[Equest-users] Fw: insufficient heating capability

[Brad Robinson]

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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>>>
>>>
>>
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>>
>
>
>-- 
>Carol Gardner PE
>

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