Insulated solar radiation screen

Hi everybody

I finished putting together a new solar radiation screen to house a humidity and temperature sensor

I purchased a white plastic toilet brush holder lol

The container is opaque white And it narrows from the top to the bottom ,

First stage was to cut a hole at the bottom of the container to the size of a plastic pipe
The plastic pipe creates a Wall space which I filled With liquid insulation foam

next stage was to make a top which could be easily removed for maintenance, top consists of cutout plastic to hold the fan and also the housing clips into a lid

The top was off an old LED outdoor light


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Looks professional :smiley:

Looks very good Mick, due to the insulation, i wonder how it would fair being attached to a fence
I wonder if the insulation properties would be ok, actually, thinking a bit more about it, perhaps not
cause the fan will still draw in the radiant heat from the fence, shame as i am limited to where i can
have my temp/hum sensor and i have been thinking of ways to have it set up, I have got hold of
some more Louvre panels to make another screen…

yours should be good in direct sunlight though, away from a radiant heat source, yes?

My issue is i am in a bungalow, back garden is north facing, but, i am surrounded by 6ft fencing on the 3 sides
The only place i can have my sensor at present is attached to the conservatory, this will be far from ideal
soon because the sun will start to heat up the decking and cause radiant heat issues, im ok for prob another
few weeks at most…

Please let me know how ya get on with ya testing stage??

Hi

Based as much as I can on the specification from the aspirated radiation shield from Apogee Instruments

They have an amazing video explaining about their Solar radiation screen
have a look at the you tube video

It is difficult sometimes to mount sensors in optimum place due to surroundings

If you’re solar radiation screen is well insulated and using a small fan to draw the air through the bottom over the sensors the airflow and through the top
My sensor mounted on a post I do have a garage wall close by so I need to have as much insulating material to stop As much I can heat coming from and reflecting from the brickwork

I have a thermometer made by casella London Ltd it’s a very accurate It is a blackball on the end which will pick up radiant heat from surrounding brickwork
I will test it by having it outside near the concrete garage wall then placing his inside the solar radiation Shield and compare different temperatures hopefully there will be a big difference

mick

Overcast day Outdoor temperature 10c (new radiation screen Mounted northside on a post)

Wooden screen box Met Office pattern (BS692 Sheathed Thermometers met spec 10.2 (Mounted on the other side of the post North side )

Test Thermometer thermal blackball ooutside temperature 11.2 (Next to the new solar shield)

Test Thermometer thermal Blackball Inside new shield 10c ( all tests in shade northside overcast day know sun temperature difference picking up from garage wall)

Will redo the tests on a sunny day

Cheers Mick, interesting video, gets ya brain working, trying to think of ways to make on, tis hard to watch and think lol
I was wondering about ya loo brush holder, ya might need to come back to that one as i am fairly sure it will not
be UV resistant plastic and may only last a season before it becomes brittle, unless ya paint it of course :slight_smile:

I may have a go and make one too, been thinking about the fan idea and i know i have played in the past with a couple
of setups, including solar powered fan and mains 12v fans, i think there could be a flaw in his idea regarding the fan slowing
down on a cloudy day, some cloudy days in the summer you can still feel the heat coming from the sun and if its a calm
day this would deffo have adverse effects on the readings wouldnt you think? but then thats me all over, over thinking things :lol:

I wonder how fast (rpm) the apogee fan goes? looked just like a decent PC fan to me mind, i used to have one in an older PC
that had a variable speed adjuster, thats would have been ok, i feel a few trips to maplin coming on soon…

As for your liquid insulation, not so sure i know of any myself, all i can think of is the expanding foam and i am sure it aint that lol
i am going to assume its similar to the stuff they use to do the wall cavities? and perhaps wickes etc will do it?

BTW, where does ya sensor fit in please? its ok, i see the hole now :slight_smile:
And where did ya get ya round fan please?

I would add a reflective layer, either aluminum duct tape (thin aluminum metal tape with an adhesive backing), or aluminized bubble wrap insulation. In my experience either one of those stands up well to the high UV that we see here. Don’t know if you those commonly available in the UK.

If you are mounting it to a fence or wall you might consider adding a 90 deg extension at the bottom so it’s not directly sucking the solar warmed air flowing up the vertical surface.

Yeah we have aluminium duct tape, aesthetically it will prob look tacy though, a lick of sandtex paint would resolve that though :slight_smile:

i think the 90

Hi
Don’t forget there is an inner tube which is easy to put on foil tape

The insulation is expanding foam Worked really well

Due to the way the gardeners and a small hill My sensors are most the time in shade

I would probably approach it differently if it was exposed to the sun all the time, I would use a UV type paint and probably second chamber

I use the expanding foam as I had some left over

The fan is running at a constant speed

Thank you for the pointers and suggestions,

mick

I was thinking more to protect the outer plastic shell from UV with extra insulation being an added benefit. But if it’s shaded most of the time that shouldn’t be an issue for you.

I can see you are better with canned foam than I am, it would have been a huge mess if I had tried that :lol:

You should see my first attempt using canned foam lol

The secret is to use small amounts and watch its incredible stuff

mick

Hi
Any ideas on what type of paint which will block UV?
I have come across this spray paint, I wonder if a few coats of this would be enough
http://www.ebay.co.uk/itm/Ambersil-Acrylic-Paint-Matt-White-400ml-RAL-9010-Fast-Drying-5m-UV-Resistance-/191429629454?hash=item2c9218560e:g:XvQAAOSwofxUeJ9c

Almost any paint will block UV. Probably the bigger question is what will stick to the plastic? In my experience latex based house paint has survived very well on exposed PVC conduit here. But I imagine that brush holder is a different plastic. I suggest dulling the surface with some fine emery paper or an abrasive pad to have the best chance of the paint sticking and just use whatever light colored outdoor paint you have.

Niko is right, 800 grit paper will give a decent key though and thats the important part, its the deeper gouges (not as bad as it sounds)
Just a gloss will do, you can go one better, and grab a tin of flexibond, ask ask for the flexi coat that goes on to plastic, then add your
top coat, you could use a car spray paint if you are going to flexi coat it, if thats the case then prob use 1200 grit paper…

I am gonna nip to wickes and see what pricing there ducting/pipe is at, see if i can find some UV resistant stuff, prob pushing it mind]as most will be for underground :confused:

Hi

Going to spray with a coating of matte white flexi designed for plastic

The Fan I am using is designed for a graphics card
Rated voltage:

12 V DC

Rated Current:

0.18Amp (MAX)

Air Flow :

22.8 CFM

Speed:

2800RPM


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Are you going to use any insect screen material?

Hi

Thank you for reminding me yes I will put some insect screen material on the bottom to stop any creepy crawlies

Hi Mick, just a wee thought, at the bottom will prob reduce coanda effect some what,
ideally you only need something to cover the fan so perhaps near that?

Hi Mick, can i pick ya brains (electronic) please?

I have 3 of these http://www.maplin.co.uk/p/twin-spot-solar-light-with-pir-sensor-n12hn
and i was wondering if the solar panel off one would run a PC fan (when the sun is out)
I think it would work as combined battery power is 1.8 amps, just want to make sure before
i break one up :lol: :? :roll:

How big is the solar panel?

What volt/amps rating is the fan?

Hi
The fan I am using is1 2 V DC

Rated Current:

0.18Amp (MAX)

Air Flow :

22.8 CFM

Speed:

2800RPM