my solar cup boileth over

hot_rod

on an overcast day I got the water up to 137F. Hopefully with a sunny day, with some insulation around the cup, I can enjoy a solar cup of tea. Powered by one Oventrop evac tube.

hr

michael_34

It looks as if...

your having to much fun! I'm jealous!
Michael

lee_7

How long did it take to get that warm?

Gordy

One Creative

Dude Hot Rod......I'm just sitting here picturing the transformation from imagination. The copper smith strikes again! A tea bag hanging out would put it farther over the top.


Gordy

hot_rod

warm up time??

I put the cup on around 10:30, ran tho the dentist for 2 hours and it was that hot by 1:30.

Supposed to be sunny and 50- 60's here tomorrow, I'll keep an eye on it all morning.

I tried it Sunday with a small 20" long demo evac tube. I hit around 100F with the small tube.

Heat loss got me today as it was fairly windy, mid 50's. I'll look for a piece of HTArmaflex to cover it, and a lid!

hr

Ron Huber_2

O.K. Hot Rod

No one can hold a candle to you when it comes to fabricating so many neat gadgets. I would love to spend a day with you in your shop. Now, I know you have all the Caleffi/Resol controls and data loggers at your disposal. How about hooking up 30 tubes to an 80 gallon tank, one that actually has a real world (4 to 5 occupants) draw, so by 11 PM most of the hot water is used up and the solar tank is down to say, 70 to 60 degrees. Let's see what the tank can get back up to on a good sunny day at a location specified in the test, lets see what the tank with no draw during the day will get up to, and do one with flat plates on an 80 as well. I am not trying to be a wise guy, but I see all these guys putting in tube systems and getting all excited about getting their tanks up to 140 by 1 PM etc. . but what did those tanks start out at?

hot_rod

the stars may lie, but

the panels never do. Putting them under actual working condition tells all.

That's what I like about that www.solarishot.com website. It shows the tubes and flat panels side by side, under actual working conditions.

hr

Mark Hunt_6

Cool info

Don't you work for Caleffi?

Rick_91

I had something like that in college

It was made out of ABS, thought you weren't supposed to smoke out of copper, ahh, err, never mind...

Rich L.

solarishot.com

Awesome site HR! I've never seen it before but it appears to be giving a real time side by side comparison. It's very enlightning. Thanks.

Dave Yates (GrandPAH)_11

comical note

Kinda brings a mental pic to mind like the yard of beer mugs(G). Drinking a yard+ of solar when lifting mug and tube to tilt for a swig. Hope that's lead-free solder so's you avoid plumbism!

hot_rod

from 67F to boil

in 28 minutes, mid afternoon 3:15. 65 F outdoor temperature, mostly sunny, some clouds, as seen in the back ground. About 5 degrees per minute temperature rise, 16 oz of water.

I missed the first warm up and boiled about 1" of water from the cup. The second try was late in the day.

I predict a clear sunny day about 20 minutes to boil.

Now to try a flat panel collector and compare.

hr

Charlie from wmass

I was thinking, dangerous I know, but if the flat plate in flat plat heat exchangers had a rougher surface. Some thing like a hammered finish would the heat better? you know more surface area to absorb heat and more angles for the radiation to bounce of from instead of simple angles? P.s. if anyone uses this idea and it works be so kind as to at least say thanks.

hot_rod

Yes

there are some absorber plates that are ridged, like a "Ruffles" potato chip. That combined with some of the new high tech selective surfaces do add a few efficiency % points.

But like any improvement, does the additional cost to produce them add enough efficiency to offset it?

Same question with double layer (storm window) glass on flat panel. Does the added r value offset the cost and lack of performance in warm conditions?

I do like the look of the purple color surface.

Here is a pic of the absorber inside an Oventrop tube. Ruffled and colored.

hr

Paul B_5

And here's another pic of my 10 year old thermomax as you can see somewhat purplely blue and the tubes are rippley as well. Paul