Silent simulation crash without issuing a Fatal or Severe error

In some simulations, a model may fail without producing a clear error message. This is especially problematic when the .err log does not contain a severe error or the usual summary of warnings and errors. Instead, the simulation terminates abruptly, making it difficult to determine what went wrong.

What Happened

• The simulation crashed midway, without issuing a Fatal or Severe error.
• The .err file was truncated—missing the standard end-of-file diagnostic summary.
• No meaningful clues were provided in the output to explain the crash.

Possible Causes

This type of silent crash can occur for a number of different reasons. One known cause is the stratified water heater. When this component is used with Autosize settings, the simulation engine can fail to resolve the configuration properly. This leads to an internal failure that halts the simulation without triggering a standard error message.

How to Fix It

To resolve this silent crash, use one of the following approaches:

1. Set the water heater type to 1-Mixed
   • This configuration is simpler and more stable across a wide range of models.
   • It avoids the internal complexity that can cause the crash.
2. Avoid using Autosize for stratified water heater Tank height parameter
   • Manually define Tank height.
   • Ensuring this parameter is explicitly defined helps the simulation engine avoid the internal error.

Conclusion

If your simulation is crashing without a clear error message, and the error log is abruptly cut off, check for the use of a stratified water heater with autosized Tank height parameter. Switching to a mixed-type water heater or fully specifying the Tank height should allow the simulation to run successfully and restore standard error reporting behaviour.

See also: https://designbuilder.co.uk/helpv7.3/#WaterHeaterStratified.htm