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

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 (CC), 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 CC, less CDE, and FT produces higher EE when the electric load is larger. However, FE produces less CC, 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 CC, CDE and EE. And the second CET is the optimal one when dealing with CC and EE. Moreover, the laws are strictly correct for different buildings in qualitative terms. (C) 2014 Elsevier B.V. All rights reserved.