SolTech Passive Solar Glass Roof Tiles

Passive solar energy in cold climates?  Yes, with the new SolTech Energy glass roofing tiles, homeowners can trap and use warm air to help heat interior spaces.  Curved glass tiles use thermal imbalance to create maximum air flow through fabric-covered channels in the system.  As hot air rises, it flows around horizontal frames, becoming superheated on its way to the building’s heating system.  A fan helps propels the hot air loops, as well.

Consider this diagram:

How passive solar roof tiles heat building interiors

The solar glass roof tiles work in any climate.  In fact, SolTech debuted its passive solar system in cold, often snowy, Sweden.  This year, the company was honored with the “Hottest New Material 2010,” award from the North Building Fair, Nordbygg, a construction-related trade fair held in Stockholm.  Not only can you heat your home with the passive solar system, but it can also help you remove snow from your rooftop!

Currently, you can purchase the solar tiles in Sweden and Spain.  Hopefully, the rest of the world will soon be able to install and use this amazing solar technology.  SolTech Energy reports that it expects to start selling to the U.S. construction and roofing markets in 2011.

Glass roof tiles are durable and efficient

The inventive solar glass roof tiles resemble solar roofing found in building integrated photovoltaics applications, but they do not actually generate solar electricity like their thin film solar “cousins.”  Nonetheless, expect the shiny cool passive solar system to warm your interior for years with minimal maintenance.  The glass tiles meet current building code standards for roofing materials and last longer than most roofing shingles or tiles because the glass is UV resistant and erosion-proof.

No matter how you currently heat your home – gas, electricity, geothermal, or boilers/radiators, the SolTech solar glass roof tiles can be integrated to reduce your heating costs with passive solar energy.

Passive Solar: Let the sun shine in!

You want to tap into solar power, but you may be a bit wary of the investment required for solar panels.  Have you considered passive solar energy?  It provides easy renewable solutions without the need for expensive equipment and installation.

All you need to do is consider the relation between your living space and the sun.  Its easy to to make your place a solar house, tapping into passive heating in winter months, and cooling when the temperature rises.

Basically, when you design for passive solar, you employ shading during summer months and allow the sun to shine in and warm living spaces during the winter.  Energy is saved when you use less heating and cooling.  No need for fans or pumps to circulate air within your home.

Passive solar design

Think that passive solar energy is a new innovation?  Think again!  Cave persons used the approach to keep cool during summer, and then to trap heat to stay warm when the snows started to fall.  You can also see solar home design in greenhouses.  The design of these structures traps radiant heat, which warms the interior.

If you live in the Northern Hemisphere, you’ll want to have southern facing windows to allow as much sun in during the winter as possible.  But in warmer climates, position your largest windows facing west or east, and then put up awnings to allow for shading and cooling.

If you are building your home, or simply remodeling/redecorating, consider these simple solar home design tips:

• Plant trees on the north and west sides of the property to buffer from chilling winds
• Overall landscaping with trees and shrubs can provide shade and cooling during summer months
• Position “warm” rooms like the kitchen and laundry room on the north side of the property to provide heat where your home gets coldest
• Consider installing drapes or shade cloths on windows to both block the sun through the summer, and trap heat inside (insulation) over winter
• Open windows over summer nights (and definitely in cool mornings) to circulate cooler air throughout your home

You don’t need solar panels to use energy from the sun to your advantage!  Heating and cooling with passive solar homes can – quite literally – be a breeze.

White Roofs Reflect Solar Energy

Apparently, they have the right idea in the Greek isles.  White roofs reflect solar energy and can dramatically reduce our cooling costs if other nations across the world would also paint their rooftops with reflective paint.  Talk about a super easy, low-cost passive solar energy change you can make to reduce electricity consumption.

Such a low-tech idea may be the hottest thing to hit the solar energy sector recently.  U.S. Department of Energy Secretary Steven Chu observed that global warming may be slowed merely by painting rooftops white.  Instead of investing in expensive renewable energy technology, like solar panels or wind turbines, could we find a viable answer to global climate change in our local hardware store?

Secretary Chu observed:

Making roofs white “changes the reflectivity . . . of the Earth, so the sunlight comes in, it’s reflected back into space.  This is something very simple that we can do immediately.”

A town covered with white roofs

Remember when mom told you to wear light-colored clothing during the summer to keep cool?  Along the same lines, it has been shown that dark-colored roofs absorb more than 80% of solar energy, but white roofs can reflect 75% of it away.  Just think of how much less A/C we’ll need if we all “go white.”

Considering the potential energy savings, California has required most flat-roofed buildings to be white, since 2005.  Walmart has installed them on 75% of its stores in the United States.

While white roofs reflect solar energy, they do not minimize the underlying cause of global climate change – greenhouse gas emissions.  Still, they can address the increased heat from which we suffer during long summer months.  Said Mike Tidwell of the Chesapeake Climate Action Network:

“We may have to figure out a way to artificially cool the planet while the atmosphere is still super-saturated with greenhouse gases, because the planet, it’s a closed system, it’s an absolutely closed system, except for one thing: sunlight.”

Of course, there are several things to keep in mind with white roofs:  First, check your local development code to make sure there are no restrictions on reflective material use.  Second, be sure to maintain the roof so that it does not become damaged or dirty, which will reduce its reflectivity.  Finally, white roofs are generally best suited to flat, rather than sloped, surfaces.  Flat roofs require more maintenance, particularly if it rains often in your region.

Are you sold on the idea of white roofs?  What do you think – great idea, or a bunch of “white-washing”?

My in-laws are ahead of the game!  When they built their home in sunny Central Oregon 25 years ago, they positioned the house just right considering the arc of the sun’s travel through the sky.  In the morning, when its cool, they throw open the doors and allow fresh breezes inside.  Then, when the sun warms things up, the doors shut and blinds go down until the sun does.  Strategically-placed trees also provide shade, making their house a prime example of passive solar energy at work.

How can you do this yourself?  To use passive solar energy, building elements such as walls, floors, roofs, windows, roofing and siding, and landscaping are included specifically to manage heat generated by sun.  Consulting a professional with expertise in passive solar energy will be worth it.  He or she can include solar heating designs that will allow your building to trap and store thermal energy from direct sunlight.  Passive solar energy designs also have a cooling component to minimize the effects of solar radiation through shading or generating air flows with convection ventilation.

Here is a short video that illustrates a “fly around” of a home designed and built for passive solar energy:

Now, come with me to France, where we can see an actual home built for passive solar energy in this video (no translation needed because the house speaks for itself!):

Perhaps the most important elements of a building design for passive solar energyare the windows, insulation and landscaping.  These all play a role in daylighting, passive heating and passive cooling – the primary solar energy elements.

Image from Solcomhouse.com

Daylighting: Reduce your overall electricity bill simply by using the natural light from the sky and not just the daylight. Not only will the light create a more pleasant environment, but A/C costs will also be lowered when you use less lighting.  A considerable amount of heat is generated by light bulbs.

Passive Heating: Not surprisingly, you can heat your home simply by maximizing the absorption of thermal heat from the sun.  The best window orientation to accomplish this goal is towards the south. You can then heat the entire building and not just the room in which the sunlight is entering.  For passive solar heating you should construct a ratio of eight percent window to floor area on south-facing walls.  Adequate insulation is needed to minimize heat loss.  With high performance windows that have insulated frames, multiple glazing, low-e coatings, insulating glass spacers and inert gas fills, heat loss can be reduced up to 75%.

Passive Cooling:  Those of us that live in warmer climates will want to use opposite techniques to maximize passive cooling (i.e. fewer, smaller south-facing windows).  Installation of shading devices such as awnings and/or shady trees should be considered in order to reduce solar gains by up to 90%.  Again, good insulation is required.  You should also consider glazing on windows and reflective walls and roofing materials.  Position your home to maximize cross-ventilation (consider direction of prevailing winds).  In the morning and evening, you can open things up to allow cooling breezes through.

Even if your home is already built, you can still incorporate passive solar energy design elements and practices.  Take advantage of natural cooling and heating simply by opening your shades in the morning, closing them in the afternoon and strategically placing trees and shrubs to provide shade, like my in-laws have done.  Believe me, my husband and I learned by their excellent example.  Most importantly, enjoy the extra “green” in your pocket as a result of passive solar energy design.