Energyplus design heating load and airflow is zero
Hi,
For my masterthesis I have to perform a simulation of a passive school building equipped with 5 AHU's for heat recovery and 4 of them have adiabatic cooling. I did manage to put the building and the HVAC components into Energyplus. For the HVAC system I used Open Studio and copy pasted into my E+ file. But I keep getting a lot of errors and can't manage it to fix them:
* Warning * Calculated design heating load for zone=CAFETARIA is zero. * ~~~ * Check Sizing:Zone and ZoneControl:Thermostat inputs. * Warning * Calculated design heating load for zone=CLASSROOMS EAST is zero. * ~~~ * Check Sizing:Zone and ZoneControl:Thermostat inputs.
... and this for all my zones,
AND
* Warning * ManageSizing: Calculated Heating Design Air Flow Rate for System=AIR LOOP HVAC 1 is zero. * ~~~ * Check Sizing:Zone and ZoneControl:Thermostat inputs. * Warning * ManageSizing: Calculated Heating Design Air Flow Rate for System=AIR LOOP HVAC 2 is zero. * ~~~ * Check Sizing:Zone and ZoneControl:Thermostat inputs. * Warning * ManageSizing: Calculated Heating Design Air Flow Rate for System=AIR LOOP HVAC 4 is zero. * ~~~ * Check Sizing:Zone and ZoneControl:Thermostat inputs.
AND
* Warning * GetAirPathData: AirLoopHVAC="AIR LOOP HVAC 1" has no Controllers. * Warning * GetAirPathData: AirLoopHVAC="AIR LOOP HVAC 2" has no Controllers. * Warning * GetAirPathData: AirLoopHVAC="AIR LOOP HVAC 3" has no Controllers. * Warning * GetAirPathData: AirLoopHVAC="AIR LOOP HVAC 4" has no Controllers. * Warning * GetAirPathData: AirLoopHVAC="AIR LOOP HVAC 5" has no Controllers.
So i did some research and tried to fix it:
- I checked the thermostats but them seem fine to me. (link
- Also I tried to add compact schedules for the internal gains only for the design days. link text
But then I just get additional errors:
* Warning * GetInternalHeatGains: Zone="KITCHEN" occupant density is extremely high. * ~~~ * Occupant Density=[20] person/m2.
* ~~~ * Occupant Density=[5.066E-002] m2/person. Problems in Temperature Out of Bounds may result.
... I checked these schedules, but again they look fine?
Everything I know is from the internet and some reading, so I am not that experienced with Energyplus. Could anyone that is more experienced with Energyplus take a look? Please, let me know and I will send you the IDF-files.
The occupant warning says you have 20 people per m^2. You mentioned you checked the schedule, but what you need to do is look at is the design level of your
Peopleobject. For cafeteria should be about 1 person per m^2, which is pretty high vs. the 0.05 person per m^2 for an office. Note that input may be in m^2 per person which would be the inverse of what is shown above. The schedule just applies a fractional value of the design load to use and a given time step.It is possible that people are fully heating all of your spaces.
Without adding the compact schedules for the design days (Winter and Summer) there is no warning about internal load due to people. However, for my HVAC system I had a that zero heating load, so I did some research and found this article about a zero cooling load. In the comments is mentioned that the problem could be the internal loads, they may not be zero during design days. So I added additional compact schedules for the internal loads and took the highest number of occupants per zone for the design days.
Unfortunately, I get this warnings about an outraged internal load due to people. But I cannot figure out were the problem comes from. Or is it not allowed to use a yearschedule AND a different (compact) schedule for design days?
Normally, one would use a single schedule reference to cover all day types. Sure, you can do what you did above as long as the design day schedules in peopleschedule_refter_year are zero. Otherwise you'll get people from both objects during sizing.