Journal Club 13 July 2011 Tuğrul Çağrı CİNKARA

MIT, mechanical engineering

Solar energy Solar Energy  Photovoltaic (PV) cell o electron-hole pair  Solar Thermal Process o electricity generation by mechanical heat engines o solar hot-water system

Challenge  Significant temperature difference Solution  Optically concentrate the solar radiation by lens. Depending on the length of the thermoelectric element, optical concentration must be  Increase concentrate by using absorber.

Efficiency  Thermoelectric Device Efficiency η te 1- operating temperature 2- materials properties (dimensionless figure of merit ) (ZT) Where, S (seebeck coefficient) σ (electrical conductivity) k (thermal conductivity) T (temperature) MAX = ideal material (ZT=1)

Efficiency  Opto-thermal efficiency η ot  T h has a trade-off between η te and η ot. Depending on the thermoelectric material and solar absorber ; 160 C < T h < 250 C  Bi2Te3 is the best one.

Efficiency

Device

Performance

 Improving ZT of the thermoelectric materials  improving of the selected surface performance  combination of thermal and optical concentration