[EnergyPlus_Support] Simple Glazing, Complex Glazing and frames

["Jean marais" <jeannieboef@xxxxxxxxx>]

Dear Group,
1) in the simple glazing material specification there is no parameter for the density of the glass. is this a "no mass" material, i.e. the surface temperature of the glass is assumed to be that of the air in contact with that surface?

2) is this the same for complex glazing?

3) is this the same for frames/dividers?

Background: I'm modelling a large factory hall with an almost fully glazed roof. It is a very light weight structure where the only heavy contruction is the slab. During a summer type run period over a day, I get fatal errors because IRTsurfaces that I am using to virtually partition the hall, are reporting negative 120 deg C temperatures at 09:00.

Due to the concave nature of some of the factory roof, I am limited to using the FullExterior solar distribution model which divides equally the incoming radiation on all surfaces in that zone. Instead of the majority of radiation hitting the slab, the sum is equally split and too much of it is assigned to my no mass type IRTsurface partitions. I have to use the CTF heat transfer algorithm with this type of material. I suspect that the algorithm is trying to see what delta T is required to transfer a large amount of energy over to the other side and comes up with -120 deg C in some cases. Although the CTF object has a temp upper limit, there is no lower limit for me to relax and hence the program errors out.

I can get it to run by using internal mass objects, because when I increase the total surfaces in the zone less energy gets put on the no mass IRTsurfaces.

Any other thoughts are appreciated. I wish users did not have to worry about this kind of issue (too much or too little internal mass, or too thick walls either)



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