrigerant to be cooled flows, the header 2 that branches the refrigerant flowing from the inlet passage 1 into the plurality of passages 3, and the plurality of passages 3. Fins 4 formed.

The heat exchanger 5 including the plurality of flow paths 3 is inclined in parallel with the gravitational direction as shown in FIG. 2, or the liquid condensed based on the refrigerant viscosity can efficiently flow out of the sealed cooling tower 20 by gravity. And installed.

In the present embodiment, by spraying water droplets of fine particles with spray nozzles 6 inclined to the heat exchanger 5 obliquely downward from the outer upper part of the heat exchanger 5 installed on both surfaces of the sealed cooling tower 20, Condensation cooling of the cooling target refrigerant flowing in the plurality of flow paths 3 of the exchanger 5 is performed.

As shown in FIG. 4, the closed cooling tower 20 according to the embodiment of the present invention performs special control from the upper part to the lower part of the heat exchange surface of the heat exchanger 5 depending on the positions of the fan 9 and the heat exchanger 5. It is an arrangement that can provide a gradient in the air volume distribution without the need. The spray nozzle 6 is installed in such a manner that the spray distribution amount is in proportion to the fan air flow gradient from the outer upper portion of the heat exchanger 5 so as to be proportional to the fan airflow gradient.

The size of the water droplets sprayed from the spray nozzle 6 is preferably in a state of fine particles that does not evaporate before reaching the plurality of flow paths 3 of the heat exchanger 5 from the spray nozzle 6. The diameter of the water droplet sprayed from the spray nozzle 6 is, for example, 150 μm or less. Further, the minimum diameter of water droplets sprayed from the spray nozzle 6 varies depending on conditions such as the distance between the spray nozzle 6 and the plurality of flow paths 3 and the air volume. It is preferable to arrange the pipes constituting the plurality of flow paths 3 so as to avoid overlapping as much as possible so that the water droplets sprayed from the spray nozzles are evenly contacted.

When spraying to the whole of the plurality of flow passage portions (heat exchange portions), as seen in FIG. 6, the multiple flow passage portions that are close to the inlet flow passage 1 of the heat exchanger 5 are compared with the portions that are far away. If a spray nozzle having a spray distribution that can send a large amount of spray flow is used, spray water can be used effectively. This is because a large amount of refrigerant flows through the plurality of flow paths 3 close to the inlet flow path 1 of the heat exchanger 5, so that the necessary heat exchange amount of the plurality of flow paths 3 close to the inlet flow path 1 also increases accordingly.

The flow rate of water droplets sprayed from the spray nozzle 6 does not evaporate until the water particles arrive at the heat exchanger 5, but most of them effectively use latent heat while passing through the heat exchanger 5. The flow rate is set so that it can be evaporated. It is preferable to set the amount so that it can evaporate while passing through the heat exchanger 5, and spraying is performed as close as possible from the heat exchanger 5. With such a configuration, scattering of water sprayed from the spray nozzle 6 can be prevented. At this time, the position is adjusted so that the sprayed water is applied to the entire heat exchanger 5. The spray nozzle 6 may be a one-fluid nozzle that sprays only water or a two-fluid nozzle that sprays water and compressed air simultaneously.

The distance between the heat exchanger 5 and the spray nozzle 6 is set so that the spray width reaches the front of the heat exchanger 5 and the distance is as short as possible. The spray nozzle 6 is installed with an inclination angle that is proportional to the airflow distribution gradient above and below the heat exchanger 5 caused by the fan 9 installed at the top of the closed cooling tower 20.

Since the inclined spray nozzle 6 sprays fine water droplets obliquely downward from the outer upper part of the heat exchanger 5, the upper part of the heat exchanger 5 near the spray distance from the nozzle has a larger spray amount per unit area. Since the spray amount decreases as the distance from the spray nozzle 6 increases, a spray amount having a gradient with respect to the same heat exchanger 5 can be realized. With respect to one heat exchanger 5, a plurality of heat exchangers 5 can be combined by a combination in which a spray amount by the spray nozzle 6 is large at a location where the fan air volume is large and a spray amount by the spray nozzle 6 is small at a location where the fan air volume is small. Optimization according to the required heat exchange amount of the flow path 3 becomes possible.

The water sprayed in the form of fine particles is a device composed of a pipe or tube from the tank 11 to the spray nozzle 6 in addition to the pump 10, the pressure gauge 7, the circuit breaker (not shown), the flow rate adjusting valve 8, the thermometer (not shown), etc. Is supplied by The spraying by the spray nozzle 6 of the present embodiment is assumed to be applied only when the wet bulb temperature is high and the condensation performance is lowered in summer, etc., so refer to the outside air wet bulb thermometer and the refrigerant temperature flowing in the system. Done.

In addition, it can be set as the structure which increased the contact area of external air and the sprayed water droplet by increasing the number of piping of the several flow path 3 which comprises the heat exchanger 5 in the sealed cooling tower 20. FIG. In addition, the piping of the plurality of flow paths 3 constituting the heat exchanger 5 is designed in consideration of the influence such as an increase in pressure loss caused by reducing the pipe diameter.

The fan 9 installed on the upper surface of the casing 13 of the hermetic cooling tower 20 causes an air flow gradient to the plurality of flow paths 3 of the heat exchanger 5 installed in parallel to the direction of gravity. The air volume gradient caused by the fan 9 is hereinafter referred to as a fan air volume gradient. FIG. 4 is a conceptual diagram showing the air volume distribution in the vicinity of the heat exchanger by the fan of the cooling tower according to the embodiment of the present invention. The fan 9 causes an air volume distribution gradient as shown in FIG. The spray nozzle 6 for spraying water droplets of fine particles there is arranged so that the spray distribution amount of the spray nozzle 6 is proportional to the fan airflow gradient with respect to the heat exchanger 5 from the outer upper part of the heat exchanger 5 as shown in FIG. Install with an inclination.

Note that it is possible to provide a plurality of inlet channels 1 of the heat exchanger 5 instead of a single one as shown in FIG. The relationship between the inlet flow path 1 of the heat exchanger 5 and the nozzle flow rate distribution by the spray nozzle will be described. FIG. 6A is a diagram showing an overview when the number of the inlet channel of the heat exchanger is one and the flow rate distribution of the spray nozzle that matches the position of the inlet channel, and FIG. 6B is the inlet channel of the heat exchanger. It is a figure which shows the flow volume distribution of the spray nozzle which fits the general appearance and inlet flow path position in case there is a plurality.

As shown in FIG. 6 (a), the selection of the spray nozzle and the position of the spray nozzle are taken into account that the maximum point of the nozzle flow rate distribution is below the inlet flow path and the spray width is within the heat exchanger surface. Select the selection and installation direction. When there are a plurality of inlet channels 1 of the heat exchanger 5, as shown in FIG. 6B, the maximum point of the nozzle flow rate distribution comes below the plurality of inlet channels, and the spray width is heat exchange. The spray nozzle is selected, the position of the spray nozzle is selected, and the installation direction is selected considering that it fits on the vessel surface. By such selection and installation, the heat flow velocity value distribution inside and outside the heat exchanger can be made closer and the flow rate can be optimized.

[Description of cooling operation]
The refrigerant to be cooled that has become vapor due to the heat from the heat source flows into the heat exchanger 5 from the inlet channel 1 via the pipe 12a. Particulate water droplets sprayed from the spray nozzle 6 are also efficiently vaporized on the surface of the plurality of flow paths 3 of the heat exchanger 5 or in the vicinity thereof by the contribution of air blown by the fan 9. The heat exchange by the heat exchanger 5 causes the refrigerant to be cooled to condense. The refrigerant to be cooled that has become liquid is sent again to the vicinity of the heat source via the pipe 12b by gravity. By circulating the refrigerant to be cooled via the heat exchanger 5, the hermetic cooling tower 20 of the present embodiment performs cooling.

[Description of effects]
According to the sealed cooling tower 20 of the present embodiment, fine particles sprayed by sending air to the heat exchanger 5 including the plurality of flow paths 3 with the spray nozzle 6 while sending air with the fan 9. Are efficiently vaporized on or near the surface of the plurality of flow paths 3. The heat exchanger 5 condenses the refrigerant to be cooled by the heat exchange action. The heat exchange performance can be improved by vaporizing the water droplets of the sprayed fine particles.

By using the sprayed water droplets of fine particles, the coolant to be cooled can be condensed while reducing the amount of water used, and the heat exchange performance can be improved. The heat exchange performance of the heat exchanger 5 can be improved, and the hermetic cooling tower 20 with improved heat exchange performance can be realized.

Compared with the cooling tower of Patent Document 2 in which water is sprayed on the heat exchanger, the amount of water used can be reduced. The problem that the amount of water becomes excessive and the latent heat cannot be used efficiently can be solved. Further, by reducing the amount of water used, it becomes possible to delay the manifestation of the problem that the components such as calcium, magnesium, and silica contained in tap water are condensed and crystallized to form a scale. The problem of decrease in heat transfer coefficient due to scale generation can be solved, and frequent maintenance and filter installation can be eliminated.

As a result, in a closed cooling tower with condensation, the heat exchange performance is improved, the load on the system is reduced by pressure loss, the circulation system is eliminated by reducing the amount of sprinkling, and the reliability is improved by solving the scale related to water circulation. Can be realized.

The hermetic cooling tower 20 according to the embodiment of the present invention is suitable for a cooling method using latent heat when the sprayed water is efficiently evaporated when cooling with the fan 9 alone is difficult due to an increase in the outside air temperature. . It is conceivable to measure the outside air temperature and the temperature of the cooling target refrigerant so that spraying is performed under necessary conditions.

[Usage example of closed cooling tower]
As a method of using the hermetic cooling tower according to the embodiment of the present invention, cooling of IT (Information Technology) equipment such as a server in a data center can be mentioned. A server rack 22 is installed in the server room 21 of the data center 30 in FIG. 7, and a heat receiving unit 23 is installed on the rack rear door side. A server is installed in the server rack 22, and heat generated from the IT equipment in the server is air-cooled by a fan mounted on the server, and air heated at that time is cooled by a heat receiving unit 23 installed on the rack rear door side. As a result, the air discharged to the outside of the server rack 22 is cooled. At this time, the heat absorbed by the heat receiving unit 23 is carried into the heat exchanger of the closed cooling tower 20 by circulation of the refrigerant, and is radiated to the outside air there. The heat exchangers of the heat receiving unit 23 and the sealed cooling tower 20 are connected by a liquid pipe 24 and a steam pipe 25. The hermetic cooling tower 20 is installed above the server room 21, and the refrigerant in the heat receiving section 23 becomes vapor due to phase change, and the refrigerant vapor is directly generated by the hermetic cooling tower 20 of the embodiment of the present invention. To be cooled. The heat exchanger of the hermetic cooling tower 20 becomes a condensing unit, and the refrigerant liquid after being condensed in the heat exchanger is returned to the heat receiving unit 23 via the liquid pipe 24 to circulate the refrigerant. Cool down. The refrigerant liquid after being condensed in the heat exchanger reaches the heat receiving part 23 via the liquid pipe 24 by the gravitational action.

In the closed cooling tower 20 with condensation as in the present embodiment, problems such as improvement in heat exchange performance, reduction of load on the system due to pressure loss, elimination of the circulation system by reduction of the amount of water spray, and scale related to water circulation, etc. The improvement of reliability is expected by the solution. Although FIG. 7 shows a case where the sealed cooling tower 20 is installed above the server room 21, the sealed cooling tower 20 is installed above the server room 21 and a refrigerant using a pump. May be installed in a place not above.

A large amount of cooling power is consumed in the exhaust heat of IT equipment such as servers in the data center. Instead of cooling using a cooling air conditioner, direct cooling to the outside air enables a significant reduction in cooling power. It becomes. The heat transport to the outside air by the fan has sufficient cooling capacity when the outside temperature is low, whereas the cooling capacity is lost in an environment where the outside temperature is high such as summer. By using a cooling tower with a high cooling capacity, it is possible to dissipate the outside air even in an environment where the outside air temperature is high, which can greatly contribute to the reduction of the cooling power.

[Second Embodiment]
Next, the cooling tower by 2nd Embodiment of this invention is demonstrated. The cooling tower of this embodiment differs in the heat exchanger to be used compared with the cooling tower by 1st Embodiment. Since the configuration other than the heat exchanger is the same as that of the cooling tower according to the first embodiment, a detailed description thereof will be omitted. FIG. 8 is a general view for explaining a heat exchanger used in the cooling tower of the second embodiment of the present invention.

[Description of structure]
In the heat exchanger 5a of the present embodiment, a gradient is provided so that the pipe diameters of the plurality of flow paths 3 constituting the heat exchanger 5a become thicker as the distance from the inlet flow path 1 increases. In FIG. 8, among the pipes of the plurality of flow paths 3, the pipe diameter of the pipe 3 b is larger than the pipe diameter of the pipe 3 a close to the inlet flow path 1. Further, among the pipes of the plurality of flow paths 3, the pipe diameter of the pipe 3c farther from the inlet flow path 1 is larger than the pipe diameter of the pipe 3b.

In the heat exchanger 5a having a gradient that increases the pipe diameter of the plurality of flow paths 3 at a distance close to the inlet flow path 1 as the distance from the inlet flow path 1 increases, The refrigerant vapor flowing from the path 1 can be evenly distributed over the plurality of flow paths 3. By equally distributing the refrigerant flowing from the inlet flow path 1 to the plurality of flow paths 3, it is possible to improve the cooling capacity and reduce the size of the heat exchanger 5a and the closed cooling tower 20.

[Third Embodiment]
Next, the cooling tower by 3rd Embodiment of this invention is demonstrated. The cooling tower of this embodiment differs in the heat exchanger to be used compared with the cooling tower by 1st Embodiment. Since the configuration other than the heat exchanger is the same as that of the cooling tower according to the first embodiment, a detailed description thereof will be omitted. FIG. 9 is an overview for explaining a heat exchanger used in the cooling tower of the third embodiment of the present invention.

[Description of structure]
In the heat exchanger 5b of this embodiment, a gradient is given so that the header volume at the top of the plurality of flow paths 3 constituting the heat exchanger 5b increases as the distance from the inlet flow path 1 increases. As shown in FIG. 9, the pipe diameters of the plurality of flow paths 3 are made constant, and as the distance from the plurality of flow paths 3 close to the inlet flow path 1 to the inlet flow path 1 increases, The volume of the header 2a is increased with a gradient.

In the present embodiment, in the heat exchanger 5b having a gradient so that the header volume at the top of the plurality of channels 3 increases as the distance from the inlet channel 1 increases, a plurality of refrigerant vapors flowing from the inlet channel 1 are used. It can be evenly distributed over the entire flow path 3. By equally distributing the refrigerant flowing from the inlet channel 1 to the plurality of channels 3, it is possible to improve the cooling capacity and reduce the size of the heat exchanger 5 b and the sealed cooling tower 20.

[Fourth Embodiment]
Next, the cooling tower by 4th Embodiment of this invention is demonstrated. The cooling tower of this embodiment differs in the heat exchanger to be used compared with the cooling tower by 1st Embodiment. Since the configuration other than the heat exchanger is the same as that of the cooling tower according to the first embodiment, a detailed description thereof will be omitted. FIG. 10 is a schematic view for explaining a heat exchanger used in the cooling tower of the fourth embodiment of the present invention.

[Description of structure]
In the heat exchanger 5c of this embodiment, as shown in FIG. 10, a recess 2c is formed on the bottom surface of the header 2b, which is located below the inlet channel 1. In the recessed portion 2c, the height of the bottom surface of the header 2b is lower than the height of the other portion of the bottom surface of the header 2b. By attaching the recess 2c to the bottom surface of the header 2b located below the inlet channel 1, the refrigerant liquid contained in the refrigerant vapor flowing from the inlet channel 1 is concentrated in the recess 2c. With the structure in which the refrigerant liquid contained in the refrigerant vapor is concentrated in part, the liquid film generated by the refrigerant condensation in the plurality of flow paths 3 of the heat exchanger 5c can be thinned. By reducing the thickness of the liquid film, the heat transfer rate is improved. As a result, the cooling capacity can be improved and the size of the heat exchanger 5c and the enclosed cooling tower 20 can be reduced.

In the heat exchanger 5c of FIG. 10, the pipe diameters of the plurality of flow paths constituting the heat exchanger 5c become thicker as the distance from the inlet flow path 1 becomes longer, like the heat exchanger 5a of the second embodiment. It has a slope to do. In FIG. 10, the pipe diameter of the pipe 3 b is larger than the pipe diameter of the pipe 3 a close to the inlet channel 1. Furthermore, the pipe diameter of the pipe 3c farther from the inlet channel 1 is larger than the pipe diameter of the pipe 3b.

In the heat exchanger 5c having a gradient that increases the pipe diameter of the plurality of flow paths 3 at a distance close to the inlet flow path 1 as the distance from the inlet flow path 1 increases as in this embodiment, The refrigerant vapor flowing from the inlet channel 1 can be evenly distributed throughout the plurality of channels 3. By using such a gradient of the pipe diameters of the plurality of flow paths 3, it is possible to further improve the cooling capacity and further reduce the size of the heat exchanger 5 c and the closed cooling tower 20.

[Fifth Embodiment]
Next, the cooling tower by 5th Embodiment of this invention is demonstrated. The cooling tower of this embodiment differs in the heat exchanger to be used compared with the cooling tower by 1st Embodiment. Since the configuration other than the heat exchanger is the same as that of the cooling tower according to the first embodiment, a detailed description thereof will be omitted. FIG. 11 is an overview for explaining a heat exchanger used in the cooling tower of the fifth embodiment of the present invention.

[Description of structure]
The heat exchanger 5d of the present embodiment has a configuration in which a recess 2c is formed on the bottom surface of the header 2d, which is located below the inlet flow channel 1, with respect to the heat exchanger of the third embodiment described above. In the recessed portion 2c, the height of the bottom surface of the header 2d is lower than the height of the other portion of the bottom surface of the header 2d. By providing the recess 2c on the bottom surface of the header 2d located below the inlet channel 1, a part of the refrigerant liquid contained in the refrigerant vapor flowing from the inlet channel 1 is concentrated in the recess 2c, for example. .

Due to the structure in which the refrigerant liquid contained in the refrigerant vapor is partially collected, the liquid film generated by the refrigerant condensation in the plurality of flow paths 3 of the heat exchanger 5d can be thinned. By thinning the liquid film, the heat transfer rate is improved, and as a result, the cooling capacity can be improved and the size of the heat exchanger 5d and the closed cooling tower 20 can be reduced.

Further, in the heat exchanger 5d having a gradient such that the header volume at the top of the plurality of flow paths 3 increases as the distance from the inlet flow path 1 increases as in the present embodiment, the refrigerant flowing from the inlet flow path 1 Steam can be evenly distributed throughout the plurality of flow paths 3. By evenly distributing the refrigerant flowing in from the inlet channel 1 to the plurality of channels 3, it is possible to further improve the cooling capacity and further reduce the size of the heat exchanger 5d and the closed cooling tower 20.

FIG. 12 shows the measurement result of the thermal resistance value due to the change of the wet bulb temperature when cooled using the heat exchanger 5 constituted by a plurality of flow paths 3 parallel to the direction of gravity as in the embodiment of the present invention. It is a graph to show. FIG. 12 shows a case in which the water droplets of fine particles are sprayed and cooled together with the blowing by the fan 9 as in the above-described embodiment, and a case in which large water droplets that are not fine particles are sprayed on the heat exchanger and cooled. In FIG. 12, the water droplet diameter of the sprayed fine particles used for cooling is set to be 150 μm or less.

¡The refrigerant to be cooled is warmed in the heat receiving part and cooled in a closed cooling tower. Rcv shown in FIG. 12 is the heat receiving portion thermal resistance, Rvw is the heat radiating portion (cooling tower) thermal resistance, and Rcw is the sum of the heat receiving portion thermal resistance Rcv and the heat radiating portion (cooling tower) thermal resistance Rvw.

Rcv spray is the heat resistance of the heat receiving part when the water droplets of fine particles are sprayed and cooled, and Rvw spray is the heat resistance of the heat radiation part (cooling tower) when the water droplets of fine particles are sprayed and cooled. Furthermore, Rcwrayspray represents the sum of the heat receiving portion thermal resistance Rcv spray when sprayed with water droplets of fine particles and cooled and the heat radiation portion (cooling tower) heat resistance Rvw spray when sprayed with water droplets of fine particles and cooled.

The measurement results of the thermal resistance value showed a significant improvement in thermal resistance, indicating an improvement in cooling capacity. According to the embodiments and examples of the present invention, it is possible to improve the cooling capacity by improving the thermal resistance and reducing the pressure loss. As a result, it is possible to realize the cooling using the outside air at the time when the wet bulb temperature is high.

The preferred embodiments and examples of the present invention have been described above, but the present invention is not limited thereto. In the above-described embodiment, for example, FIG. 2, the case where the heat exchanger 5 is installed so that the plurality of flow paths of the heat exchanger 5 are parallel to the direction of gravity has been described, but the present invention is not limited to this. The present invention can also be applied to the heat exchanger 5 installed with an inclination to the extent that the fluid to be cooled after the fluid to be cooled is heat-exchanged and condensed by the heat exchanger 5 and can be circulated by using gravity. And it can apply to the enclosed cooling tower using the heat exchanger 5 installed in such an inclination.

Further, for example, the fluid to be cooled used in the hermetic cooling tower 20 may be water or other refrigerant. Moreover, as a fluid to be cooled, a liquid, gas, or mixed fluid state is assumed. Further, the amount of water sprayed from the spray nozzle 6 to the sealed cooling tower 20 is about the amount of latent heat of vaporization, and therefore, a circulation system of sprayed water and a filter are not required.

The cooling tower of the embodiment of the present invention is a cooling system using a refrigerant circulation cycle that cools exhaust heat from a data center or the like by absorbing heat using a refrigerant as a medium in a heat receiving unit and circulates the absorbed refrigerant. Can be used.

As a method of use in the refrigerant circulation cycle, an application in natural circulation using the density difference of the gas liquid due to the phase change of the refrigerant in the circulation cycle can be considered by installing the heat dissipating part at a position higher than the heat receiving part. Alternatively, as a usage method in the refrigerant circulation cycle, an application in forced circulation using a pump or the like without considering the position of the heat radiating portion can be considered.

(Summary of effects)
The effects of the closed cooling tower according to the embodiment of the present invention are summarized as follows.

The first effect is that the pipes of the plurality of flow paths for performing heat exchange are installed in parallel with the direction of gravity or with an inclination that allows the condensed liquid to flow into the outside of the cooling tower efficiently using gravity. The thickness of the liquid film formed by the condensed liquid in the pipes of the plurality of flow paths is made as thin as possible. Thereby, the improvement of a heat transfer rate is accelerated | stimulated. As a result, the cooling capacity per unit volume is improved and the size of the heat exchanger is reduced. Further, by reducing the thickness of the liquid film formed by the condensate, the cross-sectional area in the effective pipe through which the pre-condensation steam passes is increased, resulting in a reduction in pressure loss. In the heat transport process with phase change, the pressure loss greatly affects the heat transport amount, so that the cooling capacity is improved as a result.

The second effect is that the position of the fan and the heat exchanger as shown in FIG. 4 makes a gradient from the upper part to the lower part without requiring special control of the air volume passing through the heat exchanger. It is possible. Evaporation can be efficiently promoted by spraying the spray nozzle with an inclination so that the spray distribution amount is proportional to the fan airflow gradient from the upper part of the heat exchanger to the heat exchanger. As a result, the cooling capacity is improved. Moreover, not only has an effect of saving water by efficient evaporation, but also it is possible to increase the spray width and reduce the number of necessary nozzles by providing an inclination.

Similarly, as can be seen in FIG. 6, by selecting and positioning the nozzle where the maximum point of the nozzle flow distribution is below the inlet flow path and the spray width is within the heat exchanger surface, The outer heat flow velocity value distribution is made closer, and the flow rate can be optimized.

The third effect is that by spraying water droplets in the form of fine particles in the cooling tower, the vaporization of water is promoted and the heat transfer coefficient can be improved even under conditions where the ambient wet bulb temperature is high. The heat transfer coefficient is calculated by a mathematical formula (heat transfer coefficient = thermal conductivity × area × ΔT ÷ thickness). Here, ΔT is a temperature difference. When the water droplet diameter is reduced, the (thickness) of the above formula is reduced, and as a result, the heat transfer coefficient is increased. Therefore, the heat transfer coefficient is improved by reducing the diameter of the fine water droplets to be sprayed.

Also, in order for water particles to exist as droplets, the surface tension needs to be balanced with the internal pressure, and the internal pressure increases as the water droplet diameter decreases. Therefore, when the water droplet diameter decreases, it becomes difficult to maintain the stability of the water droplets. At this time, when other water droplets exist in the vicinity of the water droplets, they merge and exist as large water droplets, but when there is a distance from other water droplets, the evaporation of the droplets that cannot maintain stability is promoted. As a result, it promotes vaporization.

¡Spraying water in a fine particle state for a flow rate that can evaporate not only reduces water consumption, but also eliminates the need for a water circulation system for sprinkling and associated circulation power (pump power, filtering). This eliminates the problem of scale generation due to crystallization of components (calcium, magnesium, silica, etc.) contained in tap water, and the maintenance thereof. There are cases where chemicals that are harmful to the human body are used to remove silica, which contributes to improved safety. In addition, the size of the water storage tank can be reduced by reducing the required flow rate.

そ の 他 Other problem-solving methods specified below contribute to the improvement of cooling capacity. First, by installing the pipes constituting the plurality of flow paths 3 of the heat exchanger 5 so that the direction of the pipes is parallel to the direction of gravity, the pipes are horizontally installed as in Patent Document 1, and then the inside of the cooling tower. Compared with the pipe shape that meanders to increase the distance, the heat exchangeable surface area within the same volume can be increased.

This is because the piping can be more densely installed by eliminating the volume loss at the curved portion of the piping. Further, in the method of the present invention in which each pipe distance is shortened and the number of pipes is increased, the time for holding the liquid generated by condensation in a plurality of pipes is short, and as a result, not only the heat transfer rate is improved, but also the liquid It is possible to greatly reduce the pressure loss that occurs when transporting the outside of the cooling tower.

Secondly, as shown in FIG. 8 and FIG. 10, the method of providing a gradient that increases the pipe diameter of the plurality of flow paths 3 as the distance from the inlet flow path increases is as follows. Evenly distributed to contribute to improving cooling capacity. Third, as shown in FIG. 9 and FIG. 11, the structure is such that the pipe diameters of the plurality of channels are made constant, and the header volume at the top of the plurality of channels is increased with a gradient as the distance from the inlet channel increases. Has the same effect as the previous example. Fourth, as shown in FIG. 10 and FIG. 11, by reducing the height of the bottom surface of the header located below the inlet channel as compared with other portions of the bottom surface of the header, By concentrating the liquid mixed in to a part, it contributes to the improvement of heat transfer coefficient.

As described above, various modifications are possible within the scope of the invention described in the claims, and it goes without saying that these are also included in the scope of the present invention.

Some or all of the above-described embodiments and examples can be described as in the following supplementary notes, but are not limited thereto.
(Appendix 1) A plurality of parallel flow paths in which fine droplets are sprayed, and a plurality of parallel flow paths installed in a direction in which the fluid to be cooled is circulated in the direction of gravity or the condensed fluid can be circulated by using gravity A heat exchanger including a flow path.
(Appendix 2) The appendix according to appendix 1, further comprising an inlet channel into which the fluid to be cooled flows, and a header that branches the fluid to be cooled flowing in from the inlet channel into the plurality of parallel channels. Heat exchanger.
(Supplementary note 3) The heat exchanger according to supplementary note 2, wherein the pipe diameters of the plurality of parallel flow paths are sloped so as to increase as the distance from the inlet flow path increases.
(Additional remark 4) The heat exchanger of Additional remark 2 with which the volume of the said header is inclined so that it may become so large that the distance from the said inlet flow path becomes long.
(Additional remark 5) The heat exchanger of Additional remark 3 or Additional remark 4 in which the hollow part is formed in the bottom face of the said header located under the said inlet flow path.
(Supplementary note 6) The heat exchanger according to any one of supplementary notes 2 to 5, wherein a plurality of the inlet channels are provided.
(Supplementary note 7) The heat exchanger according to supplementary note 6, wherein fine droplets are sprayed respectively corresponding to the plurality of inlet channels.
(Appendix 8) The heat exchanger according to any one of appendices 1 to 7, a fan that blows air so that air passes through the heat exchanger, and sprays particulate droplets onto the heat exchanger. A cooling tower including a spray nozzle and a pipe connected to the heat exchanger.
(Supplementary note 9) The cooling tower according to supplementary note 8, wherein the spray nozzle sprays the particulate droplets onto the heat exchanger in a direction inclined with respect to the direction of gravity.
(Additional remark 10) The said heat exchanger is installed so that the said several parallel flow path of the said heat exchanger may become substantially parallel to the direction of gravity, and the said spray nozzle is the said heat | fever diagonally downward. 9. The cooling tower according to appendix 8, wherein the particulate droplets are sprayed onto an exchanger.
(Appendix 11) The fan causes an air flow gradient to the plurality of parallel flow paths of the heat exchanger, and the spray nozzle has the spray distribution amount proportional to the air flow gradient so that the heat exchanger The cooling tower according to any one of appendices 8 to 10, wherein the cooling tower is installed with an inclination with respect to the plurality of parallel flow paths.
(Supplementary note 12) The cooling according to any one of Supplementary notes 8 to 11, wherein the spray nozzle is installed so that a maximum point of a nozzle flow rate distribution is located below an inlet flow path of the heat exchanger. Tower.

The present invention has been described above as an exemplary example of the above-described embodiments and examples. However, the present invention is not limited to the above-described embodiments and examples. That is, the present invention can apply various modes that can be understood by those skilled in the art within the scope of the present invention.

This application claims priority based on Japanese Patent Application No. 2015-251191 filed on Dec. 24, 2015, the entire disclosure of which is incorporated herein.

DESCRIPTION OF SYMBOLS 1 Inlet flow path 2, 2a, 2b, 2d Header 2c Recessed part 3 Multiple flow paths 3a, 3b, 3c Piping 4 Fin 5, 105 Heat exchanger 6, 106 Spray nozzle 7 Pressure gauge 8 Flow control valve 9, 109 Fan 10 Pump 11 Water storage tank 12 a, 12 b Piping 13 Case 20 Sealed cooling tower 21 Server room 22 Server rack 23 Heat receiving section 24 Liquid pipe 25 Steam pipe 30 Data center 103 Parallel flow path 100 Cooling tower

Claims (12)

A plurality of parallel flow paths on which fine droplets are sprayed, and a plurality of parallel flow paths installed in an inclination in which the fluid to be cooled can be circulated in the direction of gravity or the condensed fluid can be circulated by using gravity. Including heat exchanger. 2. The heat exchanger according to claim 1, further comprising an inlet channel into which the fluid to be cooled flows, and a header that branches the fluid to be cooled that has flowed in from the inlet channel into the plurality of parallel channels. . The heat exchanger according to claim 2, wherein the pipe diameters of the plurality of parallel flow paths are inclined so as to increase as the distance from the inlet flow path increases. The heat exchanger according to claim 2, wherein the volume of the header is inclined so as to increase as the distance from the inlet channel increases. The heat exchanger according to claim 3 or 4, wherein a recess is formed on a bottom surface of the header located below the inlet channel. The heat exchanger according to any one of claims 2 to 5, wherein a plurality of the inlet channels are provided. The heat exchanger according to claim 6, wherein fine droplets are sprayed in correspondence with the plurality of inlet channels. The heat exchanger according to any one of claims 1 to 7,
A fan that blows air through the heat exchanger;
A spray nozzle for spraying fine droplets onto the heat exchanger;
And a cooling tower including piping connected to the heat exchanger. The cooling tower according to claim 8, wherein the spray nozzle sprays the particulate droplets onto the heat exchanger in a direction inclined with respect to the direction of gravity. The heat exchanger is installed such that the plurality of parallel flow paths of the heat exchanger are substantially parallel to the direction of gravity;
The cooling tower according to claim 8, wherein the spray nozzle sprays the particulate droplets to the heat exchanger obliquely downward. The fan causes an air flow gradient to the plurality of parallel flow paths of the heat exchanger;
11. The spray nozzle is installed with an inclination with respect to the plurality of parallel flow paths of the heat exchanger so that a spray distribution amount is proportional to the air flow gradient. The cooling tower as described in any one of these. The cooling tower according to any one of claims 8 to 11, wherein the spray nozzle is installed such that a maximum point of a nozzle flow rate distribution is located below an inlet channel of the heat exchanger.

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