Capacity:__________________Y in LPD.
Solar water heating system of capacity at 60 0 C. Can generate heat in K.Cal/Day.
i.e. Capacity x Temperature Difference (60 0 C- 30 0 C.)
Y x 30 0 C (assumed average ambient temperature : 30 0 C.)
Comparing with present source of water heating system i.e. ELECTRICITY required for heating water Y ltrs at 60 0 C.
Capacity x Temperature difference
860 x 0.80 (efficiency of electric heater)
Y x 30 0 C
= --------------- = Z units/day
860 x 0.80
Considering prevailing rate of electricity is Rs. 5.00 per unit per day, the expenditure on electricity will be Z units per day x Rs. 5.00 per units = Rs. Z x 5.00/-
As per Indian climatic condition and the data available, solar system can give desired average output for 300 days.
Hence Yearly savings will be : Z x 5.00/- x 300 days = Rs. X per year.
Hence the pay back period will be :
Cost of the equipment – Subsidy from MNRE
= ---------------------------------------------------------
Yearly savings (X)
=Pay back period
Note: As per the Ministry for New & Renewable Energy, New Delhi , the subsidy is applicable for the year 2009-2010 – Rs. 1400/- per Sq. Mtr. Same has been considered while working out the payback of system.
EXAMPLE:-
For Capacity 125 LPD
Solar water heating system of capacity at 60 0 C. Can generate heat in K.Cal/Day.
i.e. Capacity x Temperature Difference (60 0 C- 30 0 C.)
125 x 30 0 C = 3750 K.Cal/Day
Comparing with present source of water heating system i.e. ELECTRICITY required for heating water Y ltrs at 60 0 C.
Capacity x Temperature difference
860 x 0.80 (efficiency of electric heater)
125 x 30 0 C
= --------------- = 5.5 units/day
860 x 0.80
Considering prevailing rate of electricity is Rs. 5.00 per unit per day, the expenditure on electricity will be Z units per day x Rs. 5.00 per units = Rs. 5.5 x 5.00/- = 27.5
As per Indian climatic condition and the data available, solar system can give desired average output for 300 days.
Hence Yearly savings will be : 5.5 x Rs5 x 300 days = Rs.8250 per year.
Hence the pay back period will be :
Cost of the equipment – Subsidy from MNRE
= ---------------------------------------------------------
Yearly savings (X)
21,000/- – 2800/-
= --------------------------------------------------------- = 2.2
8250/-
= 2.2 years
Note: As per the Ministry for New & Renewable Energy, New Delhi , the subsidy is applicable for the year 2009-2010 – Rs. 1400/- per Sq. Mtr. Same has been considered while working out the payback of system. |
