[Equest-users] Hot Deck Leaving Air Temperature Incorrect

[Bruno Lee]

The "Temp of air leaving heat coil" is in fact not applicable for most  
system types including VAVS (see attached). For VAVS, it is the "Temp  
of air leaving cool coil" that does the "heating" work. Just pick any  
hour from your hourly report, with some hand calculations (a few heat  
transfer / mass flow equations), you will be amazed to find that the  
"Temp of air leaving cool coil" is indeed doing all the "heating".

Bruno Lee
M.S. Student
Department of Architectural Engineering
Penn State University


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On Sep 26, 2008, at 3:55 AM, Xavier Garc?a Casals wrote:

> I have also found very strange results on the hourly reports of  
> heating coil temperature, cooling coil temperature , and coil  
> entering temperature. Often the reported values do not make much  
> sense, and depending on the system type the nosense is in one way or  
> in another. In general, it seems the 'entering coil temperature'  
> gives the right value for the mixing of return and OA air. The 51?F  
> for the heating coil temperature looks like a standard for this  
> hourly output (almost always the same). It always alarms rather a  
> lot to find these numeric values without sense (you can't help  
> thinking what about the other values you are using to take important  
> desitions from your simulation results...), but I have done some  
> testing and it seems that energy values are on the right direction  
> in spite of this wrong reported coil temperatures (whe baseboards  
> are present energy values do not fit as good as with coil heating,  
> but still it goes on the right direction).
> So, I would think this afaire is mostly a bug in reporting those  
> variables, but it would be nice if one of those involved in eQuest  
> development could confirm this point.
> Regards,
>
> En/na Doebber, Ian ha escrit:
>>
>> For a strange reason, during the Winter Time (cold outside air at  
>> ~35 F and return air at ~70 F) result in Mixed Air ~60?F that needs  
>> to be heated up.
>>
>> Even though the Mixed Air entering the Unit is ~60?F the air  
>> temperature leaving the Heating Coil is constantly 51 F despite the  
>> Central Heating Coil consuming around 40 kBtu/hr.
>>
>> Is there simply a reporting bug or is this indicative of a larger  
>> bug that the Heating Coil is consuming energy but not providing any  
>> heat.  As a result, my Electric Resistance Reheat at the VAV Boxes  
>> is huge.
>>
>> Any suggestions on how to properly turn on my HHW Coil would be  
>> very appreciated.
>>
>> Regards
>> Ian Doebber
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>>
>>
>>
>
> -- 
>
> Xavier Garc?a Casals
>
> Sistemas Solares, Eficiencia Energ?tica e Ingenier?a Bioclim?tica
> AIGUASOL INGENIER?A
>
> Sistemes Avan?ats d?Energia Solar T?rmica SCCL
> C/ Palermo, 17. Bajos dcha. 28043 Madrid
> Tel: (+34) 91 142 27 88
>
> C/ Roger de Ll?ria,  29 3r 2a 08009 Barcelona
> Tel: (+34) 93 342 47 55  Fax: (+34) 93 342 47 56
>
> Mobil: 660 22 94 45
> xavier.garcia at aiguasol.coop
> http://www.aiguasol.coop
>
>
>
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