How is dew point used/applied practically?

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Binary

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I was working on my monitoring system, and ran into the pulsegrow device. I had every measurement they offer on my system (and more!), but saw they were also calculating dew point. I was curious, if VPD is controlled - fair to say that dew point wouldn't become a problem?

How would one apply a dew point temperature in practice? For example right now I have:

* Temp: 24.91 C
* Humidity: 64.64%
* VPD 0.87 kPa

Calculating Dew Point yields 17.78 C -- what can I glean from this?

Thanks for taking the time to teach!
 
Aqua Man

Aqua Man

26,480
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I was working on my monitoring system, and ran into the pulsegrow device. I had every measurement they offer on my system (and more!), but saw they were also calculating dew point. I was curious, if VPD is controlled - fair to say that dew point wouldn't become a problem?

How would one apply a dew point temperature in practice? For example right now I have:

* Temp: 24.91 C
* Humidity: 64.64%
* VPD 0.87 kPa

Calculating Dew Point yields 17.78 C -- what can I glean from this?

Thanks for taking the time to teach!
Dew point is the point where the air becomes saturated with moisture and it begins to condensate. Warmer air will hold more moisture (water) then colder air. The amount of moisture in the air compared to its maximum capacity is expressed as RH (relative humidity). Humidity is a measurement of the percentage of moisture the air is holding of its maximum capacity (dew point). Relative is the term used to incorporate temperature to the equation. Put them together and you get the percentage of maximum water holding capacity for that specific temperature.

This is why when our temperature drops the RH goes up. Remember cooler air has less water holding capacity. If temps change quickly then your exhaust or dehumidifier may not be able to keep up and you will reach the dew point causing condensate and favorable conditions for fungus, mold and bacteria.

Now with the pulses dew point temp it's simply stating at the current temp and humidity if there is no air exchange or dehumidification that if the temperature drops to that number you will have reached the dew point.
 
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Binary

Binary

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Thanks for the thorough explanation. So if I were to use that number as an indicator, it's truly just to ensure that my actual temperature maintains a safe margin/delta? Or would you simply use it as an 'alarm' notification, if your temp has dropped <= dew point?
 
Aqua Man

Aqua Man

26,480
638
Thanks for the thorough explanation. So if I were to use that number as an indicator, it's truly just to ensure that my actual temperature maintains a safe margin/delta? Or would you simply use it as an 'alarm' notification, if your temp has dropped <= dew point?
Personally dew point doesn't need to be there. The graph showing the RH change as the temp change will tell you everything you need to know in terms of seeing an RH spike after lights out from temp change.

2 things we can do to adjust it if it's an issue... Lower temp slower or increase the air exchange/dehumidification. Personally I use a temp controller with heater and I can set the temp to drop as fast or slow as I like. Drop 1f every 10 min if I want or 1f every hour. It has 12 setpoints.

Inkbird sells a combo on Amazon. Cheap, plug and play and easy to use. The combo will do heating, AC and humidity for like $70. Cheaper than Going out and getting a new dehuey just for that spike if the one you have works for the rest of it. Just a note when using equipment they control it by cutting power so you need to make sure they are either manual on/off or if electronic have autorestart.
 
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Aqua Man

Aqua Man

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But the pulse will paint a clear picture of what's going on
 
Binary

Binary

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I'm trying to learn how to apply the number. I've got it calculated and can see it - I'm also managing rh/temp effectively with my AC Infinity fan -- but wanted to let the software notify me if the shit hit the fan or is about to (which I am doing by way of VPD thresholds currently) - but I wanted to know if Dew Point should be a configurable alarm point as well. I just don't know if the game is to simply not go below it, or if there's more to it (thresholds, etc.).
 
Aqua Man

Aqua Man

26,480
638
I'm trying to learn how to apply the number. I've got it calculated and can see it - I'm also managing rh/temp effectively with my AC Infinity fan -- but wanted to let the software notify me if the shit hit the fan or is about to (which I am doing by way of VPD thresholds currently) - but I wanted to know if Dew Point should be a configurable alarm point as well. I just don't know if the game is to simply not go below it, or if there's more to it (thresholds, etc.).
Avoid dew point at all costs. An alarm would be good
 
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