DIY Solar Radiation Shield

[Orion]

Great work and a nice and neat design.

I am working on something similar using your design and have a couple of questions.
What is the purpose of painting the inside of the dishes, I assume to absorb heat away from the sensor?
How effective was the screen without the fan and with the fan.
Is the fan at the bottom blowing up or at the top drawing up. The fan is not shown on the original plan.

HI
The only reason i painted the insides matt black was because the met office now seem to recommend that the insides are black
it is supposed to absorb accumulated heat better
not sure it makes a great deal of difference but I am getting excellent results

Have a look at this link
http://www.advantagein.com/instrumentshelter/

the small fan did not last long got a bit damp and it gave up
Think a 12v PC fan would be a lot better
a fan would need draw air in the bottom and push it out of the top

[The QCC]

Hello:

I have a similar radiation shield with a 5v, 65mm solar powered fan.
I painted the inside of the shield matte black on the recommendations in a white paper by Environment Canada.

According to their research, the black absorbs six times more radiated heat than a white interior.

I did not make any before and after tests, but the FO WH1080 sensor is within + or - 1 °C of a reference temperature sensor on a North wall.

The solar shield was an experiment. I have a Davis Vantage Vue coming within the next week and hope it is better shielded than the FO WH1080.

[StuartWalkerPhoto]

I have made a shield based on Roy's plans but with some changes.

I could not source the same bowls (no stock through Amazon) so went for smaller ones from Argos. They are just big enough for the specified internal cut-out and mounting holes.

Instead of metal threaded rods I used nylon ones, with most of the spacers replaced with 5 nylon nuts to give 25mm spacing. The rods were pre-cut to 250mm so I had to sacrifice some separation between the top and bottom 2 bowls. I re-used the original mounting bracket after cutting off the sensor end.

I have installed a 50x50x10mm 12v PC fan above the sensor unit. I felt that the fan would draw in a considerable amount of air straight from outside (through the gap between the bowl it was mounted on and the one below it) so used a cut-out spray can lid as a shroud to funnel the airflow over the sensor unit.

I also painted the inside of the bowls black. I was going to miss this step out, but while putting the bowls together it became clear that a lot of light was being reflected into the shield by the curved outer parts.

My temp and humidity readings are in agreement with a nearby small airport weather station, but I am not sure yet how well the shield holds up against direct sun (that's Scotland for you). I am certain that it will be much better than the original shield.

Good fun working on this, many thanks to everyone for posting their plans, etc.

[Jonsey]

Looking good, they are quite easy to make once you get all the parts, here's the one I made over 2 years ago (still going strong) and looks nice and weathered in....

[Solorize]

Hi Orion,

Just a quick question:

How do you change the batteries when they run out?
I.e. do you have to undo the wingnuts at the bottom of the screen and then drop the bottom plates and
spacer pipes off to get to the transmitter, then try and put them all back on without them sliding back off?

Or do you have to take down the complete screen (which I guess would be tricky as you have all the cables
coming out and secured back in place, and then put it on a table and undo and access the transmitter from there.

Also what lengths did you cut the 3No.threaded rod to?

As I am thinking of making a new screen as per your instructions, but want to make sure that changing batteries will be easy.

Mark

[Orion]

Hi Solorize

Changing the batteries only takes a few mins
3 wing nuts and washers are holding on the bottom 2 plates
and the plates above are held together with 3 normal nuts

I bought 1 mtr of threaded rod and cut it into 3 equal pieces
you will probably need each rod to be about 280mm in the end

[Solorize]

Hi Roy,

Thanks for posting back with the answers to my questions.

How easy is it to re-assemble to bottom plates back onto the screen?

i.e. how do you keep the spacers "cut pipes" in situ' and stop them sliding back down
the threaded rod while you try to re-seat the plates?

Surely wouldn't they just slide back off the threaded rods while you pick up
the plate to offer it onto the rods? Or do you just try and hold them in place
with one hand while offering up the 9th plate, then repeat the process for the 10th.



FYI.
Also as I am thinking of utilizing a Solar Fan from my current screen, which will need
to be positioned on top most plate, (via an ingenious method that I am currently devising LOL),
I will need to have the screen supported from the bottom most plate via two brackets, so
am thinking of using 4No. threaded rods so I can have a pair of rods located into each bracket.
then would have to lift the whole screen up away from the two bottom most plates,
Which is kind of how my current set-up is.

I will have to have a bit of a think and will probably draw something up to make sure it all
works before I start cutting holes in the plates etc..

But I will definitely be basing it on your design for the most part

[TomV]

Reading this document:
http://hortsci.ashspublications.org/con ... 2.full.pdf

They are using foil bubble wrap insulation. Maybe worth a try if you have it lying around. Looks easy to construct.

[Solorize]

I finally managed to finish my new Radiation Shield, based on Orion's
original design, but with a few modifications of my own.

The modifications I have done are;

1.
Used 4No. threaded rods instead of the original 3No and have it bottom mounted.


2.
Added the solar fan from my existing shield.

I could not believe my luck when I was looking for something to couple the fan
to the top bowl. I found an old Homebase "deep gap filler" pot which fit snugly
inside the circular lip on the bottom of the bowl. The added bonus was the the
top of the pot was the exact size to let the mounting plate for the fan (which has
a circular lip running around it in the center of the plate), fit tightly inside! LOL
what a result!! I though I was going to have to get something made bespoke, which
I did not need to do thankfully.

Also using the pot has created a small plenum between the fan and the shield which
is an added bonus.

I will now have to keep an eye on my readings and see if they are better
with this new screen

Pictures of my Radiation Shield installed and working.

New_StevensonScreen_01.jpg

New_StevensonScreen_02.jpg

HomeBase "Deep Gap Filler" pot

DeepGapFillerPot.jpg

[Hargi]

Hi Roy have clicked on dropbox pdf link but error 404 appears is pdf no longer available

Ernest

[laserray]

If you still have it, could you repost the PDF. The original link no longer works. Thanks,

Ray

[Orion]

If you still have it, could you repost the PDF. The original link no longer works. Thanks,

Ray

Here you go took ages to find
I have updated the original link as well

https://drive.google.com/file/d/0B5lqXr ... sp=sharing

[laserray]

For everyone, I send you a big thank you. I am sure it took a good bit of work to find it (3 years of dust). Now, down to the local dollar store to get the parts.