Enhanced exergy analyses of a gas engine heat pump (GEHP) dryer for medicinal and aromatic plants

In this study, the performance of a gas engine heat pump (GEHP) drying system is evaluated using both conventional and advanced (or enhanced) exergetic analysis methods. The results indicated that the inefficiencies within the compressor and the drying ducts are mainly due to the internal operating conditions while the efficiency of the condenser could be improved by structural improvements of the whole system and the remaining system components. High levels of endogenous exergy destruction show that the component interactions do not contribute significantly to the thermodynamic inefficiencies. Thus, one should focus on how to reduce the internal inefficiency rates of the components. On the overall system basis, the value for the conventional exergetic efficiency is in the range of 79.71-81.66% while that for the modified exergetic efficiency varies between 84.50 and 86.00%, through improving the overall components.