Parametric analysis and yearly performance of a trigeneration system driven by solar‐dish collectors

Abstract

Solar-driven polygeneration systems are promising technologies for covering many energy demands with a renewable and sustainable way. The objective of the present work is the investigation of a trigeneration system, which is driven by solar-dish collectors. The examined trigeneration system includes an organic Rankine cycle (ORC), which operates with toluene, and an absorption heat pump, which operates with LiBr/H2O. The absorption heat pump is fed with heat by the condenser of the ORC, which operates at medium temperature levels (120°C to 150°C). The absorption heat pump produces both useful heat at 55°C and cooling at 12°C. The ORC produces electricity, and it is fed by the solar dishes. The examined ORC is a regenerative cycle with superheating. The total analysis is performed with a developed model in Engineering Equation Solver (EES). The system is investigated parametrically for different ORC heat-rejection temperatures, different superheating levels in the turbine inlet, and various solar-beam irradiation levels. Furthermore, the system is investigated on a yearly basis for the climate conditions of Athens (Greece) and for Belgrade (Serbia). It is found that the yearly system energy and exergy efficiencies are 108.39% and 20.92%, respectively, for Athens, while 111.38% and 21.50%, respectively, for Belgrade. The values over 100% for the energy efficiency are explained by the existence of a heat pump in the examined configuration. For both locations, the payback period is found close to 10 years and the internal rate of return close to 10%. The final results indicate that the examined configuration is a highly efficient and viable system, which operates only with a renewable energy source.