Re: [EnergyPlus_Support] Re: Limited Cooling Capacity

[Fred Buhl <wfbuhl@xxxxxxx>]

Well, that's certainly a reasonable thing to want to do. And it would be
nice to have an ideal air conditioner to do it - but we don't have one.

The only thing I can think of doing is to use a window AC with a DX
coil (Coil:DX:CoolingBypassFactorEmpirical) and make the 2 capacity
modifier curves constants.

Fred Buhl

Florian Stift wrote:
> Fred,
>
> Thanks for your quick answer!
>
> My problem is that I want to get the air temperatures of a zone with 
> a limited cooling capacity from any ideal system.
> I do not need to define any supply air temperatures or maximum flow 
> rates.
>
> Basically I just want to limit the cooling capacity to e.g. 2kW, to 
> examine the resulting zone air temperatures. I used to use BLAST, 
> where it was quite easy to do that (limit the cooling capacity in the 
> controls tab). 
>
> Do you have any idea how to simulate that within EnergyPlus?
>
> Your help is greatly appreciated.
>
>
>
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Fred Buhl <wfbuhl@...> 
> wrote:
>   
>> Florian,
>>
>> Since one  can't  set the cooling  capacity of Purchased Air  
>>     
> directly,  
>   
>> (one  can  only  set
>> the maximum flow rate) I assume you are comparing "Purchased Air 
>> Sensible Cooling Rate"
>> with "Zone/Sys Sensible Cooling Load". "Zone/Sys Sensible Cooling 
>>     
> Load" 
>   
>> is calculated
>> after the zone temperature is updated at the end of the HVAC 
>>     
> timestep; 
>   
>> "Purchased Air Sensible Cooling Rate"
>> is calculated using the zone (or return) temperature befor the 
>>     
> update. 
>   
>> If the zone temperature is
>> tightly controlled, there will be no difference. If the zone 
>>     
> temperature 
>   
>> is rising, the zone load
>> will be larger than the Purchased Air output.
>>
>> Fred Buhl
>>
>> Florian Stift wrote:
>>     
>>> I am interested in the air temperatures of a zone in response to 
>>>       
> a 
>   
>>> limited cooling capacity. I don't want to take any system loads 
>>>       
> into 
>   
>>> account.
>>>
>>> When limiting the cooling capacity using the Purchased Air 
>>>       
> Option, the 
>   
>>> air temperature exceeds its setpoints as I supposed but 
>>>       
> the "Zone/Sys 
>   
>>> Sensible Cooling Load" is higher than the limited cooling 
>>>       
> capacity. How 
>   
>>> can simulation results outrun the cooling capacity entered?
>>>
>>> Thanks for your help!
>>>
>>>  
>>>
>>>
>>>
>>>
>>>
>>> The primary EnergyPlus web site is found at:
>>> http://www.energyplus.gov
>>>
>>> The group web site is:
>>> http://groups.yahoo.com/group/EnergyPlus_Support/
>>>
>>> Attachments are not allowed -- please post any files to the 
>>>       
> appropriate folder in the Files area of the Support Web Site.
>   
>>> EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf 
>>>       
> under the Documentation link and press the "search" button.
>   
>>>  
>>> Yahoo! Groups Links
>>>
>>>
>>>
>>>
>>>       
>
>
>
>
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
>
> The group web site is:
> http://groups.yahoo.com/group/EnergyPlus_Support/
>
> Attachments are not allowed -- please post any files to the appropriate folder in the Files area of the Support Web Site.
>
> EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
>  
> Yahoo! Groups Links
>
>
>
>   


[Non-text portions of this message have been removed]



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