Unitialized EMS variable is misused

[shorowit]

Issue overview

The provided IDF has an EMS program like so:

EnergyManagementSystem:Program,
  ev_discharge_program,                   !- Name
  Set power_mult = (1.412768*(site_temp_adj^0))+(-0.03910397*(site_temp_adj^1))+(0.0009408235*(site_temp_adj^2))+(8.97156e-06*(site_temp_adj^3))+(-7.699244e-07*(site_temp_adj^4))+(1.265614e-08*(site_temp_adj^5)), !- Program Line 1
  Set site_temp_adj = site_temp,          !- Program Line 2
  If site_temp < -17.778,                 !- Program Line 3
  Set site_temp_adj = -17.778,            !- Program Line 4
  ElseIf site_temp > 37.778,              !- Program Line 5
  Set site_temp_adj = 37.778,             !- Program Line 6
  EndIf,                                  !- Program Line 7
  ...

The EMS variable site_temp_adj is being referenced before it is defined. This is supposed to be caught, but is not. If you look at the eplusout.edd file, power_mult is calculated as zero on the first timestep, suggesting that site_temp_adj was initialized as zero and used.

Operating System (Multiple choices)

Ubuntu

Operating System Version

24.04

Version of EnergyPlus

25.1

Unmethours link or helpdesk ticket number

N/A

Defect file

ems_bug.idf.txt