Topic: VP2 FARS airflow

[Old Tele man]

SIZE = mass which has temperature lag, so bigger device isn't good for TEMP readings.

However, SIZE of RH sensor could benefit because (using a Bloodhound analogy) it would have a bigger NOSE to sniff the air with.

So, it's a ONE up and ONE down packaging problem.

[WxLover16]

SIZE = mass which has temperature lag, so bigger device isn't good for TEMP readings.

However, SIZE of RH sensor could benefit because (using a Bloodhound analogy) it would have a bigger NOSE to sniff the air with.

So, it's a ONE up and ONE down packaging problem.

Well, I'd much rather have accurate/fast responding temp than humidity anyday anyway so that is more than fine by me.

[jgentry]

SIZE = mass which has temperature lag, so bigger device isn't good for TEMP readings.

However, SIZE of RH sensor could benefit because (using a Bloodhound analogy) it would have a bigger NOSE to sniff the air with.

So, it's a ONE up and ONE down packaging problem.

Gotcha.

Then really, the SHT-31 performs very well then in terms of RH with the chip being small.

[CW2274]

SIZE = mass which has temperature lag, so bigger device isn't good for TEMP readings.

However, SIZE of RH sensor could benefit because (using a Bloodhound analogy) it would have a bigger NOSE to sniff the air with.

So, it's a ONE up and ONE down packaging problem.

Gotcha.

Then really, the SHT-31 performs very well then in terms of RH with the chip being small.

Considering the SHT1X is what, 3-4 times the size of the SHT3X with less accuracy and less range of accuracy, temp and humidity, I'd say size doesn't matter.

[Old Tele man]

SIZE = mass which has temperature lag, so bigger device isn't good for TEMP readings.

However, SIZE of RH sensor could benefit because (using a Bloodhound analogy) it would have a bigger NOSE to sniff the air with.

So, it's a ONE up and ONE down packaging problem.

Gotcha.

Then really, the SHT-31 performs very well then in terms of RH with the chip being small.

Considering the SHT1X is what, 3-4 times the size of the SHT3X with less accuracy and less range of accuracy, temp and humidity, I'd say size doesn't matter.

Encapsulating compound is not the same as sensor die size (wink,wink).

[CW2274]

SIZE = mass which has temperature lag, so bigger device isn't good for TEMP readings.

However, SIZE of RH sensor could benefit because (using a Bloodhound analogy) it would have a bigger NOSE to sniff the air with.

So, it's a ONE up and ONE down packaging problem.

Gotcha.

Then really, the SHT-31 performs very well then in terms of RH with the chip being small.

Considering the SHT1X is what, 3-4 times the size of the SHT3X with less accuracy and less range of accuracy, temp and humidity, I'd say size doesn't matter.

Encapsulating compound is not the same as sensor die size (wink,wink).

I hope I'm not the only one who has absolutely no idea what you just said....

[Old Tele man]

SIZE = mass which has temperature lag, so bigger device isn't good for TEMP readings.

However, SIZE of RH sensor could benefit because (using a Bloodhound analogy) it would have a bigger NOSE to sniff the air with.

So, it's a ONE up and ONE down packaging problem.

Gotcha.

Then really, the SHT-31 performs very well then in terms of RH with the chip being small.

Considering the SHT1X is what, 3-4 times the size of the SHT3X with less accuracy and less range of accuracy, temp and humidity, I'd say size doesn't matter.

Encapsulating compound is not the same as sensor die size (wink,wink).

I hope I'm not the only one who has absolutely no idea what you just said....

ANALOGY - The size of the bun does not tell you how big the hotdog is inside (wink,wink)!

TRANSLATION - Bun = encapsulating compound; hotdog = sensor itself, the tiny metallic material(s) deposited on silicon substrate material, called a die.

[dendrite]

Since this came up, I had this setup in my back yard. A piece of plexi glass with a fan (120cfm) blowing on it. Last night we had perfect conditions. Lots of rain yesterday, high humidity and no wind.

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This morning this is the result. A bit difficult to see the condensation on the pictures but I think you will get the idea even in the picture above. Where there were good airflow, no to minimal condensation. Also discussed in another thread.

More pictures
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Wind definitely increases evaporation rate, but our T/H sensors aren't exposed to rain or clear skies at night so they won't be losing longwave IR radiation out to open space. Even without a fan, the sensor could be "dry" in the shield while you're forming dew on the grass and plexiglass. The heat lost by the sensor is reradiated back to it inside of the shield.

Maybe I need to reread this thread to see what you're getting at.

[dendrite]

More MASS means more heat HELD...hence my original wording 'temperature lag.'

Hope you realize I wasn't responding to you.

[Bashy]

Hi

What is better the FARS or a DFARS converted to 24 hr and why please?

I am using the latter, 12v mains operated 24 hours.

[CW2274]

Hi

What is better the FARS or a DFARS converted to 24 hr and why please?

I am using the latter, 12v mains operated 24 hours.

The 24hr FARS is designed to be aspirated, whereas with DFARS it's not as necessary since it draws air from the sides unlike the 24 hr design which only draws air from underneath. For the utmost in accuracy, the 24hr is the way to go, only if it's aspirated. Davis themselves state that the DFARS is only 75% as effective at reducing solar insolation compared to the 24hr design. That's a big deal some places, like mine.

[ValentineWeather]

Here is the main difference the Dfars sensor is left open and draws from side while the 24 hr sensor goes down in a sensor tube triple walled  that uses airflow as insulator and includes a heat shield.

[Bashy]

Thanks guys, so for here in the UK, would you say unlikely to benefit?

[CW2274]

Thanks guys, so for here in the UK, would you say unlikely to benefit?

Probably. I've been to your lovely country in June and am recalling how remarkably low the angle of the sun is, I'd say don't bother. Just keep the fan going in what you have.

[Bashy]

Thanks, Tis what I thought after your replies..