JPH0318863Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention is a closed type cooling tower, in particular, a closed type cooling tower in which the fluid to be cooled flowing inside the cooling coil is cooled by evaporative heat exchange between air flowing through forced draft and water sprayed from the top of the cooling coil. It concerns cooling towers. [Prior Art] When using closed type cooling as described above in winter or in a cold region, there is a problem that when the closed type cooling is stopped, for example at night, the fluid to be cooled remaining in the cooling coil freezes, causing damage to the cooling coil. Conventional countermeasures include using antifreeze, wrapping a band heater around the cooling coil, and continuing to flow water at the minimum flow rate. However, when using antifreeze, it is expensive when there is a large amount of water in the circuit, band heaters are difficult to install, and the method of continuously flowing water at the lowest flow rate is not effective. None of them were satisfactory. [Purpose of the invention] The present invention was developed against the background of the above-mentioned circumstances, and is a reliable, simple, and inexpensive method that prevents the fluid in the cooling coil from freezing when the cooling coil is stopped, such as at night, even when used in winter. Therefore, it is an object of the present invention to provide a closed type cooling tower that can prevent damage to the cooling coil. [Structure of the invention] The present invention has been made to achieve the above-mentioned object, and is aimed at at least the above object in a closed cooling tower that cools the fluid flowing in the cooling coil by forced draft and evaporative heat exchange with sprayed water. A header connected to a cooling coil is disposed at a submerged position in a water storage tank in which the sprayed water is stored when the closed cooling tower stops operating, and a heater is provided to heat the stored sprayed water. It is said that [Example] The present invention will be described in detail below based on an example shown in the drawings. Figures 1 and 2 show an embodiment of the present invention. Figure 1 is a front view of a closed cooling tower with the louver removed from the ventilation inlet, and Figure 2 is a vertical cross-section of a portion of the tower. It is a diagram. Packing material 2 in closed cooling tower 1
are arranged in multiple stages in the vertical direction, a predetermined gap 2a is provided between each filler 2, and each unit plate 2b constituting the filler 2 is vertically arranged in parallel with the ventilation direction, and the closed type An upper header 3 and a lower header 4 are disposed above the cooling tower 1 and near the spray water receiving tray 1a, respectively, so as to extend in the ventilation direction (from the front surface to the rear surface in FIG. 1). A large number of cooling coils 5 are arranged in parallel in the ventilation direction so as to meander through the gaps 2a of the filler 2 in a plane perpendicular to the ventilation direction. The water storage tank 1b for spraying water is composed of a receiving tray 1a and a drop portion 1c connected to the receiving tray 1a and provided approximately in the center of the bottom of the cooling tower 1. The location of the lower header 4 is such that the lower header 4 is exposed when the cooling tower 1 is in operation, that is, when the sprayed water is circulating within the cooling tower 1 and the amount of water stored in the water storage tank 1b is decreasing. It may be in either a position where the cooling tower 1 is stopped or a position where it is submerged, but at least it is a position where it is always submerged when the cooling tower 1 stops operating, that is, when the sprayed water returns to the water storage tank 1b and the amount of water stored increases. . Further, the lower header 4 is preferably made of a material with better thermal conductivity because it becomes more effective. Furthermore, a heater 6 is provided in the drop-in portion 1c of the water storage tank 1b to heat and maintain the sprayed water in the water storage tank 1b at a desired temperature. In addition, 7 is a fan and 8 is an upper water tank. Next, to explain the operation of the closed type cooling tower as described above, as in the conventional case, the fluid to be cooled flows up or down between the upper header 3 and the lower header 4 through the cooling coil 5, and during that time, the Sprayed water is evenly distributed from the water tank 8 to the cooling coil 5 and the filler 6, and forced ventilation is performed by the fan 7, and wind flows in from the ventilation inlet, and the water is cooled by evaporative heat exchange between the sprayed water and the wind. The fluid is cooled. Next, when the operation is stopped, such as at night, when the operation is stopped, the sprayed water in the upper water tank 8, the sprayed water attached to the cooling coil 5 and the filler 2, etc. flow down and are stored in the water storage tank 1b. and submerge the lower header 4 in water. Then, when the heater 6 is activated to heat and maintain the spray water in the water storage tank 1b at a constant temperature, the heated spray water exchanges heat with the fluid in the lower header 4 via the lower header 4, and the heat is Convection is generated in the residual fluid in the cooling coil connected to the lower header 4, and this convection heats the residual fluid in the upper cooling coil, thereby maintaining the residual fluid in the cooling coil above the freezing temperature. It happens. Here, the table and FIG. 3 show the measured values of the spray water temperature and the cooling coil surface temperature over time when the temperature of the spray water in the water storage tank was maintained at 10° C. above the outside air. Furthermore, the third
In the figure, a is the spray water temperature in the water storage tank, b is the surface temperature of the upper coil (), c is the surface temperature of the middle coil (), and d is the outside air dry bulb temperature.

【table】

[Table] In this table and Figure 3, as the temperature of the sprayed water in the water storage tank decreases, the coil surface temperature increases, and the fluid in the cooling coil causes convection and the heat of the sprayed water in the water storage tank is quickly transferred. It can be seen that the conduction reaches the upper stage of the coil. And the temperature efficiency is: Temperature efficiency = (upper surface temperature of the coil - outside air dry bulb temperature) / (sprinkling water temperature in the water tank - outside air dry bulb temperature)
×100, and for example, the temperature efficiency is approximately 35% from the measured value after 125 minutes. Additionally, as shown in this table, the rate of increase in coil surface temperature without a water seal is slower than with a water seal in the coil, and the case with a water seal in the coil is extremely effective. It also became clear that [Effects of the invention] As mentioned above, the present invention takes into consideration the location of the header and has a configuration in which the heater is installed, which makes it easier and cheaper to use the cooling tower in winter, etc., compared to the conventional method. Not only can the residual fluid in the cooling coil be prevented from freezing when the operation is stopped, but also the sprayed water in the water tank can be prevented from freezing at the same time. In particular, it has various effects such as being extremely effective in cases where conventional antifreeze measures such as brine cannot be used.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, in which FIG. 1 is a front view with the louver removed, FIG. 2 is a vertical sectional view of a portion thereof, and FIG. 3 is a graph. 1 is a closed cooling tower, 1a is a saucer, 1b is a water tank, 1c is a drop-in part, 2 is a filling material, 3 is an upper header, 4 is a lower header, 5 is a cooling coil, 6
is a heater.

Claims (1)

[Scope of utility model registration request] In a closed type cooling tower that cools the fluid to be cooled flowing in a cooling coil by forced draft and evaporative heat exchange with sprayed water, at least a water storage tank in which the sprayed water is stored when the closed type cooling tower stops operating. 1. A closed type cooling tower, characterized in that a header connected to a cooling coil is disposed at a submerged position, and a heater is provided for heating the stored spray water.