Friday, March 20, 2009

Master Solar Panel Efficiency

We're back today to bring you another hot idea... efficiency. The way I see it, you can get efficiency for something in two ways. First, you can simply do whatever it is you're doing well, and get nearly everything out of your efforts that you put into it, without using any tricks. That is difficult to accomplish though and actually somewhat rare. The second strategy is to do what you do and receive moderate return for what you put in, but then boost your efficiency by reusing some of the wasted product.

An example of the first method might be a teeter-totter. Whatever energy (or weight) you put into pushing down on the one side, is going to be roughly the amount of lifting power you receive on the other side... assuming of course that the middle is pivoting nearly friction free.

For the second example, we might think of a turbo charger on a car engine. Some of the exhaust from a moderately efficient power stroke in the engine, is recycled and fed back into the engine to be more completely burned.

So those may be simplistic examples but that sets us up for today's topic on how to master solar panel efficiency. Oh, and let me state that we are speaking today of solar panels for heating water, not solar photovoltaic panels for generating electricity. If you're going to make a solar panel, you're going to want to make one that gets you as much heat as possible, or it won't be very beneficial to spend all your free weekends huddled over tinker-fodder in your workshop instead of enjoying life.

My brainstorm solution today involves gathering heat, separating heat from cold, and capturing a little extra mechanical oomph to power the circulating pump, and recycle some of the cold fluid.

Solar heating panels can be set up in many different configurations, most of which are designed to allow them to work in sub zero temperatures. There are open systems, closed loop systems, drain back systems and many others. The basic difference between all of these is how they handle the potential problem of having water freeze in the collector's pipes overnight when the sun isn't shining. In a drain back system, water is used in the pipes during the day when the temperature in the collector panel is sufficiently warm, and then completely drained from the pipes into a reservoir for the evening. Closed loop systems use two separated loops, one of which contains ethylene glycol, an antifreeze, which circulates around the solar collector on one side and then through some sort of heat exchanger in a water tank on the other. The glycol carries the heat from the panel to your water tank and then heats your water inside the tank.

Regardless of which configuration you decide to use, I think my idea can help it. You see there is a somewhat obscure science that, for the life of me, I don't know why we've overlooked. It is the science of vortex phenomena. Rather than explain the full details of a device which employs this feature, I will simply provide you with a link to an excellent article about harnessing the vortex to separate hot from cold in a pipe of compressed air or fluid (whatever is in the pipe). The device is referred to as a HILSCH" VORTEX TUBE.

The first issue I want to deal with is the inefficiency of converting solar rays into heated water. There are many different tricks employed in construction of a well built homemade solar collector but I'm content to settle for moderately heated water coming out of it. You see, coming out of the solar panel, I would configure a Hilsch Vortex Tube to extract hotter and colder streams of water. Since we are removing cold water from the moderately heated water, we end up with a higher temperature stream of water that we can use more easily in the house. It's what to do with the cold water stream that gets us the opportunity to increase our efficiency.

Now I want to introduce, or rather, RE-introduce an engine that is really interesting but not used much. I'm talking about a Stirling engine, or heat engine. In Stirling engines, air is used as a quickly expanding and contracting gas, to move pistons. These engines make use of a heating container, and a cooling container. They usually work best when the difference between the two is greatest. Air enters the heating container and expands, pushing the piston out. At a slightly delayed interval, a displacer piston follows the original piston, and moves the heated air into the cooling chamber on the other side of the now returning original piston. The hot air is then cooled by the cooling chamber and contracts, pulling the original piston back again. Again, there are better explanations out there, so click here to see a good one.

So what would happen if we hooked up a vortex tube to the exiting pipe from the solar collector, send the heated water into the house to be used, took the colder water and use it to cool the cooling container on a Stirling engine, while using a parabolic solar mirror to heat the hot end, and then harness the mechanical energy to run a circulating pump for the whole system?

And there you have it. A solar collector that makes far better use of the available renewable energy source, the brilliant Sun!!

Let me know what you think, below and leave some comments!

Until next time,



  1. Energy4Power, excellent article! We have be working hard for the last 2 years to produce a system just like this ( There are plenty of challenges but we are committed. We already see customer returns of more than 2x of standard solar photovoltaic (PV)systems. Someday we will have nearly free energy ! Keep up the great work and send me a note anytime regarding solar, energy, music or life. Thank you.
    Glenn Booth

  2. Hey, thank you!
    I checked out your company's website... VERY cool! Sam Weaver sounds pretty neat, in fact the whole company sounds like the kind of place I'd just LOVE to hang out in.
    I will definitely keep a watchful eye for Cool Energy Inc. in the future.
    Question: Does the solarheart engine employ any vortex tube technology yet?