Tuesday, February 17, 2009


Many people looking for work are considering a career shift with the change in the political status of this country. Solar demands should see a sharp rise in use and there may be great opportunities with enough time to jump on the wave. Anyone with an electrical background or, if a licensed electrician is a friend or family member, may have a great start. It amazes me how many skilled electricians contact me asking advise on how solar works. I assumed they just knew:-)

While I have consulted several people on solar basics and offered information through our videos, detailed installations require advanced knowledge and a licensed electrician. Anyone with basic skills or someone who takes a solar workshop/schooling should have an easy path to finding work. The cost of PV photovoltaic panels are estimated to drop dramatically as technology advances and this should translate into increased demand.

Several people have emailed me about classes and various training courses they have taken with pretty good results. Colleges are now offering solar technology in their curriculum. The fact that this is new to the college world is a big plus to anyone looking for a new line of work as the competition is still limited. The other type of stuff we do on our website with solar dishes and Fresnel Lenses was once only covered by engineering majors and physicists but that too is changing. 

Learning the basics and obtaining a good grasp of DC power, inverters, wind turbines, PV, and solar water heaters, increases the chances of becoming an in demand consultant. A simple degree from an online course or community college will stand up well against the degrees currently out there. In another four years, that might not be the case so now is the time to get your foot in the door and bag some valuable experience. A solid working resume of successful installations and references will offer a nice defense to all the college degrees you will be competing against in years to come.

Look around and see what you can find. Please feel free to post any good sites that relate to this subject. Also, remember that it is not the cost of the class that makes a difference. We had our own graphic arts business doing layout and design work for years and never took a single course (about $15,000 for a degree). Solar is a bit different because you are messing with peoples houses and botching an electrical job could have tragic results. My point is, don't fall for big promises. Spend your money wisely and choose a place you are comfortable with. The goal is to have a good job and make a good living, not go deeper in debt. Read all the contracts, shop around, ask for references.

Below are 3 links to our videos on solar panels PV photovoltaic. I encourage you to watch them. This WILL NOT make you a licensed anything, but it is equivalent to learning your ABC's before you start school. Stay safe and good luck.

Sunday, February 1, 2009

Heat a Swimming Pool with a Large Fresnel Lens.

I receive viewer mail weekly asking, "With all that heat produced by a Fresnel Lens, can I point it at my swimming a few hours a day and heat it?" The simple answer is no. Water is clear and any light collected from the Fresnel lens will simply pass the focal point and continue into a wide pattern exiting as reflective light bouncing off the bottom of the pool. The big misconception regarding any magnifying glass or Fresnel lens it the belief that they "magnify or amplify the sunlight" when all they really do is concentrate it.

"What if I focused the lens on a dark object just below the water surface?"

While that would be much better, you would transfer more heat to your pool if you simply got a black object the size of your lens and sunk it to the bottom, no lens needed. Square footage or square meters are what counts when it comes to sunlight. A one meter by one meter (39" x39" ) Fresnel lens concentrates sunlight to produce roughly 1000 watts of heat energy to a very small point. A sheet of heavy black plastic absorbs the same amount of solar energy but over a large area. Since plastic or almost any material transfers heat effectively when submerged in water, the 1M x 1M black plastic sheet would add 1000 watts of solar heating. Even better, the sheet is heating water at the bottom so you are taking advantage of the thermal layer above. Several black sheets can add a lot of heat assuming sunlight reaches the bottom of your pool. Many pools do not get direct sunlight to the bottom especially in the winter months due to the angle of the Sun.

I know of a person who incorporated 300 Fresnel page magnifiers into a solar blanket for a pool and tested it against a normal clear solar blanket. He was thinking of applying for a patent but was confused with the negative results he was getting. The non-Fresnel blanket was better insulated so it kept the heat in. The Fresnel Lenses basically did nothing other than provide an escape route for heat. I am not sure what came of his project.

If you are set on using a Fresnel Lens, the best way is to create a small copper loop and circulate the pool water through it with either a small solar pump or tapping the pool's pump system. The advantage to this is that the lens is not blocking light that falls on the pool so you are adding 1 square meter off to the side at a high transfer efficiency. You will still need to track the Sun with a heliostat.

This is true for large water tanks also. Unless the Fresnel lens is larger than the water tank, focusing light does nothing assuming the entire tank is painted black. Mirrors are a different story. Because mirrors redirect sunlight, they do not impede the direct light falling on the tank so each additional mirror adds sunlight based on whatever size it is. Again,  Fresnel lens would be best suited away from the tank circulating fluid, in this case, as a passive system.

The easiest way to heat your pool is described in the three videos below: 

Check out our other videos at


Dan Rojas

Monday, January 5, 2009

My First Blog Page

This is a test of hopefully good things to come:-)

I finally got the hang of the Blogger account and will be doing posts often on ideas that are either in the works of a future video, revisiting a past video, ideas that need immediate attention and sharing some thoughts. We start our New Year with a heavy heart as a few days before Christmas, one of our dogs "Sable", became unable to walk and it quickly spread from her rear legs to her entire body. Despite several trips to a speciality vet and near 24 hour a day service through the holidays, we lost the battle on January 3rd. The cause was unknown & it was hard to say goodbye to a friend of 10 years:-(

We are looking forward to producing 100 videos this year and growing our reach of subscribers to over 10,000 on YouTube. Our goal of sharing knowledge has become a mission. We truly believe that by making science fun and exciting, this generation and future ones to come can enjoy energy independence and a cleaner environment. 

For those of you new to GreenPowerScience, an additional goal was landing a show on the Discovery Network or National Geographic Channel. After some rejection letters we are considering the Net home for now. We enjoy the creative freedom of doing our own thing and tailoring our episodes around our ideas and viewer requests. The large networks seem to be stuck on the "just like mythbusters theme". 

This season we would like to cover several topics using: 
Fresnel Lenses
Parabolic Reflectors
PV Photovoltaic
Peltier Cooler
Neodymium Magnets
Homemade Optical Fiber
Steam Engines
DIY Geothermal
Much more under the Solar Powered Alternative Energy Category.

Thank you to all the viewers of 2007 & 2008 
who has enjoyed our work 
and been kind enough to spread the word.

Also, if you are considering a Blog of your own & do not 
know where to start, 
feel free to email me through GreenPowerScience.com website, 
I would be glad to help.

Happy New Year