M, L, K, H2O Solar Help

[KEG]

Hi All

I was looking at halfcrazy's solar H20 panel and was wandering if type m, l, or k was the best for one of those, is the idea to transfer the heat as fast as you can or store it in a thicker pipe ie: type k. I have also seen sepenteen and header types is one better then the other? And would it be better to put more pipe into the some space or is to much a bad thing.  

Kevin

[zap]

Hey Kevin

Your questions are a little too vague.

It's hard to say which is "better" when it comes to thicker vs. thinner and serpentine vs. header without knowing what you're planning. Are you looking at a batch(passive)or circulating(active) system?

Have a look at this site for a quick description of different systems. http://jc-solarhomes.com/how_to.htm

THEN head over to this site for even more info. http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm

[KEG]

Hi Zap and Thanks,

What I was looking at in Halfcrazy,s post was a parrellel desiegn, I am looking at making one like that becouse my climate is to cold in the winter so it will need to be a glycol system, the main question was, is the main idea to tansfer the heat as fast as you can thru type M or let the thicker type K store more heat in the pipe or should this not even be an issue. The site on solar homes listed both, type L on the parellel and type M on the serpanteen. I am in the HVAC trade so making this is not a problem, infact it be easy.

One other thought was instead of a lead type soilder would ther be and advantage to purging the piping with nitrigon to keep the inside clean for a better transferof heat, just a thought.

Thanks Kevin

[GaryGary]

Hi Kevin & Zap,

You don't want to store any heat in the collector itself.  The lower its thermal mass the better.  Low thermal mass allows it to heat up fast when the sun first comes onto it, and to not have much heat wasted when the sun goes off of it.  Any heat you store in the collector just ends up be lost quickly out the collector glazing when the sun goes off the collector.

I'd use the thinner wall copper tubing just because of the cost, but I think that either will work fine.

I don't think that you need to worry too much about special cleaning of the inside of the pipe.  When water is flowing through the collector, a thin film of slow moving water forms near the pipe walls, and this film does not conduct heat very well into the main flow of water -- this film of water will be the biggest thermal resistance, and the copper wall will be so much less that it hardly counts.

Gary

[ghurd]

Has anyone though of adding a little turbulence in the copper pipe? Sort of like the fins in a gas water heater center pipe.  Maybe every foot drill a hole clear through the copper, same sixe as solid #10 or #12, and solder a piece in. Stir it up a little.

Stray thought...

[kitno455]

ghurd- there are under chassis radiator tubes for race cars to cool engine or trans oil. they use little folded baffles inside the tubes, like reversed fins. trying to reach central flow. wonder how they would do?

allan