Calculate the efficiency of solar water heater

DATE: 01/02/2022

INTRODUCTION: Efficiency is the ratio of energy input and the energy output by 100%.We calculate efficiency because input energy as possible should be transferred into useful energy store.

Procedure:

Firstly we measure the diameter and length of the evacuated tube with the help of metric tape.

Diameter of evacuated tube = 5.5 cm

Length of evacuated tube = 174cm

Now,

Area of one evacuated tube collector= l * b

=5.5*174 = 957 cm²

But here total 32 evacuated tube

Hence,

total area of evacuated tube collector= 957*32 =30624 cm² =3.06 m²

Temperature of water at 9 am= 42°C

Temperature of water at 5 pm=48°C

Capacity of storage water tank = 500LPD

energy in 1 m² = 813

Now,

Input = Total area of ETC× Energy in 1 m² ×Time

= 3.06×813×8×3600

= 71.648 × 10⁶ J

Output= Capacity of storage tank × 4.186 × Temperature difference

= 500 × 10³ × 4.186 × 6

= 12.558 × 10⁶ J

Therefore,

Efficiency of solar water heater= Output/Input

= 12.558 × 10⁶ / 71.648 ×10⁶

= 0.1752

= 17%

Result: We got the efficiency of solar water heater is 17%. This efficiency is low hence increases this efficiency with cleaning dust on evacuated tube.