Recovered annual kiln heat calculator

Apply duct losses after calculating preheated-air energy.

Units

Q_{\text{rec}} = \dot{m} \times c_{\text{p,avg}} \times T_{2} - T_{1} \times 60 \times h \times N \times \left(1 - L\right)

Calculator

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

Given

Q_{\text{rec}} = 88 \times 0.25 \times 360 \times 60 \times 4200 \times 2 \times \left(1 - 0.08\right) \approx 3.672 \times 10^{9}

Symbol	Meaning	Unit
$Q_{\text{rec}}$	annual useful recovered heat	Btu/yr
$\dot{m}$	air mass flow per kiln	lb/min
$c_{\text{p,avg}}$	average air specific heat	Btu/(lb·°F)
$T_{2} - T_{1}$	air temperature increase	°F
$h$	annual operation	h/yr
$N$	number of kilns	count
$L$	duct heat-loss fraction	fraction

Symbol	Meaning	Unit
$Q_{\text{rec}}$	annual useful recovered heat	kWh/year
$\dot{m}$	air mass flow per kiln	kg/s
$c_{\text{p,avg}}$	average air specific heat	kJ/(kg·K)
$T_{2} - T_{1}$	air temperature increase	K
$h$	annual operation	h/yr
$N$	number of kilns	count
$L$	duct heat-loss fraction	fraction

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