Energy, exergy, economic, and environment (4E) assessment of a temperature cascading multigeneration system under experimental off-design conditions

Abstract

Multigeneration systems offering superior energy utilization efficiency are considered to be the next alternatives to conventional energy supply methods. In this study, a novel combined cooling, heating, power, and potable water system is proposed and experimentally investigated. An absorption chiller, a desiccant dehumidifier prototype, an indirect evaporative cooler prototype, and an adsorption chiller prototype are incorporated to realize an integrated energy/temperature cascade utilization system that recovers dissipated waste heat from a gas turbine. The proposed system's performance is firstly assessed by means of a 4E (exergy, energy, economic, and environment) off-design analytical method. Key results reveal that 71% of the dissipated waste heat can be recovered, and the primary energy saving ratio is 32.5%. In addition, the proposed system is capable of reducing up to 256 tons of CO2 emission every year compared with the conventional system. Results further highlight that the payback period of the proposed system is about 1.1 years when the annual operation time and power ratio of the gas turbine are 8000 h and 0.9, respectively. In addition, the effects of different variables on the economic feasibility of the proposed system are analyzed. Results also indicate that both national grid efficiency and fuel price exert greater influence on the payback year of the proposed system. Further, a case study is performed based on a typical tropic city's electricity, cooling, and heating demands. Lastly, the proposed system can be employed as a promising energy source supply taking into consideration its excellent energy saving potential, environmental sustainability, and economic feasibility.