Tinted WindowsTinted Windows

ByBy

Mark Thompson, Owen Carlson, Mark Thompson, Owen Carlson, Spencer SmithSpencer Smith

IntroductionIntroduction

Tinted windows reduce solar radiation that Tinted windows reduce solar radiation that damages car interiorsdamages car interiors

Tint also keeps cars cool during summer Tint also keeps cars cool during summer and winter monthsand winter months

Tint reduces glare while drivingTint reduces glare while driving

ProblemProblem

Calculate the heat flux reduction through Calculate the heat flux reduction through tinted windows.tinted windows.

Conduction Vs. RadiationConduction Vs. Radiation

Tinting is so thin that it is negligible in Tinting is so thin that it is negligible in reducing heat transfer into the car through reducing heat transfer into the car through the windows. the windows.

Combination of convection and conduction Combination of convection and conduction through the rest of the car is important but through the rest of the car is important but has nothing to do with tinted windowshas nothing to do with tinted windows

Reflecting radiation from the sun is what Reflecting radiation from the sun is what tinting does. tinting does.

Equipment & CalculationsEquipment & Calculations

Radiation MeasurementRadiation Measurement

A large part of the radiation is in the visible A large part of the radiation is in the visible region.region.

F( 0->.4)= 0.1240F( 0->.4)= 0.1240 F(.4->.7)= 0.3676 (visible)F(.4->.7)= 0.3676 (visible) F(.7->∞)= 0.5084F(.7->∞)= 0.5084

Because of lack of equipment we couldn’t Because of lack of equipment we couldn’t measure any of the other regionsmeasure any of the other regions

ResultsResults

Incident Light

0

10

20

30

40

50

60

70

80

11:02AM

11:20AM

11:38AM

11:56AM

12:14PM

12:32PM

12:50PM

1:08PM

1:26PM

1:44PM

2:02PM

2:20PM

2:38PM

2:56PM

Time

Lig

ht

(fo

ot

can

dle

s)

Light Outside of Tint

Light Inside of Tint

Light Outside w/o Tint

Light Inside w/o Tint

ResultsResults

Temperature Variations

-5

0

5

10

15

20

10:48 AM 11:16 AM 11:45 AM 12:14 PM 12:43 PM 1:12 PM 1:40 PM 2:09 PM 2:38 PM

Time

Tem

per

atu

re (

C)

Temp Outside

Temp Inside Tint

Temp Inside No Tint

CalculationsCalculations

Tinting reduced visible radiation about 60%Tinting reduced visible radiation about 60% Even if tinting doesn’t block radiation in any Even if tinting doesn’t block radiation in any

other regions it still accounts for about: other regions it still accounts for about: .6 x .3676 = .22 or.6 x .3676 = .22 or

22%22% of total incident solar radiation of total incident solar radiation

Most likely tinting also reduces radiation in other Most likely tinting also reduces radiation in other regions that would help reduce temperature and regions that would help reduce temperature and damage caused by solar radiation.damage caused by solar radiation.

ConclusionConclusion

Tinting reduced the amount of visible light Tinting reduced the amount of visible light in the carin the car

It also reduced the temperature in the carIt also reduced the temperature in the car Tinting can protect car interiors from Tinting can protect car interiors from

harmful lightharmful light