Economizer electric-energy savings calculator

The example converts avoided cooling load to electric input using COP and 3412 Btu/kWh.

Units

\Delta E = \frac{H \times \dot{V} \times 60 \times \rho}{\mathrm{COP} \times 3412}

Calculator

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

Given

\Delta E = \frac{8600 \times 9800 \times 60 \times 0.075}{3.4 \times 3412} \approx 32{,}693

Symbol	Meaning	Unit
$\Delta E$	avoided electricity	kWh/yr
$H$	integrated favorable enthalpy difference	Btu·h/(lb·yr)
$\dot{V}$	airflow	ft³/min
$\rho$	air density	lb/ft³
$\mathrm{COP}$	air-conditioner performance	ratio

Symbol	Meaning	Unit
$\Delta E$	avoided electricity	kWh/yr
$H$	integrated favorable enthalpy difference	kJ·h/(kg·year)
$\dot{V}$	airflow	L/s
$\rho$	air density	kg/m³
$\mathrm{COP}$	air-conditioner performance	ratio

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