| Fossile energy is dying,but human demand for energy would never decline because of the development of science and technology.Concentrated Solar Power technology is an effective solution for solar radiation-thermal power-electricity conversion in the range of renewable technology application.Development of CSP attributes to relief human being’s dependency on fossile energy.The receiver plays an important role in CSP system,of which optimization of thermal performance will improve total efficiency of the system.In recent reseach field of solar receiver,a series of research progress has been achieved by institutes and individual researchers in world-wide.However,it exists some issues which are necessary to be thoroughly studied,as well as some knowledge gaps need to be filled.In first part of this paper,a review of recent research status was presented in order to summarize all published achievements.Through this work,it found that no investigations into the geometric parameters of a cylindrical cavity receiver with helical pipe have been performed for investigating the heat-transfer characteristic in the present research field.As a result,this study proposed a design and an optimization method for a solar cavity receiver with the capability of achieving high operating temperatures.It brought an exploration which will be proposed for seeking high-level security and stability of solar reicever in the futureInnovatively developing a theoretical model for the cavity geometry,results of this study provided a prediction of the real situation and a sensitivity analysis of the cavity receiver design.The aperture diameter,inner diameter,and cavity inner length are the three critical geometric parameters of the cavity receiver.The influence of these three parameters was analyzed on heat losses and thermal performance in this paper.It achieved an optimal solution of this receiver of aperture diameter,inner diameter and cavity inner length,which optimal thermal efficiency was as highly as 71.41%.By concsructing an optical model,a software simulation has been estabilished of the whole dish concentrator generation system.The simulation investigated several influence factor of optical efficiency,such as position of focus spot,aperture diamerter and distance between aperture diameter and focus point.Consequently,as the distance increased in the range of 0 to 0.30 m,optical efficiency initially increased and finally decreased.At the same time,the distance for optimal optical efficiency was achieved in a larger value with a larger aperture diameter.Then,a cylinder cavity receiver with helical pipe inside will be numerically studied with the help of computational fluid dynamics(CFD)simulations in this study.The distribution contours of tempertature,pressure and velocity are revealed by the numerical simulation.Based on the simulation result,the effects of indensity solar flux,air mass flow of inlet and some critical geometric parameters on thermal performance are investigated.To validate and improve the preliminary work of cavity receiver design and optimization,a simulation validation has also been proposed with a comparison between numerical simulation result and published data from theoretical model.A good agreement is achieved through this validation.After,depending on experimental sub-system of solar cascade utilization system in INEW,the designed cavity receiver is veritably tested for performance analysis.The experiment investigated the effect of direct normal irridiance,air mass flow of inlet and working medium temperature of inlet on heat-transfer characteristic.A good agreement is achieved through the comparison between former work and experimental investigation result.This study proposes an intensive research on themal performance investigation of cavity receiver,which fills in gaps in the research fileld of CSP technology and expands space of further study in the future. |
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