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Unformatted text preview: in winter and gain more heat in summer than any other surface in the home _______ gas is used in gas ﬁlled windows to improve thermal performance Correct A ) Krypton Inert gases like Argon and Krypton are used in gas ﬁlled windows to improve thermal performance The heat loss through a window (U value = 0.33) 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 0.1250. Assume hea*ng price to be $10/MMBTU and the cost for ﬁlling Argon is $20. Correct D ) 0.32 years R value of new window = 1/0.125 = 8 Heat lost through new window per year = (10 x 3) / 8 = 3.75 MMBTUs/yr
Reduc*on in heat lost per year = 10  3.75 = 6.25 M MBTUs/yr
Savings in energy cost per year = 6.25 x 10 = $62.5
Payback period = 20 / 62.5 = 0.32 yrs We have a window with S HGC=0.61 and V T=0.67. What is the L SG? Correct A ) 1.1 LSG = 0.67 / 0.61 = 1.098 The __________ the U Factor the less heat the window allows to pass through.
Correct A ) Smaller The smaller the U Factor the less heat the window allows to pass through We have a window with S HGC=0.72 and V T=0.48. What is the L SG? (3 Points) Correct B ) 0.67 LSG = 0.48 / 0.72 = 0.666 Insola*on is a combina*on of the following words _____. Correct B ) Incident solar radia*on The amount of solar radia*on reaching the earth is called the insola*on. This is a short form for INcident S OLar radiATION The heat loss through a window (U value = 1) 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 B ) 0.23 years R value of new window = 1/0.1429 = 7 Heat lost through new window per year = (10 x 1) / 7 = 1.42 MMBTUs/yr
Reduc*on in heat lost per year = 10  1.42 = 8.58 M MBTUs/yr
Savings in energy cost per year = 8.58 x 10 = $85.8
Payback period = 20 / 85.8 = 0.23 yrs ___________ measures how well a product prevents heat from escaping. Correct A ) R value R value mesures how well a product prevents heat from escaping Visual TransmiFance / Solar...
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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 Penn State.
 Spring '07
 PISUPATI,SARMAVE

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