[Equest-users] eQUEST - new user

Josh Doherty jdoherty at dcengineering.net
Wed Mar 11 08:12:10 PDT 2009

Hi Karen,
In response to your comment about making sure you do not model closets separately, how do you treat small janitor and mech/electrical closets (small rooms)?  How you should model these areas gets complicated because of the LEED requirement that all zones must be modeled as being heated and cooled, even though these types of areas are typically supplied with just an exhaust and they "steal" some heating and cooling from surrounding spaces.  I have been grouping all these areas into one HVAC system and assigning a "dummy" heating and cooling system.  What is wrong with this approach?  Let's take for example an open office area floor plan.  Should the closets just be included in the open area zone or should they be assigned to their own zone?

Also, I am currently working on building a model of a system with active chilled beams.  I believe eQuest can closely approximate a chilled beam system with the available Induction Unit HVAC system type.  Do you have any experience using the Induction Unit to represent the active chilled beam systems?

Thanks for all your help.

Josh Doherty

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Karen Walkerman
Sent: Wednesday, March 11, 2009 8:49 AM
To: Aswan Ali
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] eQUEST - new user

Hi Aswan,

1.  This depends partly on what the model is for.  If this is a LEED model, the zones should be modeled as designed in the mechanical plan.  If it's not, you may want to simplify further, combining zones with similar uses and exposures as long as you are pretty confident that the hourly heading and cooling loads will be similar.  Definitely err on the side of simplicity and whatever you do, don't model closets separately.

2.  You can define one AHU that serves multiple spaces, regardless of where those spaces are.  You might have to do some fine-tuning in detailed edit mode in order to get everything set-up the way you want.  There is no chilled beam in eQuest.  You'll have to modify an airside cooling system to approximate the chilled beam.  Search the archives for info on how to do this.  There have been at least a few discussions on the list serve in the past regarding this issue.

3.  It's possible to model CHP systems in detailed mode.  Basically, create an electric generator, select the fuel source and select the heat reject loops.  You can adjust the performance curves to match the type of equipment you want to model.  A word of caution: eQuest does not know the temperature at which the generator is rejecting heat.  Therefore it's possible to model a generator that rejects heat at 85 F into a loop that needs to be maintained at 180 F, but this violates the laws of thermodynamics!

On Wed, Mar 11, 2009 at 6:21 AM, Aswan Ali <aswan.ali at hurleypalmerflatt.com<mailto:aswan.ali at hurleypalmerflatt.com>> wrote:

Hi all,

I've just started creating my first model on eQuest and can really do with some advice.

The project is quite complex and consists of 2 high quality office towers and an 8-storey trading and banking building.

The HVAC systems serving the 3 buildings vary from VAV, chilled beams, perimeter trench heating, AHUs with reheat to CHPs.

I have the following questions please:

 1.  What things should I consider when creating the HVAC zones?

 1.  How should I model the different HVAC systems? For example, when one or more AHUs are serving multiple floors, do I define each AHU separately and assign them to the various HVAC zones?

 1.  How can I model a combined heat and power (CHP) system?

Your help is very much appreciated.

Kind regards,

Aswan Ali
Graduate Mechanical Engineer

Building Services Division


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