Cooling tower system

Abstract

To provide a cooling tower system which can recover moisture in exhaust air of a cooling tower at a high recovery rate without installing a new power device, such as a blower, be applied to an existing cooling tower, and achieve low electric power cost.SOLUTION: A cooling tower 1 includes: a tower body 2 having a louver 3 on a side surface, an exhaust fan 8 at a top part, and a lower water tank 4 at a lower part; and a filler 5 which is arranged within the tower body 2 and into which water is poured from above. A heat exchanger 22 for cooling exhaust air from the exhaust fan 8 exchanges heat between air attracted to the louver 3 by the operation of the exhaust fan 8 and the exhaust air from the exhaust fan 8 to cool the exhaust air.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cooling tower system having a cooling tower and a water recovery mechanism that recovers moisture in the exhaust gas from the cooling tower. [Background technology]

[0002] In an open cooling tower, the fan at the top of the tower is operated and water is sprayed onto the packing material placed inside the tower, so that the water that runs down the packing material is cooled by the heat of vaporization. The air that passes through the packing material is exhausted upward by the fan at the top of the tower.

[0003] This cooling tower exhaust contains a large amount of moisture such as water vapor, and in winter, the water vapor may condense and produce white smoke.

[0004] As a cooling tower equipped with a mechanism for preventing such white smoke, Patent Document 1 describes an air-cooled heat exchanger provided in the upper part of the cooling tower, which cools the water vapor-containing air rising inside the tower and condenses the water vapor, thereby reducing the amount of moisture in the cooling tower exhaust. Atmosphere or air at a lower temperature is ventilated into the low-temperature fluid passage of the heat exchanger.

[0005] Patent Document 2 describes a method in which a corona discharge type water droplet removal device is installed on the fan outlet side of a cooling tower, water droplets are charged by corona discharge and attracted to an electrode, and the water droplets are removed from the exhaust air. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2006-502365 [Patent Document 2] Japanese Patent Application Publication No. 8-49989 Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, the air-cooled heat exchanger is installed inside the cooling tower, which increases the size of the cooling tower. In addition, it is difficult to retrofit an existing cooling tower and install an air-cooled heat exchanger inside the cooling tower.

[0008] In the cooling tower of Patent Document 2, water droplets in the exhaust gas from the cooling tower can be removed from the exhaust gas by a corona discharge type water droplet remover, but uncondensed water vapor cannot be removed, so water droplets are not collected very often during hot periods such as summer, resulting in a low water recovery rate. In addition, the corona discharge type water droplet remover consumes electricity, resulting in high electricity costs.

[0009] The present invention aims to provide a cooling tower system that can recover moisture in cooling tower exhaust at a high recovery rate without installing a new power unit such as a blower, can be applied to existing cooling towers, and has low electricity costs. [Means for solving the problem]

[0010] The cooling tower system of the present invention is a cooling tower system having a cooling tower and a heat exchanger for cooling exhaust air from an exhaust fan of the cooling tower, and the heat exchanger cools the exhaust air by exchanging heat between air drawn into the cooling tower by operation of the exhaust fan and the exhaust air from the exhaust fan.

[0011] In one aspect of the present invention, the heat exchanger is arranged facing the air intake on the side of the cooling tower so that air drawn toward the air intake passes through the heat exchanger.

[0012] In one aspect of the present invention, the heat exchanger comprises a plurality of flat, hollow chamber boxes arranged in parallel with spaces between each other, each of which has open upper and lower end faces and a pair of closed side edges, with the exhaust air flowing into each chamber box through an open opening on the upper end face and flowing out through an open opening on the lower end face, with the air passing through the space between each of the chamber boxes.

[0013] In one aspect of the invention, the system further comprises an air cooler for cooling the air drawn into the heat exchanger.

[0014] In one aspect of the present invention, the air cooler is an evaporative cooling device that cools air by heat of vaporization caused by evaporation of water.

[0015] In one aspect of the present invention, the exhaust gas cooler further cools the exhaust gas that has passed through the heat exchanger by exchanging heat with a low-temperature fluid. Effect of the Invention

[0016] In the cooling tower system of the present invention, the exhaust air from the cooling tower is ventilated to the heat exchanger by utilizing the blowing force of the cooling tower fan. Also, the air attracted by the fan and attempting to flow into the cooling tower is circulated through the heat exchanger and exchanges heat with the exhaust air. In this way, both the exhaust air and the air are ventilated to the heat exchanger by the blowing force and suction force of the cooling tower fan, so there is no need to install a new blower device other than the fan. Therefore, the equipment cost and the power cost are low.

[0017] In the present invention, the heat exchanger is disposed outside the cooling tower, so that an existing cooling tower can be easily retrofitted to the cooling tower system of the present invention. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a configuration diagram of a cooling tower system according to an embodiment. [Diagram 2] FIG. 2 is a schematic perspective view of a heat exchanger. [Diagram 3] FIG. 1 is a configuration diagram of a cooling tower system according to another embodiment. [Figure 4] FIG. 1 is a configuration diagram of a cooling tower system according to another embodiment. [Diagram 5] FIG. 11 is a schematic perspective view showing another example of a heat exchanger. [Figure 6] FIG. 11 is a schematic perspective view showing another example of a heat exchanger. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment will be described with reference to the drawings.

[0020] FIG. 1 is a configuration diagram of a cooling tower system according to a first embodiment, showing a cooling tower as a schematic vertical cross section.

[0021] This cooling tower 1 comprises a casing (tower body) 2, and a lower water tank (pit) 4 for storing cooling water is provided at the bottom of the casing 2. Louvers 3 are provided on two opposing side surfaces of the casing 2 as air intakes. Filler 5 is placed inside the casing 2, and an upper water tank 6 is placed above the filler 5. The bottom plate of the upper water tank 6 is composed of a spray plate 6a with many small holes. An empty chamber 7 is provided in the center of the casing 2 (the center when viewed from above), and a fan 8 is provided above this empty chamber 7.

[0022] The suction side of a pump 9 is connected to the bottom of the lower water tank 4, and the discharge side of the cooling pump 9 is connected to one end of a body 12 to be cooled, such as a heat exchanger, via a cooling water supply pipe 10. The other end of the body 12 to be cooled, such as a heat exchanger, is connected to the upper water tank 6 of the cooling tower 1 via a cooling water return pipe 13.

[0023] Although not shown in the figure, the lower water tank 4 is provided with a ball tap to which a water supply pipe for make-up water (groundwater, tap water, industrial water, etc.) is connected, so that the water level of the lower water tank 4 is maintained within a set range. In addition, the lower water tank 4 is provided with a blow pipe having a blow valve (or a blow pump), and an overflow pipe.

[0024] The sides of the fan 8 are surrounded by a cylindrical shroud 20 .

[0025] One end of a duct 21 is connected to the upper end of the shroud 20, and the other end of the duct 21 is connected to a heat exchanger 22. The heat exchanger 22 is disposed outside the casing (tower body) 2, facing the louvers 3 on one side of the casing 2.

[0026] 2, the heat exchanger 22 is a configuration in which a plurality of flat, hollow chamber boxes 22a are arranged in parallel with a gap between them. The upper and lower end faces of the chamber boxes 22a are open, and one pair of side edges is closed. Exhaust air from the fan 8 flows into the chamber box 22a from an open opening on the upper end face of the chamber box 22a and flows out from an open opening on the lower end face. Air (atmospheric air) passes through the spaces between the chamber boxes 22a and flows into the casing 2 through the louvers 3.

[0027] The chamber boxes 22a are made of a substantially rectangular plate-like material made of a material with high thermal conductivity such as aluminum or copper, with a pair of side edges joined together and the top edges and bottom edges not joined together. The chamber boxes 22a are arranged in parallel with their plate surfaces facing the louvers 3.

[0028] In this cooling tower system, a fan 8 is rotated by a motor (not shown), and a pump 9 is operated to spray water onto the filler 5 from a spray plate 6a of an upper water tank 6.

[0029] The attractive force of the fan 8 causes the air (atmospheric air) to pass through the heat exchanger 22, the louvers 3, and the filler 5. Then, the air, now highly humid, is exhausted from the chamber 7 through the fan 8 to the duct 21.

[0030] The water that runs down through the filler 5 becomes cold due to the heat of vaporization when it evaporates, and falls into the lower water tank 4. The water in the lower water tank 4 flows through the pump 9, piping 10, cooled body 12, and piping 13, and flows into the upper water tank 6, and is sprayed onto the filler 5 again.

[0031] The high humidity exhaust air discharged into the duct 21 by the blowing force of the fan 8 passes through the heat exchanger 22, where it exchanges heat with the air and is cooled. Then, the water vapor contained in the exhaust air condenses to become condensed water.

[0032] This condensed water flows out into the drain pipe 22b through a water collector (not shown) provided below the heat exchanger 22. The water from the drain pipe 22b is sent to a recovered water reuse facility and used as cooling water for a cooling tower, boiler feed water, or the like.

[0033] The exhaust gas cooled by the heat exchanger 22 is released into the atmosphere through the duct 23. Since a large portion of the water vapor in the fan exhaust gas has been removed from this exhaust gas, the generation of white smoke is prevented or suppressed even if the exhaust gas is released into the atmosphere.

[0034] In this cooling tower system, by operating the fan 8 of the cooling tower 1, the atmosphere is drawn in, and air as a low-temperature fluid flows into the heat exchanger 22, while the blowing force of the fan 8 causes the exhaust air from the fan 8 to be ventilated into the cooled fluid flow path of the heat exchanger 22. Therefore, a separate power device (i.e., other than the fan 8) for ventilating the heat exchanger 22 is not required.

[0035] In this cooling tower system, the duct 21 and the heat exchanger 22 are arranged outside the casing 2, so that the cooling tower system of the present invention can be constructed even in an existing cooling tower by attaching the duct 21 and the heat exchanger 22.

[0036] In FIG. 1, the heat exchanger 22 is installed only on the outside of one of the louvers 3, but it is also possible to install a heat exchanger 22 on the outside of each louver 3 and ventilate the exhaust air from the fan 8 to each heat exchanger 22.

[0037] In FIG. 1, atmospheric air is assumed to pass through the heat exchanger 22 as the air, but air at a lower temperature than the atmospheric air may be supplied to the heat exchanger 22.

[0038] In the present invention, in order to lower the temperature of the air passing through the heat exchanger 22 and achieve more efficient evaporation water recovery, an air cooler 24 may be installed on the intake side of the heat exchanger 22 as shown in Figure 3, within the scope that does not significantly impede ventilation.

[0039] As the atmospheric cooler 24, an evaporative cooling device, a heat storage material, a heat exchanger, etc. can be used. The evaporative cooling device is a device that cools air by utilizing the heat of vaporization caused by the evaporation of water. The evaporative cooling device is not particularly limited as long as it is a device that uses the heat of vaporization to cool air, and it is sufficient that the water sprayed for cooling comes into contact with the air taken into the heat exchanger 22. In order to efficiently carry out the contact, the device may be a device that sprays water or a filler is placed on the intake side of the heat exchanger 22 and sprays water on the filler.

[0040] The water used in the evaporative cooling device is not particularly limited, and industrial water, tap water, well water, recycled wastewater water, cooling water, condensed water, etc. can be used.

[0041] A thermal storage material can be used in the air cooler 24 to cool the air using cold available at another location or time. Types of thermal storage materials include, but are not limited to, latent heat storage materials and sensible heat storage materials.

[0042] In the present invention, as shown in FIG. 4, an exhaust cooler 26 for further cooling the exhaust gas by a low-temperature fluid may be installed downstream of the fan exhaust flow of the heat exchanger 22, thereby allowing further recovery of evaporated water.

[0043] The low-temperature fluid used to cool the exhaust gas in the exhaust cooler 26 is not particularly limited, and may be industrial water, tap water, well water, recycled wastewater, cooling water, condensed water, brine, process fluid, etc. In FIG. 4, the cooling liquid is passed through the exhaust cooler 26 by pipes 27 and 28.

[0044] However, the exhaust cooler 26 cools the exhaust gas using cold energy, and the cold energy source is not limited to liquid, but may be gas.

[0045] In the present invention, both the atmospheric cooler 24 of FIG. 3 and the exhaust cooler 26 of FIG. 4 may be installed.

[0046] Other heat exchanger configurations, such as those shown in FIGS.

[0047] A heat exchanger 30 in FIG. 5 has two gas flow sections 32, 33 separated by a partition plate 31. Exhaust gas is ventilated through one gas flow section, and atmospheric air is ventilated in the opposite direction through the other gas flow section.

[0048] 6 is a plate-fin type heat exchanger in which a plurality of corrugated fins (wave plates) 41 are stacked in multiple stages with partition plates between them so that the corrugation direction is perpendicular to each other for each stage. Exhaust air is circulated along the odd-numbered corrugated fins 41 and air is circulated along the even-numbered corrugated fins 41, or exhaust air is circulated along the even-numbered corrugated fins 41 and air is circulated along the odd-numbered corrugated fins 41. EXAMPLES

[0049] [Example 1] Equipped with a cooling tower, water capacity 0.1m 3 A cooling tower system was constructed by externally installing a duct 21 and a heat exchanger 22 on the cooling tower equipment as shown in Fig. 1. A heat exchanger manufactured by HEATEX (size of chamber box 22a: H600 x W300 x t600 mm, spacing between chamber boxes 22a: 12 mm, number of chamber boxes 22a: 12) was used as the heat exchanger 22.

[0050] The cooling tower system was operated under the following conditions:

[0051] Cooling water circulation flow rate: 19.6L / min Cooling water inlet temperature of cooled body 12: 30°C Cooling water outlet temperature of cooled body 12: 37℃ (ΔT set to 7℃) Cooling tower fan power: 100W Makeup water amount: 0.217L / min Evaporation rate: 0.217L / min Non-Blow Outside temperature: 28℃

[0052] Table 1 shows the amount of evaporated water recovered and the recovery rate after 5 hours of operation.

[0053] [Comparative Example 1] The operation was carried out under the same conditions as in Example 1, except that the ducts 21, 23 and the heat exchanger 22 were not installed.

[0054] Table 1 shows the amount of evaporated water recovered and the recovery rate after 5 hours of operation.

[0055] [Comparative Example 2] In Comparative Example 1, operation was carried out under the same conditions as in Example 1, except that the fan exhaust was ventilated to a corona discharge mist collector (MCH-08A manufactured by Midori Anzen Air Quality Co., Ltd.).

[0056] Table 1 shows the amount of evaporated water recovered and the recovery rate after 5 hours of operation.

[0057] [Table 1]

[0058] As shown in Table 1, Example 1 allows for a higher recovery rate of evaporated water than Comparative Examples 1 and 2. It was also found that the corona discharge mist collector of Comparative Example 2 hardly increased the water recovery rate. [Explanation of symbols]

[0059] 1 cooling tower 3 Louver (air intake) 4 Lower tank 5 Filling material 6 Upper tank 6a Sprinkler plate 8. Exhaust Fan 12 Cooled object 21 Duct 22 Heat exchanger 22b Drainage piping 24 Air Cooler 26 Exhaust Cooler

Claims

1. 1. A cooling tower system having a cooling tower and a heat exchanger for cooling exhaust air from an exhaust fan of the cooling tower, The heat exchanger in this cooling tower system exchanges heat between the air drawn into the cooling tower by the operation of the exhaust fan and the exhaust air from the exhaust fan, thereby cooling the exhaust air.

2. 2. The cooling tower system according to claim 1, wherein the heat exchanger is disposed facing the atmospheric air intake on the side of the cooling tower so that air drawn toward the atmospheric air intake passes through the heat exchanger.

3. The heat exchanger is a plurality of flat hollow chamber boxes arranged in parallel with a space between each other, The chamber box has an open upper end surface and a closed lower end surface, and a pair of closed side surfaces. The exhaust gas flows into each chamber box through an opening at an upper end surface thereof and flows out of the opening at a lower end surface thereof, 3. The cooling tower system of claim 2, wherein the air passes through spaces between each of the chamber boxes.

4. 3. The cooling tower system of claim 2 further comprising an atmospheric air cooler for cooling said air induced into said heat exchanger.

5. 5. The cooling tower system according to claim 4, wherein the atmospheric cooler is an evaporative cooling device that cools air by heat of vaporization caused by evaporation of water.

6. 6. The cooling tower system according to claim 1, further comprising an exhaust cooler that further cools the exhaust gas that has passed through the heat exchanger by exchanging heat with a low-temperature fluid.

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