[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [EnergyPlus_Support] Cooling load calculation in naturally ventilated zones





System capacity calculations should only include leakage infiltration. You can't size a zone with the windows open. Consiquently, occupants will often be uncomfortable whilst they ventilate. The desision to ventilate depends on many factors. To start, checkout the new object

AirflowNetwork:OccupantVentilationControl

You could additionally write an EMS to increase opening probability based on CO2 levels, etc. Check out WINDOW SIMULATION METHODS REQUIRED FOR MANUAL WINDOW VENTILATED BUILDINGS


2015-07-22 15:28 GMT+02:00 farhang.tahmasebi@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx>:
 

Dear all,


My question seems to be simple but has preoccupied me for a while:


Is it a credible approach to calculate annual cooling demand (using the idealLoadsAirSystem) for a naturally ventilated zone (with cooling system operation and natural ventilation at the same time)?


One may argue that when a zone is being air conditioned, the occupants are not supposed to naturally ventilate the room (and if they do, it increases the cooling demand). Therefore it does not make sense to conduct such a simulation and talk about cooling demand as a performance indicator for naturally ventilated buildings. 


But, as far as I know, in EnergyPlus, at each time step first the room air is mixed with the specified amount of outdoor air provided via natural ventilation or infiltration, and then the ideal system calculates the required cooling energy to cool the indoor air down to the cooling set point.


If so, would it be valid to use a ZoneVentilainDesignFlowRate object (with appropriate temperature thresholds to activate natural ventilation) and Ideal load air system to see the potential of natural ventilation in reducing the building cooling demand?


I would be very grateful, if you comment on this.


Regards,

Farhang


Farhang Tahmasebi

University Assistant, MSc

TU Wien

Department of Building Physics & Building Ecology

Karlsplatz 13, 1040 Vienna, Austria
Tel: +43 1 58801 270 31
e-mail: farhang.tahmasebi@xxxxxxxxxxxx





__._,_.___

Posted by: Jean Marais <jeannieboef@xxxxxxxxx>


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.




Visit Your Group
Yahoo! Groups
PrivacyUnsubscribeTerms of Use

__,_._,___