Modelling area space with Glass walls in HAP
Modelling area space with Glass walls in HAP
(OP)
I have modeled an area space with glass walls with a southern exposure in Carrier HAP, but whenever I run the hourly load reports, it says that I still require cooling even during at night in the middle of the winter (I understand if it is during the day, since that area space does get hot due to the solar gains as a result of the walls being completely glass). I understand that this is true to some extent due to to the area space acting as a big thermal heat sink (essentially accepting the solar gains during the day and re-radiating it back to the space during the hours when the sun has set). However, I find it hard to believe that the space still requires cooling in the late hours when the space is being cooled to maintain setpoint during the day. Is there a particular option in HAP I may have missed when creating the model? (I also tried reducing the building weight and it improved the results a bit but does not completely eliminate night time cooling).





RE: Modelling area space with Glass walls in HAP
Obviously calling HAP support could help.
RE: Modelling area space with Glass walls in HAP
The only explanation I have with this is the thermal mass of the building causing the heat to re-radiate during night time, but it shoudn't be this severe that it causes it to need cooling at around 11PM to 4AM in the morning. I have been told that the actual space cools back down during night time so I know there is something wrong with this model. I have double checked my parameters and still can't find the reason. Unless it has to do with the alrgorithm that HAP calculates its solar gain loads.
RE: Modelling area space with Glass walls in HAP
Assuming the adjacent spaces have same setpoints, they shouldn't radiant heat back. and if that space in questions keeps at setpoint during day, it itself shouldn't have heat stored in the structure. the glass should make it cool down rather quickly. You probably already checked all the U-values, infiltration etc. so that you correctly simulate heat losses at night.
i find it hard to believe HAP is wrong, in most cases the problem is in front of the PC :) Call them, sure some mundane error you made. I use Trace and find odd things in my models all the time.
RE: Modelling area space with Glass walls in HAP
RE: Modelling area space with Glass walls in HAP
RE: Modelling area space with Glass walls in HAP
May be you have put the total Number of people and you used people/SF as a unit, or total Watts and then you picked watts/Sf as a unit.
That kind of things you should look into.
RE: Modelling area space with Glass walls in HAP
On occasion I forgot some mundane detail and had Trace support help me. It is really hard for us without seeing the file to tell what you may have entered wrong.
RE: Modelling area space with Glass walls in HAP