Simulation and evaluation of a CCHP system with exhaust gas deep-recovery and thermoelectric generator

Combined cooling, heating and power (CCHP) systems are thought to be highly efficient in energy utilization. But there are still potentials to further improve system performance. This work proposed a CCHP system based on internal combustion engine (ICE) for power generation, refrigeration and domestic hot water production. Thermoelectric generator (TEG) and condensing heat exchanger are applied to efficiently recover the exhaust gas waste heat of ICE. All the energy flows are designed based on energy cascading utilization principle. Basing on the test results of a 16 kW ICE, CCHP system characteristics are investigated by simulation from idling condition to full load condition. Especially, the part load performance of TEG and absorption chiller are simulated and discussed. The feasible operating zone of ICE and feed water flow rate are figured out to keep the domestic hot water temperature within a certain range. Results show that the primary energy efficiency of system can reach 0.944, thanks to the condensing heat recovery from exhaust gas. The primary energy saving ratio and cost saving ratio can reach 0.304 and 0.417, respectively. Considering some more equipment is incorporated, the total investment increment is about 11.1%.