The set of outputs that describe the Zone Air Balance was expanded to include a category of missing system output. Zone Air Balance System Convective Gains Rate output added for non-air equipment such as convection from baseboards. (CR #8983)

[axelstudios]

Baseboard heat appears to be missing from Zone Air Balance variables - and thus from Sensible Heat Gain Report

Added on 2012-09-18 10:04 by @mjwitte

Description

MJW 18 Sep 2012 So, while trying to give an answer on this ticket (user trying to balance heat flows), I see that the baseboard heat output is not showing up in the Sensible Heat Gain Summary Report. This file has ZoneHVAC:Baseboard:Convective:Electric for heat.

According to the I/O Ref, the "HVAC Input Sinsible Air Heating/Cooling" columns use output variable "Zone Air Balance System Air Transfer Rate".

So, is the convective output from baseboard heat completely missing from the "Zone Air Balance *" group of variables?

If the convective portion is added to ""Zone Air Balance System Air Transfer Rate" then where do we put the radiant portion from baseboards in the Sensible Heat Gain Components summary report?

Point this to Brent first to confirm is baseboard heat is missing from zone air balance variables.

Inputs: 8983-* Weather: Chicago (sorry - gotta run - test file could be improved to use rates instead of energy, and should make one that include convective/radiant baseboard as well)

[BG 9-19-2012] looking at the code it does appear to be missing for the convective portions of all baseboards. The high temperature radiant systems convective portion is included in "Zone Air Balance Internal Convective Gains Rate ." The baseboard's convective heating is actually added to zone air balance via NonAirSystemResponse term. The intent for "Zone Air Balance System Air Transfer Rate" would not cover this -- only air inlet node type system air. Could either include NonAirSystemResponse term in "Zone Air Balance Internal Convective Gains Rate " or add a new output called something like "Zone Air Balance System Convective Gains Rate"

[BG 9-20-2012] checked in source to add ôZone Air Balance System Convective Gains Rateö for non-air system response terms in air heat balance. Moved high temperature radiant system convective gains from ôZone Air Balance Internal Convective Gains Rateö to the be on the new output variable. Modified predefined report called SensibleHeatGainSummary to include this new term in system gains.

Further Details for Users

The missing non-air system output was also added to the SensibleHeatGainSummary predefined report. Non-air system output includes the convection portion of baseboards, the added convection from cooled beams, and the output from refrigeration zone chiller sets.

External Ref: Ticket 6410 Addressed in 12.09.20 V7.2.0.005 by Brent Griffith Last build tested: 12.09.05 V7.2.0.004

[BobHenninger]

RHH went back and looked at this CR in Jan 2014 which had been pre3viously looked at in Sep 2012 and marked as follows:

FIXED??? - When comparing reports for v7.2.0.004 vs v7.2.0.005, the following changes in the Sensible Heat Gain Report were observed

For "HVAC Input Sensible Air Heating" -- values changed from 0.0 to 50.361 For "Opaque Surface Conduction & Other Heat Addition" -- values changed from 27.943 to 0.0 For "Opaque Surface Conduction & Other Heat Removal" -- values changed from 0.0 to -22.368

Got same results with v8.1

[mjwitte]

Looks like BG added a new output variable "Zone Air Balance System Convective Gains Rate" as part of this fix. Would be good to add this to the test file and see if it has the expected values in it (should match the baseboard heat output, I think).

[BobHenninger]

Took the v8.1 idf file and added "Zone Air Heat Balance System Convective Gains Rate" output variable and reran with v8.1. The Zone Air Heat Balance System Convective Gains Rate values matched the Baseboard Total Heating Rate values exactly each timesetp. So based on MJW comment above, this issue appears to be fixed.