Energy utilization evaluation of CCHP systems

Combined cooling, heating and power (CCHP) is getting more attention for its energy saving. However, until now it is not clear yet that how to evaluate the energy utilization of CCHP scientifically and if energy saving is intrinsic to CCHP systems. One of the reasons for this lies in the inappropriate selection of reference situations that making the comparison between the gas cogeneration and the separate production fueled by coal. Another is that the ideal efficiencies of CCHP units are often cited and the differences of various practical performances are often ignored in the comparison. In this paper, an appropriate reference situation is suggested and the practical statistical performances of various units are introduced. Then, a static calculation methodology for evaluating the primary energy consumption for CCHP and separate productions is presented. Fuel energy saving ratio (FESR) definition and the boundary conditions that have to be met by CCHP systems for being energy saving to separate productions are given. Moreover, the energy saving performances of various types and sizes systems in heating and cooling modes are analyzed. Energy saving is not intrinsic but conditional to CCHP systems. The systems with the larger electric power have the higher energy saving potential.