In the present work, we focus on an incomplete combined heat and power (CHP) system. The supplementary thermal performance has been designed to increase the efficiency of the heating system by designing a shell and tube heat exchanger to recover the heat from the exhaust gases. A plate heat exchanger has also been designed for cooling the biogas-diesel generator and the exhaust gases. Two types of nanofluids with the same concentration (4% v/v) were then prepared for use as the circulating fluid to recover heating power from the CHP system. The results show that using nanofluids enhances the thermal performance of the CHP system, and the use of aqueous CuO is more advantageous than the use of aqueous Al2O3 as a cooling nanofluid. This change also causes a dramatic increase in the outlet flow of the hot water from the unit.

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