[Equest-users] peak heating demand

[Arpan Bakshi]

Deepika

Sizing is based only on peak load or what is also called design load.

Building A could have a peak load which is half of Building B, but if  
Building A is running its systems at peak capacity 24/7, its annual  
energy use could be many times that of Building B.



Arpan Bakshi, LEED AP BD+C
YRG sustainability

On May 18, 2011, at 5:44 PM, deepika khowal <deepika.khowal at gmail.com>  
wrote:

> Thanks Alex
> I think the explanation you gave was very clear.
> so when we design HVAC system, which loads we should consider?
> for windows with better R-values, the peak load may b lesser but its  
> overall annual demand will be higher.
> how to account for this in HVAC sizing?
>
>
> On Wed, May 18, 2011 at 12:02 PM, Alex Krickx <akrickx at seriousmaterials.com 
> > wrote:
> Hi Deepika,
>
>
>
> I’m not sure how eQUEST calculates loads, but I can imagine a scenar 
> io where your results make sense:
>
>
>
> Peak heating load probably happens at night/early in the morning,  
> right? So it probably depends on insulation (R-value) and not solar  
> gains (SHGC). My guess is the window with the higher peak demand has  
> low R-value (since you need lots of heat to make up for losses). But  
> this window could have a high SHGC, so when the sun is out you  
> benefit from passive heating (and have lower annual heating demands).
>
>
>
> I’m guessing your other window (with lower peak heating) has a bette 
> r R-value - it retained heat better. This window may have a lower SH 
> GC (possibly due to additional low-e coatings) and so it get less pa 
> ssive heating throughout the year and needs more heat to be added to 
>  the building during daytime hours.
>
>
>
> This will depend on the windows you’ve modeled, building type and cl 
> imate. Perhaps if you share some more info on the project the answer 
>  will present itself.
>
>
>
> Regards,
>
> Alex Krickx
>
>
>
> Alex Krickx, LEED AP
>
> Building Energy Specialist
>
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>
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>
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> From: equest-users-bounces at lists.onebuilding.org [mailto:equest- 
> users-bounces at lists.onebuilding.org] On Behalf Of deepika khowal
> Sent: Wednesday, May 18, 2011 11:19 AM
> To: equest-users at lists.onebuilding.org
> Subject: [Equest-users] peak heating demand
>
>
>
> Hi all
>
> I am modeling the performance of different glazing types in a  
> building.
>
> I realized for one glazing, the peak gas demand is lower than other  
> glazing but total heating energy is higher?
>
> how does equest calculate these loads and energy?
>
> Thanks
>
>
>
>
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