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Posted on Sep 25, 2012



by Lee Ewald
photos by Lee Ewald

Several years ago, I wrote an article for The Natural Life Network describing our home in northern Michigan that incorporated passive solar techniques and a new HVAC system with an air-to-air heat pump that interfaced with our solar hot water system.  After more than 2 years since the installation, I can report that the system has worked extremely well.  It has saved us a great deal of money, and created a lot of satisfaction in the process…knowing that we cut our carbon footprint significantly.

We are located just off of Lake Michigan at the 45th Parallel, and do get a lot of cloud cover and lake effect snow from November to March.  However, I still felt that the investment would be worth the effort and contribute further to the reduction of our carbon footprint.  The deciding factor was that Michigan passed a Renewable Portfolio Standard (RPS) and net metering.  Also, the cost of solar PV panels had been dropping…making such a system more cost effective.

In Michigan, power companies are required by law to pay a producer of renewable energy the same price that they are charged for electrical use (in our case, 11 cents per Kwh).  Under these circumstances, payback is rather slow.  With Michigan sitting right next to the Province of Ontario and seeing what was initially available as a “Feed-in Tariff” this was quite disconcerting for someone who has fought for a FIT program in Michigan.  Many renewable energy enthusiasts throughout America are envious of the Ontario program!  Also, after visiting Germany three years in a row, we could see what the FIT program had done to transform that nation and we were hopeful that politicians here would see a more viable option for American’s energy by implementing this type of program.

Uni-Solar Thin-Film Laminate PV System

On a trip to Florida in 2010, I visited friends at Solar Source in Largo, one of the largest installers in Florida that also have an educational division called Solar Source Institute, which trains and certifies individuals who want to become installers of PV systems.  On this trip, I also visited Sun Electronics in Miami Gardens who were packaging systems at a discount.  Gathering brochures of solar components and systems at both places gave me the reading material that I needed to make a clear decision about which system to install.

After doing a lot of research on panels for our inclement weather, I decided to purchase a system with Uni-Solar thin film laminate panels.  I was planning to put the panels on a building that had previously been used for a large outdoor gas kiln.  For many years, I had been a professional potter, but in 2010, I sold my walk-in gas kiln and put the money aside for re-purposing the building as a garden shed for my wife, which would also hold the new solar panels.  I ordered 10 panels rated at 128 watts each, their model PVL-128.  One issue with this building is that it has a 5/12 pitch, hardly ideal for winter solar gain…but for late spring, all summer and early fall, it provides a good enough angle.

While these thin-film PV laminates are not as efficient as newer crystalline solar panels, they mount on steel roofing between the ribs of steel panels that are 16 inches wide.  Northern Michigan winter snow loads can be enormous and I wanted panels that the snow would slide off of….just like it does off a metal roof. 

Mounting the Solar Panels on a Metal Roof

For those of you who have done roofing recently, I am sure you are familiar with the product called Grace Ice and Water Shield.  It is a roof underlayment that is typically installed near the edge of a new roof for protection from ice dams and damage done by wind and rain.  The back of the Uni-Solar panels has this type of adhesive material adhered to them.  Anyone who has dealt with such a product knows the inherent problem that once it’s down…IT IS DOWN…and cannot be moved. 

The same is true with the PV laminate solar panels … once you start to adhere them to a metal roof, they cannot be moved.  The biggest suggestion that I can make if you decide to tackle a project such as this … set yourself up in the shade where sun cannot beat down on the panels.  Also, I should caution you a little about the length … I had my steel roof panels cut 4” shorter than the distance from the tip of the ridge of my roof to the lower roof edge to allow for a “trench” at the top for running the panel wires on a non metallic surface.

Matt Oliver, of Matt’s Mechanical Contracting, the person who installed my HVAC system, helped me with the task of adhering 10 solar PV laminates on the individual steel roof panels.  While I made a table for mounting the laminates, we had to move the whole setup out of the sun when the morning sun rose above the trees and we started having problems with the thin film laminates getting too sticky. 

The process is a 2-man job, with one person pulling off the protective backing, while the other adheres the laminates to the steel “pans”, first by hand and then with a soft counter top roller to make sure they are totally adhered.  The process is tedious, but if one takes their time, a successful job can be accomplished.  Of course, as with any solar panel, checking them for open circuit voltage is a must.  In my case, each panel measured 40 VDC.  I measured each laminate’s voltage before adhering them to the steel roof by laying them in my driveway in full sun.

After the adhering process was completed, I hired Bud Person of Person Construction, Inc (an expert roofer) who stripped my old asphalt shingles off the building and put down Grace High Temperature Ice and Water Shield over the entire bare wood surface of the building’s roof.  I then carefully slid each steel panel (with the solar laminates pre-adhered) up to Bud, and with his helper he screwed the steel panels down as prescribed by the manufacturer.  In my case, I used Jensen Bridge Steel Roofing for the project.  The steel panel “pans” between the ribs that are spaced 16 inches must be completely flat as prescribed in the installation handbook by Uni-Solar for proper adherence.  

The Electrical Side of the Installation

As part of a complete solar PV system, I purchased a SMA 3000 US inverter, a MidNite Solar 3-way combiner, and an analog GE AC power output meter as a backup for the digital display that also monitors generated AC Kwh in the SMA inverter.  The wiring is pretty straightforward for anyone understanding both AC and DC electrical circuits.  I built a large plywood mounting board for the components, and mounted that to the wall, then my son Kurt came over to help me mount the heavy inverter to the board and do the wiring inside the building.  Since I have bare stud walls in the old kiln building, I ran all wiring in insulated electrical PVC to dress up the project … meeting all code and safety requirements as well.  

Copyright © John Wilson 2015 - v2