i am doing a project on BUGATTI VEYRON, i would like to know the drag coefficient and how to reduce it?

I am however concerned about freezing problems, more due to glued joints at the ABS pipe at the top and bottom of an assembled panel bursting. I plan to have a large holding tank of water used directly with the panels without a heat exchanger to the holding tank so I’m not too interested in using a bunch of anti-freeze. I am planning to build a drainback system using these panels, and just painting them black.

I also saw that polypropylene does not tolerate UV light well and will become brittle and break after long exposure. Coroplast can however be made special order with a UV absorber mixed in with the polypropylene. I am getting some regular Coroplast from a local sign shop that does not have the UV protection, so I’m looking into paints that absorb the UV. If the prototype works well I’ll look into getting UV protected Coroplast for additional panels.

Thanks for your time

I’d like to use this design to heat a hot tub (in addition to a bio-gas powered water heater: read more about biogas here: http://solarcities.blogspot.com/)

I’m a bit worried about chemicals leaching into the water. I’m not planning on drinking the hot tub water, but are there any issues with exposure to the plastic chemicals?

if you want to use it for heating purposes, you can dramatically increase (double, triple) the COP of a dehumidifier or airco (in fact they are the same thing: both are heat pumps) by installing it in or connected to your solar attic: the warmer the air in, the warmer the air out
venting your humid rooms to the attic will also improve the condensation effects: warm air can contain more moisture than cold air.
pump the warm, dry air back to the room. As this air is warmer, it will dehumidify better
win win win

you can also dramatically increase the efficiency of your solar attic by putting in a simple baffle (which will reduce heat losses during the night) and stocking the surplus energy in a stack of plastic water bottles for release at night

Please go take a look at the littlehouses forum owned by Laren Corie, a very experienced man in passive solar house design
all these ideas and more are Laren’s, you can find them on the forum

frank

You said: “I posted an article about that project but enough readers expressed concerns about carbon monoxide poisoning that I took it down (a ridiculous concern really since a single pilot flame is unlikely to produce enough carbon monoxide to do any harm, even if exhausted directly into your home).”

You are correct. Consider that old gas ranges and stoves had a full time pilot light.

In any case, if you have a gas hot water heater you should have a carbon monoxide detector nearby.

I came across your site a few months back while I was prototyping my own plastic thermal panel. I think plastic solar panels have the potential to completely revolutionize the industry by lowering the cost. However, you hit on the problem I was working on:

“because the whole collector is made of plastic, it is important that the temperature doesn’t get too high or it will soften and possibly spring a leak. 80 degrees C (176 degrees F) is about the limit. Don’t think it can get that hot? Think again. …Therefore this may not be a practical design for residential installation”

Well, I put some thought into it and I think I have a solution that will prevent the panel from overheating (the panel turns itself off when no water is flowing), which means that it can be insulated and hopefully compete with commercial systems, only at 20% the cost. I think the efficiency may also end up being higher then commercial systems. I built a prototype:

http://www.particlepanels.com

…and posted a video of it to youtube.

I just wanted to give you a big thanks for your website and the work you are doing. Its people like you that are going to save this planet.

Blue Skies,

Alex

For a simple example, consider an electric fan. If the motor is 80% efficient (actually fan motors are typically very inefficient), then 20% of the input electrical energy is converted to heat in the motor. The other 80% does “useful work” meaning it is transmitted through the motor shaft in the form of torque and angular displacement. This useful work will be converted to heat at the interface of the fan blades with the air (similar to how the space shuttle heats up moving through earth’s atmosphere only on a much smaller scale) or in the air itself (due to turbulence induced by the fan) or at another surface that the air hits. When you turn the fan off and the air stops moving, there is no more work. It has all been converted to heat.

The operation of the motor, compressor and fan inside a dehumidifier is more complicated but there is no need to consider the details. The law of conservation of energy requires that unless energy is stored, any work done must produce heat exactly equal to the amount of work done.

In other words, for most electrical appliances that operate inside your building envelope, the heat input into your home is exactly equal to the electrical energy consumed, regardless of any work done. A 200W fan will put exactly the same amount of heat into your home (200W) as a 200W heater. A dehumidifier is a special case since heat is output both from the electrical consumption and from the condensation of the water.

Rob

I don’t want to rain on your parade….but. A dehumidifier does not put heat equal to the kw used.

The dehumidifier does useful work from the kw ie: motors for the compressor and fan, they are not 100% efficient, so the only heat from the kw is that amount between useful work and 100%. Typically an electric motor will be some where between 50 and 90% efficient, the compressor like wise isn’t 100% efficient, so the only heat is the delta of efficiency. Heat is only generated in the delta, in other words if you were generating 100% heat from the kw you would have heating elements, if all kw went to heat the motors, fans and compressor would not run.

Lloyd