For a double-effect evaporator, its heat transfer function is indispensable; without it, the evaporator is merely a heap of scrap metal and has no value. During actual use, numerous factors may affect the heat transfer of a double-effect evaporator. Below, we will delve into the specific factors that can impact the heat transfer of a double-effect evaporator:

What Factors Affect the Heat Transfer of a Two-effect Evaporator?

An analysis from a thermodynamic perspective typically reveals that refrigerant entering the evaporator after throttling and under the evaporation pressure Po is usually in a liquid or a liquid-vapor mixture state. The refrigerant absorbs heat from the cooled medium through a heat transfer wall, thereby lowering the temperature of the cooled medium. Meanwhile, the refrigerant liquid boils and vaporizes into saturated vapor or superheated vapor at a relatively stable low temperature and pressure, which is then drawn into the refrigeration unit after leaving the evaporator.

From a thermodynamics perspective, although there are various forms of evaporators, they generally fall under the category of inter-wall heat exchangers, where the refrigerant and the cooling medium exchange heat on either side of the heat exchange wall. On the refrigerant side, the refrigerant absorbs heat through the phase change of vaporization. On the other side, the cooling medium continuously flows through the heat exchange wall, releasing sensible or latent heat according to process requirements, and then gets cooled, liquefied, or frozen.

In most cases, the evaporator is the primary heat exchange device in a refrigeration system. Like the condenser, the evaporator's heat transfer depends on factors such as the heat exchange surface area, the heat transfer temperature difference, and the heat transfer coefficient. For a selected evaporator, the heat exchange area is fixed, so the main focus is on increasing the heat transfer coefficient, in addition to appropriately raising the heat transfer temperature difference. The enhancement of the heat transfer coefficient is influenced by factors such as the thermophysical properties of the cold and hot fluids, their flow conditions, the characteristics of the heat transfer surface, and the structural performance of the evaporator. Similarly, analyzing these factors is beneficial for implementing measures in the design, installation, management, and operation and maintenance of the evaporator to improve its heat transfer efficiency.

Here are some factors that can affect the heat transfer of a double-effect evaporator. Generally, factors influencing the heat transfer of an evaporator are unavoidable, but we can try to minimize the impact on the heat transfer of the double-effect evaporator in our daily use.