A family uses 8 kW of power. (a) Direct solar energy is incident on the horizontal surface at an average rate of 200 W per square meter. If 20% of this energy can be converted to useful electrical energy, how large an area is needed to supply 8 kW? (b) Compare this area to that of the roof of a typical house.

Question

Philoid · Accepted Answer

Given,

Power used by the family, P = 8 kW = 8000 W

Solar power incident per square meter, E = 200 W

Efficiency of energy conversion, η = 20%

(a) Let A be the area required to supply 8 kW power.

So, 8×10³ = 20% × (A × 200)

⇒

⇒ A = 200 m²

(b) 200 m² is equivalent to a rooftop with dimensions 14m×14m.