Performance of a small-scale solar cogeneration system in the equatorial zone of Malaysia

•A small-scale solar cogeneration system is simulated based on the climate of the equatorial zone country of Malaysia.•The system comprises parabolic trough collector, thermal storage and organic Rankine cycle.•An analytical study for the degree of the superheated condition of the organic Rankine cycle is conducted.•The measured solar condition at the geographic location of 3.1728 °N, 101.7215 °E is discussed.•The monthly performance of the system is applied to deduce for an annual operation period. Solar energy is one of the most promising renewable energy sources in the equatorial zone of Malaysia. The availability of moderate solar energy during the year makes it possible to be used as a heat source for a solar thermal system. In order to determine the potential application of the solar thermal system, a feasibility study of a small-scale solar cogeneration system under measured solar radiation condition is conducted. In this work, the concept design of a 50-kW solar cogeneration system is proposed which consists of a parabolic trough collector with aperture area of 1154 m2, thermal storage system and an Organic Rankine Cycle power conversion system. The performance of the system was simulated using the measured direct normal irradiance during the months of May, June and July in 2018. A net gross electric power of 6373 kWh, 6201 kWh and 5155 kWh were produced with the total monthly available solar energy of 82,809 kWh, 77,592 kWh and 64,239 kWh for May, June and July, respectively. The efficiency of the solar to electric was around 8% and was in good agreement with the findings in the literature. The results for the solar cogeneration system can serve as an evaluation reference for the application of solar thermal system in the moderate solar radiation localities in Malaysia.