New eQuest VRF capabilities - Questions

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Hi everyone!

I have a couple questions to pose as I'm wading into the new VRF capabilities built into the new eQuest build 3.65-7175, in doe 2.3 mode. Curious if anyone else in parallel has solved any of the following, or else would like to pile on with additional queries:

1. Where in the eQuest interface can I review/edit the input for MAX-CAP/UNIT in a VRF system? I've seen repeated references to this between the SIM outputs and the reference help files, and I know the default is affected by the indoor cassette type selection (VRF-TERM-TYPE)... I just can't find the input in the airside system (PVVT), zonal inputs, or Condensing unit input windows... Probably I'm just missing it, but is it perhaps missing in the interface?

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1. Expanding on the last question, am I correct in understanding the NUMBER-OF-UNITS input within the preceding reference article for MAX-CAP/UNIT is referring to this input under "Unit Staging" in the Basics tab for Air-Side Systems? Seems from the article this could serve as a proxy for MAX-CAP/UNIT in effect...

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1. For determining thermal losses, is refrigerant line insulation an editable input for branch (airside system) and leader/header (condensing unit) refrigerant piping? Is that just a constant omitted for simplicity of inputs?
2. For illustration, is there a system diagram anywhere at present in the reference manual, similar to those provided for existing SYSTEM articles? (I'm thinking this might provide an overview of the terminology like leader vs header vs branch piping, and diagram the split between what inputs are specified at the CONDENSING-UNIT vs the airside SYSTEM)
3. I don't have the impression that the condenser inputs for AUX-POWER are intended to cover auxiliary/secondary heat sources for when a VRF's heating capacity needs an extra kick during wintertime operation. I reckon electric baseboards are the natural answer for supplemental heat at the zone, but which inputs fields are most appropriate (if any) for radiators in an outdoor unit enclosure (Literature: https://www.daikinac.com/content/assets/DOC/White-papers-/BPG-EXTAMB.pdf)?
4. Would it be possible to identify makes/models of real world equipment that the library performance curves are based upon?
... Answering my own question: Comments within the BDLLIB.DAT file (eQuest Data Directory --> ../DOE23/BDLLIB.DAT), starting on line 25094, provide some sources for the VRF library performance curves.

Here is a curve commentary reference I made for myself - may as well share:

VRF Curve Comment
VRF-FAN-EIR-FPLR $1.4 exponent for multi-speed fans
VRF-HP-Resys-ClCap-fSST&ODB $Daikin RXYMQ48MVJU, no SST dependence
VRF-HP-Resys-ClEIR-fSST&ODB $Daikin RXYMQ48MVJU, no SST dependence
VRF-HP-Resys-ClEIR-fPLR $Coefficients from Daikin for EER~11 excluding indoor fan heat
VRF-HP-Resys-Cycle-fPLR $Estimated, 1.6 minutes at 50% cycle
VRF-HP-Resys-HtCap-fSCT&OWB $Daikin RXYMQ48MVJU, no SCT dependence
VRF-HP-DefrostCap-fOWB $Daikin and Mitsubishi similar
VRF-HP-Resys-HtEIR-fSCT&OWB $Daikin RXYMQ48MVJU, no SCT dependence
VRF-HP-Resys-HtEIR-fPLR * no comment *
VRF-HP-Resys-Crankcase-fPLR $Used for both heating and cooling
VRF-EP-Cap-fSDT&SST $From EnergyPlus sample input - high speed curve
VRF-EP-EIR-fSDT&SST $From EnergyPlus sample input - high speed curve
VRF-EP-EIR-fPLR $From EnergyPlus sample input, refitted - Ratio & DT
VRF044-Cap-fSST&SDT $DanFoss VZH028-035-044
VRF044-EIR-fSST&SDT $DanFoss VZH028-035-044
VRF044-EIR-fPLR $DanFoss VZH028-035-044
VRF088-Cap-fSST&SDT $DanFoss VZH088AG
VRF088-EIR-fSST&SDT $DanFoss VZH088AG
VRF088-EIR-fPLR $DanFoss VZH088AG
VRF_CL_ThermLoss_fPLR&SST $From typical piping layout for 20 ton system
VRF_HT_ThermLoss_fPLR&SDT $From typical piping layout for 20 ton system
VRF_COOL_DTSAT_fSST $From typical piping layout for 20 ton system
VRF_HEAT_DTSAT_fSDT $From typical piping layout for 20 ton system

Thanks,

~Nick

[cid:image002.png at 01D47829.1A069BE0]
Nick Caton, P.E., BEMP
Senior Energy Engineer
Regional Energy Engineering Manager
Energy and Sustainability Services
Schneider Electric

D 913.564.6361
M 785.410.3317
F 913.564.6380
E nicholas.caton at schneider-electric.com

15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States

[cid:image003.png at 01D47829.1A069BE0]

Nicholas.Caton at schneider-electric.com's picture
Joined: 2016-02-26
Reputation: 0

Nick,

Here are some answers to your questions:

1. I believe Bill is correct in his response yesterday.

2. NUMBER-OF-UNITS is an alternative to MAX-CAP/UNIT. However,
MAX-CAP/UNIT will still have an effect if the total system capacity divided
by NUMBER-OF-UNITS exceeds the MAX-CAP/UNIT value. This prevents having
unrealistically high capacity handled by the refrigerant piping.

3. Refrigerant line insulation is not editable. The thickness of
insulation depends on pipe size and whether it is a liquid pipe or a gas
pipe as follows.

High Pressure Liquid Pipe:

<= 0.375 inch nominal pipe size: 0.375 inch insulation thickness

Larger pipe: 0.5 inch insulation thickness

Suction Gas Pipe:

< 2 inch nominal pipe size: 1 inch insulation thickness

Smaller pipe: 0.75 inch insulation thickness

Insulation conductivity is 0.25 Btu/hr-in-F

4. The only system diagram I have is shown below. Leader is the line from
the outdoor unit to the first branch, header is the main line from the first
branch to the last branch, and a branch is from the header to an indoor
unit.

5. The AUX-POWER represents energy for controls, not backup heating. Maybe
electric baseboards could work for supplemental. Probably should be
addressed in a future release.

Doug Maddox2's picture
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Joined: 2018-12-04
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A huge thank you to Doug and Bill for the quick responses - I have pasted both replies below for continuity and convenience with others following this thread.

I'm really excited by these developments, and with how this is likely to evolve the way I see VRF systems in particular assessed, developed, and ultimately performance-specified for handoff to the manufacturers in my circles. Pretty ground shaking stuff!

I'm definitely still scaling a learning cliff on the construction and application for the performance curves, specifically. Will probably have more questions before I get to the top.

Kind regards,

~Nick

[cid:image002.png at 01D47C17.AA1FA680]
Nick Caton, P.E., BEMP
Senior Energy Engineer
Regional Energy Engineering Manager
Energy and Sustainability Services
Schneider Electric

D 913.564.6361
M 785.410.3317
F 913.564.6380
E nicholas.caton at schneider-electric.com

15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States

[cid:image003.png at 01D47C17.AA1FA680]

Nicholas.Caton at schneider-electric.com's picture
Joined: 2016-02-26
Reputation: 0