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Re: [EnergyPlus_Support] simulating Duct efficiency without ADS model



The ADS model is designed to do exactly what you want.  For you system the 
input should be quite simple if you want to consider just thermal losses and 
ignore air leakage.  One other approach might be to create a supply plenum zone 
which has a low-resistance interzone wall between it and the basement with an 
area that matches the exposed duct area. But I am not sure if this would save 
you any effort.

Mike


On 26 Apr 2004, at 21:45, Ian Doebber wrote:

> Is there a more complicated way to simulate duct loss.  I will try specifying a
> small percentage of my conditioned air flow into the basement and have the same
> amount of air return to the system.  Yet I am interested if there were a way to
> essentially decrease the energy content of the supply air by roughly 20% say by
> changing the air temperature between when it leaves the HVAC system to when it
> enters the zones; increasing this temperature during the cooling season and
> decreasing this temperature during the heating season.  
> 
> I essentially did this in my zone and system sizing.  For example, the air
> temperature leaving the heating coil is 40.6 C and enters the zones at 36.7 C. 
> Therefore this change in temperature represents the reduction of energy of the
> supply air due to duct losses.  Looking back on this, I don't think this is a
> correct way to do this because it just causes my system sizing to be increased. 
> Thus this energy reduction will not be incorporated into the annual simulation. 
> How can I incorporate duct losses for the entire year simulation.  What other
> ways are there.
> 
> Thanks
> Ian
>   ----- Original Message ----- 
>   From: Michael J. Witte 
>   To: EnergyPlus_Support@xxxxxxxxxxxxxxx 
>   Sent: Monday, April 26, 2004 5:12 PM
>   Subject: Re: [EnergyPlus_Support] simulating Duct efficiency without ADS model
> 
> 
>   One way to model a simple duct loss is to add a DIRECT AIR terminal unit that
>   dumps a specified flow into an attic or basement zone, or a dummy zone.  The
>   receiving zone must has a return connection to statisfy the air loop
>   structure. If you expect the air to be lost, then it must be balanced with an
>   equal amount of outside makeup air in the system.  
> 
>   Mike
> 
> 
> 
>   On 25 Apr 2004, at 12:17, Ian Doebber wrote:
> 
>   > I checked out the new Air Distribution System with the latest version of
>   Energy > Plus for modeling of duct efficiency.  I am going to give it a try
>   but was also > wondering whether there were a simple way to model a 80% duct
>   efficiency.  How > can I model my air distribution system and then thermal
>   distribution system for > a heat pump and then a furnace/CAC system and
>   incorporate these duct losses. > > Thanks > Ian Doebber > Graduate Student >
>   Virginia Tech > > [Non-text portions of this message have been removed] > > >
>   > > The primary EnergyPlus web site is found at: > http://www.energyplus.gov >
>   > The group web site is: > http://groups.yahoo.com/group/EnergyPlus_Support/ >
>   > Attachments are not allowed -- please post any files to the appropriate
>   folder > in the Files area of the Support Web Site. > > Yahoo! Groups Links >
>   > > > > 
> 
> 
> 
>   ========================================================
>   Michael J. Witte, GARD Analytics, Inc.
>   EnergyPlus Testing and Support      
>   EnergyPlus-Support@xxxxxxxx
> 
> 
> 
>   The primary EnergyPlus web site is found at:
>   http://www.energyplus.gov
> 
>   The group web site is:
>   http://groups.yahoo.com/group/EnergyPlus_Support/
> 
>   Attachments are not allowed -- please post any files to the appropriate folder
>   in the Files area of the Support Web Site.
> 
> 
> 
> 
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> 
> 
> [Non-text portions of this message have been removed]
> 
> 
> 
> 
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
> 
> The group web site is:
> http://groups.yahoo.com/group/EnergyPlus_Support/
> 
> Attachments are not allowed -- please post any files to the appropriate folder
> in the Files area of the Support Web Site.
> 
> Yahoo! Groups Links
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> 
> 
> 
> 



========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx



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