Cooling tower system

Abstract

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 gas 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 gas from the exhaust fan 8 to cool the exhaust gas.

Description

Cooling Tower System

[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.

[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 flows down the packing and is cooled by the heat of evaporation. The air that passes through the packing is exhausted upward by the fan at the top of the tower.

[0003] This cooling tower exhaust contains a large amount of water vapor and other moisture, 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 a cooling tower in which an air-cooled heat exchanger is provided at the top of the cooling tower, and the water vapor-containing air rising inside the tower is cooled to condense the water vapor, thereby reducing the amount of moisture in the cooling tower exhaust. Atmospheric air or air at a lower temperature is ventilated through 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, and water droplets are charged by corona discharge and attracted to an electrode, thereby removing water droplets from the exhaust gas.

[0006] International Publication No. 2003 / 040638, Japanese Patent Application Laid-Open No. 8-49989

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

[0008] In the cooling tower of Patent Document 2, water droplets in the cooling tower exhaust can be removed from the exhaust by a corona discharge water droplet removal device, but uncondensed water vapor cannot be removed, so in hot seasons such as summer, not many water droplets are recovered and the water recovery rate is low.In addition, the corona discharge water droplet removal device consumes electricity, resulting in high electricity costs.

[0009] The present invention aims to provide a cooling tower system that can recover moisture from 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 power costs.

[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 from the exhaust fan by exchanging heat between the air drawn into the cooling tower by the operation of the exhaust fan and the exhaust air.

[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 gaps between them, each chamber box having an open upper end surface and a closed lower end surface, and the exhaust air flows into each chamber box through an open opening on the upper end surface and flows out through an open opening on the lower end surface, with the air passing through the space between each chamber box.

[0013] One aspect of the present invention includes an air cooler for cooling the air drawn into the heat exchanger.

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

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

[0016] In the cooling tower system of the present invention, the exhaust air from the cooling tower is ventilated to the heat exchanger using the blowing force of the cooling tower fan. Furthermore, air drawn into the cooling tower by the fan is circulated through the heat exchanger and exchanges heat with the exhaust air. Because both the exhaust air and the air are ventilated to the heat exchanger using the blowing force and suction force of the cooling tower fan, there is no need to install a separate blower other than the fan. This reduces both equipment costs and power costs.

[0017] In the present invention, the heat exchanger is located outside the cooling tower, so that existing cooling towers can be easily retrofitted to the cooling tower system of the present invention.

[0018] Fig. 1 is a configuration diagram of a cooling tower system according to an embodiment. Fig. 2 is a schematic perspective view of a heat exchanger. Fig. 3 is a configuration diagram of a cooling tower system according to another embodiment. Fig. 4 is a configuration diagram of a cooling tower system according to another embodiment. Fig. 5 is a schematic perspective view showing another example of a heat exchanger. Fig. 6 is a schematic perspective view showing another example of a heat exchanger.

[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. A filler material 5 is installed inside the casing 2, and an upper water tank 6 is installed above the filler material 5. The bottom plate of the upper water tank 6 is composed of a spray plate 6a with many small holes. A void 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 void 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 cooled object 12 such as a heat exchanger via a cooling water supply pipe 10. The other end of the cooled object 12 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, the lower water tank 4 is provided with a ball tap connected to a water supply pipe for make-up water (groundwater, tap water, industrial water, etc.), so as to maintain the water level in the lower water tank 4 within a set range. The lower water tank 4 is also provided with a blow pipe having a blow valve (or 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 made up of a plurality of flat, hollow chamber boxes 22a arranged in parallel with gaps between them. The chamber boxes 22a are open at the top and bottom, and one pair of side edges is closed. Exhaust air from the fan 8 flows into the chamber boxes 22a through the open opening at the top of the chamber boxes 22a, via the duct 21, and flows out into the duct 23 from the open opening at the bottom. 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-shaped material with high thermal conductivity, such as aluminum or copper, and are configured by joining a pair of sides together, but not joining the top sides together or the bottom sides together. The chamber boxes 22a are arranged in parallel with their plate surfaces facing the louvers 3.

[0028] In this cooling tower system, the fan 8 is driven to rotate by a motor (not shown), and the pump 9 is operated to spray water onto the filler material 5 from the spray plate 6 a of the 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. The air, now highly humid, is then discharged from the chamber 7 through the fan 8 to the duct 21.

[0030] The water that flows down through the filler 5 becomes low-temperature water due to the heat of vaporization when it evaporates, and falls into the lower water tank 4. The low-temperature 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, from which it 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 form condensed water.

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

[0033] The exhaust gas cooled by the heat exchanger 22 is released into the atmosphere through a 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 when the exhaust gas is released into the atmosphere.

[0034] In this cooling tower system, by operating the fan 8 of the cooling tower 1, atmospheric air is drawn in, and air as a low-temperature fluid flows into the heat exchanger 22, and the airflow force of the fan 8 causes the exhaust air from the fan 8 to flow into the cooled fluid flow path of the heat exchanger 22. Therefore, no separate power device (i.e., other than the fan 8) is required for ventilation to the heat exchanger 22.

[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 through 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, as long as it does not significantly impede ventilation.

[0039] The atmospheric cooler 24 can be an evaporative cooling device, a heat storage material, a heat exchanger, or the like. An evaporative cooling device is a device that cools air by utilizing the heat of vaporization produced by the evaporation of water. The evaporative cooling device is not particularly limited as long as it has a mechanism for cooling air by utilizing the heat of vaporization, and may be one in which water sprayed for cooling comes into contact with the air taken into the heat exchanger 22. The evaporative cooling device may have a mechanism for spraying water to efficiently effect contact, or for installing a filler on the intake side of the heat exchanger 22 and spraying 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 atmospheric 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 gas cooler 26 for further cooling the exhaust gas with a low-temperature fluid may be installed downstream of the heat exchanger 22 in the fan exhaust flow, thereby enabling further recovery of evaporated water.

[0043] The low-temperature fluid used to cool the exhaust gas in the exhaust gas 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 gas cooler 26 via 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 a liquid, but may also be a 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] In the present invention, heat exchanger 22 may be replaced by heat exchangers of other configurations, such as those shown in FIGS.

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

[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 in between, with the corrugation directions of each stage perpendicular to each other. Exhaust gas flows along the odd-numbered corrugated fins 41, and air flows along the even-numbered corrugated fins 41, or exhaust gas flows along the even-numbered corrugated fins 41, and air flows along the odd-numbered corrugated fins 41.

[0049] [Example 1] Cooling tower equipped with water capacity of 0.1 m 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 (dimensions: 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: 19.6 L / min Cooling water inlet temperature of cooled body 12: 30°C Cooling water outlet temperature of cooled body 12: 37°C (set at ΔT = 7°C) Cooling tower fan power: 100 W Make-up water amount: 0.217 L / min Evaporation water amount: 0.217 L / min Non-blow Outside temperature: 28°C

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

[0053] Comparative Example 1 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 Comparative Example 1 was operated under the same conditions as in Example 1, except that the exhaust air from the fan 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]

[0058] As shown in Table 1, Example 1 allows for the recovery of evaporated water at a higher recovery rate 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.

[0059] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible within the scope of the effects of the invention. This application is based on Japanese Patent Application No. 2023-117715 filed on July 19, 2023, the entire contents of which are incorporated by reference.

[0060] REFERENCE SIGNS LIST 1 Cooling tower 3 Louver (air intake section) 4 Lower water tank 5 Filler 6 Upper water tank 6a Spray plate 8 Exhaust fan 12 Cooled body 21, 23 Duct 22 Heat exchanger 22b Drainage pipe 24 Air cooler 26 Exhaust cooler

Claims

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, wherein the heat exchanger cools the exhaust air by exchanging heat between the air drawn into the cooling tower by the operation of the exhaust fan and the exhaust air from the exhaust fan.

2. The cooling tower system of 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 cooling tower system of claim 2, wherein the heat exchanger is a plurality of flat, hollow chamber boxes arranged in parallel with spaces between each other, the chamber boxes having open upper and lower end faces and a pair of closed side edges, the exhaust air flows into each chamber box from the open opening on the upper end face and flows out from the open opening on the lower end face, and the air passes through the space between each chamber box.

4. A cooling tower system as claimed in claim 2, further comprising an atmospheric air cooler for cooling said air induced into said heat exchanger.

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

6. A cooling tower system according to any one of claims 1 to 5, further comprising an exhaust cooler which further cools the exhaust gas that has passed through the heat exchanger by exchanging heat with a low-temperature fluid.

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