Structure and function of cooling tower

Working principle of cooling tower cooling tower is a kind of equipment which uses the contact of water and air to dissipate the waste heat produced in industry or refrigeration and air conditioning through evaporation The basic principle of its work is: the dry (low enthalpy) air enters the cooling tower from the air inlet network after being pumped by the fan; the high-temperature water molecules with high partial pressure of saturated steam flows to the air with low pressure, and the hot and humid (high enthalpy) water self seeding water system sprays into the tower When the water drops contact with the air, on the one hand, because of the direct heat transfer between the air and the water, on the other hand, because of the pressure difference between the water vapor surface and the air, evaporation occurs under the effect of pressure, which takes away the heat in the water, namely evaporation heat transfer, so as to achieve the purpose of cooling Take the working process of circular countercurrent cooling tower as an example: The hot water main machine room circulates the water pressure to the water distribution system of the cooling tower through the pipes, cross pipes, curved pipes and central pipes at a certain pressure through the water pump, and evenly spreads the water on the filler through the small holes on the water distribution pipes; the dry air with low Han value enters the tower from the bottom into the air network under the action of the fan, and the hot water forms the water film and air to heat when passing through the filler surface Exchange, the hot air with high humidity and high Han value is drawn out from the top, the cooling water drops into the bottom basin, and flows into the main engine through the outlet pipe In general, the air entering into the tower is dry and low wet bulb temperature air There is obviously a concentration difference and kinetic energy pressure difference between water and air When the fan is running, under the static pressure in the tower, water molecules continuously evaporate into the air and become water vapor molecules The average kinetic energy of the remaining water molecules will be reduced, so that the temperature of the circulating water will drop 。 From the above analysis, it can be seen that the evaporation cooling has nothing to do with the air temperature (usually the dry bulb temperature) being lower or higher than the water temperature As long as the water molecules can continuously evaporate into the air, the water temperature will decrease However, the evaporation of water into the air will not go on endlessly When the air in contact with water is unsaturated, water molecules continuously evaporate into the air, but when the air on the water gas contact surface reaches saturation, water molecules will not evaporate, but in a dynamic equilibrium state The number of water molecules evaporated equals the number of water molecules returned from the air to the water, and the water temperature remains the same It can be seen from this that the drier the air in contact with water, the easier the evaporation will be and the water temperature will be reduced The cooling tower is divided into natural ventilation cooling tower, mechanical ventilation cooling tower and mixed ventilation cooling tower 2 According to the contact mode of hot water and air, there are wet cooling tower, dry cooling tower and dry wet cooling tower 3 According to the flow direction of hot water and air, there are counter flow cooling tower, cross flow (AC) cooling tower and mixed flow cooling tower IV cooling tower for general air conditioning, industrial cooling tower and high-temperature cooling tower according to the purpose V according to the noise level, it can be divided into ordinary cooling tower, low-noise cooling tower, ultra-low noise cooling tower and ultra quiet cooling tower Vi others such as jet cooling tower, fan less cooling tower, hyperbolic cooling tower, etc