Sorry, but when I need to type fast I tend to use English since my Portuguese is soso. I never practice my dads language in The NEtherlands sorry for that!
So this summer we did not go to Portugal because the last few years the heat, even on the coast in Algarve even for me was too excessive. Well "even for me" is not correct. I can deal with heaht I just hate it. And here in NL we had our modest form of it and THNAK GOd it was mostly the dry form. So I could easily work in our garden with 34 C (and RV 23%). I felt nothing. But....that also gave me time to realise after all those years and kids playing around now that I actually have a thing know as "hobby's" Long story short: I started to build new sensorscreens. The KNMI Vaisala type first but in 2022 I also had an idea of station that should do better than that one, in the sense that it should remain cooler underhigh irradiance low wind conditions. It is difficult to put in works how it looks, but what it does is that it prevents heat build up onder the louvres of a multiplate screen, it allows this heat to move through the screen up while nt reaching the sensor. So while the outside louvres are quite open and far apart, it is impossible to see the sensor in the screen no matter hw you look. So indirect (let alone direct sunlght) cannot reach the sensor.
Of course the outside is now brightl glossy white and the inside is matte black (well it is not, because I did a quick and dirty job since it was just a test so white spray paint got inside the screen).
So the very first day of testing was this Sunday. Now the air was incredibly bright. Zero clouds, deep blue and no winds. But my design was all mat black and not painted yet. On saturday evening that is no problem so I installled it next to the Vaisala screen. Both were equipend with dataloggers with calibration certificate and they register identical temperatures, always within 0,1 C from oneanother when they are put in the same screen. RV is measured in 0,1%. Also virtually identical
That night saw the Vaisala getting to 7,5 C and my own design to 7,6 C. So I thought: let's paint but then remembered a small version of the Vaisala was tested by me in all black....Jan Barani Meteoshield showed only 0,3 to 0,4 K difference when it was all black compared to a white Meteoshield. So why not try that with a Vaisala....well...after a few hours in the warm sun I got cured...The Vaisala was simply 2 C warmer in all black as compared to a white one.
Okey...so how would my own design fair under these high radiation low wind conditions?? It did VERY, VERY well. the maximum difference with the white glossy Vaisala was a mere 0,4 K. I was simply astonished that it seemed to work.
So I think on Tuesday in the early morning I did a very quick and dirty job of painting the screen white outside and not inside, accepting some pray pain would enter the screen. Of course the sensor was removed. It workd out fine, but no primer so the plastic if I want (and I do) can be all blakc without to much effort. If I put strain on the HDPE plates the paint will easily peel off. But for now...So what happened under less sunny, but for Dutch pretty warm weather? My own design screen during the day now as consistently significantly cooler than my Vaisala screen. Up to 0,6 C and on average 0,3 C. Both are within 50 cm of eachother on the same pole. So Tx was 27,1 on my screen vs 27,5 C on the KNMI Vaisala. The next day got a bit warmer with more wind. Nevertheless, the endresult was identical when it comes to the difference: my screen 28,8 C the other one 29,2 C.
Just to check I exchanged the sensors of the screens. It did not matter: We got 26,1 vs 26,5 C as Tx and yesterday we had a lot less wind, but also no full sun.
Today I realised I did not have the sensor put in one place, they were loosly placed pretty close to the lower of the two topplates. I always made sure the sensor was not sticking out under the louvres, but still. So this morning I both firmly attacked them about 3 cm under their lower topplate. And luckily enough we got some brighter spells with low winds and you guessed it: same results again. Up to 0,6 C cooler....But now, at noon, we got a good downpoor of 10 mm in 12 minutes....Now the Vaisala was 0,2 C colder also 30 minutes after the downpour. What was the reason? Well the Vaisala screen read 95% RV whereas my own design screen remained drier at 90,1 C. So the Vaisala essentially was affecting by a wet(ter) bulb and wind which means the sensor cooled off more...I did not expect it!
I also compared my Vaisala white screens with a white round plated Davis screen (sued with passive Vantage Pro 2). That screen under dry and warm conditions is up to 1,4 C WARMER than my Vaisala!. Who would have expected that!
Okey, so here some pics of the screens. The smaller Vaisala screen is in the middle but was not used for ths comparison. The left and the right screen both use the exact same plates.
The fun part of it all is that these screens cost me may be 30-40 euro max to build. hat is with paint, plates, stainless steel rods, nuts and bolts etc.
If it works, I will probably share with you how to make one yourself if people are interested. May be nice for you too?
First pic below: lefthand my own design (it is of course a modification of the well known existing multiplate screens, not claiming to be some kind of wizard!. Middle is a KNMI Vaisala type homebrew with smaller 11 cm plates. righthand is a bigger version of the middle one. BTW: the middle one is perfectly fine, it is within 0,1 to the one on the right).
2nd pic below: KNMI Vaisala selfbuilt (prototype, rods need to be cut etc) view from the bottom. So apart from the topplate it is matte black inside.
3rd pic: my own design testing being completely black vs the larger KNMI Vaisala. These saucers I sued are 13,5 cm in diametre. To be clear: in none of the case the sensor can be seen no matter what angle you look, so indirecte sunlight cannot reach it....
So this summer we did not go to Portugal because the last few years the heat, even on the coast in Algarve even for me was too excessive. Well "even for me" is not correct. I can deal with heaht I just hate it. And here in NL we had our modest form of it and THNAK GOd it was mostly the dry form. So I could easily work in our garden with 34 C (and RV 23%). I felt nothing. But....that also gave me time to realise after all those years and kids playing around now that I actually have a thing know as "hobby's" Long story short: I started to build new sensorscreens. The KNMI Vaisala type first but in 2022 I also had an idea of station that should do better than that one, in the sense that it should remain cooler underhigh irradiance low wind conditions. It is difficult to put in works how it looks, but what it does is that it prevents heat build up onder the louvres of a multiplate screen, it allows this heat to move through the screen up while nt reaching the sensor. So while the outside louvres are quite open and far apart, it is impossible to see the sensor in the screen no matter hw you look. So indirect (let alone direct sunlght) cannot reach the sensor.
Of course the outside is now brightl glossy white and the inside is matte black (well it is not, because I did a quick and dirty job since it was just a test so white spray paint got inside the screen).
So the very first day of testing was this Sunday. Now the air was incredibly bright. Zero clouds, deep blue and no winds. But my design was all mat black and not painted yet. On saturday evening that is no problem so I installled it next to the Vaisala screen. Both were equipend with dataloggers with calibration certificate and they register identical temperatures, always within 0,1 C from oneanother when they are put in the same screen. RV is measured in 0,1%. Also virtually identical
That night saw the Vaisala getting to 7,5 C and my own design to 7,6 C. So I thought: let's paint but then remembered a small version of the Vaisala was tested by me in all black....Jan Barani Meteoshield showed only 0,3 to 0,4 K difference when it was all black compared to a white Meteoshield. So why not try that with a Vaisala....well...after a few hours in the warm sun I got cured...The Vaisala was simply 2 C warmer in all black as compared to a white one.
Okey...so how would my own design fair under these high radiation low wind conditions?? It did VERY, VERY well. the maximum difference with the white glossy Vaisala was a mere 0,4 K. I was simply astonished that it seemed to work.
So I think on Tuesday in the early morning I did a very quick and dirty job of painting the screen white outside and not inside, accepting some pray pain would enter the screen. Of course the sensor was removed. It workd out fine, but no primer so the plastic if I want (and I do) can be all blakc without to much effort. If I put strain on the HDPE plates the paint will easily peel off. But for now...So what happened under less sunny, but for Dutch pretty warm weather? My own design screen during the day now as consistently significantly cooler than my Vaisala screen. Up to 0,6 C and on average 0,3 C. Both are within 50 cm of eachother on the same pole. So Tx was 27,1 on my screen vs 27,5 C on the KNMI Vaisala. The next day got a bit warmer with more wind. Nevertheless, the endresult was identical when it comes to the difference: my screen 28,8 C the other one 29,2 C.
Just to check I exchanged the sensors of the screens. It did not matter: We got 26,1 vs 26,5 C as Tx and yesterday we had a lot less wind, but also no full sun.
Today I realised I did not have the sensor put in one place, they were loosly placed pretty close to the lower of the two topplates. I always made sure the sensor was not sticking out under the louvres, but still. So this morning I both firmly attacked them about 3 cm under their lower topplate. And luckily enough we got some brighter spells with low winds and you guessed it: same results again. Up to 0,6 C cooler....But now, at noon, we got a good downpoor of 10 mm in 12 minutes....Now the Vaisala was 0,2 C colder also 30 minutes after the downpour. What was the reason? Well the Vaisala screen read 95% RV whereas my own design screen remained drier at 90,1 C. So the Vaisala essentially was affecting by a wet(ter) bulb and wind which means the sensor cooled off more...I did not expect it!
I also compared my Vaisala white screens with a white round plated Davis screen (sued with passive Vantage Pro 2). That screen under dry and warm conditions is up to 1,4 C WARMER than my Vaisala!. Who would have expected that!
Okey, so here some pics of the screens. The smaller Vaisala screen is in the middle but was not used for ths comparison. The left and the right screen both use the exact same plates.
The fun part of it all is that these screens cost me may be 30-40 euro max to build. hat is with paint, plates, stainless steel rods, nuts and bolts etc.
If it works, I will probably share with you how to make one yourself if people are interested. May be nice for you too?
First pic below: lefthand my own design (it is of course a modification of the well known existing multiplate screens, not claiming to be some kind of wizard!. Middle is a KNMI Vaisala type homebrew with smaller 11 cm plates. righthand is a bigger version of the middle one. BTW: the middle one is perfectly fine, it is within 0,1 to the one on the right).
2nd pic below: KNMI Vaisala selfbuilt (prototype, rods need to be cut etc) view from the bottom. So apart from the topplate it is matte black inside.
3rd pic: my own design testing being completely black vs the larger KNMI Vaisala. These saucers I sued are 13,5 cm in diametre. To be clear: in none of the case the sensor can be seen no matter what angle you look, so indirecte sunlight cannot reach it....
