Analysis of Solar-Thermal Power Cycles for Distributed Power Generation Available to Purchase

In this study, the thermoeconometric feasibility of a 12.5 kW solar thermal power system is discussed. A previous study by these authors examined five potential 12.5kW solar thermal cycles and preliminary thermoeconometric analyses based on the collector area. The current study expands to six potential power cycles, including the five from the previous study, the Rankine, R123 Organic Rankine, toluene Organic Rankine, ethylbenzene organic Rankine, and the Kalina cycle, with the addition of the Maloney-Robertson cycle as well as detailed cost analysis for the components associated with each cycle. A detailed first law thermodynamic analysis for the Maloney-Robertson and Kalina cycles is presented. Likewise, the pinch point analysis is used for the inclusion of the sink and source stream as well as a developed heat exchanger model. The thermoeconometric study includes cost-per-component estimates for all of the components in the cycles; thus, increased component cost is taken into account for the ammonia-water cycles. The findings from this study show that R123 is the only cycle that operates with a source temperature below 225°C within the cycle applied operating constraints for meso-scale distributed power generation.. When higher temperatures are achieved, the Kalina cycle has the highest thermal efficiency but also the highest cost-to-efficiency ratio. Therefore, the thermoeconometrics study shows that the toluene and ethylbenzene ORCs have the lowest cost-to-efficiency ratio when source temperatures reach 225°C to 350°C even though they do not have the highest cycle efficiencies.