Evaluation of a novel coupling system for various load conditions under different operating strategies

• System models under FTL and FEL strategies are built and calculated.
• System performances for various load conditions under two strategies are evaluated.
• The key design parameter is revealed; the preferred operation strategy is suggested.

In previous research, a novel coupling system, which integrates the combined heating and power system and the ground source heat pump system, is proposed and investigated. In this paper, in order to make the novel system more suitable for the buildings load demand, the performance characteristics for various load conditions are evaluated under two different operation strategies: following the thermal load and following the electricity load. For the comparison, the reference system integrated with common approach is also presented. The models for both systems are developed to examine their primary energy consumption. Energy saving ratio is selected as the evaluation criteria. Furthermore, a numerical case is given to illustrate the feasibility and availability of the novel system. The results show that the primary energy consumption of novel system is fewer than the reference system. The outlet temperature from the ground source heat pump system in novel system is the key design parameter; the lower outlet temperature can lead to a fewer primary energy consumption and a bigger energy saving ratio. Additionally, for the application of the novel system, the following the electricity load operation strategy should be preferred.