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OACtrl/ThrmlZn Ventilation Control Updates #310

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
Describe the translation issue or enhancement:

The SDD properties used to describe ventilation air at the ThrmlZn and OACtrl 
have been revised/amended to facilitate the following:

ThrmlZn includes revised properties that that better map to OS/E+ 
DesignSpecification:OutsideAir.  Also, VentCtrlMthd enum as been amended to 
include 'CO2Sensors' i.e. DCV.  When any ThrmlZn have this control, the 
Controller:MechanicalVentilation Field: Demand Controlled Ventilation should be 
Yes.

Properties have been added to OACtrl to describe three methods for scheduling 
OA.  
Constant = Field: Minimum Outdoor Air Schedule Name is always 1.0

FollowAvailability = Create schedule of 1/0 that follows Parent 
AirSys:AvailSchRef, modified by AvailSchOffsetStart and AvailSchOffsetEnd 
integers, primarily to adjust for morning warm-up hours

Scheduled = Field: Minimum Fraction of Outdoor Air Schedule Name matches the 
schedule defined by OASchRef

Please provide any additional information below.

Attached are revised Sim Model.txt file for comparison to current SDD Sim 
Model.txt and a sample SDD XML file with new properties.

Original issue reported on code.google.com by da...@360-analytics.com on 11 Oct 2013 at 6:51

Attachments:

GoogleCodeExporter commented 9 years ago 
I mentioned in today's NREL call a spreadsheet that analyzed the design/min 
ventilation rates by ACM by SpaceFunction (SpcFunc); I've attached here for 
reference.

Conclusions from this analysis:
- Based on the design occupancy assumptions for each SpcFunc, there are 18 in 
which the DCV is required.
- There are only 2 SpcFuncs where the DCV is not required, and the minimum 
ventilation rate required at all times by the code (even if DCV is used) is 
less than the minimum design ventilation rated dictated by the ACM

This analysis does not address any combinations of different occupancy into one 
thermal zone, so there may be more situations where DCV is beneficial.  IN any 
case, if users primarily have thermal zones compromised of a single SpcFunc, 
there few cases where proposed DCV controls will yield lower ventilation rates 
than the baseline design.

Original comment by da...@360-analytics.com on 11 Oct 2013 at 8:35

Attachments:

GoogleCodeExporter commented 9 years ago 
Kyle has described in separate communications that the OSM code that aggregates 
Space:DesignSpecification:OutdoorAir objects into one object for translation to 
E+ needs to by updated to support both the Sum and Maximum methods. The Maximum 
method is important to correctly simulating DCV according to the rules of the 
ACM.

In follow-up discussions, some changes to the SDD have been made to support 
both methods.  Attached is an updated example file with both the Maximum and 
Sum methods described for ThrmlZns  'Wing1_Side1_Zn' and 'Wing1_Side2_Zn'.  
Here is a summary of SDD Sim Model properties and assumptions for translations:

ThrmlZn:
  VentSpecMthdSim = Enums: 'NoVentilation', 'Sum', 'Maximum'
  VentPerPersonSim = Float, cfm/person
  VentPerAreaSim = Float, cfm/area

The SDD->OS translator will assign the same DesignSpecification:OutsideAir to 
each Space that comprises the ThrmlZn.  All objects will have the same 
specification method.  The OS->IDF translator will recombine the 
Space:DesignSpecification:OutsideAir objects to the ThrmlZn, preserving the 
spec method in the E+ simulation and having the sames values as those shown in 
the SDD for ThrmlZn.  

Also attached is a spreadsheet that illustrates the rules for combining 
SDD:Space inputs into ThrmlZn properties.

Original comment by da...@360-analytics.com on 15 Oct 2013 at 12:52

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GoogleCodeExporter commented 9 years ago 
To be clear there will be no VentPerZoneSim (ccm)  property or similar in any 
model?

Original comment by kbe...@gmail.com on 16 Oct 2013 at 7:25

GoogleCodeExporter commented 9 years ago 
No, I decided it made more sense to use the PerArea description for the 
combined, not PerPerson components.

Original comment by da...@360-analytics.com on 16 Oct 2013 at 7:33

GoogleCodeExporter commented 9 years ago 
Working on the offsets for oa schedule.  All other aspects of this ticket 
should be covered.

Original comment by kbe...@gmail.com on 18 Oct 2013 at 8:33

GoogleCodeExporter commented 9 years ago 
Regarding the changes we discussed this morning, here is what I propose:

Revise the OACtrl:OASchMthd enum from "FollowAvailability" to 
"FollowHVACAvailability"
Revise the OACtrl:AvailSchOffsetStart property name to "StrtHrDelay"
Remove the OACtrl:AvailSchOffsetEnd property from the SDD, since we decided it 
was not necessary.

I'll post a test file here shortly if you guys can confirm this works for you.

Original comment by da...@360-analytics.com on 25 Oct 2013 at 7:42

GoogleCodeExporter commented 9 years ago 
Will StrtHrDelay always be positive values?

Original comment by kbe...@gmail.com on 25 Oct 2013 at 7:43

GoogleCodeExporter commented 9 years ago 
Yes. 

E+ I/O ref says for Field: Minimum Outdoor Air Schedule Name: 
This schedule is useful for reducing the outdoor air flow rate to zero during 
unoccupied or start up hours.

So perhaps the property is more intuitive as StartUpDelay, a positive integer 
of unit hour(s).

Original comment by da...@360-analytics.com on 25 Oct 2013 at 7:51

GoogleCodeExporter commented 9 years ago 
Attached is a sample XML file that reflects the following "FINAL" changes:

Revise the OACtrl:OASchMthd enum from "FollowAvailability" to 
"FollowHVACAvailability"
Revise the OACtrl:AvailSchOffsetStart property name to "StartUpDelay"
Remove the OACtrl:AvailSchOffsetEnd property from the SDD, since we decided it 
was not necessary.

For reference, here is the DESCRIPTION information in the rule:

  DESCRIPTION
    "If the OAScheduleMethod is 'FollowHVACAvailability', this positive integer 
     value indicates the number of hours that the system outside air flow is zero 
     during system start up."

Original comment by da...@360-analytics.com on 25 Oct 2013 at 8:28

Attachments:

GoogleCodeExporter commented 9 years ago 
Closing issue; translator updates complete.  Will post new issue if find bugs 
in these updates.

Original comment by da...@360-analytics.com on 9 Nov 2013 at 1:28