You Bet Your Glass : May-June-2010
By Frank Fulton
The PV wave is coming
By Frank Fulton
As everyone is aware, the limited supply of energy and never-ending
escalating fuel costs have created a growing demand for more efficient
As everyone is aware, the limited supply of energy and never-ending escalating fuel costs have created a growing demand for more efficient building materials.
The development of energy efficiency in glass products arguably took root in the 1950s with the introduction of insulating glass on a commercial scale.
A lot of developments have taken place since then including but not limited to tinted glass, low-emissivity coatings, gas filling, thermally broken aluminum, and vinyl windows to name a few.
I recall a meeting with people from the National Research Council of Canada (NRCC) in the early 1990s where we were discussing the development of more energy-efficient windows. They told me then that if a window could achieve an R-value of 8, it would actually become a source of energy gain in a house as opposed to being an energy loser. At the time, I didn’t think there would ever be a window produced that would get close to that kind of performance. The windows we were making then at Fulton Windows would get an R-2 at best.
Now, prototype buildings are being put up, without furnaces, in cold weather locations. The buildings are designed in such a way and built with materials so that the entire building becomes a source of energy gain from the sun and from underground. The building actually powers itself.
The next wave of energy technology coming our way in the glass and related products industries will be photovoltaic (PV) glazing. Windows, curtain walls, and skylights glazed with PV glass will be capable of collecting energy from the sun and transforming it to electricity to power lights, heating systems or other applications in the building.
Solar cells, also called photovoltaic (PV) cells by scientists, convert sunlight directly into electricity. PV gets its name from the process of converting light (photons) to electricity (voltage), which is called the PV effect. Although Charles Fritt constructed the first solar cell in the 1880s, solar cells first started to look viable in 1954, when scientists at Bell Telephone built the first silicon solar cell.
The evolution of solar cell technology is now reaching the point where it soon will be economically feasible and practical to use PV glazing in homes and other buildings.
Traditional solar cells are made from silicon, usually are flat-plate, and generally are the most efficient. Second-generation solar cells are called thin-film solar cells because they are made from amorphous silicon or nonsilicon materials such as cadmium telluride. Third-generation solar cells are being made from a variety of new materials besides silicon, including solar inks using conventional printing press technologies, solar dyes, and conductive plastics.
The approach currently being developed by the major glass companies involves the deposition of thin layers of non-crystalline-silicon materials or cadmium telluride on glass, not unlike the application of low-e coatings. It is the least energy intensive of the three generic manufacturing approaches for commercial photovoltaics. It also will be possible to apply similar coatings to stainless steel and aluminum sheet to collect energy at the spandrel areas of curtain walls.
There are companies out there already working on commercial applications using this fast-approaching technology. I came across a Dutch company that is in the process of installing windows and sliding doors on pilot projects using a PV insulating glass they developed. In addition to the glass functioning as a solar collector and generating electricity, the window is equipped with a switch that works like a light bulb dimmer. The glass is clear but can be made reflective or tinted to cut down on solar overheating by a simple turn of the switch. If you want total privacy, instead of drawing the blinds, a further turn of the switch uses a mirror effect to scatter the light and make the glass totally opaque.
I think you’ll be seeing a big change in the products you’re currently selling and installing within the next few years as PV technology comes on line. Keep your eyes open and get ready now to ride the wave.
Frank Fulton is president of Fultech Fenestration Consulting. He has been in the industry for 30 years and can be reached via e-mail at email@example.com.