Plate heat exchanger used as evaporators.

The research included in this paper was performed in the Thermodynamics Laboratory, part of the Technical University of Civil Engineering, Bucharest. The research refers to the evaporation of ammonia in plate heat exchangers, used for liquid cooling. The authors present a theoretical modeling of convective heat transfer coefficient. The convective heat transfer coefficient of evaporating ammonia in narrow spaces is calculated using different correlations. Simultaneously, the authors present the experimental modeling, together with the measured values and the data acquisition system. Further a comparison is made between the experimental and theoretical data, aiming to confirm the correlations’ validity for both the geometry and the given functioning conditions of the plate type evaporator. The conclusions section recommends the use of the plate heat exchanger as an evaporator, in operating conditions similar to those used in the experiment. The present interest of this paper comes also from its focus on ammonia – a natural and ecological refrigerant – having no ozone depleting potential and low global warming effect.