Question

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.

Answer 1

(a) Usable power per square meter$=8\times {10}^{3}W$

Solar energy received per square meter $=200W/m^2$

The efficiency of conversion from solar to electricity energy = 20%

Area required to generate the desired electricity is $A$.

As per the information given in the question, we have

$8\times {10}^3=\frac{20}{100}A\times 200$

$A=200m^2$

(b) The area of a solar plate required to generate 8 kW of electricity is almost equivalent to the area of the roof of a building having dimensions 14 m x 14 m. (close to 200 sq m).