# What effect on the predicted Tio did adding the second layer of Mylar have?

the graphical solution approach to predict the internal oven temperature (Tio). Refer to the Solar Oven Excel Guide and the Solar Oven Basics documents for guidance. Please complete and submit this assignment as an Excel spreadsheet.

In this assignment, you are to compare the predicted internal oven temperature (Tio) of four different solar oven designs (two designs in Problem 1, and two more designs in Problem 2).

No reflectors will be used on these ovens. In addition, the Solar Oven Project oven volume constraint (1,000 cm3) does not apply to these oven examples.

Problem 1: The oven in a) has a window made of a single sheet of Mylar, and the oven in b) has a window with two layers of Mylar. In each case, the thickness of the insulation (wadded newspaper) is 150 mm, and the cardboard is 4 mm thick. The size of the window(W and L measurements) is 6 cm x 6 cm, and the depth of the oven cooking chamber is 10 cm.

Prepare graphs of Tio vs. Uw, assuming that θs = 50°, β = 40°, τ= 0.92, a=0.9, Tambient = 21°C and Io=1000 watts/meter2. Be sure to show the intersection point on the graphs that you construct.

1. a) What is thepredictedTio of this oven with one layer of Mylar for the window?
2. b) What is thepredictedTio of this oven with two layers of Mylar for the window?

Problem 2: Now increase the size of the window to be 18 cm x 18 cm. The oven in c) has a window made of a single sheet of Mylar, and the oven in d) has a window with two layers of Mylar. All other parameters are the same as stated in Problem 1, including the cooking chamber depth of 10 cm. Prepare two more graphs of Tio vs. Uw. Be sure to show the intersection point on the graphs that you construct.

1. c) What is thepredictedTio of this oven with one layer of Mylar for the window?
2. d) What is thepredictedTio of this oven with two layers of Mylar for the window?

Additional questions: Answer the following questions in your Excel file. Type your answers into a text box for easy formatting. For questions 1 through 3, quantify your answers using the percent change in the predicted Tio value:
New Value-Old ValueOld Value×100%

1. What effect on the predicted Tio did adding the second layer of Mylar have?
2. What effecton the predictedTio did increasing the size of the window have?
3. Whichof these two changeshad the larger impact on the predicted Tio?