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Unformatted text preview: wnings can signiﬁcantly reduce the energy required for air condi*oning Typically, windows have an R value ________ the wall. Correct A ) Lower than Typically, windows have an R value lower than the wall Heat always ﬂows from ______ temperature to _______ temperature Correct A ) high, low Heat naturally ﬂows from high temperatue to low temperature The R value for a window is the reciprocal of the Correct A ) U value or U factor R value is a measure of how well it resists conduc*on of heat through the material. R value = 1 / U value = 1/ U factor The higher the light to solar gain ra*o, the _______ the room is without adding excessive amounts of heat Correct A ) brighter Light to Solar Gain = Visual TransmiFance / Solar Heat Gain Coeﬃcient
The higher the light to solar gain ra*o, the brighter the room is without adding excessive amounts of heat Inert gas ﬁlls between two window panes reduces Correct A ) convec*ve heat loss between the panes Inert gas ﬁlls between two window panes reduces convec*ve heat loss between the panes The heat loss through a window (U value = 0.5) is 10 MMBTU/year. Calculate the payback period (in years) if Argon is ﬁlled in the window to increase the eﬀec*ve U value of the window to 0.100. Assume hea*ng price to be $10/MMBTU and the cost for ﬁlling Argon is $20. Correct C ) 0.25 years R value of new window = 1/0.100 = 10 Heat lost through new window per year = (10 x 2) / 10 = 2 MMBTUs/yr
Reduc*on in heat lost per year = 10  2 = 8 M MBTUs/yr
Savings in energy cost per year = 8 x 10 = $80
Payback period = 20 / 80 = 0.25 yrs The __________ the U Factor the less heat the window allows to pass through. Correct A ) Smaller U factor is a reciprocal of R factor. The smaller the U factor the less heat is allowed to pass through ______________ measures how well a window blocks heat from the sunlight Correct A ) Solar Heat Gain Coeﬃcient (SHGC) SHGC measures how well a window blocks heat from the sunlight The ___________ a window's solar heat gain coeﬃcient, the less solar heat it transmits. Correct A ) lower Solar Heat Gain Coeﬃcient is expressed as a number between 0 and 1. The lower a window's SHGC, the less solar...
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 Spring '07
 PISUPATI,SARMAVE

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