When a man returns to his well-sealed house on a summer day, he finds that the house is at 35°c. he turns on the air conditioner, which cools the entire house to 20°c in 38 min. if the cop of the air-conditioning system is 2.8, determine the power drawn by the air conditioner. assume the entire mass within the house is equivalent to 800 kg of air for which cv = 0.72 kj/kg·°c and cp = 1.0 kj/kg·°c

1353.38 Watt

Explanation:

T₁ = Initial temperature of the house = 35°C

T₂ = Final temperature of the house = 20°C

Δt = Time taken to cool the house = 38 min = 38×60 = 2280 s

m = mass of air in the house = 800 kg

Cv = Specific heat at constant volume = 0.72 kJ/kgK

Cp = Specific heat at constant pressure = 1.0 kJ/kgK

Heat removed

q = mCvΔT

⇒q = 800×720×(35-20)

⇒q = 8640000 J

Average rate of hear removal

∴ Power drawn by the air conditioner is 1353.38 Watt