Synergy of Two Mid-temperature Solar-driven Reactions for Thermochemical Power System at Off-design Solar Radiation Conditions

摘要

In our previous research, we ever proposed a solar-driven methanol decomposition system by using solar heat at temperature around 300°C for producing solar fuel to generate power. The system performance at solar radiation from 100~400W/m~2 was poor, the daily average solar to electricity efficiency was only 14-16% due to varied solar radiation. Here, in contrast to the 'individual' methanol decomposition system, we proposed a 'synergetic' system which use the methanol steam reforming and methanol decomposition together to match the varied solar radiation. Exergy destruction of solar fuel combustion is disclosed. In addition, the inherent reason of reducing the exergy destruction was also disclosed by using the concept of the energy level. As a result, the daily average exergy destruction in the 'synergetic' system is 9% lower than the 'individual' system, the daily average solar to electricity efficiency reaches 19%, which is 3～5 percentage points higher, leading to the increase of average work output and providing the possibility of reducing the size of solar field. The results here would provide an approach to improve the poor performance of solar thermochemical power system at varied solar radiation conditions.