[Equest-users] How to model a DOAS serving corridors with a Chilled Water Coil

[Nicholas Caton]

Hi Julien,



I think there are multiple options that could fit the criteria you’ve
provided, more than one could work depending on circumstances of your
project…



*General* advice for “what system should I use” queries follows.

1.       Ask a few questions of the system equipment/design:

-          How the actual system is controlled – is it constant volume with
heating/cooling triggered via one space/duct thermostat only, or something
more complex?

-          Do you have just one central fan or additional fans in each zone
for independent circulation?

-          One set of central heating/cooling coils or are there separate
reheat / cooling coils occurring at individual zones?

2.       QC your work:

-          Answer for yourself how the system’s fans/cooling/heating should
operate, and when/to what degree ventilation OA is delivered

-          After initially setting up your systems/zones (or perhaps the
first set of many), perform some test runs to QC your efforts

-          Verify each intended behavior/output via hourly reporting



Considering you can generally force 100% OA and constant volume  with
system and/or zonal minimum OA/flow ratio inputs, as appropriate, peruse
the help file diagrams for systems of interest that include features of
interest.  You probably want to consider/review the articles for FC, VAVS,
and PIU.



>From your coil description, you may further consider an airside system type
to leverage a 2-pipe loop set to an outdoor snap temperature (or perhaps a
seasonal schedule) – see the operation tab under the loop in detailed edits.



Hope that helps get you started!



~Nick



*NICK CATON, P.E.*
*Owner*



*Caton Energy Consulting*
  1150 N. 192nd St., #4-202

  Shoreline, WA 98133
  office:  785.410.3317

www.catonenergy.com



*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] *On
Behalf Of *Julien Marrec
*Sent:* Monday, December 08, 2014 3:29 AM
*To:* equest-users at lists.onebuilding.org
*Subject:* [Equest-users] How to model a DOAS serving corridors with a
Chilled Water Coil



Hi,

I've got a building with a DOAS (AHU with 100% outside air) serving
corridors (no reheat, no fan in there, just ventilation grilles). The DOAS
has one coil, served by hot water in winter and cold water in summer.

There is no economizer, and the supply temperature is simply set by a
thermostat set as 70°F year round.

I have modeled DOAS before but I was using a PSZ or a PVVT. Those have DX
cooling coils, so it's not an option.

Seems like I could use MSZ or VAV for example, but I'm not sure which would
be more appropriate.


What type of system do you recommend using in my case?

How would you control it in order to get the proper supply temperature
(70°F) and avoid simultaneous heating and cooling (Is using an availability
schedule the only option?)?





Also, if you have an .inp snippet I could use to set it up correctly, I'll
greatly appreciate it!





Thanks,
Julien

--
Julien Marrec, EBCP, BPI MFBA
Energy&Sustainability Engineer
T: +33 6 95 14 42 13

LinkedIn (en) : www.linkedin.com/in/julienmarrec
LinkedIn (fr) : www.linkedin.com/in/julienmarrec/fr
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