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A water-heater is covered with insulation boards over a total surface area of 3 m2. The inside board surface is at 75°C and the outside being at 20°C and the conductivity of material being 0.08 W/m K. Find the thickness of board to limit the heat transfer loss to 200 W ?

A water-heater is covered with insulation boards over a total surface area of 3 m2. The inside board surface is at 75°C and the outside being at 20°C and the conductivity of material being 0.08 W/m K. Find the thickness of board to limit the heat transfer loss to 200 W ? Correct Answer 0.066 m

Steady state conduction through board. Q = k A ∆T/∆x ⇒ ∆Τ = Q ∆x / kΑ ∆x = 0.08 × 3 ×(75 − 20)/200 = 0.066 m.

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