Converting sunlight to electricity with solar cells has an efficiency of 15%. It
ID: 1270990 • Letter: C
Question
Converting sunlight to electricity with solar cells has an efficiency of 15%. It's possible to achieve a higher efficiency (though currently at higher cost) by using concentrated sunlight as the hot reservoir of a heat engine. Each dish in the figure concentrates sunlight on one side of a heat engine, producing a hot-reservoir temperature of 550C . The cold reservoir, ambient air, is approximately 28C. The actual working efficiency of this device is 30%.
What is the theoretical maximum efficiency?
Explanation / Answer
efficiency = 1- Tc/Th= 1- (273+30)/(27+500)
= 1- 0.39 = 0.608
=0.608 x 100 = 60.8 %