How to fix warmup convergence failing during sizing?

edit

I am running several models using JEPLUS (parametrice study) and some models fail the convergence test. Any idea how to fix the problem?

I tried o increase tolerances but did not work out for all models. I increased the number of warmup days without any success. The challenge is that it is a building is only occupied from 18-8 hours and 12-14 hours. Thus, the HVAC system is only running during this time. Furthermore, it is mixed mode operation, i.e. that HVAC is only running when natural ventilation cannot fullfill the needs for cooling. It further has to be noted that Setpoints are controlled by operative temperature not by air temperature. For any hints how to solve the problem, I am very grateful.

~~~ * Warmup Convergence failing during sizing. * ~~~ * ...Environment(SizingPeriod)="WINTERDESIGNDAY-WEATHERFILE"

* ~~~ * ..Max Temp Comparison = 4.64E-002 vs Temperature Convergence Tolerance=0.40 - Pass Convergence

* ~~~ * ..Min Temp Comparison = 2.70E-005 vs Temperature Convergence Tolerance=0.40 - Pass Convergence

* ~~~ * ..Max Heat Load Comparison = 1.2628 vs Loads Convergence Tolerance=0.20 - Fail Convergence

* ~~~ * ..Max Cool Load Comparison = 0.0000 vs Loads Convergence Tolerance=0.20 - Pass Convergence

* Severe * CheckWarmupConvergence: Loads Initialization, Zone="ROOMWEST" did not converge after 25 warmup days.

* ~~~ * ...Environment(SizingPeriod)="WINTERDESIGNDAY-WEATHERFILE"

* ~~~ * ..Max Temp Comparison = 0.15 vs Temperature Convergence Tolerance=0.40 - Pass Convergence

* ~~~ * ..Min Temp Comparison = 0.34 vs Temperature Convergence Tolerance=0.40 - Pass Convergence

* ~~~ * ..Max Heat Load Comparison = 2.2887 vs Loads Convergence Tolerance=0.20 - Fail Convergence

* ~~~ * ..Max Cool Load Comparison = 0.0000 vs Loads Convergence Tolerance=0.20 - Pass Convergence*

In the error file the following recommendations are given:

*** ===== Final Error Summary ===== *** The following error categories occurred. Consider correcting or noting. *** Loads Initialization did not Converge *** ..1) very high thermal mass such as very thick concrete (solution: increase max number of warmup *** .. days in the BUILDING object); *** ..2) moderate mass and inadequate space conditioning such that the building keeps getting warmer *** .. and warmer on successive days (solution: add HVAC, check building thermal properties, *** .. check if infiltration is included, make sure HVAC properly controlled); *** ..3) a soil layer modeled below the concrete slab - (solution remove this layer and read about *** .. ground temperatures in the Auxiliary Programs document). *** ..4) unreasonable (too small) limits in the BUILDING object for temperature (.4 default) or *** .. loads tolerances (.04 default)