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[EnergyPlus_Support] Re: Air Curtains Modeling
Dear James,
Thank you for information provided in your reply, it is appreciated.
Hisham
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Jim Dirkes <jim@...> wrote:
>
> Hisham,
> An â??air curtainâ?? in the USA is strictly a fan that recirculates air at a door. Occasionally it has a heating source. (For some automotive applications, it is also uses 100% outdoor air!)
>
> · A recirculating fan cannot change zone air pressure, only the micro-climate pressure in the immediate vicinity of the door. (Consider the definition of 100% recirculation!)
>
> · The device normally cycles on when the door opens, and may have a minimum operating cycle time, so you will need to determine approximate operating time and reflect it in a schedule.
>
> o The fans often discharge air at high velocity (20 m/s | 4000 f/min) and are fairly low efficiency, so they use significant power.
>
> · If they have heating capacity, discharge temperature is often fixed at about 35-40C. (You should confirm this with the design engineer or temperature controls schematics)
>
> · It seems impractical to precisely account for mixing between zones, but you might assign a fraction to each of the adjacent zones. I think I would put all the energy in the â??coldâ?? zone (e.g., warehouse)
>
> Good luck! This should not be difficult for you.
>
> James V Dirkes II, PE, BEMP, LEED AP
> www.buildingperformanceteam.com<http://www.buildingperformanceteam.com/>
> Energy Analysis, Commissioning & Training Services
> 1631 Acacia Drive, Grand Rapids, MI 49504 USA
> 616 450 8653
>
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of jeannieboef@...
> Sent: Wednesday, December 11, 2013 2:26 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Cc: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: Re: [EnergyPlus_Support] Air Curtains Modeling
>
>
> If anyone has some experience modelling air curtains in e+, I would also like to know.
>
> I would guess the space is over pressurized. Check the AHUs air balances. A percentage of the heat from the unit will be locally lost without "entering" the zone proper (much like a cooker with a hood exhaust).
>
> A good place to start is a manufacturer data sheet. Keep us posted.
>
> On 11.12.2013, at 06:11, "hisham.rashrash" <hisham.rashrash@...<mailto:hisham.rashrash@...>> wrote:
>
>
> Dear all,
> I have a warehouse project where hot-water-heated air-curtains are installed over gates for storage spaces and electrically-heated air-curtains are installed over doors for offices.
>
> I am not sure how to model them. Should these be considered as internal loads? then I am not sure of what schedule to follow, also, not sure about the way I should account for mixing of cold air running into zones when gates or doors assumed open and air-curtains are running.
>
> Total power for these air-curtains is 2.5[MW]!!!
>
> Please advise.
>
> Thank you very much.
>
> Hisham
>
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