حاسبة استرداد الحرارة Sensible Heat Recovery air flow (cfm) t1 (oF) t2 (oF) recovery efficiency t2 - outside air temperature after the heat exchanger t1 - outside air temperature before the heat exchanger Total Heat Recovery air flow (cfm) h2 (Btu/lb.ºF) h1 (Btu/lb.ºF) recovery unit efficiency h1 - enthalpy outside air after the heat recovery unit (Btu/lb.ºF) h2 - enthalpy outside air before the heat recovery unit (Btu/lb.ºF)