Closed cooling tower (also called evaporative air cooler, closed circuit cooling tower) places the tubular heat exchanger in the tower, through the heat exchange of circulating air, spray water and circulating water to ensure cooling effect. Because it is a closed cycle, it can ensure that the water quality is not polluted, well protect the efficient operation of the main equipment, and improve the service life. When the outside temperature is low, the sprinkler system can be stopped to save water.
The working principle of the closed cooling tower is simply closed circulation cooling, which consists of the following systems:
1. Internal circulation: The cooled circulating medium flows and cools through the closed tube bundle, and is completely isolated, closed and non-contact with the outside world.
2. External circulation: also known as spray water, water is pumped from the top of the tower, and sprayed evenly to the outside of the heat exchange tube bundle by a low-lift high-flow spray pump, covered with a thin water film, heated by the high-temperature medium in the tube, and the water film absorbs thermal energy, It is converted into latent heat of vaporization, evaporated into water vapor, and takes away heat energy.
3. Air exchange system: The dry and cold air enters from the lower part of the heat exchange tube bundle, passes over the tube bundle at a high speed, conducts convective heat exchange with the tube wall, and at the same time entrains water vapor and turns into a high-enthalpy gas, which is exhausted by an axial flow fan and sent out of the tower. The purpose of transferring heat energy to outside the tower is realized.
4. Auxiliary systems: air inlet grille, drift eliminator, water distribution system, control system, etc., to ensure the normal operation of the closed cooling tower. In particular, the control system automatically switches between air cooling and air cooling + spray mode according to the temperature of the outlet water and whether it meets the process requirements, completely realizing automatic operation without manual intervention, and realizing efficient operation of water and electricity saving.