Analysis of single-effect evaporator desalination systems combined with vapor compression heat pumps

A comparison was performed for four different types of single-effect evaporator desalination systems. The systems are driven by vapor compression heat pumps including thermal (TVC), mechanical (MVC), absorption (ABVC), and adsorption (ADVC). The study includes the development of mathematical models for the four systems. The models include equations for energy and mass conservation. In addition, design equations are used to determine the heat transfer areas in the evaporator and the condenser. The analysis is based on comparison of the performance ratio, specific power consumption, specific heat transfer area, and specific cooling water flow rate. For the four systems the specific surface area for the evaporator and the condenser is decreased upon the increase of the boiling temperature. The performance ratio for the thermal vapor compression system is decreased as the boiling temperature and pressure of motive steam are increased. In the MVC system, the specific power consumption is found to decrease with the increase of the boiling temperature and its difference with the temperature of the compressed vapor. The ABVC and ADVC systems have higher potential than the other two configurations. This is because of the higher performance ratio found in both systems and the generation of hot utility water.