Reasons and treatment methods of insufficient heat exchange in the evaporator of the chiller
The evaporator is one of the four major components of the chiller. The evaporator is a heat exchanger that allows the low-temperature liquid refrigerant to exchange heat with the medium that needs to be refrigerated. There are probably two reasons for the insufficient heat exchange of the chiller evaporator: 1. Evaporation Insufficient water flow in the evaporator, 2. Foreign matter in the evaporator is blocked (or the surface of the evaporator tube in the evaporator is scaled or crystallized, resulting in insufficient heat exchange)
1. Insufficient water flow in evaporator:
The main factors that cause this phenomenon are the failure of the water pump or the entry of foreign matter in the impeller of the water pump, or the leakage of the water inlet pipe of the water pump (which is difficult to check and requires careful analysis), resulting in insufficient water flow.
Treatment: replace the water pump, or disassemble the water pump to clear the foreign matter in the impeller, then the fault can be eliminated.
2. The evaporator is blocked or fouled:
To judge whether the evaporator is clogged or the evaporator tube is fouled, the problem of the water pump must be eliminated first, and it can be determined after ensuring that the water pump and the water inlet pipe are normal. The evaporator blockage or structure has a common and very obvious feature (only applicable to medium-temperature chillers): when the equipment is normal, there will be no large amount of condensate or frost or ice on the surface of the compressor. When you see a lot of condensate or frost on the surface of the compressor, it can basically be judged that the evaporator is blocked.
Treatment: If the evaporator is blocked or the evaporator tube is fouled, the evaporator should be disassembled, and the evaporator tube should be unloaded and rinsed with a high-pressure water gun or soaked in a special chemical liquid.
Note: Some evaporators use chemical liquids, such as refrigerators in aluminum oxidation (anodic oxidation) processing plants. The evaporators contain sulfuric acid liquids. When certain conditions are reached, the sulfuric acid will crystallize and block. If the evaporator is blocked by pure sulfuric acid crystals, as long as the hot water above 50 degrees is circulated in the evaporator, the crystals can be dissolved. Some are used in electroplating plants, such as acid zinc plating. Some acidic zinc plating solutions contain "potassium chloride". When the "potassium chloride" liquid passes through the surface of the evaporation tube of the evaporator, the surface temperature of the evaporation tube is very low (below the saturation temperature), which will cause " "Potassium chloride" precipitates crystals, these crystals will wrap the evaporator tube with a thick layer of "potassium chloride" clothing over time, making the evaporator lose its heat exchange capacity. Minor is manifested as a decline in refrigeration capacity, and in severe cases it causes low pressure failure. (In this case, the selection is incorrect at the time of purchase)