Introduction; cooling tower is set aerodynamics, thermodynamics, fluid, chemistry, biochemistry, materials science, quiet, multi-disciplinary dynamic structural mechanics, and processing technology as one integrated product. Water quality is a function of more variables, cooling is multifactorial, multi-variable and multi-effect integrated process. A variety of disciplines as one integrated product. Water quality is a function of more variables, cooling is multifactorial, multi-variable and multi-effect integrated process. Definition is the use of air cooling towers with water contact (direct or indirect) round cooling tower water to cool equipment. Is a water circulating coolant absorbs heat from the system and discharged to the atmosphere, thereby reducing the tower air temperature, manufacturing equipment cooling water can be recycled for use. Applications are mainly used in air conditioning cooling tower cooling systems, refrigeration series, plastic, leather, foam, power generation, steam turbine, aluminum processing, air compressors, industrial water cooling and other fields, the most widely used for air-conditioning cooling, freezing, plastic chemical industry. Specific division, as follows: A, air temperature adjustment categories: air-conditioning cooling towers located round equipment, refrigerator, freezer, refrigeration, heating and air conditioning; B, manufacturing and processing categories: food, medicine, metal casting, plastic industry , rubber, textiles, steel mills, chemical industry, petrochemical products, etc.; C, the mechanical operation of cooling categories: generators, turbines, compressors, hydraulic machines, engines, etc; D, other types of cooling tower industry ...... role is to carry the waste heat of the cooling water in the inside of the tower for heat exchange with the air, so that the waste heat is transferred to the air and scattered into the atmosphere. Classify cooling tower cooling tower, divided by ventilation mode: ① natural draft cooling towers; ② mechanical draft cooling towers; ③ mixing ventilation cooling tower water and air by way of contact points: ① wet cooling towers; ② dry cooling towers; ③ wet and dry cooling towers. Square cross-flow cooling tower by hot water and air flow direction points: ① cooling tower; ② cross-flow (direct exchange) cooling towers. Divided by field of application: ① industrial cooling towers; ② air conditioning cooling towers. Divided by the noise level: ① common type cooling towers; ② low-noise cooling towers; ③ ultra-low-noise cooling towers; ④ ultra-quiet cooling tower. By shape points: ① round cooling tower: ② square cooling tower. Other types of cooling towers, such as jet-flow cooling tower, no fan cooling tower. Square counterflow cooling tower cooling tower cooling tower general structure generally consists of filler (also known as thermal material), water distribution systems, ventilation equipment, air distribution device (such as: air inlet shutters, wind deflector, wind torso), retaining device ( or close the water), a sump (or sump) and other parts, different combinations of the above structure can be configured to different types of cooling towers. Principle of the generic term "cooling tower" is used to describe the direct (open) and indirect (closed) cooling equipment. While most think of a "cooling tower as a heat sink in direct contact with open", indirect cooling tower, sometimes called "closed circuit cooling tower" is but also a cooling tower. A direct, or open cooling tower is sealed inside the structure as a means to distribute it in warm water to feed the labyrinth packing or "fill." Padding provides a greatly expanded aviation, evaporation of water and heated air interface occurs. Cooling water, because it is filled by gravity through falls, and in direct contact with the air across it. In the cooling water, and then collected in a lower than it is from the whole process back to absorb more heat pump cold water basin fill. Heat and humid air is filled from left filling the air discharge point remote enough air inlet to prevent them from being involved in the cooling tower back. Filling may include multiple, mostly vertical, water, wet surface upon which the spread (filled) or landscape elements to create a splash with a larger surface area of ??many small droplets cascading several levels films (splash). Indirect, or closed circuit cooling tower does not involve air, liquid, usually water or a glycol mixture in direct contact, is cooled. The difference is that open cooling towers, indirectly owned by two separate fluid circuit cooling tower. An external circuit water is in the second track, which is outside the circle bundle hot fluid process (closed coil) is connected to a closed cooling and return. Air is drawn across the water cascading through the loop heat pipe outside, provide similar open evaporative cooling tower. In the operation of the heat from the internal fluid circuit, through the coil tube wall, the external circuit, and then evaporated by a number of heated air and water, into the atmosphere. Indirect cooling tower operations, it is very similar to the open cooling tower with one exception. This process is the coolant in a "closed" circuit, is not directly exposed to the atmosphere or external circulating water. In counterflow cooling towers or air travel by filling up the bundle, the downward movement across the water. Move down in the cross-flow cooling tower air moves horizontally through the fill water. There is also a feature of the cooling tower, which means the aeronautical mobile mechanical draft cooling towers rely on electrically driven fan to attract or forced air tower. High growth in the use of natural draft cooling tower exhaust chimney draft air buoyancy provided. Fan-assisted natural ventilation using mechanical draft cooling towers, in order to increase the impact of buoyancy. Many draft air wind generated by the cooling tower earlier. Cooling tower operating principle if the cooling water from the cooling tower back to reuse some of the water must be replaced or added to the constitution, that part of the flow of evaporation. Including pure water due to evaporation, minerals and other solid circulating water concentration of dissolved tends to increase, unless some dissolved solids under control as a means to combat offers. Some water is also lost with the exhaust gas being carried (drift) spray, but this is usually reduced to a very small amount of the bezel-like device, called drift eliminators, collect droplets. Must be equal to the amount to make up for evaporation, blowing down the total drift, such as wind power and other water seepage blowout loss to maintain a stable level.