Abstract
This paper presents a thermodynamic evaluation of a combined power generation cycle for utilising the energy of low-temperature heat sources such as solar energy and industrial waste energy. The cycle connects the simple Organic Rankine Cycle (ORC) with the Trilateral Flash Cycle (TFC) via a cascade condenser. By applying the TFC in the high-temperature circuit and the ORC in the low-temperature circuit, the combined cycle enjoys the merits of the two subsidiary cycles. For evaluating the thermodynamic performance of the cycle, an Excel-based model is used that determines the fluid properties by using special functions developed with Microsoft’s Visual Basic for Applications (VBA). The performance of the combined cycle is compared with those of the simple TFC and ORC for a heat-source available at 120oC and various values of the cascade-condenser temperature by using R152a as the refrigerant in all three cycles.