Internal Temperature Rise

Question

I am working on a project where the mechanical specification allows for a 2degC temperature rise but when I try to apply this parameter in the CIBSE Gains Design Data Tab the project freezes at 0%. 
 I can make other design parameter changes but this one.

Shane Regan · Answer

Thanks Grant. I notice that the units in this project are set to imperial, is that correct? 
 The issue is much as I suspected - the supply air temperature to cool the rooms has been set to 71.6F in CIBSE Gain: 
 
 Which is the same as the design temperatures for your rooms (for both Winter and Summer): 
 
 Please note for your room to be cooled the temperature of the supply air used to cool the room must be less than the design temperature. The additional affect of the 2degree temperature rise means that in effect your cooling supply air temperature is higher than your allowed room design temperatures - this is invalid so is leading to the crash.

Shane Regan · Answer

Hi Grant, 
 The guidance on using Fresh Air Loads in the following article should assist. 
 Calculations - Using Fresh air loads in Design Database 
 Primary Fresh Air assumes there is also local cooling in the room via a fan coil. The Supply Air Temp is for that fan coil and so should be lower than the room design. 
 The following should also be of interest: 
 CIBSE Gain calculation - Allowing temperatures to rise