Evaluation of an Organic Rankine Cycle Using a Non-Imaging Solar Concentrator for Different Working Fluids

Abstract

The Organic Rankine Cycle (ORC) is a feasible technology that can be applied for small-scale power generation in residential and commercial buildings. However, a solar thermal power plant may not compete with that of a thermal power plant using conventional heat source such as coal or natural gas but environmental impact. On the other hand, the cost of a power plant may be reduced by improving the system performance. Using non-imaging concentrators can eliminate the necessity of sun tracking system. Covering the concentrators by evacuated glass tube can reduce the heat loss from the absorber, and improves the effective life-cycle of optical components. Therefore, a nonimaging concentrator was considered as a steam generator of solar power plant. In order to evaluate the system performance, simulations were conducted by using aspen HYSYS software for different working fluids. The maximum performance is obtained for the case of R-141b for the pressure difference of 39 bars to be 15.3%. The best performance improvement is attained for water and R-141b to be about 8.2% and 7.8%, respectively. The working fluid, R-141b shows a better performance due to its lower boiling point and may be preferable for small scale applications.