Different efficencys in solar panel design

[DigitalDreams]

I am in the process of building four different 4X8 hot air solar panels all will have same motor for active thermostat control and all will have same furnace snap switch 90/130 as original I just completed but first one it is made using aluminum drier tube 4 inch the good kind the heavy duty flexible ones approx 64 foot of it from intake to output so far it kicks in about 10 to 15 minutes after the panel is hit by direct sunlight and runs approx 20 minutes before it shuts down either due to room reaching temp on thermostat or snap switch reaching low end the next panel will be flat plate collector design same specs all will have 3/16 single pane low iron tempered glass cover glass same as first on the recycle time on the first panel seems to be about 10 minutes heating up and 20 minutes cooling down i am sure those times will change as it gets colder out but even if that triples it will still save me a mint in furnace oil this winter.I plan to plot each panels recoup times and temp of heat to run time ratios to get a Btu average for each will post those when completed or is there is one that is really impressive or data gets to big I publish it to one of my web sites with a link and pictures of it I am trying a rather radical design for the last one I build but all will be 4X8 surface to keep capture area at a constant.All the panels I am building will cost under 400 dollars to build if you have access to basic tools and materials all will be made from off the self materials you can by at most home supply or hardware stores the only item not available from local stores would be the snap switch in the panel mark sells those.

[Mark]

Hi,

We would be interested in seeing your solar heater designs. I take it that the sun heats the dryer tubes and it then the tubes heat the air? Which part of the country do you live and how cold is it now?

During the dead of winter, I'd have a hard time believing that the heavy dryer tubes would heat-up that quickly. Based upon experiments I did, I would give it a 1-2 hour heat-up time in the dead of winter. Way too long, which is why I had the best success heating the air directly. But we're definitely interested in knowing your test results.

Also, if you're tripping the snap switch that quickly, you may find that you have too big of a motor on the fan.

Mark

[DigitalDreams]

I guess after marks post I should expand on my first panel design.

The box i built is 2x8 back of it is 1/2 ply ac grade and the insulation is 2 inch polycanite with foil both sides. Excuse me if I spelled the foam name wrong but it was the most expensive part of the panel it is 50 dollars a sheet.
The box is totally sealed with a 1 inch air space between glass and tubes,and total interior is painted with high heat matte black paint.
The snap switch is projected into air stream on exit end so air temp must be 130 degrees in tube for it to close not just the metal temp.

I am only assuming that by the time the air in tube triggers panel switch metal is probably close to 150 to 175.

I live in southern minnesota so temps are little warmer than northern now, but like I said I am building 4 panels all same design except for heat sink design.

Each will be different in that the design of the first one was a tube design using drier tube because the ribbing creates a lot of turbulence in air stream.

The second panel will be flat plate design with baffles and aluminum heat sink.

The third will be concentrator reflector design which has been proven to work quite well by a guy in Iowa, who stumbled on the design quite by accident.

And the fourth will be based on the test from other four designs.

I don't need to build one like marks ,as I have a friend who already has one based on the direct air heat idea.

I am plotting his already.

I want to base comparisons over this winter,and see which one preforms best based on,time from sun hitting it to first kick in, then how often it kicks in and how long it runs till air stream drops to 90 degrees cut out.

And which design puts out most heat over month of testing.

The one good thing here is all the glass is consistent as I get it from a friend in the glass manufacturing biz, so I was able to get four sheets that came from the same glass run.

All alike in color quality's and thickness.

I do have one question for mark is your panel single or duo pane glass.

The reason I am building four panels different design is because even tho you can go on the web and get design ideas up the kazoo.

Most of the designs are either real vague because they are being produced commercially and of coarse the makers don't wanna say hey you can build one of these at home for a lot less than the 1200.00 I'm asking, or they just are old designs that have been handed down from the 70's before the web and a lot of the info is left out of the plan.

Also most types of insulation and glass has improved in the last 30 years.

But my main reason for building four different types is, research on my own ,with four panels of like size will tell me.

1. What design is most efficient.
2.What is cost to benefit derived from each design.
3.Most cost to output efficient one ,I will convert all of them to in end of research.
4.I'm a cheap scape,excuse me wife says frugal person and if I can heat for free why not.

Project after these are done is wind generators.

And sorry wrote this post in a hurry one morning ,tend to ramble so now hope it easier to read.

[flcruising]

Not to be rude, but could you punctuate your sentences? I'm having a heck of a time reading your posts.

[mokehillannie]

Leaving a space every 3 or 4 lines would make it easier to read, also.

See how Mark breaks up his posts. It makes the post much easier to follow.

Thanks