People Dissatisfied

ApacheCalc – Heat loss/gain calculations using CIBSE procedures to determine design heating/cooling loads.
ApacheLoads – Design heating/cooling loads calculations using ASHRAE Heat Balance Method.
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People Dissatisfied

Postby Dav » Thu May 31, 2012 3:30 am

Hi all,

As far as I know, PPD index is representative of thermal comfort in the room concerned.
However, I get a PPD around 25% while my room average air temp is around 24, my RH about 55% (Tdew=14, moisture = 100g/kg, etc.), which comply with EN standards....With these values, I usually get a PPD around 15%...

Is there any other parameter taking into account in IES VE for PPD evaluation?



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Re: People Dissatisfied

Postby KasperS » Thu May 31, 2012 9:50 am


You say your average temperature is 24 °C. This means there will be many hours where it is 25 and 26 °C which will make people dissatisfied. Instead of using averages you should count the hours of a specific temperature and use that as an indication. The reason i would do this is, that its easy to get a good average, like if you have 25 % of the time with a tempature of 20 °C, 25 % with 22 °C, 25 % with 26 ° and 25 % with 28 °C. I am pretty sure more than 15 % would be dissatisfied with this.


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Re: People Dissatisfied

Postby david373348 » Wed Dec 05, 2012 11:10 am

in the definition of PPD and PMW comfort probabilities there are already 5 or 10% (I don't remember well) of the people which it will be dissatisfied even if you put them in Hawaii with a beer on the size :lol:

So you need to take this in account for your analysis,


David Garcia

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