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Posted

Whenever we get extreme weather, the same questions come up.

So to answer them, I have created a calculator that works out the dewpoint temperatures and absolute humidity from air temperature and relative humidity.

 

You should be able to change the relevant cells, though I cannot check this as I do not have Excel (only Calc).  There is a text box giving instructions.

I have also added some of my local weather data as a time series.  This is as an example only and can be deleted, or replaced with your own data.

I hope it is useful.

 

 

 

Dewpoint and Absolute Humidity Calculator(Excel).xlsx

Posted
26 minutes ago, ToughButterCup said:

it is useful

Can be used to take a lot of the guess work out of it.

Could also be useful for controlling UFH in cooling mode, especially when you consider the statistical nature of thermodynamics.

Posted

It's a nice idea but my computer doesn't seem to like it. I downloaded the file into Excel but can't type into the input cells. I get a message saying the spreadsheet is protected.

An alternative for anybody having the same problems as me, is to use a psychrometric chart. I'm attaching one here and have marked it up with an example:

Relative humidity 70%, Temperature 20o C

Start at the top and follow the 70% line down to where it intersects 20o C on the x axis. Gives a dew point (wet bulb or saturation temperature) of 16.5o C.

Unlike @SteamyTea's spreadsheet, it doesn't account for different atmospheric pressures though. I'm not sure how much difference that makes.

psychrometric-chart-en-uk.pdf

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