Development of direct energy conversion system from high temperature thermal radiation to electricity by solar themophotovoltaic system

热光伏发电被认为是一种新型的环保型发电系统。在本研究中，我们研究了以聚光太阳能热能为一次能源驱动的太阳能光伏发电系统，称为太阳能光伏发电系统，是一种清洁可再生能源系统。该项目计划在日本进行第一次太阳能-TPV实验示范。本文还对太阳能聚光器、太阳能热接收器、稀土选择性发射体、太阳能光伏电池等关键组件技术进行了研究。本课题取得了以下研究成果：(1)搭建了抛物面聚光器自动跟踪系统。通过测量太阳热量的空间分布来评估焦点处的太阳图像。利用这些数据设计了太阳能热接收器，并在真实太阳系下进行了测试。在本实验中，我们用钼热屏蔽法获得了1500K以上的接收器温度。除此之外，还发现选择性发射器系统引导接收器温度。这可以归因于热辐射光谱较窄。(2)对提高TPV效率的关键技术--选择性散热器进行了研究。稀土(Er)掺杂的选择性发射体具有与NASA相比的高选择性辐射和高达20K的热稳定性。建立了金属钨衬底上表面光栅结构的制作工艺。我们观察到与表面周期相对应的清晰的发射峰。在本研究中还得到了高温电阻W栅格。(3)光伏电池实验表明，光伏系统中光伏电池与散热器之间存在最佳距离。

Thermophotovoltaic (TPV) power generation is considered to be a new environment friendly power generation system. In this study, we have investigate the TPV system driven by concentrated solar thermal energy as the primary resource, which is called as solar-TPV and is the clean and renewable energy system. The first demonstrate of solar-TPV experiment in Japan is planned in this project. Several key component technologies, such as solar concentrator, solar thermal receiver, rare-earth selective emitter, and photovoltaic cell for TPV, are also investigated in this study. The following results are obtained in this project.(1) We have constructed the system, which was composed of the auto-tracking parabolic concentrator using CCD camera. A solar image at the focal point is evaluated by measuring the spatial distribution of solar heat. Using this data a solar thermal receiver is designed and tested under real solar system. From this experiment, we obtained receiver temperature more than 1500K by using Mo thermal shield. In addition to this, it is found selective emitter system boots the receiver temperature. This can be attributed to narrow thermal radiation spectrum. (2) Two kind of selective thermal radiators, which are a key technology to increase the TPV efficiency, are investigated in this study. Rare-earth (Er) doped selective emitter shows high selective radiation as compare as that developed by NASA and high thermal stability up to 20OK. The manufacturing process of surface grating structure on tungsten metal substrate is established. We observe the clear emission peak corresponding the surface periodicity. The high temperature resistive W gratings is also obtained in this study. (3) PV cell experiment revealed that the optimum distance between PV cell and radiator exist on TPV system.