[Equest-users] Fw: Fw: insufficient heating capability

[Brad Robinson]

Hi Jeremy,


Yes there are a few areas with significant glazing, although the majority of the areas have relatively small glazing areas. The building is located near Toronto, so yes heating is required in winter. For one zone, the perimeter heating consists of radiant panels. Almost all rooms within this zone show this warning.  


The 2nd zone is a VAV system that does not have any reheat or baseboards, so I would expect this warning to pop up.  


My question still is should this not show up as unmet heating hours in the SV-R report if there is a heating problem?  Both zones have almost zero unmet heating hours. 

Thanks.



________________________________
From: Jeremy Poling <Jeremy.Poling at transwestern.net>
To: Brad Robinson <brad.robinson at yahoo.com>; equest-users at lists.onebuilding.org
Sent: Monday, July 25, 2011 10:16:47 AM
Subject: RE: [Equest-users] Fw:  insufficient heating capability


By chance, does the building have a significant amount of glass at the exterior in a climate where heating is required at some point during the year?  I have seen this warning persist in energy models of buildings where the envelope load is unsatisfied due to lack of baseboard heat.  This is a design issue, though, and should probably be brought up to the system designer instead of tweaked in the model until it goes away.  Cost and aesthetics are often used as reasons to eliminate baseboard heat, whereas the energy model and some basic ASHRAE 55 calcs may show that to be a bad choice (or at least give the energy modeler and the system designer a CYA when the occupants start complaining).
 
Just a thought…
 
Jeremy R. Poling, PE, LEED AP+BDC


 
From:equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Brad Robinson
Sent: Monday, July 25, 2011 6:48 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Fw: insufficient heating capability
 
 
 
I am not clear what this warning is saying as the wording is "MIGHT" have insufficient heating capability.  I too am getting this warning, but I have very little unmet heating hours. Increasing the cfm/sq.ft only increases total energy use but does not get rid of the warning.  It seems to me it may be a software issue rather than a design issue?
 
 

________________________________

From:DongEun Kim <equested at gmail.com>
To: Carol Gardner <cmg750 at gmail.com>
Cc: equest-users at lists.onebuilding.org
Sent: Monday, July 25, 2011 7:12:44 AM
Subject: Re: [Equest-users] insufficient heating capability
Thank you Carol!
 
I modified "Min Design Flow(cfm/ft2) .
 
However, "insufficient heating" warning is keep showing. 
 
Only thing seems to work to solve this problem is to increase heating capacity is Reheat delta T.
(Its system is VAV with Reheat).
 
What I can't understand the most is that specifying heating capacity of main heating coil doesn't 
 
affect the heating capacity anyhow.
 
Any thoughts on this anyone???
 
Thank you!
 
DE
 
2011/7/25 Carol Gardner <cmg750 at gmail.com>
Hi DE,

If you look around at all the defaults you will probably find that somewhere eQUEST is
 defaulting to 0.5 cfm/sf for your supply air. This is often insufficient to meet your heating/cooling requirements. Things I have done in the past to fix this is to use the same cfm/sf as the proposed building uses, or look in the little ASHRAE Pocket Guide for what they recommend for your building type. These two numbers will likely be similar

Carol. 
 
On Sun, Jul 24, 2011 at 5:16 PM, DongEun Kim <equested at gmail.com> wrote:
Thank you John,
 
But isn't airflow supposed to be auto-sized if not specified?
 
I intentionally leave the flowrate blank to let the program calculate the cfm that serves load the best.
 
Should still  I specifiy cfm?
 
DE
2011/7/23 John Aulbach <jra_sac at yahoo.com>
Try increasing airflow.
 
From:DongEun Kim <equested at gmail.com>
To: equest-users at lists.onebuilding.org
Sent: Friday, July 22, 2011 12:13 AM
Subject: [Equest-users] insufficient heating capability
 
Hi eQuesters!
 
Can anyone help me here?
 
I installed main heating coil as well as reheat coil with delta T=30.
 
Heating capacity and cfm is not defined so that they will be auto-sized.
 
And, I keep having this warning saying that the system "might have insufficient heating capability."
 
I increased "Zone Entering Max Supply Temp", "Hot Deck Max Leaving Temp."  But, the problem stays.
 
 
How do I increase the heating capability?
Thank you !!
 
DE
 

 
 
 
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-- 
Carol Gardner PE
 

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