Different results while using ideal air loads and actual hvac system?

asked 2016-07-25 23:24:37 -0600

siddharthpatil5's avatar

updated 2017-05-06 08:30:51 -0600

__AmirRoth__'s avatar

I don't know if this question is asked before or not, I tried searching it but couldn't find the exact answer. I am modelling a single zone room using an ideal air loads system. Also tried using a actual hvac system to the same zone using Rooftop unit. Why are the annual heating/cooling loads using a hvac system less than the ideal air load system?( for eg. with ideal air loads district heating load 7.8 Mbtu and for system using rooftop unit 2.7 Mbtu). why a huge difference?

thanks,

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Hard to pinpoint exactly without seeing your file, but what heating device is used on your rooftop unit? I'm gonna go ahead and guess a Coil:Heating:DX:SingleSpeed.

Julien Marrec's avatar Julien Marrec  ( 2016-07-26 00:15:11 -0600 )edit
1

I would agree here it is to do with the efficiency of the heating and cooling equipment, they are set to 1 in the ideal loads and can be anything from 0.8 to 6 in the systems.

Annie Marston's avatar Annie Marston  ( 2016-07-26 14:47:29 -0600 )edit

@Julien Marrec, I am currently using natural gas as heating unit for rooftop hvac. Can you send me your email Id so that I can email you my osm file. Thanks

siddharthpatil5's avatar siddharthpatil5  ( 2016-07-27 23:41:49 -0600 )edit

Can you upload it somewhere (box, dropbox, google drive, whatever) and post the link in your post?

Julien Marrec's avatar Julien Marrec  ( 2016-07-28 03:51:43 -0600 )edit

osm file googledrive locations: https://drive.google.com/open?id=0B3a...

the heating and cooling loads while using a hvac system should be higher than ideal air loads system or should it be other way around?

siddharthpatil5's avatar siddharthpatil5  ( 2016-07-29 23:26:12 -0600 )edit
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