A comparative study and graphical analysis in designing and operation of Solar Thermal circular concentrator for enhancing efficiency of solar concentrating system

The present line concentrator system with constant concentration ratio exhibits rise in temperature of working media, however if the difference between outlet and inlet temperature of working media is large then they exhibit lower efficiency. Also the rate of fall of efficiency with increase in its temperature difference is high. To overcome this problem it is proposed to have a variable concentration ratio concentrator system. The variable concentration ratio is achieved by employing receiver consisting of the pipes having different diameters; with the larger diameter pipe at start followed by small diameter receiver. Thus, the concentrator system will have different diameter receivers offering variable concentration ratio system. This concept is confirmed with the help of G.O. Lof, Fester and Duffie Beck paper. The present paper describes above concept by graphical analysis carried out for the newly proposed circular line concentrator with variable concentration ratio. The results of superimposition of graphs leads to confirmation for the promisingly use of variable concentration ratio receivers for enhancing efficiency of solar concentrating system.

Waveguide analysis for ultrasonic medical instruments (comparison of different methods)

Transition matrices are derived on the basis of some analytical solutions for a number of waveguides. Initial parameters method is used to analyze the waveguide longitudinal oscillations. This paper contains a comparative analysis of different types of concentrators. The waveguide design scheme presents a straight bar of variable cross-section with different boundary conditions. For given concentrator arrangements, the amplitude axial displacements and longitudinal forces in the ultrasonic medical instrument (UMI) are calculated for a certain excitation frequency. Numerical method for calculation of eigenfrequencies and eigenmodes of the ultrasonic medical instrument (UMI) waveguide is presented. Analysis of the cantilever straight-line concentrator based on the methods of transition matrices and numerical integration by the Runge-Kutta method are under comparison. Sufficient agreement of the results is demonstrated.

Design Parameters Optimization and Theoretical Performance Analysis of Linear Fresnel Reflector Solar Concentrator with Multi Tube Absorber

Linear Fresnel reflector solar concentrator technology is similar to solar trough technology in which the sunlight is reflected by a series of mirrors onto an absorber tube, thus linear F resnel reflector solar concentrator , is a linear line concentrator. The performance of the system depends on the design parameters, mass flow rate, etc. In the present work, by using MATLAB simulation program, a detailed design parameters analysis including the effect of variation in the height of the absorber, width of the absorber plane and the width of the reflector mirror elements on the concentration on the surface of the absorber plane has been made. The width of the absorber plane was investigated by using analytical and ray tracing technique s . Then, the optimized width of the absorber plane was used to design the absorber tubes. Also, detailed thermal performance analysis for the above design has been made. Results have been plotted graphically and discussed.