Rough+Cost+Analysis

This is a rough cost analysis projecting how many years it would take to break even with our system of using PV panels and our element design versus the current natural gas tank at The Grange. The natural gas estimates are based on previous trends of natural gas usage at The Grange from their bills. I am not too sure about the PV costs because it varies depending on installation fees and price of panels.

Grange natural gas usage: Assume 20% goes towards water heating In December- month with largest usage 90 Therms*.20=18 Therms 18 Therm=1,800,000 BTU over one month used to heat water Avg daily therms: 2.7*.20=.54=53,987.1 BTU Cost per Therm gas commodity=$.28668 Cost per Therm gas transportation=$.54727 Charge per day 33days =$.49315

For 90 Therms in 33 days =$91.32+$11.99taxes=$103.31 $103.31*.20=$20.662 for natural gas for water heating in December ~$1.147/Therm

For April 38 Therms 38*.20=7.6 Therms 7.6 therms=759819 BTU Average daily therms:1.3*.20=25,993.8 BTU For 38 Therms in april $52.89*.20=$10.578 ~$1.39/Therm

Avg=$1.26/therm And average is about 12 therms for water heating for a month 12 thems*$1.26/therm=$15.12/month $15.12/month*12 months=$181.44/year of money spent on natural gas for heating water at The Grange Average residential water heating estimates are $192/year. So this estimate seems reasonable.

Cost for DC electric water heating with PV panel system Swivel piece=$16.50 Element=$11.28 Thermostat=$7.75 Total=$35.53

For panels and installation ~$1600 So $1635 total for PV DC water heating

8.33 year pay back

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