[Equest-users] Repost - how to simulate a revolving door

Thu Feb 25 09:17:48 PST 2016

Apologies for not contributing sooner(I’ve been in a busy week myself), but I notice a few critical points may have been missed in the discussion so far:

·         The numbers 90.1 cites for window (0.4 cfm/ft2 ) and door (1.0 cfm/ft2) leakage are at NFRC-400 testing conditions (75 pascals).  These represent maximum permissible infiltration in a closed state with head-on windspeed equivalent to 75 Pa.  

·         Open windows & swinging doors will infiltrate much more than closed assemblies.  The real-world problem of airflow through free openings is rather complicated depending upon many variables (including relative temperatures, windspeed direction vs. orientation, building pressurization, stack effects, whether and where other nearby openings are occurring…).  

·         Conservatively & for a back of envelope / sanity check with free openings, I might consider CFM = hourly windspeed(fpm) x free area(ft2) on an hourly basis.

·         Revolving doors by design are never “open” in the above sense – see this image from Wikipedia <https://en.wikipedia.org/wiki/Revolving_door>  if that isn’t immediately clear:

So the whole picture is perhaps a bit more complicated than you might have initially thought, but I believe you will find eQuest is generally well-equipped to tackle all of the above!

·         Your weather file has windspeed data that can be used each hour for calculations

·         Looking to your SPACE inputs for infiltration, you can read up on the variety of options for how sophisticated you want to make your simulation.  Most options do account for hourly windspeed.  In all cases, you can define an INF-SCHEDULE to account for behavior like swinging doors & windows opening.  

·         If this is all flying a little too high in complexity for your purposes/timeframe, I suggest leveraging the wizards to observe what infiltration schedules and inputs are generated using a few dummy ‘shell’ models.  Note “perimeter” vs. “core” infiltration schedules are commonly generated side by side and will be named accordingly.  

·         I’d personally prefer leveraging a custom hourly report for this sort of assessment.  Starting variables to spot check my expectations would include

o   SPACE infiltration (cfm) as calculated,

o   local windspeed

o   ZONE temperature

o   ZONE tstat setpoint 

Other thoughts:

·         Ultimately you are going to be making a “Yes/No” decision based on how the temperatures in this space float.  Step back before getting too far into the study and make some decisions regarding what would be subjectively “acceptable” comfort criteria considering anticipated atrium/staircase usage, occupancy profile, & expectations specific to your regional climate/locale.

·         High-level assessment idea, if you don’t want to assess this “manually” via hourly outputs:  You could perhaps most simply create a pair of zone temp schedules reflective of maximum comfort thresholds, then leverage simulation unmet hours inform how often & when you cross those lines.

·         At only 2 stories effects probably won’t be extreme, but keep in the back of your mind that eQuest/doe2 assumes “perfect thermal mixing” within a zone hour by hour.  If your space does not have fans or other means of consistent circulation, there’s potential for buoyancy/stack effects in the real world to result in different conditions on the 1st vs. 2nd level.

Probably more than you’re looking for… sorry for the wall of text!

~Nick

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  Senior Energy Engineer
  Energy and Sustainability Services
  North America Operations
  Schneider Electric

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From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Sharad Kumar
Sent: Thursday, February 25, 2016 3:04 AM
To: equest-users
Subject: Re: [Equest-users] Repost - how to simulate a revolving door

Hi Zarah,

As per my understanding you need to know the cooling load requirement of any space for any time.

For this one can do peak load calculations and try to find out the cooling load requirement of any space at desired time.

I have also referred ASHARE 90.1 and have found that the swinging door has 1 cfm / sq. ft. and windows have 0.40 cfm / sq .ft as infiltration.

............................................................................................................

eQUEST have the option to input the required infiltration in Internal load tab and input it in as cfm /sq. ft for the space.

The infiltration being input is the total infiltration in that space.

You need to have proper weather file as per location, have some cooling system as per project and proper infiltration as input.

Then from the hourly report being derived from the File< Export File< Hourly result (CSV) and have the finding in cooling end-use energy.

This will help you to find out whether that space at any desired time needs the cooling or not. Additionally one needs to have proper schedules.

The better software to have these kind of analyses is IES-VE but eQUEST can also help.

The design time is the cooling load having the most peak value of cooling energy in Hourly report.If the Cooling requirement is less than 300 hours over the year then may be you can ignore installing cooling system.

If it is for the major part of year then you can choose to have cooling system. Also have a go on the cooling plant requirement size.

Hope this can be helpful.

Thanks,

Sharad. Kumar.

Green Horizon Consulting LLP.

Gurgaon.

2016-02-24 5:17 GMT+01:00 zhouzarah <zarahzhou at hotmail.com>:

Dear eQuesters,

Sorry for the repost! I do need your help about this due to time limit. If any one can give a hint, I really appreciate that!

My client requires to do a thermal simulation for a two-story atrium/staircase to check if the cooling system is required for it. The atrium has a revolving door, which revolves once every 30 minutes, and the swing door opens for 30 minutes every 8 hours for shift change. My question is how to simulate the revolving door and swing door in eQuest? I noticed that ASHRAE 90.1-2010 mentioned the infiltration from these two types of doors is 1.0 cfm/ft2 tested at a pressure of at least 1.57 pounds per square foot (psf), but I do not quite understand what this means and how to use this number in my model. If any one has an idea, please give the comments. Thank you so much!

Best regards,

Zarah 

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