Welcome to the Solar Collector
Brainstorming and Development Page!


 

Home

Hot Air Collector

Hot Water Project 1

Hot Water & Space Heating

Solar Electric

Solar Construction 101

FAQs

Best Collectors

Simply Solar
Register Calendar Latest Topics
 
 
 


Reply
  Author   Comment   Page 2 of 7      Prev   1   2   3   4   5   Next   »
stmbtwle

Avatar / Picture

Registered:
Posts: 2,731
Reply with quote  #11 
No, sorry, it's just a readout. I could log the data by connecting it to a laptop and saving the file, but all I'd get is strings of numbers and I'm not sure how to convert it into a graph. I don't have the equipment to put it on the internet live, nor would I know how if I did.

__________________
Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay

stmbtwle

Avatar / Picture

Registered:
Posts: 2,731
Reply with quote  #12 
OK here's the first test from 1030 this morning:

Air into HEX  121F
Air out  HEX  81
Wtr in          78
Wtr out        80

Calculated BTU/sq ft/ hr 83
Insolation per meter      322
Calculated efficiency       26%

Dead space in front of screen 124F

It appears my heater-coil HEX is working pretty well considering it's only 6" square by 2" thick.   I'm getting a 40°  drop in air temperature going through it.  Water temp is rising 2-3F 

What puzzles me is that the air in front of the ZP screen is actually WARMER than the air in the "channel"  If the screen was working as expected I'd think that space should be cooler.  

Comments?


__________________
Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
SolarInterested

Avatar / Picture

Spam Stomper
Registered:
Posts: 1,027
Reply with quote  #13 
Quote:
Originally Posted by stmbtwle
... What puzzles me is that the air in front of the ZP screen is actually WARMER than the air in the "channel"  If the screen was working as expected I'd think that space should be cooler.  

Comments?
My thought - It's dead air so there's little or no circulation. Sort of like a hot box or solar oven which would warm up over time.

__________________
Both temperature rise and airflow are integral to comparing hot air collectors
stmbtwle

Avatar / Picture

Registered:
Posts: 2,731
Reply with quote  #14 
What have the ZP experts been getting?


__________________
Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
stmbtwle

Avatar / Picture

Registered:
Posts: 2,731
Reply with quote  #15 
Noon: I'm now getting 55F temp drop through the HEX, but that means 55F RISE through the collector and the fan is running wide open.  I think I need more fan.

Switched from the battery to the solar panel... fan will run faster, we'll see how it does.

1245: seems to be making a difference.  Now 45F rise.

__________________
Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
gbwillson

Avatar / Picture

Registered:
Posts: 2,233
Reply with quote  #16 
Willie-

If you have two screen layers and both are made from solar screen, then the sun isn't actually getting through to the air gap between the screens. Most of the heat is staying between the glazing and the top screen layer. So a lighter screen material for the top layer would allow more of the suns rays to heat the air where you want it, between the two screen layers. You might also consider raising the back screen layer a little above the back surface if you have the space. It can't hurt, and may allow the moving air to move in and out of the screen gap a bit to better break up the laminar flow. 
As far as how much of a temp increase you get with a ZP, it all depends on the CFM. Mranum posted a couple of weeks ago he was getting a 45˚ temp increase while still outputting 450CFM. Krautman's new ZP has an even higher temp increase, but he still has ducting issues. His first ZP was putting out about the same as Matt's. Myself, I'm usually pushing around 400CFM, with a temp increase of 35˚ to 40˚. But now that the sun is finally above the treeline, I expect a higher temp output.

And I think you are correct about needing more fan. The ZP needs a LOT of CFM to not only draw off the heat, but a pretty fair amount of airflow is also needed to help keep the air flowing between the screen layers. 
Greg in MN
stmbtwle

Avatar / Picture

Registered:
Posts: 2,731
Reply with quote  #17 
No the top screen is "standard" screen, only the back screen is "solar" screen.  More airflow certainly won't hurt, so I'll install a second fan this afternoon or evening. As I'll have to remove the solar screen to do that, I'll see what I can do about raising it a bit.  Don't expect much airflow through it though, that solar stuff is pretty dense.

testing, in vertical position: zp test 1.jpg 



__________________
Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
gbwillson

Avatar / Picture

Registered:
Posts: 2,233
Reply with quote  #18 
Willie-

Do you have a scrap of the solar screen that you could place next to the regular screen and snap a pic? I'd like to see the comparison...


Greg in MN

stmbtwle

Avatar / Picture

Registered:
Posts: 2,731
Reply with quote  #19 
Here 'tiz: IMG_0603.JPG 

__________________
Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
gbwillson

Avatar / Picture

Registered:
Posts: 2,233
Reply with quote  #20 
The one on the left is very dense. The "regular" screen on the right looks more dense than my screen does. I know you call the one on the left solar screen, but is it shade screen, in that it actually blocks out a certain percentage of the incoming sun?

Greg in MN


Previous Topic | Next Topic
Print
Reply

Quick Navigation:

Easily create a Forum Website with Website Toolbox.

 

web statistics