1. Solar Hot Water Heater

2. Flat Plate Collector Problem A flat plate solar collector is used as a solar hot water heater. The collector area equals 20 square meters. The collector is located in a location with annual average daily solar insolation equal to 5.0 kWh/square meter/day.

3. 1. Calculate the amount of solar energy incident on this collector each day.  Solar Energy =  = 5.0 kWh / sq m / day 20 sq m  = 100 kWh / day

4. 2. Assuming that the efficiency of the solar collector and the rest of the system equals 50%, calculate the average daily energy produced (as hot water) by this system. Express your answer in kWh/day.  Average Produced Energy/day =  = 100 kWh / day 0.50  = 50 kWh / day

5. 3. Calculate the amount of energy produced by this system each year. Express your answer in kWh.  Annual Energy Production =  = 50 kWh/day 365 day/year  = 18,000 kWh / year

6. 4. Assuming that the solar energy replaces the heating of hot water by electric energy and that electric energy cost 10¢/kWh, calculate the yearly savings in electricity costs as a result of using the solar hot water system. Express your answer in $/year.  Money Saved =  = 18,000 kWh $0.10/kWh  = $1,800 / year

7. 5. Suppose this solar hot water system were to cost $5,400 (installed). Calculate the payback period for this system  Payback = Cost / Savings  = $5,400 / $1,800 /year  = 3 years