Photovoltaic Part 2: Specifications and Installation
In an earlier post, I described the process leading up to the installation of our house’s photovoltaic system. This post describes the system itself and its installation.
As described previously, the design of our system was done by the contractor, based on the electric bills we provided and input such as the fact that we wanted the system to be somewhat sensitive to aesthetics, not wanting to cover the front of our house (which faces south) with solar panels. Instead, we opted to have half of the panels on the front, in an area that isn’t as visible from the street, and half on the back, facing west.
The system consists of:
- 24 each Sanyo HIP-200BA3 panels (12 panels each facing south and west)
- 2 each Xantrex 3.8 GT series inverters (1 each for the south and west arrays)
- 1 lot mounting hardware, AC disconnect, etc.
The Sanyo HIP-200BA3 panels are rated at 200 W (180 W guaranteed) and are about 52 x 35 inches in size (132 x 89 cm), with a total area of 12.7 square feet per panel. One of the things I like about these panels compared with others I have seen is that the frame is anodized black, which is much less conspicuous than ones that are their natural aluminum color. The total area covered by the panels is about 305 square feet.
The Xantrex inverters operate independently in order to better optimize their efficiency for the different time of day that the two arrays peak. The use of two inverters did increase the cost of the system somewhat, but provided good efficiency while maintaining the aesthetics of the house. Each inverter has a serial output that can be used to monitor the inverter output from a remote PC using software available from Xantrex. More on that in a future posting describing the results from the system. The inverters also have a display on the front of each unit and a very unusual but practical user interface: knock on the front of the inverter to change the display.
The system cost (in mid 2006) was about $36,000 for the hardware and $5,500 for installation. We got substantial incentives and rebates at the time, but these vary with time and locality.
The installation of our system took place in Fall, 2006, with the installation being performed by Renewable Alternative Technologies of Gilroy, California. They did an excellent job; with all of the support posts I was concerned about possible roof leaks, but there haven’t been any at all. You can see some more pictures of our system on their website under “Los Altos – 4.2 KW Grid-tied System.”