The principle structure and classification of cooling tower


How cooling towers work

  The cooling tower is a device that uses water as a circulating coolant to absorb heat from the water circulation system and discharge it into the atmosphere to reduce the water temperature;Its cooling is completed by the evaporation process of water, so that the cooling water can continue to be recycled.The cooling tower sprays the hot water in the system to the surface of the heat-dissipating material and contacts the flowing air. The heat exchange between the hot water and the cold air occurs, and part of the hot water is evaporated.Due to the endothermic effect of evaporation, the evaporated water vapor takes away the heat of the hot water, so that the original hot water temperature is lowered and cooled. , and then absorb heat.This achieves the purpose of heat transfer.

Cooling Tower Structure

  Usually the main structure of the cooling tower mainly includes:Motors, cooling fans, water distributors, fillers, float control valves, air inlet nets, brackets, casings, overflow pipes, and if multiple towers are used in parallel, there are balance pipes between several towers.

  The motor is mainly to provide power for the fan. Generally, there is a special motor for cooling towers, and it is best to use a waterproof motor;The fan provides power for the flow of air, the material should be light and the mechanical strength should be high, no cracks, no gaps and burrs;The water distributor is to spread the water evenly on the filler. The better the water dispersion effect, the better the cooling tower effect.The filler can increase the contact area of water and air, so that the contact between water and air is sufficient, and the larger the contact area, the better the cooling effect;In the process of exchange of hot water and air entering the cooling tower, there is not only heat exchange but also mass exchange, that is, evaporation of water.Therefore, the water in the cooling system will continue to decrease with the circulation of the cooling water. In order to maintain the water level, the floating ball valve will automatically replenish water when the water level drops;If the float valve fails and the water level is too high, the overflow pipe will drain the water. The height of the overflow pipe is slightly lower than the upper edge of the sump pan but higher than the upper limit of the normal water level.

Classification of cooling towers

  There are many types of cooling towers. Generally, they can be classified according to the ventilation method, the water spraying method, the flow direction of the water and the air, and the contact method between the outdoor air and the circulating water.

(1) According to the ventilation mode, there are two types of mechanical ventilation and natural ventilation.

(2) According to the water spray method, there are four types: drip type, drip film type, film type and water spray type.

(3) According to the flow direction of water and air, there are two kinds of counter-flow and cross-flow.

(4) According to the contact method of outdoor air and circulating water, there are open system and closed system.Most of the cooling towers commonly used in air-conditioning refrigeration systems are counter-current and cross-flow, and the water spraying method adopts film type.Generally, single cooling towers and small cooling towers use circular cooling towers or square counter-flow cooling towers, while multi-seat and large cooling towers mostly use cross-flow cooling towers.

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