Saturday, December 13, 2008

New Solar Panels

Way behind on updates. Most interesting thing happening here is probably the co generation installation and operation. There are many items related to that which will take some time to write up. Until that can get updated, here is an update on the solar panels.

As mentioned in a previous post, the older Sunpower panels had a defect associated with them as one can see in the following photo. Apparently an outer coating was coming off of the surface.

Here is a picture of the Sunlight Solar employees (Milford, CT) taking down the old panels. They did this in mid September, 2008--shortly after they took delivery of the replacement panels from Sunpower.

Here is a picture of one of the new panels. These are the newer 220W panels. The older panels were rated at 215W peak power. The difference is the technological improvement over the last 2 years (about 1% improvement per year).

Finally, here is a recent shot of the new installed array. Before there were 12 panels, and now there are 14.

There are other upgrades with the new system besides the 2 additional panels. The improved efficiency has already been mentioned. The other improvement is the inverter that takes the direct current out of the panels and converts it to alternating current in sync with the electric grid. The earlier inverter was rated at 2 Kilowatts (KW) while the old panels had 2.5 KW peak output, so there was some loss when the old inverter maxed out in its capacity to convert DC to AC power. In fact, the old peak power I ever saw during operation of the old system was 1.948 KW, and during good sunny days, the system would stay just under 2KW in output for about an hour. The new inverter maxes out at 3 KW which is just under the peak power rate. I haven't measured the new actual peak rate yet....a good thing to put on the list of things to do. Given the inverter and transmission (from the roof to the basement where the inverter is located) losses, there should be some spare inverter capacity, so there should be not maxing out of the actual power output now with the new array versus the old array.

Before, the old array consisted of 12 panels with peak output of 2.5 KW with an inverter limit of 1.95KW. Now, there are 14 panels with peak output of 3 KW. This peak output has yet to be verified, but I have seen output above 2KW. In the spring when the peak output is expected, I'll make sure this is correct.

The new system represents approximately a 30% increase in actual output. While only a small step, it is nonetheless a positive one in the right direction.