Friday, November 22, 2013

Adding a rear entryway

Our cats love to try to sneak out the back door, and they have often been successful; when we open the door for a dog, out goes a cat.  So we added a rear entryway to provide an airlock, and keep the cats in.  It also will lessen sun heating in the summer, and provide a little solar warmth in the winter.

Guy, a friend and professional carpenter, works with the studs.
Studs are almost complete
Sheathing nearly finished.
Door and windows are in.
All done except stucco & painting.
Stucco guys at work.
Finished ! (except for inside painting)

Friday, November 8, 2013

Adding a new solar array

Back in March of 2010, we had 1.94KW of solar installed on the garage roof of our Las Cruces, NM home by Positive Energy Solar. In September of this year we calculated that we had generated 78% of the electricity used in the March 2010 to Sept 2013 period (We use power conservatively, and are often away during the hottest part of the year). The cost of solar has come down dramatically since then and we decided to expand our system. We chose to go with the same brand of panels and inverter so that we would be able to monitor both sets of panels as a single system using SunPower's website.  These pictures show the installation, by Positive Energy, of ten new SunPower 327Watt panels and an additional inverter. We anticipate the combined system will generate about 200% of our electrical power usage.

Marking the location of the panels
Installing the mounts
Close-up view of one of the mounts with bracket attached
Installing the rails
Installing the roof junction and roof penetration box
The first panel ready for mounting
Running the wires from the panels to the solar controls
Mounting the tenth and final panel
Moving the old 4KW inverter to handle the new 3.27KW array. The new 3KW inverter will handle the old 1.94KW array
Wiring the inverters, metering, and monitoring
Top left and center are the two inverters. Directly below them are the DC switches. Below the switches are the wiring trays. Between the trays is a breaker box where the inverter outputs are joined. Below that is a box containing the wireless monitoring equipment. The technician is working on the main solar AC breaker, and directly above it is the REC meter. From the REC (Renewable Energy Credits) meter the solar AC output is fed into the house main electrical panel which contains a bi-directional revenue meter.
The controls completed and ready to go.  The total system (1.94+3.27=5.2KW) generated around 25kWh the first sunny day after the new array was installed (It's November - I'm anxious to see what it will produce in May).
A story about the old system, with 9 months of operating results, can be seen at: