Ideal Loads Cooling Limit [W]

Hello together,

I stated the same issue a few days ago as an answer to another thread:

The problem is the following:
My task is to investigate the temperatures in an office space with internal loads under extreme weather conditions. The space has a cooling system that was designed to cover a cooling load of 700 Watts (cooling set-point of 23°C). I would like to analyse if the cooling system/device with a capacity of 700 W is enough for the space and simulate the expected hourly temperatures for the given year/weather data.

Due to the fact that the actual cooling system isn’t clear yet, I would like to use the simplified Ideal Loads system in Honeybee. Matching with task described before I need to limit the system size/cooling capacity to 700 Watts. Within the actual Honeybee component the cooling capacity can only be limited by flowrate, which in this case I don’t know about. So I tried to adjust the inputs by making use of the relatively new Ironbug plugin, but my results are quite strange:

  • the air temperature for few hours can be maintained at 23°C, but that all of sudden is decreasing and reaching temperatures of approx. 29°C
  • the cooling load/power doesn’t go up to the previously defined 700 W and only reaches values around 500 W

My presumption is that there is some kind of mechanical ventilation that brings the hot outdoor air into the room (can also be seen when looking at the results for mech. vent. energy…)

My question now is

  1. if my approach to the given task is right or if there is another, more elegant way (maybe without using ironbug) to investigate the problem?
  2. why do I have the outdoor air coming in even though I didn’t define that

@chris @MingboPeng Maybe you guys can help me…

I read all the other related posts about the Economizer, DDY etc., but all those hints didn’t lead to a solution.


/Tobi (888.6 KB)