# Radiation lamp to heat pizza

1. Apr 30, 2014

### Maylis

1. The problem statement, all variables and given/known data
Cheese Board Pizza just hired me to design a radiant pizza warming system. The pizza must be maintained at 250 F until the order is picked up by the delivery driver. The one square foot pizza sits on a ½ inch thick ceramic pan (k = 0.50 BTU /hr ft F) on a counter that is at 85 F. A fan blows air at 70 F over the top of the pizza (the convective film coefficient is estimated to be 2.0 BTU / hr ft2 F). the emissivity (ε) of the pizza is 0.60.

How hot must the radiant heat lamp be to keep the pizza at the desired temperature ?

2. Relevant equations

3. The attempt at a solution
Hello, I am having some confusion over if the blackbody radiates energy, as well as the pizza radiating energy back at the lamp, which can be approximated as a blackbody.

I originally had 4 terms, a convection and conduction term leaving the pizza, a radiation term leaving the pizza, and a radiation term from the blackbody going to the pizza. However, if I consider the blackbody radiation, I have no equation to find the Q because I don't know the view factor F12 since I don't have a ratio of the smaller side/distance between planes.

#### Attached Files:

• ###### 8.1 attempt 1.pdf
File size:
195.2 KB
Views:
425
File size:
168.3 KB
Views:
124
2. Apr 30, 2014

### Maylis

Solved disregard

3. Apr 30, 2014

### Staff: Mentor

Yeah, but now I'm hungry...

4. May 1, 2014

### collinsmark

I like pizza.