Bug in Surface Condensation Potential

[Germán Campos]

I have found that Surface Condensation Potential is not working properly in last beta version. I send a model attached where there should be condensation in the horizontal surface below the pillar.
Are you aware of this?

Regards,

Germán Campos

[Jérémy L.]

Hi,

I am having a similar issue with surface condensation potential. 

I created a simple model and the results show that my inside surface temperature is below the dew point but no surface condensation potential appear. I attached a screenshot of my model. My "inside" boundary condition is set to 22.2 C and 60% RH so the dew point should be around 14 C. My lowest "inside" surface temperature is around 10 C so it looks like a surface condensation potential should appear.

I have checked the "Show Surface Condensation Potential" check box in the display options.

Am I missing something?

Thank you in advance for your answer.

[Jean Marais]

I am having the same issue. Do you know what would be great is if the isotherms could colour dependant on how close they are to a set dewpoint. even including a dewpoint calculator should be a breeze.

[Fabrizio Prato]

Hi.
I've tried your model and it seems to work, because it draws condensation potential right where it should be, where superficial temperature is below/equal 13.2°C (considering internal air T=20°C and a relative humidity = 65%) as predicted by EN ISO 13788:2008. I post your file (with internal superficial resistance set to Rsi=0.25 (mqK)/W as to EN ISO 12011:2008 for superficial temperature simulation) and an image of the simulation with some comments on it.

Fabrizio

[Germán Campos]

Hi Fabrizio, I agree that Rsi should be  0.25 for a calculation according EN Standards. But if for whatever reason you use another Rsi (such as 7.7) and get a temperature below or equal to 13.2C you should also get condensation potential drawn in Therm. If you review that case, with 7.7, you will see temperatures below 13.2 but condensation potential does not show up. 

BTW I have found that you also need to assign a U-factor tag to the boundary conditions for the condensation potential to be displayes (when it is...)

[Fabrizio Prato]

Hi Germàn.

You are right about the fact that whatever ther reason if temperature is below 13.2°C with 65% of HR you should have condensation.
I don't think it depends on the U-factor name tag but on Rsi value, in fact I tryed again on your file and mine with Rsi = 0.13 (mqK) / W and no condensation potential is plotted.
Perhaps Therm verifies that boundary conditions are right with EN ISO 10211:2008 before proceeding.
Only those who write Therm software could answer this. Let's wait.

Have a nice day
Fabrizio

[Germán Campos]

Hi Fabrizio, I did not mean that it depends on the U-factor but it is necessary to have a U-factor name tag for the calculations to show (you can try in your "working" example). I have my doubts it has to do with Therm verifying 13788 standadr conditions...

As you say, only developers know the answer. Unfortunately I've been waiting for a year and a half and no answer....

Regards,

Germán.