roblem #$2$

$[20$ Points$]$

n energy audit of the roof indicates the following:

Area

Present $"$R$"$ value $5$

$($Estimation based on insulation thickness and type$)$

Degree$-$Days $($winter$)4,000$

Occupied hrs$/$week $40$

D$.$B$.$ Degree$-$Hours above $78F,10,000$

Fuel cost $$\frac{6}{{10}^6}$ Btu

Boiler efficiency $0\mathrm{.}65$

Electric rate

$6$ per kWh

Air$-$condition requirement

$0\mathrm{.}8kW\frac{h}{?}$ Ton$-$Hr

Roof Absorption $0\mathrm{.}3$

Solar radiation $300$ Langleys

f it is proposed that additional insulation of $R=5$ should be installed, Estimate the ossible annual energy savings $($winter and summer$).$