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Re: [EnergyPlus_Support] (unknown)




If you have economizers, you can check the System Summary report in the html file, this will tell you the actual minimum outdoor air flow of the system.  Otherwise, you could output the variables 'Air System Outdoor Air Economizer Status' and 'Air System Outdoor Air Mass Flow Rate' and compare the mass flow rates when the economizer status is disabled, or at 0.  There are probably other ways to do this but this is what came to my mind first.  I rarely use the Controller:MechanicalVentilation object.  Hope this helps.

Thanks,

Matthew Larson
303.668.2511

Big Ladder Software
2549 Irving Street
Denver, CO 80211
<http://bigladdersoftware.com>http://bigladdersoftware.com



On Thu, Mar 6, 2014 at 9:04 AM, ece k <<mailto:quecen@xxxxxxxxx>quecen@xxxxxxxxx> wrote:
>  
> Thank you for responses, then where can i check the minimum outdoor air flow rates (except from outdoor air summary tables) on html, or is there any appropriate variable output? I have checked the variables, but i couldn't find any proper one to display zone minimum outdoor air flow rates.
> 
> 
> On Thursday, March 6, 2014 2:32 PM, "<mailto:jeannieboef@xxxxxxxxx>jeannieboef@xxxxxxxxx" <<mailto:jeannieboef@xxxxxxxxx>jeannieboef@xxxxxxxxx> wrote:
>  
Note that ASHRAE 90.1 App. G says that the minimum fresh air requirements should be the same for both models. 
This does not mean that the systems will always deliver the minimum rates to all zones all of the time (it may be more). This is highly system dependant. E.g. If an economizer control is active or not (and is effected by zone conditions).
That being said, I don't think you should see huge differences on similar systems. 
1) use a text editor and do a text compare on all the relevant schedules and sizing:zone objects as well as the design outdoor air objects.
2) look closely at the controller:outdoorair.
Goodluck
> 
> Mit freundlichen Grüßen- Sent from my iPhone (excuse the brevity)
> i. A.
Jean Marais
b.i.g. bechtold
Tel.   <tel:%2B49%2030%206706662-23>+49 30 6706662-23
> On 06.03.2014, at 09:40, ece k <<mailto:quecen@xxxxxxxxx>quecen@xxxxxxxxx> wrote:
> 
>>  
Hi Matthew, 
>> Thank you for your response. I am already doing the same thin you explain. However, in the html outputs baseline and proposed buildings, the average and minimum outdoor air summary tables (mechanical ventilation (ach))  are totally different from each other. I am trying to equalize these columns. Additionally, i have tried to use controller:mechanicalventilation object (specified in controller:outdoorair). But, nothing has changed. What am i missing? :(

>> 
>> 
>> On Tuesday, March 4, 2014 5:51 PM, Matthew Larson <<mailto:matthew.larson@xxxxxxxxxxxxxxxxxxxxx>matthew.larson@xxxxxxxxxxxxxxxxxxxxx> wrote:
>>  
I'm happy to help.  I typically use the Sizing:Zone object with a DesignSpecification:OutdoorAir object name for the Design Specification Outdoor Air Object Name input.  Using the DesignSpecification:OutdoorAir object, you can specify outdoor air requirements for each zone.  This allows you to have the same outdoor air requirements between the baseline and proposed.  You can look up these objects in the InputOutputReference.pdf or at the following html location: <http://bigladdersoftware.com/epx/docs/8-0/input-output-reference/page-019.html#designspecificationoutdoorair><http://bigladdersoftware.com/epx/docs/8-0/input-output-reference/page-019.html#designspecificationoutdoorair>http://bigladdersoftware.com/epx/docs/8-0/input-output-reference/page-019.html#designspecificationoutdoorair
>> 
>> Thanks,
>> 
>> Matthew Larson
>> 303.668.2511
>> 
>> Big Ladder Software
>> 2549 Irving Street
>> Denver, CO 80211
>> <http://bigladdersoftware.com/>>> <http://bigladdersoftware.com/>>> http://bigladdersoftware.com
>> 
>> 
>> 
>> On Tue, Mar 4, 2014 at 7:14 AM, ece k <<mailto:quecen@xxxxxxxxx><mailto:quecen@xxxxxxxxx>quecen@xxxxxxxxx> wrote:
>>>  
Hi Matthew, thank you for your response. 
>>> Is it possible that you have an idea about how it can be set outdoor air flow rates identical both in proposed and baseline buildings using energyplus?
>>> 
>>> 
>>> On Friday, February 28, 2014 6:10 PM, Matthew Larson <<mailto:matthew.larson@xxxxxxxxxxxxxxxxxxxxx><mailto:matthew.larson@xxxxxxxxxxxxxxxxxxxxx>matthew.larson@xxxxxxxxxxxxxxxxxxxxx> wrote:
>>>  
You're at the right table, Table 6.8.1A "Electronically Operated Unitary Air Conditioners and Condensing Units".  You'll want to use the "Air conditioner, air cooled" equipment type followed by the correct size category based on the calculated design capacity of the coil.  The Heating Section Type is referring to the heating coil in the unit, which effects the minimum efficiency requirement of the cooling coil.  As an example, if you have a packaged unit (System 3) that is calculated to have a design capacity of 120,000 Btu/h for the DX cooling coil and a fossil fuel furnace for heating, you'll set your cooling coil efficiency to 11.0 EER, or approximately 3.2 COP.
>>> 
>>> Matthew Larson
>>> 303.668.2511
>>> 
>>> Big Ladder Software
>>> 2549 Irving Street
>>> Denver, CO 80211
>>> <http://bigladdersoftware.com/>>>> <http://bigladdersoftware.com/>>>> http://bigladdersoftware.com
>>> 
>>> 
>>> 
>>> On Fri, Feb 28, 2014 at 6:10 AM, ece k <<mailto:quecen@xxxxxxxxx><mailto:quecen@xxxxxxxxx>quecen@xxxxxxxxx> wrote:
>>>>  
Hi,
>>>> 	>>>> We have modelled a baseline building according to ASHRAE 90.1 2007 and the building has system 7 and system 3 for the zones which thermal loads are significantly different from the rest of the building. According to the LEED review comments, we have to select the efficiency values from 6.8.1A Table for the dx cooling coils. However, in this table the COP values are specified for the heating coils. Which section from the ashrae 90.1 2007 should be used for dx cooilng coils of system 3? Any suggestions?
>>>> 
>>>> qcn
>>>> 
>>> 
>>> 
>>> 
>> 
>> 
>> 
> 
> 
> 




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