Comprehensive performance of parallel feed MEE-MVC evaporation system

Abstract

Abstract The mathematical model based on conservation of energy, mass and salinity is established to analyse the comprehensive performance of parallel feed multi-effect evaporation system with mechanical vapor compression (MEE-MVC) system. It is found that the efficiency of the MVC evaporation system gradually improves as the number of evaporator effect increases. However, the optimization trend of specific power consumption (SPC) and coefficient of performance (COP) are declining when the number of evaporator effect exceeds 3, which makes the marginal effect of the efforts made to improve the system gradually weakened. Then, the three-effect MVC evaporation system is taken as the main research subject to investigate comprehensive performance of the system. It was found that the SPC of the system increases with the increase of the total heat transfer temperature difference; on the other hand, the COP decreased significantly with the increase of the total heat transfer temperature difference. Furthermore, increasing the evaporation temperature in the last evaporator as well as compressor efficiency can optimize the energy efficiency of the system. In addition, the compressor efficiency has a greater influence on the SPC when the total heat transfer temperature difference is larger, whereas the compressor efficiency has a greater influence on the COP when the total heat transfer temperature difference is smaller.