The relationships between the second law efficiency of system and the evaporation temperature (T1)are investigated when the rage of waste heat temperatures (T5) is from 423.15 K to 358.15 K with theintervals of 5 K and pinch temperature difference (T1) is 5 K in the evaporator. For simplicity andclarity, the relationship of the second law efficiency and the evaporation temperature are shown inFigure 3 for only two waste heat temperatures. Table 3 lists the OET and the second law efficiency forthe highest and the lowest waste heat temperatures investigated, respectively.