No abstract

A new process of low temperature triple-effect distillation desalination is designed. Firstly, the appropriate effect number is determined. The total heat transfer coefficients and the heat loads of each evaporator are calculated. When the pressure differences between near effects are equal to △P, the freshwater outputs and the heat transfer coefficients of every effect would be increased as △P improved; if △P is too low, the seawater un-evaporated in the last evaporator would be difficult to flow into the next one. By analysis, the appropriate value of △P is 0.005 MPa. If the seawater flowing into the first effect is preheated by the heat source flow outpouring the unit, the total heat utilization rate and the freshwater output would be enhanced.

It is studied the collected heat by collectors fixed on the outside wall of balconies when the shape and direction of balconies, and inclination angle of collectors are changed. Total heat collected by three walls of the rectangle balcony toward southeast or southwest is more than the one collected under other conditions. Total heat collected by rectangle balcony toward south would be increased when the inclination angles β of collectors are reduced. As β=70°, and the collectors were installed only on the south wall, to make water temperature above 60 °C in 150 L tank, extra energy needed is equivalent to 46.5 kg/a standard coal; if collectors were installed outside three walls of balcony, extra energy is not needed.