Example:
15 kW/m² = 21.510516 cal(th)/min·cm²
1 kW/m² = 1.434034 cal(th)/min·cm² | 1 cal(th)/min·cm² = 0.697333 kW/m²
Conversion Steps:
15 × (1000 / 697.333333331) = 21.510516252