Optimization and performance analysis of CCHP-GSHP-SE system under different start factors

•The important indicators of equipment operation are first proposed in the system.•The concept of ground source heat pump start factor is proposed.•The comprehensive performance of the system is analyzed under different start factors. The CCHP-GSHP-SE (combined cooling and heating power-ground source heat pump-solar energy) system can provide a reliable energy source. Due to the variability of building load, the energy flow of the system cannot match the building load well, resulting in low efficiency of equipment. In this paper, considering the multi-terminal supply of energy and the transfer characteristics of building load, the performance of equipment can be effectively enhanced. The operation efficiency of equipment can be improved by setting GSHP-SF (ground source heat pump-start factor). When the load level of GSHP (ground source heat pump) is lower than the start factor (SF), the GSHP stops working and transfers this part of the load to other equipment, which effectively improves the performance of devices. The performance of the system is explored under different GSHP-SF. The ACOP (annual comprehensive of performance) and AUR (annual useful ratio) are first proposed to characterize the performance of the devices. The results show that, when start factor is 0.4, the comprehensive performance of system is the most. In terms of comprehensive performance, the CCHP-GSHP-SF-SE system reaches 10.92% and CCHP-GSHP-SE system reaches 3.05% compared with CCHP-SE system. The setting suitable GSHP-SF can enhance the double effect of GSHP for the comprehensive performance of system.