VT Gets a Solar Upgrade

by Bob Lienhart

Village Terraces Cohousing Neighborhood just completed a multi-faceted upgrade to their power, heating, and domestic hot water (DHW) systems and the neighborhood is now enjoying the results. Domestic hot water for the main building had been provided by a wood-burning stove. The system lost one of its three water heating coils three years ago due to an unrepairable leak, which has made providing hot water quite challenging.

Several designs were considered over the last 2 or 3 years with none of them really being all that workable. Then one day Chris Farmer came along and suggested that we use solar-generated electricity to heat water in an ELECTRIC hot water heater. This sounds pretty silly until one remembers that electricity is 100% efficient at producing heat. Farmer had read an article 10 years ago that said when solar PV panels come down in price to $1 per watt then it would make sense to heat water with solar electricity. Well that day has come. And that is the approach that VT decided to take.

2007 view of the same building with the 1st generation of solar panels.

The final design allows VT’s existing wood-fired boiler system to provide ample domestic hot water during the cooler months at which time the new solar PV panels will keep their batteries more fully charged and their heating systems running. During the warmer months the solar electric power will be diverted to the new electric hot water heater.

For the short time this new system has been running, VT has cut its summer wood burning in half–if not more. Their hydro use and their gasoline generator use have also been significantly reduced. And their batteries are healthier than they have ever been. For a more thorough description of the system, including a tour, see Bob Lienhart.

 

Earthaven member and bookkeeper since 2008, musician and computer expert.  BS in Computer Science.  Treasurer for two homeowners associations and the Colorado Bluegrass Music Society–also CBMS president, 1998-2000.