Paying to Warm Up Provo

Nathan HillNathan HillJon MarshallJon Marshall

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Huge Gas Bills!Huge Gas Bills!

Water HeaterWater Heater

Gas stove/ovenGas stove/oven

Gas DryerGas Dryer

-- Gas Heater!! ---- Gas Heater!! --

Windows are a Windows are a huge source of huge source of energy lossenergy loss

Convection Convection leaksleaks

ConductionConductionK=1.4K=1.4

Radiation Radiation Night – lose heatNight – lose heat

Day – gain heatDay – gain heat

Single Pane Single Pane Windows are the Windows are the Worst!Worst!

Most students in Most students in Provo live in houses Provo live in houses with windows more with windows more like thislike this

Example of Double-Pane Construction

Double pane Double pane utilizes the lower utilizes the lower convection convection coefficient of coefficient of various gases various gases between the between the panes.panes.

But they can be But they can be expensive.expensive.

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AlternativeAlternativePlastic InsulationPlastic Insulation

Several Options at Several Options at any hardware storeany hardware store

This product is This product is available at Home available at Home DepotDepot

Picture of us installing here

InstallationInstallationInstalls with double Installs with double sided tapesided tape

Blow dry with hair Blow dry with hair dryer until taughtdryer until taught

Installed in 3 – 5 Installed in 3 – 5 minmin

window Is it worth it?Is it worth it?

We wanted to We wanted to compare the heat compare the heat flux between the flux between the single pane and the single pane and the plastic insulated plastic insulated windowwindow

We wanted to find We wanted to find out how much it out how much it really helpsreally helps

window

L = .003175 m

To = 292 K

Ti = 295 K

K = 1.4

Single Pane Single Pane AnalysisAnalysis

)(" oi TTL

kq

q” = 165.4 W/m2

window

L = .0254 m

Ti = 292 K

plastic

Plastic Insulation Plastic Insulation AnalysisAnalysis

29.0

Pr2.0

Pr18.0

LL

RaNu

Pr2.0

Pr10

10Pr10

21

3

53

LRa

L

H

)( oiL TTAL

kNuq

Picture of box here

Here are the Here are the NumbersNumbers

Typical Gas Heater Typical Gas Heater efficiencyefficiency

≈ ≈ 75%75%

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We want to know We want to know how much we how much we can save! can save!

Energy CostEnergy Cost

Natural Gas Natural Gas

≈ ≈ $10.00/Mbtu$10.00/Mbtu

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Assumptions Assumptions Heat radiation into Heat radiation into and out of the and out of the windows is windows is negligiblenegligible

Constant outside Constant outside temperature temperature throughout the throughout the monthmonth

With plastic: With plastic: outside surface outside surface window temp = window temp = inside surface tempinside surface temp