Refrigeration & Equipment Engineering

Unit 3 - Parts of refrigeration systems

3.2.1.2.Flooded type evaporators
In a flooded type evaporator a constant refrigerant liquid level is maintained. A front valve is used as a throttling device which maintains a constant liquid level in the evaporator. Due to the heat supplied by the substance to be cooled, the liquid refrigerant vaporizes and so the liquid level falls down. The float valve opens admit more liquid and thus maintains a constant liquid level. At a result the evaporator is always filled with liquid to the level determined by the float adjustment and the inside surface is wetted with liquid. Thus this type is called flooded type evaporator. The heat transfer efficiency increases because the entire surface is in contact with the liquid refrigerant and therefore the refrigerant change is relatively large as compared to the dry expansion type.