The Influence of Condensing Temperature on the Efficiency of Solar Power Systems with ORC

Abstract Organic Rankine cycle technology is suitable for electricity production from low-grade heat sources: solar, geothermal, waste heat. The thermal efficiency of the organic Rankine cycle is influenced the value of the minimum temperature of the cycle, which is the temperature of condensation. The paper analyzes the influence of the condensing temperature on the efficiency of the solar power systems using organic Rankine cycles. Is performed the calculus of thermal efficiency of ORC for condensing temperature in the range 25-10°C. The analyze was done for two different working fluids: R600a and R134a. The results show that the thermal efficiency and amount of electricity produced by a solar ORC system can be increased by lowering the condensing temperature.