Session: 05-02: Concentrating Solar Power I -- Heliostats and Trough Receivers

Paper Number: 130560

130560 - Modified Single Slope Solar Still With External Reflectors 

Abstract: 

Solar energy is one of the effective solutions for the water desalination process. In order to use the technology in such a dry remote area like the Northern Region of Saudi Arabia, more attention should be considered for a device that is suitable for the area. In this work, a single slope still with a single basin that has dimensions of 50 cm 50 cm and is composed of 2 mm thick galvanized iron-sheet, is designed with external reflectors to develop and maximize the system’s efficiency. The foundation tank was completely covered from the top with window glass that was 6 mm thick. The base tank's edge is adjusted for the still's glass cover, which is then sealed. Glass covers were sealed with silicone rubber. Flexible plastic pipes were used to convey the distilled water from the still into the measuring water bottles. Measurement water jugs kept below the still and attached to flexible tubing are where the distilled water is collected. This modification allows to increase the system’s heat inside the solar still that contains the desalinated water through a glass cover. The conventional design is compared with the modified design during daytime. The temperatures of the inner glass, outer glass, water in the basin, the outside temperature was recorded every half an hour. The basin and reflectors were maintained as the same size. During testing, four external reflectors were used from the still's four sides, and their effects on productivity were examined. The studies were conducted from daylight till dark. The temperature of the distilled water, the inner and outer glass covers, the water in the basin, the stills with and without reflectors, and the surrounding temperature, pressure, wind speed, and direction were all monitored every half hour. Results of the test for a typical March Day showed that the water temperature increases until it reaches its peak in the afternoon because more solar energy is absorbed than is lost to the atmosphere. Around 2 pm, the amount of solar energy lost starts to outweigh the amount of solar radiation absorbed, which results in a decrease in water temperature due to glass has a lower temperature than water, it can condense vapor. Early in the day, when the water absorbs less energy, there is less productivity since the temperature differential between the water in the glass and the air is smaller. The maximum peak solar radiation intensity increased by roughly 17%. Also, glass, water and absorber temperatures were enhanced.  Hourly and cumulative water productivities were improved by 40% and 50% respectively.

Presenting Author: Abdullah Alrashidi Northern Border University

Presenting Author Biography: Assistant professor at the Mechanical Engineering department at Northern Border University. I obtained my PhD from the University of Miami, USA. I currently lead research in renewable energy, fuel cells , thermal energy and mining.

Authors:

Abdullah Alrashidi Northern Border University