Types of Solar Panels

Monocrystalline
Generally considered the workhorses of the solar power market, these are made from cells created by cutting thin slices from the single crystal silicon block and are higher in efficiency but also higher in cost per watt. These are easily identifiable, made up of uniformly stacked rounded cells. Because they’re made from just one crystal, not multiple crystals fused together, the process of making them is one of the most complex and costly ones around.

Polycrystalline
These are made from cells created by cutting thin slices from polycrystal silicon block and are slightly lower in efficiency, but also lower in cost per watt. Polycrystal silicon is the “chicken nugget” of silicon, made by combining many individual crystals. They are easy to spot because they have an uneven color, usual blue.

Thin Film
These are made by depositing a thin layer of very finely powdered silicon (amorphous silicon) or other photovoltaic material, on a substrate. While lower in efficiency than crystalline cells, they are considerably cheaper per watt. The downside is that they take up more space per watt. They are perfect for roof mounted systems as they are incredibly strong, have superb wind uplift and produce power even in undesirable conditions. 

Is This The Future Of Cool Roofing?

Scientists at the Massachusetts Institute of Technology (MIT) have recently invented a new smart roofing tile called “Thermeleon” (rhymes with “chameleon”), which is thermochromic – in other words, when it is exposed to heat it changes color from black to white, and vice-versa.

Thermeleon works by sandwiching common polymers between several flexible plastic layers. When it is cold outside, the polymer solution stays dissolved and the black rear-face shows through to absorb the natural heat. When it heats up outside, the polymer solution condenses to form light-scattering droplets (in other words, it turns white), to reflect the heat.

We now know that a white roof reflects up to 80% of the sunlight, keeping the interior of the building beneath the roof much cooler. This can result in a 20% reduction in summer air conditioning costs. But during the winter months when you would rather your roof capture as much heat as possible from the sun, the black coloring has the reverse effect - these tiles scatter only 30% of incoming solar radiation, thereby helping to keep the building beneath the roof warmer (reducing heating costs).

The team at MIT is now working on micro-encapsulating the chemicals to create a commercially-viable, paintable or spray-on roof coating. If they can figure out how to produce this roof coating at a favorable price and proves to be durable enough for the extreme summer months in regions like we have in Florida, this could very well be a sneak peek at the future of cool roofing.

The Roofing-Mold Connection

Most owner and managers have begun to fully comprehend the potential ramifications of mold for Indoor Air Quality (IAQ). These ramifications can manifest themselves as damaged building materials, degraded IAQ, sick building symptoms, and potential lawsuits. Mold commonly occurs in most organic building materials. It is common to see lichens, or mold, growing on the top exterior surface of roofs, within wet organic roof insulation boards, and on wet wood nailers. The one thing that all these surfaces have in common is that they are above the roof deck and, therefore, have minimal impact on IAQ.

When mold growth develops on interior surfaces, IAQ can be affected and building occupants start asking questions. Most organic building materials can support mold growth if temperature and moisture conditions are within supportive limits. Typical materials include ceiling tiles, gypsum board, wallpaper, insulation, adhesives, wood trim and wood framing materials. These materials have been used for years in construction and many never experience mold growth.

 Identifying the Culprit
What is the catalyst for mold growth: temperature or moisture? Temperature seems to be unlikely, as many building types have similar interior environments, and some have mold, while others do not. It appears that moisture might be the single most probable catalyst to affect mold growth. This seems likely as most observed mold growth is associates with leaks and condensation problems in roofs, windows or walls. Studies have proven that leaks in a building can contribute to mold growth within as little as 48 hours.

Leak Response
If we know that roof leaks may be a major contributor to mold development, then keeping water out of organic building materials is paramount to preventing mold growth. We must establish an aggressive leak response program.  Technicians must investigate leaks, determine origin points and address deficiencies in a timely manner. Leaks must be stopped within 48 hours and the wet materials dried out, or mold growth is possible. Simple enough to fix when you call RAMCON.

A Proactive Step
Leak response, though important, is reactive, and materials often get wet before a problem can be identified. A better approach would be to develop and peserve an aggressive roof-maintenance program.

It appears that mold growth and roof leaks are directly related. As a result, annual roof maintenance might be the first line of defense against mold development.If leaks do occur, they must be investigated and repaired immediately. To stop mold development, you must take the position that roof leaks are not acceptable. A RAMCON preventative maintenance program can help provide tangible results in mold prevention.

White, Green, and Cool: Maximizing The Value Of Solar-Reflective Roof Membranes

Roofs are an important element in green, sustainable, architectural solutions. One of the more interesting concepts in energy efficiency is the “cool roof,” also sometimes known as a “white” or even “green” roof. The terms are not really interchangeable -- the cool roof concept is specifically defined by the Cool Roof Rating Council (CRRC) as a roof membrane (single-ply, built-up, or modified bitumen), field-applied coating or other type of roof cover (such as sheet-metal), with both a specified initial solar reflectivity and an “aged” reflectivity value. The basic concept -- reflecting the sun’s heat, absorbing and then emitting solar radiation -- is well established.

Cool roofs are definitely green (to the extent that they are sustainable and minimize adverse environmental impact) and may contribute to interior comfort while reducing energy expenditures, but they are not the garden-surface variety of the term “green roof.” Green roofs are also commonly designed with high insulation R-values.

The cool roof idea has been around for several decades, but it has gained importance with increasing environmental concerns. Building codes feature stricter standards regarding R-values and roof materials (e.g., thermal resistance value must be 20 or greater), while environmental issues add a social awareness element -- cool roofs can enhance your reputation. Materials have changed, too; a wide variety of roof membrane and coating materials are available to designers, including light (but not necessarily pure white) colors.

Caveats for Cool
Cool roofs, if properly maintained, can also reduce energy costs, thus beneficially impacting an owner’s bottom line. There are some caveats regarding cool roofs, however. 

Roof surfaces should be positively sloped to minimize the accumulation of dirt in low spots and to likewise aid in “self-washing” during normal rain.  Cool roofs are particularly appropriate for warm, sunbelt-style climates like ours with greater demands for cooling rather than heating.

Targeted Maintenance
Even when a cool roof is initially effective, targeted maintenance, which is often overlooked, is still necessary for the roof to remain clean and reflective so that it can stay cool and efficient throughout its lifecycle. Dirt, soot, sediment and similar substances will still settle on a cool roof  making the roof darker and less efficient over time. We must invest some time, effort and money in monitoring the roof’s condition and performing cleaning or repairs as necessary. Otherwise, energy-efficiency declines and cool roof benefits are largely lost.