== Panel Thermal Measurement ==
All panels were monitored for back sheet temperature at a minimum of one point. If channels were available, two points at the top and bottom of the panel were measured, as there have been recorded differences in temperature over the length of a panel. In order to translate from back sheet temperature to cell temperature, a correlation is available from [
Sandia Laboratories http://photovoltaics.sandia.gov/docs/PDF/King%20SAND.pdf] (eq.12).
The temperature of the back sheet of each panel was measured utilizing site-fabricated thermocouples. The thermocouples were created by purchasing outdoor compatible duplex insulated SLE (Special limits of error) thermocouple wire. The wires were run from the data acquisition box to each panel, and cut to length. It is critical to label both ends of the wire with a durable label to ensure proper hook-up. Both ends were then stripped and a portable [
thermocouple welder http://dcccorporation.thomasnet.com/item/thermocouple-welders/hotspot-i-ii-thermocouple-welders/item-1112?&plpver=10&origin=compare&filter=0&CTypeID=2] was used to create a solid junction at the panel side. For future designs, however, it would be recommended to utilize [ shielded thermocouple wires http://www.omega.com/ppt/pptsc.asp?ref=TT-J-TWSH&Nav=temh06] to protect against electrical interference over the long spans of wire required.