PurePoint Energy & Eco-neering in Action!

When the Greenburgh Nature Center needed a solution that would allow them to demonstrate the temperature difference between the surface of an asphalt roof and a green roof, PurePoint Energy provided it (150º vs. 75º!). We did so by troubleshooting a solution in which we were able to use a single 90-Watt solar panel with non-ideal sunlight to power two large temperature displays. The result was a 75º difference in temperature on the different surfaces. As a result—it’s easy to see that green roofing could be an interesting development in the fight to stop global warming!

PurePoint Energy LLC was founded with the goal of providing efficient renewable energy solutions to residential and commercial customers on a consulting and installation basis (top to bottom), but it’s projects like this that remind us of the long-term benefits that renewable energy can have for the environment. 

Benefits of Green Roofing:

1. Protection of roof membrane resulting in a longer material lifespan (it is estimated that green roofs will last up to twice as long as conventional roofs), resulting in decreased maintenance and savings in replacement costs;
2. Savings on energy heating and cooling costs, depending on the size of the building, climate and type of green roof.
3. Soil, plants and the trapped layer of air can be used to insulate for sound. Sound waves that are produced by machinery, traffic or airplanes can be absorbed, reflected or deflected. The substrate tends to block lower sound frequencies and the plants block higher frequencies.
4. Opportunities to recycle aggregate and compost.

www.greenroofs.org

PurePoint Energy takes a trip to Samuel Staples Elementary School!

On April 12-14th, PurePoint Energy paid a visit to six classes of eager second graders excited to learn about possibilities in renewable energy. The students were quick to differentiate between the miniature wind turbine and the large solar panel presented at the front of their classroom, just as they were confident that such a large solar panel would surely produce more energy than a small wind turbine-especially with the calm weather outside.

After coming up with some locations that we thought would be sunny and not-so-sunny, we set out on a mission. It was critical that we first learn the use of a multimeter, which would tell us how much power we were producing. There were many helpers involved in this process as we first measured the Volts, and then Amps being produced. A few mathematician/scientists in the crowd were quick to point out that all we had to do was multiply the volts by the amps to get WATTS! As we repeated this procedure in a few different spots, a small but noticeable difference was apparent when we took the panel out onto the completely unshaded soccer fields-the lack of shading provided solid access for the sun's rays to power our solar panel! As we always made sure to point the solar panel directly at the sun...it was clear that more sun=more power!

At the end of the day, the PurePoint staff had a great time taking a break from work to talk with young econeers about the importance of renewable energy in today's world. Hopefully they will each remember and take this lesson in renewable energy to heart after seeing firsthand the shocking (for a second grader) and powerful renewable resources that Earth has to offer. 

Solar Panels & Maintenance

The simple consensus on cleaning solar panels is: do it if they're dirty. The placement and orientation of your panels will likely affect whether they often require cleaning. Panels that are mounted on an angle (i.e. on a roof or ground mount with a tilt), for example, require little maintenance because the rain will naturally keep them clean. 

Things become a little more difficult when dealing with the maintenance of horizontally-oriented panels. Flat panels will naturally benefit less from rain, and are more likely to acquire a cover that can significantly affect its production. These panels should be visually checked once every few months, and more often if they situated in locations where sand and dirt is often blown around.

This study by Google found that minor accumulation of dirt on the corners of panels will not significantly detract from production. However-don't let it go too far! Solar panels rely on direct sunlight and any interference has the potential to disrupt peak production.

So how do you clean solar panels?

Always be careful! Even though the panel's live electrical components are not on the surface, you don't want to risk damaging any of the glass or plastic shielding. If anything appears cracked or broken-it might be a good idea to first consult with a professional! Otherwise-it's just like cleaning a window. Water, sponge, non-abrasive drying cloth, and if you really need it, streak-free soap/glass cleaner.

For larger projects, automatic cleaning systems may be a useful option.

PurePoint Energy offers full cleaning and maintenance services to preserve the peak production of your solar panels.

Blemished Panels: Cost effective, Identical Performance, Reliable & Safe.

Blemished panels ("B" panels) are solar panels that have been cosmetically damaged during the production process. Since PurePoint strives to use the most cost-effective panels in its projects, we were excited to hear that blemished Evergreen 205 Watt Solar panels were available at a lesser cost than their "A" panels. But was there anything wrong with these panels? Did they produce the amount of power consistent with an "A" panel? Were they safe? The answer is YES.

PurePoint Energy spoke with a technology specialist at Evergreen Solar who informed us that "B" panels are designated after all panels have gone through the same production process using the same materials. They have also already passed production and safety inspections. Inspectors will find some panels that have cosmetic imperfections such as a scratch on the frame, one side of the glass, or perhaps a corner that is left one millimeter open. The inspector then stamps these panels to show that they hold cosmetic imperfections.

So do "B" panels produce just as much power as "A" panels? YES. In fact, Evergreen offers the same 25 year guarantee on solar production for their B panels as they do for their A panels. But are they safe? YES. They pass through the same safety inspections as "A" panels. Is there anything wrong with these panels? NO-only cosmetic imperfections. Are they an extremely cost-effective solution with only minor cosmetic drawbacks? YES.

Evergreen has also offered this letter guaranteeing the performance, reliability, integrity, and lifetime of their panels.

What Photovoltaic technology is right for me?

The quick and dirty on traditional PV technologies.

What does efficiency mean in a solar panel?

Solar panels manufacturers claim efficiencies ranging from 4% to over 22%.  Efficiency refers to the ability to take solar energy and turn it into usable electricity.  It's important to understand that a 200 watt solar panel that is 10% efficient will generate as much energy as a 200 watt solar panel that is 20% efficient.  The difference is the 10% solar panel will be twice as large.  Less efficient solar panels typically are less expensive than more efficient solar panels.  So, if you have ample room for solar panels then using more affordable and less efficient solar panels will increase your return on investment.  If ROI is your goal less efficient can be more effective.

Here are the three most common technologies:

 Monocrystalline silicon cells are single wafer cells that are the most efficient in converting solar energy to electricity (15-22%).  These cells tend to be more expensive.  The wafer is cut from cylindrical ingots, meaning the cell will not cover a whole square area on a panel, and will end up with gaps.

Multicrystalline silicon are cut from square ingots and are cheaper to produce, however they are less efficient than their monocrystalline cousins.  Multicrystalline (also known as poly crystalline) cells have a square shape allowing them to take up a whole square area on a solar panel without leaving any gaps.  The typical efficiency of multicrystalline cells are 14-19%.

 

Ribbon cells is a type of multicrystalline silicon cell that is manufactured from molten silicon.  This process reduces the waste of silicon, the most expensive part of a solar panel.  Ribbon cells are less efficient than monocrystalline and traditional multicrystalline cells with an efficiency of about 13-15%.

Do you need help figuring out which solar panels will be best for your application?  Contact an expert with proven experience - PurePoint Energy


Purepointenergy.com 
203.642.4105
info@purepointenergy.com

What happens to a solar panel in a wind storm?

Modern solar panels are built to withstand harsh conditions and most come with 20-25 year warranties. They can last much longer than that if properly installed, it is important to have a trained technician doing your installation. So how do I prevent solar panels from being damaged in high winds? You don’t have to do much. Most panels have a hard, clear plastic coating. Investing in a sturdy bracket and proper installation will pay off in the long run, and prevent the wind from having any effect on your solar array. Anything that hits the solar panel like hail or small tree limbs should bounce right off without doing any damage. The durability of PV solar has been proven in outer space NASA’s oldest solar panels are over 30 years old.

It’s February, it’s cold and there’s snow on my solar panels. What do I do?

Most people in the northeast don’t believe that solar is a viable option. Here at PurePoint Energy, we want to make you aware of the advantages and disadvantages of solar in the North Country. This month we’ll blog once a week about New England solar specific topics.

Having solar panels in the north with shorter days of sunlight, colder temperatures, and snowfall might seem like a bust; we aren’t saying that Portland, Maine will generate more solar power than Albuquerque, NM – but solar is still effective. PurePoint Energy would like to explain to you the facts about solar energy in the winter. These facts will answer your questions on how snow melts off your panels and how lower temperatures can actually increase power output.

The low down on snow.

If the snow completely covers your solar panel the panel will not create any energy. Your thinking: Do I need to go up on my roof and scrape it off, risking life and limb to make sure I’m getting a good return on my investment? No.

The solar panels will typically create enough heat to melt the snow off by mid afternoon.

This graph was found at http://www.solardave.com/

Snow is translucent and will heat your dark solar panels. This graph shows the result of snow melting from morning until about 1:00pm. Typically snow will fall off in one sheet (so make sure to be careful that neither you nor your car is directly underneath). This is apparent in the graph above with the sharp increase in energy production. So when it snows be patient, just wait for the snow to melt off and think of the upside.

Yes, there is an upside:

Temperature can drastically effect the energy production of a panel, for those of us that live in the north that’s a good thing. Colder temperatures increase the efficiency of a panel while warmer temperatures decrease efficiency.

  This is a spec sheet from a GE PVp-200-M solar panel.

 

For example: this solar panel looses ½ a percent of efficiency for every 1°C increase. So if we look at the first week in February, the high in Miami FL will be 24°C while in Norwalk, CT (Pure Point Energy’s Headquarters) the high for the week will be 4°C. That’s a difference in 20°C, or 10% more power generated by your solar panels at solar noon.

So even though we live in the north we can still make solar work for us.