PRDT

    A shell and tube evaporator is a type of evaporator used in refrigeration systems. In this type of evaporator, the fluid to be evaporated is located outside the tubes, while the tube bundle is immersed in the saturated fluid contained on the shell side1. The tubes sit inside the shell and contain the chilled water, while the shell holds the refrigerant. The refrigerant and water never meet or mix, they are always separated by the metal wall of the tube and only the heat transfers between these.

    Category:

      Two types of shell and tube evaporators can be distinguished:

      Shell and tube flooded evaporators

      In the shell and tube flooded evaporator, the fluid to be evaporated is located outside the tubes. The tube bundle is immersed in the saturated fluid, contained on the shell side. Boiling can then occur by nucleation or by film, depending on the heat transfer situation. By acting on the liquid level, it is possible to ensure operating conditions and a steam overheat of up to 5 °C.

      Shell and tube dry expansion and thermosyphon evaporators

      Shell and tube dry expansion and thermosyphon evaporators work with the fluid to be evaporated circulating inside the tubes. In the case of dry expansion, it is supplied by a thermostatic expansion valve, allowing it to regulate the overheat. Used in the field of industrial refrigeration, the refrigerant circulates inside the tubes (sometimes with improved geometry) to improve transfer performance and increase the compactness of the heat exchangers. Thermosyphon evaporators are more often used in distillation processes and are located at the bottom of the column with a manometric head, allowing recirculation.