I. Dry-type evaporator Dry-type evaporator refrigerant passes through the heat exchange tube, and cold water runs outside the high-efficiency heat exchange tube. The heat exchange efficiency of such a heat exchanger is relatively low, and its heat transfer coefficient is only the light pipe heat transfer coefficient. It is about 2 times as much as that of the conventional one, but its advantage is that it is easy to return the oil and the control is relatively simple. The refrigerant charge is about 1/2 to 1/3 of the full-fluid unit charge.
2. Full-liquid evaporator: The full-liquid evaporator and dry-type evaporator operate in exactly the opposite way. Cold water passes through the heat exchanger tube, the refrigerant completely submerged the heat exchanger tube, and it absorbs heat and evaporates outside the heat exchanger tube. There are many needle-shaped holes on the surface of the heat transfer tube of the liquid-filled evaporator, and there are spiral protrusions on the inner surface of the tube to strengthen the cold water side heat exchange. This high-efficiency heat transfer tube, which simultaneously strengthens the boiling outside the tube and the heat transfer inside the tube, increases its heat transfer coefficient by about 5 times compared to a light tube.
3. Falling film evaporator: Falling film evaporator, also known as spray evaporator, this heat exchanger is similar to the full liquid evaporator, but it is different from the full liquid evaporator. The refrigerant of this evaporator is sprayed onto the heat exchange tubes from the upper part of the heat exchanger. The refrigerant only forms a thin layer of refrigerant liquid on the heat exchange tubes, so that the refrigerant will reduce when it boils and evaporates. The hydrostatic pressure is increased, which improves the heat exchange efficiency. The heat exchange efficiency is increased by about 5 compared with the full liquid unit.