Converting sunlight to electricity with solar cells has an efficiency of 15%. It
ID: 1613058 • 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 570 C . The cold reservoir, ambient air, is approximately 26 C. The actual working efficiency of this device is 30%. (Figure 1) Part A What is the theoretical maximum efficiency? Express your answer using two significant figures.
Explanation / Answer
The maximum theoretical efficiency = {1 - (Tl/Th)}x100 = {1-(299.15/843.15)}x100 = 64.52 % = 65 %.