1. A small metal building is to be constructed of corrugated steel sheet walls with a total wall surface area of about 300 m². The air conditioner consumes about I kW of electricity for every 4 kW of cooling supplied and two wall construction are to be compared on the basis of cooling costs. Assume that electricity costs S0.15/kWh. Determine the electrical energy savings per week of using 260 mm of fiberglass batt insulation to the steel sheet wall (U-0.17 W/ m² "C) instead of 159 mm of fiberglass insulation (U= 0.31 W/m² °C) assuming an overall temperature difference of 20 °C across the wall.

1. A small metal building is to be constructed of corrugated steel sheet walls with a total wall surface area of about 300 m². The air conditioner consumes about I kW of electricity for every 4 kW of cooling supplied and two wall construction are to be compared on the basis of cooling costs. Assume that electricity costs S0.15/kWh. Determine the electrical energy savings per week of using 260 mm of fiberglass batt insulation to the steel sheet wall (U-0.17 W/ m² "C) instead of 159 mm of fiberglass insulation (U= 0.31 W/m² °C) assuming an overall temperature difference of 20 °C across the wall.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter8: Natural Convection

Section: Chapter Questions

Problem 8.40P

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A small metal building is to be constructed of corrugated steel sheet walls with a total wall overall surface area of about 300 m2. The air conditioner consumes about 1kW of electricity for every 4kW of cooling supplied. Two wall constructions are to be compared on the basis of cooling costs. Assume that electricity costs 10.15 Php/kWh. Determine the electrical energy savings of using 260mm of fiberglass insulation instead of 159 mm of fiberglass insulation in the wall. Assume an overall temperature difference across the wall of 20 ° (Uo (260-mm fiberglass)=0.17W/m2 °C and Uo (159-mm fiberglass)=0.31W/m2 °C)
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