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 135 mm, and the cardboard is 4 mm thick. The size of the window (W and L measurements) is 8.5 cm x 8.5 cm, and the depth of the oven cooking chamber is 10 cm. Prepare graphs of Tio vs. Uw, assuming that s = 50,  = 40, = 0.92, a=0.9, Tambient = 21C and Io=1000 watts/meter2. Be sure to show the intersection point on the graphs. There are no reflectors. 

a) What is the predicted Tio of this oven with one layer of Mylar for the window? 

b) What is the predicted Tio of this oven with two layers of Mylar for the window? 

Problem 2 Now increase the size of the window to be 18.5 cm x 18.5 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. You have added four trapezoidal reflectors, each 37 cm long. 

 

 1c) What is the predicted Tio of this oven with one layer of Mylar for the window? d) What is the predicted Tio 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 ValueOld Value |Old Value|  100 % 1. What effect on the predicted Tio did adding the second layer of Mylar have? 2. What effect on the predicted Tio did increasing the size of the window have? 3. Which of these two changes had the larger impact on the predicted Tio? 4. What has the largest effect on predicted Tio? 5. Of the four oven combinations, which one yielded the highest temperature? Does this answer make sense to you intuitively? Explain why or why not this makes sense to you.