Dedication of off-grid solar greenhouse
By Drs. Robert & Sonia Vogl
President and Vice President,
Illinois Renewable Energy Association
In 2010, IREA commissioned a builder of energy efficient homes to design and build a solar greenhouse similar to what is used to grow food in the Himalayas. It would be off-grid and powered by solar electricity feeding new LEDs. It was highly insulated, had double pane windows and a phase change wall to moderate temperatures. We also attempted to minimize temperature swings with two 50 gallon barrels of water and extending AC power to supply additional heat during very cold spells.
The building’s location at our home, the IREA Headquarters, was temporary as our intent was to eventually stabilize its temperature by connecting it to the ground with a foundation or an earth tube.
Its performance did not meet our expectations as temperature swings were greater than expected and some of the windows cracked and needed replacement.
We planted a variety of vegetables to determine which would be productive in the soil based growing system using sunlight and early versions of LED lights. PV panels fed a battery pack which powered the lights hung above the plants.
We had some success in growing lettuce and some leafy crops but failed to produce fruit or root crops.
We had ideas for correcting its shortcomings based on the hydroponic efforts of sociology instructor Tim Bratina’s Rockford Auburn High School program, the development of LEDs used to stimulate plant growth and the benefits of linking the greenhouse to the ground to moderate temperatures.
Since the location of the greenhouse on our property was only temporary we were willing to part with it if we found someone willing to manage it. We linked with Josh Nelson’s agricultural program at Oregon High School to move it to their grounds and implement the concepts, including a hydroponics system, essential to upgrading it.
The off-grid solar greenhouse in the agricultural program will introduce students to solar energy and LED lighting for growing food. They will design experiments to integrate research techniques into their curriculum. IREA will be involved in the educational efforts and in turn the students will participate in the Fair. Several other local schools have expressed interest in participating in the program.
We consider the link with the school a way to stimulate student interest in renewable energy and sustainable living and bring a youthful presence to the IREA Fair. We include high school students as presenters as a means to support their interest in sustainable living.
An open house was held on August 27 to show the building and overall effort. The building now sits over an insulated concrete basement which will be used to grow mushrooms while it stabilizes the building temperature. A new battery pack with four times the capacity of the previous one will power the 18 new red, blue and green LED lights which stimulate plant growth.
New energy efficient triple pane windows from Germany have replaced the former vulnerable double pane windows. The glass will allow more wavelengths in the growing range to enter the building while reducing heat generating wavelengths. An overhang will be built over the windows to reduce the penetration of the summer sun.
We look forward to the results of the student experiments in hydroponic growing in the off-grid greenhouse.
Another thank you for help at this year’s fair
The Renewable Energy and Sustainable Lifestyle Fair could not have happened without the help of many people. One of them was essential to the functioning of workshops. Soren Cates, local tech expert, spent the entire weekend guaranteeing that all speakers had computers, projectors, cords and electricity for their presentations. It was an impressive job. We know, since we tried to do it ourselves one year. Thank you, thank you, thank you, Soren!
Bob, Sonia & Lin Vogl