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Unformatted text preview: 10  1.11 = 8.89 M MBTUs/yr
Savings in energy cost per year = 8.89 x 10 = $88.9
Payback period = 20 / 88.9 = 0.22 yrs Spacer materials used in a window reduce Correct A ) conduc*on losses Spaces material usually has a high R value and is used to reduce conduc*on losses in a window 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 0.1429. Assume hea*ng price to be $10/MMBTU and the cost for ﬁlling Argon is $20. Correct D ) 0.28 years R value of new window = 1/0.1429 = 7 Heat lost through new window per year = (10 x 2) / 7 = 2.84 MMBTUs/yr
Reduc*on in heat lost per year = 10  2.84 = 7.16 M MBTUs/yr
Savings in energy cost per year = 7.16 x 10 = $71.6
Payback period = 20 / 71.6 = 0.28 yrs...
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This note was uploaded on 09/24/2013 for the course EGEE 102 taught by Professor Pisupati,sarmave during the Spring '07 term at Pennsylvania State University, University Park.
 Spring '07
 PISUPATI,SARMAVE

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