Re: [EnergyPlus_Support] outside air load

["Michael J. Witte" <mjwitte@xxxxxxxx>]

1. In a full HVAC system, outside air replaces return air.  So the outside air 
load is only that required to bring the outside air to room temperature.  Any 
heating or cooing beyond that point is the same whether the air originated from 
the zone or from outside.  Also, remember that during cool weather, outside air 
can be a benefit, providing free cooling.

2.  For VENTILATION to operate at any temperature condition set "Minimum Indoor 
Temperature" and "Delta Temperature" to -99C.  Confirm this by reporting the 
ventilation flow rates on an hourly basis for summer and winter design days.

Mike


On 15 May 2006 at 6:45, hbn_pch wrote:

> Dear,
>    I created a model with purchased air and determined to introduce 
> OA as infiltration or ventilation .There is an independent oustside 
> air unit in my real hvac system,so i want to gain oa load to select 
> appropriate oa unit.I encounter some problems as follows:
> 
>   1.When i introduce oa as infiltration ,according to former 
> suggestion,i can gain oa load by compare the values between the model 
> has infiltration(oa) and the model has not.But i'm puzzled at this 
> method.In real oa unit,the outside air has been cooled to 14¡æ in 
> summer and heated to 50¡æ in winter.The oa unit and air condition 
> system worked together to cool or heat the zone.But when i introduce 
> oa as infiltration ,it seemed to that the outside air is just been 
> conditioned to zone air temp by air condition system(25¡æ in summer 
> and 22¡æin winter).Although  the total load did't change,distinctly 
> the gained oa load is smaller if i used this comparative method to 
> gain oa load.Then how can i gain the real oa load?
> 
>   2.I want to introduce oa as ventilation.I don't know how to set he 
> minimum indoor temp in ventilation.Because the temp is different in 
> summer and winter.How to set the ventilation variables?
> 
>    Thanks very much! 
>    pch
> 
> 
> 
> 
> 
> 
> 
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> 
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> 
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>  
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> 
> 
> 
>  
> 
> 
> 
> 


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





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