Investigation of Waste Heat Recovery from a 4E Perspective: Performance of Combined Cooling, Heating, and Power Systems with Various Prime Movers for Residential Applications

In this context, a baseline building with an electrical demand of 42 kW has been considered as the consumer. The simultaneous production system incorporates modes of Combined Cooling, Heating, and Power (CCHP), Combined Heat and Power (CHP), Combined Cooling and Power (CCP), and single using four prime movers with gas turbine, steam turbine, Otto, and diesel cycles. The prime movers have been modeled in EES and waste heat of each prime mover investigated. On the other hand, different configurations have been introduced in order to recover the waste heat of each prime mover. The study demonstrates that an increase in operating pressure leads to improved performance in prime movers from an energy perspective, results showed that efficiency improvement in steam turbine, gas turbine, diesel and Otto cycle is 47.7%, 52.5%, 33.7% and 21.1% for CHP mode and for CCHP mode is 50.5%, 55.8%, 35.7% and 22.4% respectively. However, the best efficiency is associaated with the Otto cycle, where the utilization of waste heat recovery can increase efficiency by an average of 40%. Waste heat recovery generates the most significant increase in exergy efficiency in gas turbine and steam turbine cycles is 175% and 306%. Specifically, the average increase in gas turbine cycle exergy efficiency is 1.58 times that of the Otto cycle in CHP mode. Furthermore, the best exergy performance occurs in CCHP mode. Ultimately, the Otto cycle demonstrates the best performance in terms of fuel savings, while the gas turbine cycle is most effective in reducing carbon dioxide emissions.