Optimizing the performance of a hybrid Solar-Biomass micro-CHP system with a TFC engine as the prime mover for domestic applications

Abstract

solar energy and biomass with a Trilateral Flash Cycle (TFC) engine as the prime mover is simulated and optimized in this work. The system is sized to meet the Space Heating (SH) demand of a typical multi-family building in Athens, Greece. Particular attention is paid to the challenging two-phase expansion phenomenon, the factor mainly affecting the efficiency of the TFC, under off-design and partial load conditions. Under optimized operating conditions, the average annual CHP efficiency, TFC thermal efficiency, and solar energy conversion efficiency were estimated to be 89.2%, 8.4%, and 4.3%, respectively. The TFC can cover 18% of the building’s SH demand and 40% of its electricity demand, with the Levelized Cost of Electricity (LCOE) and Levelized Cost of Heat (LCOH) in the range of 0.21~0.28 €/kWhel, and 0.065~0.087 €/kWhth, respectively. Furthermore, PayBack Periods (PBP), between 15 and 25 years, can be anticipated, when current market energy prices are considered.