[Equest-users] Oversized cooling

Joe Huang yjhuang at whiteboxtechnologies.com
Mon Dec 1 15:43:21 PST 2014
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Gonzalo,

The answer to your question, I believe, lies in the 
second longer part of my answer, i.e., the difference 
between LOADS loads at a fixed reference temperature 
and no OA and the SYSTEM loads at the actual room temperature
with those factors taken into account. For the mild California
climate that you simulated, these effects are quite considerable.
Without sounding like a nag, please look at the LOADS report
for the peak cooling load.

Everyone should be duly impressed that this reply is being sent by IPhone
from a hotel lobby in Shanghai China...

Sent from my iPhone 
Joe Huang
White Box Technologies
346 Rheem Blvd Suite 108D
Moraga CA 94556
(o) 1(925)388-0265
(c) 1(510)928-2683
yjhuang at whiteboxtechnologies.com

On Dec 1, 2014, at 11:29 PM, Gonzalo Lema <GLema at sumacinc.com> wrote:

> Hi Joe,
> 
> I also believe that the fan size is probably determined by the maximum heating, not the cooling, load. However, I don’t understand why after determining the airflow, it doesn’t adjust the cooling coil to have a similar capacity as the building HVAC maximum cooling load (SS-D report).
> 
> Would you like to see the input/output files?
> 
>  
> 
> Thanks for your help
> 
>  
> 
> SUMAC
> 
> Gonzalo Lema | Mechanical Engineer | LEED GA
> 
> Tel: +1.773.857.7906 Ext 7009 (Chicago, USA)
> 
> Tel: +1.305.814.8805 (Miami, USA)
> 
> Tel: +511.253.5355 (Lima, Perú)
> 
> Tel: +593.4.600.0613 (Guayaquil, Ecuador)
> Tel: + 571.3151985 (Bogotá, Colombia)
> 
> glema at sumacinc.com
> 
> www.sumacinc.com
> 
>  
> 
> From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Joe Huang
> Sent: Wednesday, November 26, 2014 3:05 PM
> To: equest-users at lists.onebuilding.org
> Subject: Re: [Equest-users] Oversized cooling
> 
>  
> 
> Without looking at the DOE-2.2 input and output files, it's difficult to give you a definitive answer, but from my experience explanations for such sizing questions can always be found with a little digging and understanding of how DOE-2 does autosizing. 
> 
> When DOE-2 does autosizing, it takes the maximum loads reported from LOADS and calculates the equipment capacity (heating, cooling, and fan) needed to meet those loads. The fact that the building is in a cool climate (Colorado Springs) has  several implications on the sizing calculation - (1) fan size is probably determined by the maximum heating, not the cooling, load, (2) fan size will also be increased significantly (1.24) due to the altitude, (3) substantial difference between the peak cooling load from LOADS and SYSTEMS, since the former is derived at a constant reference temperature with no outside air, while the latter is derived at the actual zone temperature and with outside air (e.g., economizer running earlier in the day, etc.).   To trace these differences, compare the peak loads in the LOADS reports to those in the SYSTEM reports.
> 
> Joe
> 
> Joe Huang     
> White Box Technologies, Inc.
> 346 Rheem Blvd., Suite 205A
> Moraga CA 94556
> yjhuang at whiteboxtechnologies.com
> http://weather.whiteboxtechnologies.com for simulation-ready weather data
> http://www.whiteboxtechnologies.com
> (o) (925)388-0265
> (c) (510)928-2683
> "building energy simulations at your fingertips"
> 
> 
> On 11/25/2014 11:18 AM, Sami, Vikram wrote:
> 
> Curious.
> 
>  
> 
> I do think the higher load seems to be more like what you should expect for a building this size (7501 kBTU/h = 625 tons. For a 102,000 ft2 building that’s 163 ft2/ton). That might be slightly oversized for Ft Carson, although Colorado springs gets hot in the summer. Not sure what your building loads are, but 163 ft2/ton is not unheard of for a heavy use building. I would expect something more in the range of 250-300. So the question is why is the maximum cooling load reporting as only 927 kBTU/hr (77.25 tons = 1320 ft2/ton)
> 
>  
> 
> Just my two cents from looking at this for five minutes – I might be wrong.
> 
>  
> 
>  
> 
> Vikram Sami
> BEMP, LEED BD+C 
> Associate Partner
> 
>  
> 
> ZGF ARCHITECTS LLP
> T 206.521.3509 E vikram.sami at zgf.com
> 925 Fourth Avenue, Suite 2400 
> Seattle, WA 98104
> 
>  
> 
> From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Gonzalo Lema
> Sent: Monday, November 24, 2014 12:25 PM
> To: equest-users at lists.onebuilding.org
> Subject: [Equest-users] Oversized cooling
> 
>  
> 
> Hi,
> 
>  
> 
> I have a problem with the cooling capacity. The Max cooling load is 927 kbtu/hr, but the cooling capacity is 7501 kbtu/h. I auto-sized the equipment (system and cooling coil) for 1.00, but I don’t understand why the factor seems to be 8x.
> 
>  
> 
>  
> 
> <image001.jpg>
> 
>  
> 
> <image002.png>
> 
>  
> 
>  
> 
>  
> 
> The system fan Works in part-load 0-20% all the time:
> 
>  
> 
> <image003.png>
> 
>  
> 
>  
> 
> Does anybody knows what could be causing this?
> 
>  
> 
> Thanks.
> 
>  
> 
> SUMAC
> 
> Gonzalo Lema | Mechanical Engineer | LEED GA
> 
> Tel: +1.773.857.7906 Ext 7009 (Chicago, USA)
> 
> Tel: +1.305.814.8805 (Miami, USA)
> 
> Tel: +511.253.5355 (Lima, Perú)
> 
> Tel: +593.4.600.0613 (Guayaquil, Ecuador)
> Tel: + 571.3151985 (Bogotá, Colombia)
> 
> glema at sumacinc.com
> 
> www.sumacinc.com
> 
>  
> 
> From: Dante Garcia 
> Sent: Monday, November 24, 2014 10:24 AM
> To: Gonzalo Lema
> Subject: RE: eQuest - Fort Cartson
> 
>  
> 
> Hola Gonzalo,  no he podido encontrar el error hasta el viernes que estuve avanzando.
> 
> Ahora he estado con otras prioridades, mañana puedo volver a revisar el proyecto.
> 
>  
> 
> Saludos,
> 
>  
> 
> Dante
> 
>  
> 
> SUMAC
> 
> Dante Garcia, LEED AP BD+C | Analista LEED Energía
> 
> Tel: +511.253.5355 Anexo 16 (Lima, Perú)
> 
> Cel: +51.989.685.769 (Lima, Perú)
> 
> Tel: +593.4.600.0613 (Guayaquil, Ecuador)
> Tel: + 571.3151985 (Bogotá, Colombia)
> 
> Tel: +1.773.857.7906 (Chicago, USA)
> 
> dgarcia at sumacinc.com
> 
> www.sumacinc.com
> 
>  
> 
>  
> 
> De: Gonzalo Lema 
> Enviado el: lunes, 24 de noviembre de 2014 11:17 a.m.
> Para: Dante Garcia
> Asunto: RE: eQuest - Fort Cartson
> 
>  
> 
> Buen día,
> 
> ¿Alguna novedad?
> 
>  
> 
> Yo sigo revisando también.
> 
> Saludos
> 
>  
> 
> SUMAC
> 
> Gonzalo Lema | Mechanical Engineer | LEED GA
> 
> Tel: +1.773.857.7906 Ext 7009 (Chicago, USA)
> 
> Tel: +1.305.814.8805 (Miami, USA)
> 
> Tel: +511.253.5355 (Lima, Perú)
> 
> Tel: +593.4.600.0613 (Guayaquil, Ecuador)
> Tel: + 571.3151985 (Bogotá, Colombia)
> 
> glema at sumacinc.com
> 
> www.sumacinc.com
> 
>  
> 
> From: Gonzalo Lema 
> Sent: Friday, November 21, 2014 5:52 PM
> To: Dante Garcia
> Subject: RE: eQuest - Fort Cartson
> 
>  
> 
> Como va?
> 
> Encontraste algo mas?
> 
>  
> 
> Buen finde.
> 
>  
> 
>  
> 
> SUMAC
> 
> Gonzalo Lema | Mechanical Engineer | LEED GA
> 
> Tel: +1.773.857.7906 Ext 7009 (Chicago, USA)
> 
> Tel: +1.305.814.8805 (Miami, USA)
> 
> Tel: +511.253.5355 (Lima, Perú)
> 
> Tel: +593.4.600.0613 (Guayaquil, Ecuador)
> Tel: + 571.3151985 (Bogotá, Colombia)
> 
> glema at sumacinc.com
> 
> www.sumacinc.com
> 
>  
> 
> From: Dante Garcia 
> Sent: Thursday, November 20, 2014 5:21 PM
> To: Gonzalo Lema
> Subject: eQuest - Fort Cartson
> 
>  
> 
> Gonzalo, te envío el eQuest que revisé, todavía no encuentro el error, solo edité un poco el primer piso ya que dos zonas se sobreponían, mañana seguré revisando y ver si encuentro algo, una consulta, viste este reporte, así son los cfm que deben tener cada zona o es bien alto?
> 
>  
> 
> Saludos,
> 
>  
> 
> Dante
> 
>  
> 
>  
> 
> <image004.jpg>
> 
>  
> 
> SUMAC
> 
> Dante Garcia, LEED AP BD+C | Analista LEED Energía
> 
> Tel: +511.253.5355 Anexo 16 (Lima, Perú)
> 
> Cel: +51.989.685.769 (Lima, Perú)
> 
> Tel: +593.4.600.0613 (Guayaquil, Ecuador)
> Tel: + 571.3151985 (Bogotá, Colombia)
> 
> Tel: +1.773.857.7906 (Chicago, USA)
> 
> dgarcia at sumacinc.com
> 
> www.sumacinc.com
> 
>  
> 
> ZGF Email Disclaimer 
> 
> 
> 
> 
> 
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