| With the renewable characteristic, solar energy has the advantages of environmental friendly and sustainable for uitilization. During the process of solving the traditional energy crisis, many countries focus their eyes on exploitation and research of solar energy. However, with the low power density, discontinuous radiation, solar energy generates high investments on collection, transfer and conversion, non-concentration and lower concentration solar energy block the universal application and make it to be as the auxiliary in comparision with the traditional energy.Based on the viewpoint of high efficiency and grad utilization of solar energy, modularized transmission and utilization system of high concentration solar energy, as well as energy storage at high temperature, are in consideration, which brings out a new solution to relieve the restriction of strength and time. Research results have proved the significance and the feasibility of high concentrated solar energy used under special conditions and also its market potentials. The specific contents include the following work:(1) The first law and the second law of thermodynamics are used to analyze the energy conversion of a solar concentrator with high concentration ratio, it is founded that the optimal collector temperature is 2464K and concentration ratio is 2617 suns, under which the conversion limit is 84.9%. It is of great potential in improving the energy conversion efficiency comprehensively with the high concentration of solar radiation(2) Based on geometrical optics, solar ray trace is done for the full spectrum, and high concentration schemes are optimized. By comparison of three different means based on theoretical analysis and experimental validation, the radiation characteristic is investigated including diameter of solar facular spot, relations of deviation angle and energy density, thermal efficiency, measurement on optical efficiency and analysis. Design on concentrator profile and transfer means of concentrated energy are obtained. Based on this analysis, a set of highly concentrated solar energy system with the two-stage Fresnel lens is proposed.(3) With the designed two stages Fresnel lens system, optical model of Fresnel lens is presented and simulated. The position of focus spot at different deviation angle, energy density and radiation distribution are achieved. Under the variable conditions of solar radiation, the deviation of focus spot at receiver, temperature features of focus spot, relations of solar radiation and heat flux are studied. Those conclusions have significant effect on receiver modular design for the rationality and the validity.(4) Experimental validation is done based on the design of the two stage Fresnel lens system, and the simulation model is also validated. Optical efficiency measurements have been carried out on the practical Fresnel lens group, including heat and light transfer performance. According to this study, 50~60% of the collected solar radiation can transmit through the Fresnel lens group under condition of over 1000 suns, light transfer efficiency is near 50% in the four in one light path. Infrared ray can transmit more than 70% through light tube. The track angle error of two stage system can be limited within 1°, which shows that the designed device has the higher precision on solar tracking and lower investment.(5) To exploit the application of highly concentrated solar energy, a combination system of photovoltaic and thermal system is introduced and investigated, and thermal and power characteristics of this coupled system are analyzed. The results of photovoltaic process show that the combination system has the potential ability on efficiency improving, and more exergy can be obtained in large scale solar energy storage by using thermal partition technology. It is found that the whole efficiency can be expected more than 70%.
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