In hot and dry areas, the environmental temperature is relatively high in summer. Even if reducing temperature difference of the air cooled heat exchanger and increasing heat transfer area, the temperature of the process fluid in the tube cannot be cooled to the required value. Therefore, air coolers with special structures need to be used in hot and dry areas.

(1) Humidifying air cooled heat exchanger

In continental climates or desert areas, the temperature is high and dry, and the difference between the dry bulb temperature and the wet bulb temperature is greater than 30°F. If the method of humidifying the air can be used to reduce the dry bulb temperature of the air to close to the wet bulb temperature, the heat transfer temperature difference can be increased, and the cooling capacity can be improved. The humidifying air cooler is composed of a humidifying chamber, a water separator, a circulating water pump and an air cooler. The water is continuously sent from the pool to the water distribution plate by the circulating water pump, and sprayed into the humidification chamber. When the air passes through the humidification chamber, it is cooled to close to the wet bulb temperature due to the evaporation of water, and then passes through the water separator to remove the water and enters the air cooler. When the air temperature is higher than the design value, the air door of the ventilation chamber is closed. When the air temperature is lower than the design value, the air door is automatically opened and the water is automatically cut off, so that the air directly passes through the fin tube bundle. In this way, in the summer night, autumn and winter, the circulating water pump can not be started, and the air cooler runs in dry way. Humidifying air coolers are used in some countries, mainly in the Middle East. The relative humidity is relatively high in most areas of China, with the exception of western regions, humidification air coolers are rarely used.

(2) Combined use of air cooler and cooling tower

The air cooler is combined with the cooling tower. The high-temperature air is directly contacted with water in the cooling tower to be quenched, and the cooled low-temperature air is then supplied to the air cooler as a cooling medium to cool the process fluid. The advantages of this method are:

①　Low water consumption;

②　The operation mode of the cooling tower can be adjusted according to the change of the air temperature. When the temperature is low, the cooling tower is stopped and the air enters the air cooler directly;

③　There is no need to carry out water treatment, and water with salt or alkali can be used;

④　The air discharged from the air cooler does not contain water mist or condensed water droplets, because after the air passes through the finned tube bundle, the water vapor in it is unsaturated and there is no water mist;

⑤　The air passing through the fin tube bundle is clean. After the summer air is washed by the cooling tower, the dust, sand and insects are washed away.

In addition, the existing cooling tower can also be combined with an air cooler, that is, the air cooler is installed next to the cooling tower, and the cold air drawn from the lower part of the cooling tower is used as the cooling tower air of the air cooler. This not only increases the processing capacity of the cooling tower, but also meets the needs of the air cooler.

The combined system of air cooler and cooling tower designed and manufactured by Luoyang Gaohua has been applied to the drying of Ningxia and Inner Mongolia in China, and the cooling effect has been recognized by customers.