Question

A house has well-insulated walls 15.0 cm thick (assume conductivity of air) and area 500 m2 , a roof of wood 5.0 cm thick and area 270 m2 , and uncovered windows 0.55 cm thick and total area 30 m2 .

I don't need help with question A, I got it right but i don't know how to do b and c

A) Assuming that heat is lost only by conduction, calculate the rate at which heat must be supplied to this house to maintain its inside temperature at 25 ∘C if the outside temperature is -19 ∘C.

Answer was 2.3*10^5 Watts

B) If the house is initially at 11 ∘C, estimate how much heat must be supplied to raise the temperature to 25 ∘C within 60 min . Assume that only the air needs to be heated and that its volume is 750 m3. Take the specific heat of air to be 0.24 kcal/kg⋅C∘.

C) If natural gas costs $0.080 per kilogram and its heat of combustion is 5.4×107 J/kg, how much is the monthly cost to maintain the house as in part (A) for 24 h each day, assuming 90% of the heat produced is used to heat the house?

Answer 1

If you have any doubt, feel free to ask.

Alright Dude, If this worked for you... don't forget to give THUMBS UP.(that will work for me!)