Negative values of Peak Melting/Freezing Temperatures for PhaseChangeHysteresis

asked 2024-04-17 05:10:46 -0500

Zakaria's avatar

updated 2024-04-17 09:38:38 -0500

Hello everyone,

I am opening an old question here that has no answers.

I am trying to model a sub-zero-temperature PCM with phase hysteresis incorporated on the construction walls.

The PCM has melting/freezign peak temperature of -21/-22 °C. However, the following severe error occurred after running the model:

** Severe  ** <root>[MaterialProperty:PhaseChangeHysteresis][PCM_SP-17][peak_freezing_temperature] - "-22" - Expected number greater than 0.000000
** Severe  ** <root>[MaterialProperty:PhaseChangeHysteresis][PCM_SP-17][peak_melting_temperature] - "-21" - Expected number greater than 0.000000

I am using the 9.2 version of EnergyPlus, but the same error occurs when using a newer version, such as 24.1.0.

Also, reviewing the InputOutput Document (V9.2) it is defined that the Peak Melting/Freezing Temperature as the center (peak) of the melting/freezing curve, in Kelvin.. However, on the EPlauch interface, it is defined in °C.

On the other version, 24.1.0, it is mentioned in °C in both the InputOutput Document and EPlauch interface.

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I don't know if there's a reason the model prohibits negative values, but I created a feature request here. As you observed, the documentation was corrected in more recent E+ versions to show that these inputs are in Celsius.

shorowit's avatar shorowit  ( 2024-04-18 12:57:30 -0500 )edit

Thank you, @shorowit for initiating the request!

I'm not well-versed in C++, but if I want to locate where the error message ("Expected number greater than 0") is generated within the source code file, what steps should I take?

I've already examined the file but couldn't spot it.

Zakaria's avatar Zakaria  ( 2024-04-25 09:55:02 -0500 )edit

It's in the Energy+.idd file:

shorowit's avatar shorowit  ( 2024-04-25 10:00:31 -0500 )edit