Analysis of combined cooling, heating, and power systems under a compromised electric–thermal load strategy

• Analysis is performed when the thermal load is larger or the thermal load is larger.
• The performance of different operation strategies in CCHP system is discussed.
• Efficacy coefficient method is used to get the compromised degrees.
• Compromised electric–thermal load strategy is proposed innovatively.

Following the electric load (FE) and following the thermal load (FT) strategies both have advantages and disadvantages for combined cooling, heating and power (CCHP) systems. In this paper, the performance of different strategies is evaluated under operation cost (OC), carbon dioxide emission (CDE) and exergy efficiency (EE). Analysis of different loads in one hour is conducted under the assumption that the additional electricity is not allowed to be sold back to the grid. The results show that FE produces less OC, less CDE, and FT produces higher EE when the electric load is larger. However, FE produces less OC, less CDE and higher EE when the thermal load is larger. Based on a hybrid electric–thermal load (HET) strategy, compromised electric–thermal (CET) strategies are innovatively proposed using the efficacy coefficient method. Additional, the CCHP system of a hotel in Tianjin is analyzed for all of the strategies. The results for an entire year indicate the first CET strategy is the optimal one when dealing with OC, CDE and EE. And the second CET is the optimal one when dealing with OC and EE. Moreover, the laws are strictly correct for different buildings in qualitative terms.