Cooling limit capacity exceeded (with ZoneHVAC:IdealLoadsAirSystem object)

asked 2022-08-09 09:18:54 -0500's avatar

updated 2022-08-16 06:59:09 -0500


I tried to put a cooling limit capacity to the object ZoneHVAC:IdealLoadsAirSystem on the idf input file but in the results the limit seems to be exceeded. I had no problem with the heating capacity limit.

The ZoneHVAC:IdealLoadsAirSystem is defined as:

ZONE+00_+01_+00 Ideal Loads,    !- Name
,                         !- Availability Schedule Name
ZONE+00_+01_+00 In Node,    !- Zone Supply Air Node Name
ZONE+00_+01_+00 Ex Node,    !- Zone Exhaust Air Node Name
,                         !- System Inlet Air Node Name
50,                       !- Maximum Heating Supply Air Temperature
13,                       !- Minimum Cooling Supply Air Temperature
0.0156,                   !- Maximum Heating Supply Air Humidity Ratio
0.0077,                   !- Minimum Cooling Supply Air Humidity Ratio
LimitCapacity,            !- Heating Limit
autosize,                 !- Maximum Heating Air Flow Rate
30000,                    !- Maximum Sensible Heating Capacity
LimitCapacity,            !- Cooling Limit
autosize,                 !- Maximum Cooling Air Flow Rate
100000,                   !- Maximum Total Cooling Capacity
Heating Availability Schedule,    !- Heating Availability Schedule Name
Cooling Availability Schedule,    !- Cooling Availability Schedule Name
None,                     !- Dehumidification Control Type
1,                        !- Cooling Sensible Heat Ratio
None,                     !- Humidification Control Type
,                         !- Design Specification Outdoor Air Object Name
,                         !- Outdoor Air Inlet Node Name
,                         !- Demand Controlled Ventilation Type
,                         !- Outdoor Air Economizer Type
,                         !- Heat Recovery Type
,                         !- Sensible Heat Recovery Effectiveness
;                         !- Latent Heat Recovery Effectiveness

(remark: the problem is increased when there is heat recovery)

The TDS gives these results: image description

If I zoom in on a date with a peak above the limit: image description

Thank you for your help.

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Has anyone managed to reproduce this bug or does anyone have a clue to explain it ? Thanks, your answers will help us a lot. :)'s avatar  ( 2022-08-24 03:42:23 -0500 )edit