Comparable analysis methodology of CCHP based on distributed energy system

• A comparable assessment methodology on DES-based CCHP is proposed.
• Energy cost of low valued heat consumed by CCHP is calculated based on energy grade.
• DES-based hot-water-driven cooling system is more efficient than electric chillers.

Energy and environmental issues have become increasingly prominent in the world. Distributed energy systems (DESs) and the combined cooling, heating, and power (CCHP) have been applied in the world. However, the evaluation of DESs and CCHP performance based on primary energy consumption is in dispute. Moreover, pursuing high performance of separate cooling/heating system is not beneficial for popularizing low-exergy cooling/heating technology in the field of DES in China. This study uses the pure-power-generation working condition of the DES as a baseline condition to conduct comparable analysis on DES-based CCHP according to energy grade. It is found that equivalent power consumption of steam and hot water consumed for CCHP is the power-generation capacity reduction of the DES compared with the baseline condition of the DES. DES-based steam and hot-water heating systems can save comparable energy cost (a sum of the equivalent and the direct power consumptions) by approximately 72% and 98%, respectively, compared with natural-gas-fired boilers. Hot-water-driven and steam-driven absorption cooling system based on the DES reach comparable coefficient of performances (a ratio of cooling capacity to comparable energy cost) of approximately 11.4 and 5.7. Thus, the proposed analysis methodology uses the power-generation capacity as benchmark to conduct energy grade analysis, and can more comparably and reasonably identify energy-saving capability of DES-based CCHP.