抄録
The combined system, which consists of a solid oxide fuel celJ (SOFC) and a micro gas turbine (μGT), is expected to achieve much higher energy conversion efficiency. In this paper, performance evaluation of the small-scale distributed energy system based on a μGT-SOFC hybrid system, which can be operated under the two different part-load conditions, i.e. μGT variable speed (VS) and constant speed (CS) modes, is discussed in detail. Firstly, assuming continuous operation throughout a year, the effects of the intake air temperature on the performance of the hybrid system is investigated, and it is found that ambient temperature rise does not significantly affect the system performance degradation. Secondly, the energy conversion efficiency including the effects of the waste heat recovery from the hybrid system exhaust gas is evaluated. It is clarified that the overall efficiency can be reached over 80% (LHV) and the choice of the operation modes do not have remarkable effects on the system performance. Moreover, the characteristics of a single-effect absorption chiller unit driven with the waste heat of the hybrid system is discussed, and the COP of the absorption chiller becomes higher in the case of the CS mode. However, the overall energy conversion efficiency of the VS mode is higher than that of the CS mode, because the contribution of the power generation efficiency of the hybrid system on the overall performance of the small-distributed energy system is much greater than the advantage of the waste lipnt rernvprv
