Annual solar collection and value calculator

Use annual irradiation and the same useful-heat cost basis as the avoided fuel.

Units

Q_{\text{year}} = A \times H_{\text{year}} \times \eta

Calculator

Enter the values you know and leave one box empty. Calculate finds the empty one, the result or any input.

Given

Q_{\text{year}} = 360 \times 410{,}000 \times 0.48 = 70{,}848{,}000

Symbol	Meaning	Unit
$Q_{\text{year}}$	useful annual solar heat	Btu/yr
$A$	collector area	ft²
$H_{\text{year}}$	annual incident irradiation on the chosen plane	Btu/(ft²·yr)
$\eta$	collector efficiency	fraction

Symbol	Meaning	Unit
$Q_{\text{year}}$	useful annual solar heat	kWh/year
$A$	collector area	m²
$H_{\text{year}}$	annual incident irradiation on the chosen plane	kWh/(m²·year)
$\eta$	collector efficiency	fraction

Results are estimates for study and screening. Check the inputs, units and assumptions before you use them for design, billing or contract decisions.