New Designed Thermosyphon Solar Water Heater with Small Sized Parabolic Trough Collectors

Abstract

In this paper, the performance of thermosyphon solar water heater of small-sized parabolic-trough collectors has been experimentally investigated under Libyan climate. The solar collectors were fabricated from the locally available materials. The thermosyphon system consists of two parabolic troughs with 3.16 m2 aperture area and a storage tank of 170 liters. It is erected in the main outdoor testing area at the Center for Solar Energy Research and Studies for thermal performance evaluation. Twenty days of experiments were considered for the analysis of the new system performance. The experimental results showed that the maximum outlet temperature of withdrawn hot water at the end of the day was 73.4 °C for a daily solar insolation of 27.67 MJ/m2 and diffuse ratio less than 18% (clear sky). Whereas, the minimum hot water withdrawn temperature was 37 °C with daily solar insolation of 12.82 MJ/m2 and diffuse ratio over 61%. The system performance decreases as the diffuse ratio increases due to the nature of concentrating technology. The input/output characteristics equation of the system is obtained and the performance is compared with similar systems of the same size and different collection technologies. The compassion showed a competitive performance compared to other technologies.

Keywords

• Thermosyphon SWHs
• Parabolic trough collectors
• experimental work
• collector manufacturing