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Convergence during warmup, cooling load

asked 2021-10-14 11:27:06 -0600

carwal gravatar image

updated 2021-10-14 13:55:34 -0600

Hello all,

I have been experiencing this error a couple of times and am sort of clueless about how to resolve it.

The situation is as follows: In terms of the Electrical Equipment, I want to test a low-e scenario with 10 W/m², and a high-e scenario with 32 W/m². I found that the simulation is running for the low-e scenario, but fails converging once I increase the equipment loads to 32 W/m².

I read in the forum that this might be due to constructions, surfaces or thermostats but that did not really resolve the issue. Increasing the tolerance somewhat helped but the error still pops up for high-e scenario.

The error message looks like this:

** Severe  ** CheckWarmupConvergence: Loads Initialization, Zone="THERMAL ZONE: N00101" did not converge after 25 warmup days.
**   ~~~   ** See Warmup Convergence Information in .eio file for details.
**   ~~~   ** ...Environment(RunPeriod)="RUN PERIOD 1"
**   ~~~   ** ..Max Temp Comparison = 9.46E-002 vs Temperature Convergence Tolerance=0.40 - Pass Convergence
**   ~~~   ** ..Min Temp Comparison = 8.09E-004 vs Temperature Convergence Tolerance=0.40 - Pass Convergence
**   ~~~   ** ..Max Heat Load Comparison = 1.6960E-003 vs Loads Convergence Tolerance=8.00E-002 - Pass Convergence
**   ~~~   ** ..Max Cool Load Comparison = 13.7514 vs Loads Convergence Tolerance=8.00E-002 - Fail Convergence

Does anybody have any hint on this?

Happy for any sort of help.

Best, Caro

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1 Answer

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answered 2021-10-15 10:29:49 -0600

You might try increasing the Maximum Number of Warmup Days. As the EnergyPlus documentation states:

This field specifies the number of “warmup” days that might be used in the simulation before “convergence” is achieved. The default number, 25, is usually more than sufficient for this task; however, some complex buildings (with complex constructions) may require more days.

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Asked: 2021-10-14 11:27:06 -0600

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Last updated: Oct 15 '21