Collector area at a stated irradiance calculator

The ideal noon calculation uses η=1; actual useful output includes efficiency.

Units

A = \frac{\dot{Q}_{\text{required}}}{I \times \eta}

Calculator

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

Given

A = \frac{67{,}000}{240 \times 0.52} \approx 536.9

Symbol	Meaning	Unit
$A$	collector area	ft²
$\dot{Q}_{\text{required}}$	required useful heat rate	Btu/h
$I$	incident solar irradiance	Btu/(h·ft²)
$\eta$	collector efficiency; 1 for ideal screening	fraction

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