Re: [EnergyPlus_Support] Controller:OutdoorAir minimums

[Walter Buhl <wfbuhl@xxxxxxxxx>]

Minimum Fraction of Outdoor Air Schedule Name is the name of a schedule whose values are flow fractions.

Minimum Outdoor Air Schedule Name is the name of a schedule whose values multiply a flow fraction.

The normal way of specifying the minimum outdoor air flow rate is through the input Minimum Outdoor Air Flow Rate.
This input is a fixed value in cubic meters per second. This input is converted to a minimum OA flow fraction
by dividing by the system design supply air flow rate. This value can then be modified by multiplying by the value
of Minimum Outdoor Air Schedule. 

Some users found the flow rate input for min OA very inconvenient. Minimum Fraction of Outdoor Air Schedule was
installed to provide an alternate method for inputting the min OA flow rate: as a fraction of the design flow rate. 
Minimum Fraction of Outdoor Air Schedule imposes a strict lower limit on the OA flow. It overrides Minimum Outdoor Air Flow Rate
and Minimum Outdoor Air Schedule. 

Fred Buhl

On Fri, Jul 23, 2010 at 1:33 PM, jvd2pe <jvd2pe@xxxxxxx> wrote:

Dear Forum,

I'm trying to make sense of the I/O Reference description for two of the fields that affect the minimum OA. (shown below)

Can someone explain how these are different from each other?

Field: Minimum Outdoor Air Schedule Name
The name of a schedule whose values are decimal fractions (0.0 ? 1.0) that multiply the minimum outdoor air fraction. This schedule is useful for reducing the outdoor air flow rate to zero during unoccupied or start up hours. If this field is not input, the minimum outdoor air flow rate remains constant during the simulation period.

Field: Minimum Fraction of Outdoor Air Schedule Name
This is an optional field with the schedule values in decimal fractions (0.0-1.0). This field enables the user to limit the minimum amount of outdoor air permissible and thus also helps in getting at least the minimum amount of air in.



------------------------------------

Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

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 currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Yahoo! Groups Links

<*> To visit your group on the web, go to:
   http://groups.yahoo.com/group/EnergyPlus_Support/

<*> Your email settings:
   Individual Email | Traditional

<*> To change settings online go to:
   http://groups.yahoo.com/group/EnergyPlus_Support/join
   (Yahoo! ID required)

<*> To change settings via email:
   EnergyPlus_Support-digest@xxxxxxxxxxxxxxx
   EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx

<*> To unsubscribe from this group, send an email to:
   EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
   http://docs.yahoo.com/info/terms/

__._,_.___

Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

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 currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.

Your email settings: Individual Email|Traditional
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe

__,_._,___