Life cycle performance of a distributed energy system in comparison with a conventional energy system for district heating and cooling in China

Abstract

The distributed energy system (DES) using renewable energy is an energy efficient alternative for heating and cooling swimming pools . However, analyses on the environmental performance of DES when applied to swimming pools have been scarce. In this context, DES for district heating and cooling is investigated on the basis of a comprehensive life cycle performance that is benchmarked with a conventional energy system (CES). Two life cycle assessment models are established using GaBi 8 software. Data of materials, energy, transportation and emissions are collected from site statistics, simulation results and GaBi databases. Then, the environmental performances of the models are evaluated using EI 99 method, and the carbon footprint (CF) is quantified through CML 2001 method. The Monte Carlo method is utilised to investigate uncertainty. In addition, the breakeven year is explored. Results show that DES is superior to CES in terms of acidification , climate change (CC), radiation, inhalable inorganic matter (IIoM), inhalable organic matter (IoM), fossil fuels (FF) and minerals. The environmental performance of ecotoxicity for DES is similar to that of CES, and the carcinogenic effect of DES is worse than that of CES. DES is superior to CES in the usage and demolition phases and is worse than CES in the construction phase. Raw materials and energy consumption structures significantly affect environmental performance. The environmental burden of DES is 41.80% lower than that of CES and is mainly influenced by FF, CC, IIoM and IoM. The net CFs of DES and CES are 3.73 × 10 6 and 6.04 × 10 6 kg CO 2 -eq, respectively. The breakeven years of CF, FF, IIoM and total environmental impact potential for DES is 1.0, 0.15, 0.9 and 0.45 years, respectively. The results indicate that the environmental performance of DES is superior to CES. Reducing natural gas consumption is the key to improving environmental performance. This study may provide guidance for the application development of DES.