[edr1924]

Update...
Finally after a delay of a few months I installed my OP Fan Assisted shield in the garden.

It didn't take long to get results... My 20 year old Peet bros sensor, also in a radiation shield but NOT fan assisted wil be replaced ASAP...

The differences are much greater than expected:

Afternoon, sunny, but both sensors in the shade: FA shield: 20.3 Celcius, old sensor 25.5C
I checked the outside temp with my calibrated thermometer and the difference with the new FA sensor was 0.3C

The next morning was more surprising because the non FA shield had a chance to cool off:
new FA shield: 14.1C, old sensor: 20.2C !!

Wow, never expected that! 

I think in a domestic environment, a Fan Assisted shield is more useful. In open field there's more wind to blow through the non FA radiation shield. In a town garden the situation is much different.

Well, I'm very happy with the results...

NOTE: The Fan runs 24/7.

[hornychz]

Congratulations! 

[werk_ag]

I think in a domestic environment, a Fan Assisted shield is more useful. In open field there's more wind to blow through the non FA radiation shield. In a town garden the situation is much different.

Hi edr1924,

Maybe you would like to read this:
https://www.meteocercal.info/forum/Threa...on-shields

Indeed, as the study shows, the lower the wind speed the more a fan assisted radiation shield is effective. In some places, is even a must.

[edr1924]

I think in a domestic environment, a Fan Assisted shield is more useful. In open field there's more wind to blow through the non FA radiation shield. In a town garden the situation is much different.

Hi edr1924,

Maybe you would like to read this:
https://www.meteocercal.info/forum/Threa...on-shields

Indeed, as the study shows, the lower the wind speed the more a fan assisted radiation shield is effective. In some places, is even a must.

Thank you for that URL, very interesting and point proven in my case/location.

But that's also why the wireless WeatherDuino and Davis systems etc. are so great because one can place the sensors in the best location.

BTW: I asked in another post for the choice between Inspeed and Davis wind sensors.  I decided to retire the (superior) Peet Bros anemometer I use now and use the Davis 6410 as it is widely available and better serviceable with the new model.

Moving forward to an all WeatherDuino system which is great!

[edr1924]

Hello,

Today I've received my new aspirated radiation shield - not DIY, but it made by professionals
from Hunan RIKA Electronic Technology:



I will change my old SHT21 sensor and my old DIY shield with this new one and SHT31
in the next weeks - I am already looking forward ... 

You will find that the SHT31-D sensor accuracy is amazing...
Have fun with those great products...!

[hornychz]

I will change my old SHT21 sensor and my old DIY shield with this new one and SHT31
in the next weeks - I am already looking forward ... 

You will find that the SHT31-D sensor accuracy is amazing...
Have fun with those great products...!

Hi,

I have some, one of them more than 2 years, but the head one is still SHT21...
The change will be done maybe this october (because of care about our grandchildern...), I hope 

[edr1924]

Follow-up after almost 2 years of use...

The GOOD:

- The shield still works as hoped for and much better. I love the triple (and double ventilated) shielding.
- The 12V fan (running on 9V) is in use 24/7/365 and still silent. It's a high quality 'Papst' fan but not designed for outdoor use in humid (air) conditions so I'm impressed...
- No spiders in the tubes and fan area which is a surprise.  I did use mesh protection but thought that the little ones would go through but they didn't.
- cheap spray-paint on the tubes is still good?!

The BAD:

- the SHT31 sensor broke down due to the moist air passing along it which destroyed the electronics...

The UGLY:

- the SECOND SHT31 also broke down after nearly a year... 
Although this time, I covered the electronics in epoxy glue, leaving only the sensor exposed (duh...)

The SOLUTION:

Well I should be: I bought a Sensiron SHT-30 sensor in a weather proof housing.
It's designed to sit in the rain etc but I use it (of-course) in my radiation shield (see opening post of this thread)

So I don't know what the experience is of other SHT31 users but mine has been disappointing concerning the longevity.
But hopefully the new sensor, which was designed to be used outside, will perform it's function much longer.


   

   

   

   

[tobyportugal]

Well I should be: I bought a Sensiron SHT-30 sensor in a weather proof housing.
It's designed to sit in the rain etc but I use it (of-course) in my radiation shield (see opening post of this thread)

So I don't know what the experience is of other SHT31 users but mine has been disappointing concerning the longevity.
But hopefully the new sensor, which was designed to be used outside, will perform it's function much longer.

Hello,

If I can give my opinion, it is better to use this kind of support:


Mounts like the one in your example cause a slight overheating and decrease the responsiveness of SHT.

[edr1924]

Hello,

If I can give my opinion, it is better to use this kind of support:


Mounts like the one in your example cause a slight overheating and decrease the responsiveness of SHT.

Thank you for your reply!  But why would the sensor be overheating a bit?
The metal mesh has a very open structure so 'heat' would escape easily.

And it is designed by the same very good manufacturer that made the sensor itself so I don't expect this sort of problem.

Your opinion is very much appreciated!

[tobyportugal]

It all depends on the level of accuracy you want.
When I started making Davis VP2 compatible probes with SHT75s, I made the same mistake.
The mounts, like your example, overheat by +/- 0.3° but above all there is a slow reaction to temperature changes (especially in the evening when the temperature drops).
Tests done in 7714 shelters.
The Italians (MeteoNetwork) have done tests with various solutions in MetSpec/7714/Barani shelters.
These tests led to EcoWitt making a sensor based on an SHT35.
Sorry for my English, have a nice weekend.