We will finish the roof and the exterior walls. The metal roof will be here on Tuesday and will go up Wednesday. We will wrap the house in TYVEK and be ready to install windows after break. The roof will be covered with tar paper before the metal roof panels go up.
Here is the rubric for your service learning project. Be sure to get your volunteer supervisor to sign off on your hours before you finish your paper.
For Wednesday...
- Measure the area of each of the 4 types of photovoltaic (PV) panels that are in the classroom.
- Look at the electrical specifications label on the back of the PV and find the maximum wattage.
- Find the amount of daylight that we will experience in Denver today.
- Calculate (in kWh) the amount of electricity that each of the PV cells could generate.
- Calculate electrical generation/area (kWh/m2) for each of the PV cells.
- There are 60 fluorescent bulbs in this classroom that are each rated at 32 watts. How much electricity is consumed by using those lights for a full school calendar year? (Assume 8 hours per day and 185 days each year.)
- If those 60 bulbs were to be replaced with LED (light emitting devices) that are rated at 12 watts, how much electricity would be saved?
- The fluorescent lights cost $3.95 per bulb and last for 10,000 hours. The LED's cost $39.95 and last 50,000 hours.
- What is the cost to light this room with both of these options? (Electricity in Colorado costs (on average) $0.12/kWh.)
- How long (payback period) does it take for the LED option to be less expensive?
- How many (of the most effective) PV cells would be needed to meet the electrical demand for each of (fluorescent and LED) options?
Use the CER (Claim, Evidence, Reasoning) model to shape your answer to the following questions.
- If each of the PV cells receives the same energy input (sunlight) can you rate the relative efficiencies of them?
- Why do you think the solar panels are as efficient (or inefficient) as they are?
