HomeMy WebLinkAboutSHW - Calculator Simple 09-27-2010
Simplified Solar Hot Water System Calculator:
Please answer the following two questions:Comments:
How many people live in your home?2[ Determines the amount of hot water used in the home ]
In what area of Florida do you live?South[ Determines the temperature of the city water coming into the hot water system ]
Solar Savings Results:
$200$/year
Annual energy cost savings =[ Difference in annual operating cost between standard and solar system ]
1,769kWh/year
Annual solar energy savings =[ Difference in annual energy use between standard and solar system ]
2,449lb/year
Annual CO2 savings =[ Difference in carbon dioxide emissions between standard and solar system ]
90%percent
Annual Solar Fraction =[ Percentage of hot water energy provided by solar energy ]
Economic Results:
7.5years
Simple payback period =[ Number of years for the solar system to completely pay for itself -- generally much shorter than its useful lifetime of about 30 years ]
5.17¢ / kWh
Cost of solar energy savings =[ As compared with 11.3¢ per kWh Florida September 2007 average retail price ]
15%per annum
Internal Rate of Return on investment =[ Annual compound interest rate the savings from the solar system investment produces over its useful lifetime ]
$2,908present $
Net Present Value of investment =[ Net Present Value (NPV) equals the Present Value, calculated at the discount rate, of all future cash flows minus the investment cost, which is assumed
to occur in the initial year ]
Assumptions used to achieve the above results:
Solar System Energy Factor (EF) =6.1[ Only the actual installed product rating will yield accurate calculator results ]
Hot Water Use Intensity =Medium[ Modifies gallons per day of hot water use by 1.5 (high), 1.0 (medium) & 0.5 (low), respectively ]
Solar System Cost =$3,200[ Only dealer quotes for installed solar system cost will yield accurate calculator results ]
IRS Tax Credit (30% of Cost) =$960[ Only avaliable for solar systems with EF > 1.8 ]
FL State Rebate =$500[ Only for systems manufactured in Florida, otherwise $300 ]
FL Utility Rebate =$0[ Only presently available in Progress Energy territory ]
Standard System Type =Electric[ ~90% of Florida residences do not have access to natural gas ]
Discount Rate =4.5%per annum[ Generally accepted rate for capitol investments made by corporations ]
General Inflation Rate =3.0%per annum[ Generally accepted annual cost of living inflation rate ]
Electricity Price =$0.113per kWh[ U.S. Energy Information Administration: Florida Statewide average for September 2007 ]
Natural Gas Price =$2.154per therm[ U.S. Energy Information Administration: Florida Statewide average for 2006 ]
Fuel Escallation Rate =0.0%per annum[ Generally accepted rate based on past history ]
Proceed to Page 2 to revise these assumptions.
To view or hide assumptions for the above results, click on the [+] or [-] sign in the left margin
NOTE:#NAME?
If cells C16 & C17 result is the value , then you must enable the Analysis Toolpack. Take the following actions: select
from the menu bar at the top of the screen, check the Analysis Toolpack selection and click OK. Excel will then install
the Analysis Toolpack. Reload this spreadsheet and the values in cells C16 & C17 will function properly.