Heat Transfer of a Griddle

Phil KimJosh Zimmerman

The Project• Test and Compare the Heat Transfer

Rates for two Griddles.– Time to Heat from (98°F to 300°F)– Time to Cool from (300°F to 98°F)

• Verify Power Input (1500 W)

BLACK GRIDDLE 10.5”x20.5” GRAY GRIDDLE

10”x17”

Testing Procedure• Measure Current and Voltage Entering

the Griddle. (Ammeter/Voltmeter)• Measure the Temperature in the Center

of the Griddle. (Thermocouple)• Measure the Time:

– to heat to 300°F– to cool to 98°F (To avoid burning)

• Measure Volumeand Surface Area

Heating Analysis:Heating: Temperature vs. Time

0

20

40

60

80

100

120

140

160

0 1 2 3 4

Time (minutes)

Tem

per

atu

re (

Cel

siu

s)

Actual Black Griddle

Actual Gray Griddle

Theoretical Black Griddle

Theoretical Gray Griddle

Error in Heating Time:

• Black Griddle: 1%

• Gray Griddle: 28%

Error in Temperature:

•Black Griddle: 2% Hotter than Desired

•Gray Griddle: 6.8% Cooler than Desired

Cooling Analysis:

Error in Cooling Time:

• Black Griddle: 4.2%

• Gray Griddle: 5.3%

POWER ANALYSIS:

Black Griddle uses 1446 W

Gray Griddle uses 1410 W

(both out of 1500 W)

Cooling: Temperature vs. Time

0

20

40

60

80

100

120

140

160

0 2 4 6 8 10 12 14 16 18 20

Time (minutes)

Tem

per

atu

re (

Cel

siu

s)

Black Griddle

Gray Griddle

Theoretical Black Griddle

Theoretical Gray Griddle

Observations:

• Time to heat is very sensitive to emissivity (є), and pan thickness (∂).

• Roughly 20% of overall Heating/Cooling was caused by Radiation.

Conclusions:

• Black Griddle is better than the Gray Griddle.– It heats to the correct temperature– It heats faster– It utilizes power better