from pint import UnitRegistry u = UnitRegistry()
#Overall_Plant_Efficiency_in_ntl gas (2827178 * u.btu)/(43641296 *u.feet**3)
#Overall_Plant_Efficiency_in_therms_ntl_gas ((2827178 * u.btu)/(43641296 *u.feet**3))*(100* u.feet**3/1.037 * u.therms)
#Pony_Boiler_Max_Flow (1999999 * u.BTU)/(566 * u.kwatt * u.hour)
(u.ft**2)/ u.btu