A return air plenum in a typical floor of a multistory building has the following construction and operating characteristics: Wattage of electric lights = 20 W/m? Return air volume flow rate=335 m/min Density of return air Ri= 1.2 kg/m': Air specific heat -1.006 kJ/kg.K Fraction of heat to plenum Fp=0.5 U values: exterior wall of plenum = 1.14 W/m. C U values: suspended ceiling - 1.82 W/m. C U values: floor - 1.2 W/mp. C Area of ceiling and floor - 1100 m Area of exterior wall of plenum - 180 m2 CLF of electric lights - 1.0 CLTD of exterior wall of plenum = 14C Space temperature - 24.5C Note: (60-V, P, Cp.) = 24264.7 Determine the space cooling load from the electric lights when they are recess mounted on the ceiling and the ceiling plenum is used as a return plenum. A return air plenum in a typical floor of a multistory building has the following construction and operating characteristics: Wattage of electric lights = 20 W/m? Return air volume flow rate=335 m/min Density of return air Ri= 1.2 kg/m': Air specific heat -1.006 kJ/kg.K Fraction of heat to plenum Fp=0.5 U values: exterior wall of plenum = 1.14 W/m. C U values: suspended ceiling - 1.82 W/m. C U values: floor - 1.2 W/mp. C Area of ceiling and floor - 1100 m Area of exterior wall of plenum - 180 m2 CLF of electric lights - 1.0 CLTD of exterior wall of plenum = 14C Space temperature - 24.5C Note: (60-V, P, Cp.) = 24264.7 Determine the space cooling load from the electric lights when they are recess mounted on the ceiling and the ceiling plenum is used as a return plenum