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Ideas Wanted Decision Matrix
#1
Hey Folks, 

I´d like to optimize my Basement ventliation to get rid of unwanted humidity.

But, things are not that simple, so I'd like to hear some ideas on how to implement this.

I´d like to have a Matrix to deceide, wether Basement Ventilation is usefull or not.
The Problem is to determine via a rule, if the outside absolute humidity is lower than the inside absolute humidity.
As an example:

1.) outside less water per m³ in the Air => Ventilation will dry the basement

Outside: 0°C and 60% Humidity => 3g water/m³
Inside: 20°c and 40% Humidity => 7g water/m³

2.) outside more water per m³ in the Air => Condensation on the Walls

Outside: 25°C and 20% Humidity => 5g water/m³
Inside: 18°c and 30% Humidity => 4g water/m³

I am looking for a Solution to help pilight making a smart decission based on the absolute amount of water in the air, while inside and outside temp and hum. is given.

Any ideas?


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#2
Can you put the rules you are seeking in words?
 
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#3
(02-27-2019, 09:52 PM)curlymo Wrote: Can you put the rules you are seeking in words?

That´s part of the Problem. I have no idea, how such a rule should look like.

Something like "IF (absolute outdoor humidity (outdoor.temperature 100% diagram value mutliplied with outdoor.humidity)) <= (absolute indoor humidity (indoor.temperature 100% diagram value mutliplied with indoor.humidity)) THEN switch DEVICE vent TO on"

I am afraid, there is Kind of a small database needed.
 
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#4
Can you put it in code tags?

Also, try to describe the rule in just plain English. Like, if this happens and that there should happen this. And so on.
 
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#5
Hi Curlymo,

I didn´t use Codetags, because it´s no Code... Angel 

In my first Posting I tried to describe, what I wanted to achieve.

Second try:

Depending on temperature, Air can carry more or less Water (Damp), means that air at e.g. 10°C can carry 9g Water per m³, wich is 100% humidity. If the rel.hum is 50%, it means, that the air carries 4,5g water per m³ without condensation. 

If the Basement has 18°C at 50% rel. humidity, the maximum humidity the air can carry is 16g/m³ and actual there is 8g/m³ in the air. If the outside temperature is 25°C at 40% humidity, the outside air carries 9g/m³ Water in itself => Condensation on the walls will occur, Ventilation is Useless.

I´m trying to find out wether or not Ventilation is usefull.

Better described? I am afraid, there is no IFTTT for this, because probably there is a database needed? Decission Base schould be the absolute amount of water per m³ in the air.
 
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#6
I asked for code tags because it makes it more readable. Also when it's not code. See for yourself. So please still change it.

Code:
If basement temperature is above 17 degrees and the humitidy is above 49% and the outside temperature below 25 degrees and the humidity is below 40% then ventilate?
Is that what you want?
 
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#7
(02-28-2019, 09:32 PM)curlymo Wrote: I asked for code tags because it makes it more readable. Also when it's not code. See for yourself. So please still change it.

Code:
If basement temperature is above 17 degrees and the humitidy is above 49% and the outside temperature below 25 degrees and the humidity is below 40% then ventilate?
Is that what you want?

Hi Curlymo,

No, this is easy to achieve.

Perhaps once again... Thermometers only are able to show relative humidity. So if a Thermometer says „18 degree Celsius and 50% humidity“ it means, that the air carries 50% of the Maximum damp-Volume at 18 degree. The Maximum damp Volume at 18 degree is 16g/m3 and in the Moment, there is 8g water as damp per m3 in the air.

If you lead air with e.g. 25g damp per m3 in a room with 18 degree Celsius Air Temperature, the maximum the air can carry is 18g/m3 (100% Humidity) and 7g Water per m3 will condensate on the walls. This is the reason, why you should not ventilate your Basement on summer days.

I want to have a rule, wich compares outside absolute humidity (the calculated humidity based  on the diagram of post 1)and not the relative humidity read from a thermometer to decide, wether if Ventilation will be usefull or if Air-Damp will condensate on the walls.

Hope, this explains my Problem...;-)
 
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#8
Somehow, you are not able to describe it in such i way i understand. Or i'm just too stupid Wink
 
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#9
Okay.

Code:
Get Outdoor.temperature
Determine 100% water Value from diagram at Outdoor.temperature
Outdoor.absolut=Multiply Outdoor.humidity with 100% Value

Get indoor.temperature
Determine 100% water Value from diagram at indoor.temperature
indoor.absolut=Multiply Indoor.humidity with 100% Value

If outdoor.absolut<indoor.absolut then switch Ventilator to on

Now better...? ;-)
 
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#10
But why do you need a database for this? To store the matrix values?
 
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