enter exhaust flow velocity、temperature and recovery efficiency，estimate recoverable power、annual energy saved、fuel cost saved and emission reduction CO₂。applicable to flue gas / process exhaust waste-heat recovery（air-medium approximation）。
formula：mass flow = flow velocity × 1.2 kg/m³；recovery power = flow velocity×1.2×1.005×ΔT×efficiency÷100 ÷3600 (kW)；annual heat = power×hours；
fuel saved = annual heat×3600 ÷ calorific value；air ρ=1.2 kg/m³、cp=1.005 kJ/(kg·K) as an atmospheric-pressure approximation，in practice adjust by medium。