Re: [EnergyPlus_Support] Re: (Still) airflow balances!

[Fred Buhl <wfbuhl@xxxxxxx>]

Thanks Ana; that seems clear - now let me think about it.

Fred Buhl

anarui.oliveira wrote:
> Zone 1 gets its supply air from a CAV central system with heat 
> recovery.
> Part of the airflow supplied to Zone 1 is collected again and 
> becomes return airflow, passing through the central heat exchanger 
> before being discarded. The remaining airflow is supposed to pass to 
> the adjacent Zone 2 simply by pressure difference.
> In Zone 2 there is just an exhaust fan (in the project), which keeps 
> this zone in depression and forces air renovation.
>
> Thank you for the patience,
> Ana.
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Fred Buhl <wfbuhl@...> 
> wrote:
>   
>> Ana,
>>
>> I guess we don't understand what you are trying to simulate. You 
>>     
> have 2 
>   
>> zones,
>> one of which gets supply air. Just tell us what happens to this 
>>     
> air after it
>   
>> is supplied to the 1st zone. Don't explain it in terms of 
>>     
> EnergyPlus, 
>   
>> just tell us
>> what you actually want to happen. Are there any real exhaust fans, 
>>     
> or 
>   
>> did they get
>> introduced as an attempt to model the actual situation? Just 
>>     
> explain 
>   
>> what the system
>> is that you are attempting to model (maybe you did this already, 
>>     
> but 
>   
>> please do it again).
>>
>> Fred Buhl
>>
>> anarui.oliveira wrote:
>>     
>>> Thank you all for your previous answers, and please tolerate my 
>>> insistence...
>>> I see your point about balancing airflows in the source zone, 
>>>       
> and I 
>   
>>> think I've got that covered.
>>>
>>> ...But, returning to a simple example of 2 zones:
>>> - one conditioned (Zone 1), with forced supply air (which can be 
>>> modelled by E+ system and zone level objects)
>>> - and another unconditioned (Zone 2), which:
>>>    - receives some airflow by depression from the conditioned 
>>>       
> zone 
>   
>>> (here I would use a Mixing object(source Zone 1, target Zone 2), 
>>>       
> and 
>   
>>> an exhaust fan in Zone 1 (a plain E+ Exhaust fan, no tricks), 
>>>       
> just 
>   
>>> to make sure that the source zone also feels the effect of 
>>>       
> losing 
>   
>>> that amount of conditioned air)
>>>    - but then in the unconditioned zone, the HVAC project says 
>>>       
> there 
>   
>>> will also be a regular, forced exhaust airflow (although there 
>>>       
> is no 
>   
>>> mechanical air supply directly to this zone), and it is this 
>>>       
> part, 
>   
>>> this exhaust... this balance at the unconditioned zone (which is 
>>>       
> the 
>   
>>> target zone for the mixing object), that I don't quite see how 
>>>       
> to 
>   
>>> implement...
>>>    - and should I care?... It's not very clear to me, but I 
>>>       
> seems 
>   
>>> that if I do force the exhaust of that amount of air, the 
>>> unconditioned zone will continuosly lose some its partially 
>>> conditioned air (energy), at the same time as it receives new 
>>>       
> air 
>   
>>> from the adjacent zone, while if I don't balance it, it seems it 
>>> continuosly accumulates warm air and only loses heat through the 
>>> envelope?...
>>>
>>> Sorry, I have the feeling I'm not making myself very clear, 
>>>       
> but...
>   
>>> ... again, any additional hint would be greatly appreciated!
>>>
>>> Ana.
>>>
>>>
>>> ------------------------------------
>>>
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>   
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>>>       
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>   
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>>>
>>>
>>>
>>>
>>>       
>
>
>
> ------------------------------------
>
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>
> Attachments are not allowed -- please post any files to the appropriate folder in the Files area of the Support Web Site.
>
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>
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>   


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