IES-VE User Forum

I'd like to find the mean radiant temperature, dry resultant temperature, and PPD for a particular point within a room. The results in Vista only show a mean value for the whole room. Say that I'm interested in a point centered one meter from the biggest window, and one meter above floor level. There doesn't seem to be an easy way to obtain these data.

One way to go is to create a miniroom with a volume of say 1 dm², and without partitions, within the real room. This way, in theory, I would get a good approximation of the comfort at this certain point. I tried this a time ago and recieved reasonable values. However my colleague used the same method more recently, with absurd temperatures as a result. I can't see any reason for us to get such different results. The question is if this method is trustable at all? We're not using any other modules than Apache and ModelIt (well, I was using SunCast for my simulation, that's the only difference). If I'm correct, there won't be any convection between the real room and the miniroom, since we're not using MacroFlo. How much would that affect the accuracy of this method?

Another way of investigating the thermal comfort at a certain point would be to use the surface temperatures from Vista and calculate a weighted mean radiant temperature depending on area of each surface and the distance from it to the point of interest. It's still not optimal since it's an extra work load.

Does anyone have any other ideas on how do this? Thank you.

Hi,

Just on your first approach, I was talking to one of our thermal consultants in here and agreed that there is no reason we know of that this approach wouldn't work.

Not using MacroFlo (and so having no convection) would have an impact so it wouldn't be an exact representation but it is hard to say how great that impact would be really.

We would recommend you use SunCast in this calculation to properly associate solar heat gains to the correct airspaces/surfaces in the model.

Other than that then I'd say be careful, if one study got reasonable results and the other didn't then you should review inputs in each and check you have taken consistent approaches to setting up the model. I'd also be careful with the size of the focus room, it might be worth having it 1sqm or a reasonable size. I don't know for sure but having it too small I would be concerned Apache isn't able to deal with it properly. Also make sure your focus zone isn't intersected with the main room - if it is in the centre then you would likely have to draw the main room around it.

Good luck with your study
Phil