Global Journal of Researches in Engineering, J: General Engineering, Volume 22 Issue 1

have about 80% of the population living out of reach of the electrical grid, and where the main energy source is fire wood as reported by [3&4]. Deforestation is already a severe problem, and increasingly so as the population increases. Therefore, concentrating solar collector for thermal steam generation system can fill the gap or compliment non renewable energy sector for the purpose, of transformation and remediation on the stated problems. IV. A im and O bjectives The aim of this research is to develop a parabolic concentrating solar collector for steam thermal application . The objectives are: i. Investigate the optical performance of a parabolic concentrating solar collector. ii. Design an optimal receiver for the air based heat transfer system iii. Investigate the thermal performance of the collector. V. L iterature R eview The solar thermal collectors have been widely used to concentrate solar radiation and convert it into useful heat for various thermal processes. Characteristics of solar thermal collectors, especially the concentrating type, are well established in research literature and have many applications in industry and for domestic water heating, and steam generation .[5] . The operation principle of solar concentrating collectors is the focusing the incident solar radiation onto a small area known as receiver. Many types of concentrating collectors are available, with various concentrating ratios and different operating temperature levels. Linear parabolic collectors, compound parabolic collectors, Fresnel collectors, and solar dish collectors are the most widespread concentrated collectors. Generally, solar thermal utilization can be separated to low, medium, and high temperature systems. The low temperature solar systems, which operate without sunlight concentration, have low conversion efficiency and they are used in domestic applications. The medium and high temperature solar thermal systems, which require sunlight concentration, have higher conversion efficiency [6&7], and they can used in great variety of applications. [8] has presented a study that aims to develop a 3-D static solar concentrator that can be used as low cost and low energy substitute. Their goal was to design solar concentrators for production of portable hot water in rural India. [9&10] has investigated on the photo-thermal conversion efficiency in order to improve the cost effectiveness of the examined solar system. They used the Monte Carlo ray tracing method for calculating the radiation flux distribution on the receiver and the ANSYS Fluent for calculation of radiation and convection heat transfer mechanisms. Their results proved that the maximum energy efficiency was about 52% when the direct normal irradiation was 800 W/m2. [11&12] investigated the thermal efficiency of solar a cooker with parabola diameter of 3.56 m and total aperture of 10.53 m2, with a finally thermal efficiency of 60 [13&14]have experimentally investigated a solar parabolic dish collector with 20m2 aperture in order to investigate its performance with the examined modified cavity receiver. The average value of the overall heat loss coefficient was found to be about 356 W/m2. [15]computed the flux distribution on a cylindrical receiver of parabolic dish concentrator using geometric optics method. Parameters such as concentrator surface errors, pointing offset errors and finite sun shape were taken into consideration in the geometric optics methods. [16&17] have investigated the possible use of parabolic dish collector in process industries. They presented a mathematical model for heating application using thermal oil. [18]described optical test for the DS1 (parabolic Stirling dish) prototype, a study that was carried out by CTAER. The aim of this investigation was to characterize the optical parameters of DS1 prototype. The results comparison proved that the dish surface had an average optical error of 2.5m rad and an estimated spillage value of 7%, for the examined geometry. [19&20] presented the radiation flux distributions of the concentrator-receiver system by Monte Carlo ray tracing. The final radiation flux profiles were subsequently transferred to a CFD code as boundary conditions in order to simulate the fluid flow and the conjugated heat transfer in the receiver cavity by coupling the radiation, natural convection, and heat conduction numerically. [21] presented an optical design and ray tracing analysis of a solar dish concentrator composed of 12 curvilinear trapezoidal reflective facets made from solar mirror with silvered coating layer. R esearch M ethodology a) Design Consideration A dish Stirling system or concentrating solar collector system would comprises of a parabolic dish concentrator, a thermal receiver, and a Stirling engine position would be at the focus of the dish; the whole system would be mounted on a structure that tracks the sun by pivoting on one or two axes [24]. Fig. 3.1; shows a parabola which has a locus of a point that moves so that its distances from a fixed line Analysis of Thermal and Optical Efficiency of Parabolic Concentrating System for Thermal Application lobal Journal of Researches in Engineering ( ) Volume XxXII Issue I Version I J G 52 Year 2022 © 2022 Global Journals vi. A more recent study reported that 95% of the insulation reflected from a 500 m2 dish (mirror reflectivity of 93.5%) was focused into a cavity type receiver with an aperture of 500 mm diameter [ 22&23].