Development of a Spherical Solar Collector with a Cylindrical Receiver

Abstract

Solar energy can be used for substitution of the depleting fossil fuels in thermal applications and electricity generation through thermal route. For medium and high temperature applications, a system for collecting solar energy at high temperatures was developed and built in this research work. The system, built at the center of development of renewable energy of the Algiers, consists of a 2θ m = 60° included angle, R 0 = 0.90 m diameter spherical reflector with a cylindrical receiver filled with water, tracking reflector which moves into the focus following the sun's movement. The system is capable of heating water or other fluids to temperatures above 350°C, thus making it possible to obtain process heat for domestic use and to store solar energy in a compact and economical way. An analysis of the system's optical characteristics was performed to aid in the design of the spherical reflector and cylindrical receiver. The thermal performance of the system was analyzed. The effects of mirror reflection, concentration ratio, heat transfer to the fluid (water), incidence angle, size and form of the cylindrical receiver, environmental conditions (wind, ambient temperature), have been studied by means of thermal model. The performance of the spherical reflector was tested by the temperature of the water. Total efficiencies (solar to thermal) of η th = 60% -70% were obtained for a wide range of temperatures up to 350°C. The results of the present study show that it is possible to use the spherical reflector for systems requiring process heat and make possible substantial utilization of solar energy and considerable savings relative to fossil energy in the sunny countries of the world.

Design and development of the solar cycloidal thermal concentrator and tapered receiver assembly along with theoretical evaluation of system performance

“…The flat receiver is used in this research, where the shadow effect was neglected. Beucherie (2015) and Mahdib and Bellel (2014) presented the development of a spherical solar collector with a cylindrical receiver. The intercept factor increases as the diameter of the receiver increases, but the efficiency decreases; hence, there is a need to focus on the increase in the concentration ratio.…”

Study and Characterization of a Spherical Solar Collector. I. Efficiency and Thermal Losses Coefficient

“…Among the many papers dealing with spherical solar collectors, we find scientific papers devoted to studying the characteristics of the cylindrical receiver [12], evaluating thermal performance [7], or analyzing the ability of sun tracking [13]. Other papers focus on the received solar radiation [14] or the thermal performance in heating water [15].…”

Modeling, Simulation and Analysis of Tapered Receiver Utilization in Solar Cycloidal Concentrating System for Enhancement of System Efficiency

“…The receiver must be designed to absorb maximum energy and emit minimum energy; which is achieved by having a proper coating over the receiver surface as studied by Beucherie [6]. Mahdib et al [7] presented the development of spherical solar collector with a cylindrical receiver. Intercept factor is proportional to the diameter of the receiver.…”