How should we choose the right evaporator when producing chillers?
Tuesday, 01 September 2020
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The evaporator of the water chiller is mainly composed of a heating chamber and an evaporation chamber. The evaporator is a very important part of the four major parts of refrigeration. The low-temperature condensed "liquid" body passes through the evaporator and exchanges heat with the outside air. "It absorbs heat and achieves the effect of cooling. It can be said that evaporators are widely used in the chemical industry, food industry, pharmaceutical industry and other industries. So, how should we choose the right evaporator when producing chillers?
1. The water tank immersed evaporator is used in an open circulation system that does not evaporate refrigerant. For the production process of ice making with brine ice pools, closed-loop systems cannot be used, so this evaporator is the only preferred type. For chiller refrigeration systems that cool or freeze bagged food in salt water and centralized spray air conditioning, a water tank immersion evaporator can also be used.
2. Salt water is very corrosive to ferrous metals, and when it comes in contact with air, its rust effect becomes more intense. Therefore, if the production process permits, try to use a closed loop. For volatile refrigerant circulating systems, closed loops must be used. In these two cases, the horizontal shell and tube evaporator for the chiller is the best choice.
3. When the industrial chiller adopts water tank immersion or shell and tube evaporator, the working temperature of the refrigerant should be about 5℃ higher than the temperature of the refrigerant evaporator, and the freezing point of the refrigerant should be 5 degrees lower than the evaporating temperature of the refrigerant. ～8℃ (5～6℃ for water tank immersion evaporator, 6～8℃ for shell and tube evaporator).
4. The choice of cooling pipe and air cooler: For cold storage, air cooler is usually used to increase the cooling temperature. For the freezing room of small cold storage, shelf type pipe or wall pipe plus top pipe can be used. For cold storages that need to prevent the goods from drying out, wall pipes or jacking pipes are usually used. If there is no air-drying problem, coolers are generally used.
5. For industrial chiller evaporators with low evaporation temperature, attention should be paid to the effect of the height of the refrigerant liquid column on the evaporation temperature of the chiller. The lower the evaporation temperature, the greater the impact of the liquid column, so certain measures should be taken to reduce the height of the liquid column in the evaporator.