- I think you are correct that a PTAC in EnergyPlus cannot vary outdoor air amount between occupied and unoccupied periods; it's a fixed amount, although it can differ between heating and cooling modes.
- Baseline systems are required to match the flow rate (cfm or m3/s) of the Proposed systems, and outdoor airflow during unoccupied periods must be zero for the Baseline system. (This is not very explicit in Standard 90.1, but the LEED Minimum Energy Performance Calculator clearly requires it.)
- If you create an AHU which is equivalent to PTAC, that should be perfectly valid. Details which should match typical PTAC are:
- fan power per ASHRAE 90.1
- EER / COP per ASHRAE 90.1
- The LEED reviewer won't know which part load performance curves that you choose for the DX coil, but I recommend using a curve set which is appropriate for PTAC
ÂHi all,
I meet difficulty to model ASHRAE 90.1 baseline system #1 (packaged terminal air conditioner) in EnergyPlus to match minimum outdoor ventilation rate with proposed design, which is required by 2007 version G3.1.2.5. My proposed design requires the ventilation of outdoor air flow during occupied hours, but needs to set OA flow rate to 0 during unoccupied hours.
It looks like this cannot be controlled in terms of using schedules in EnergyPlus. My question is, if it is possible for me to use an AHU (CAV, DX cooling coil, hot water coil) in baseline model instead of a PTAC system so that LEED could take it as a valid approach?
I would like very much to receive advice/comments from your experience gained from LEED projects. Thank you very much indeed.
Sean
--James V Dirkes II, PE, BEMP, LEED AP
CEO/President
The Building Performance Team Inc.
1631 Acacia Dr, GR, Mi 49504
Direct: 616.450.8653
jim@buildingperformanceteam.com
Website l  LinkedIn | May 2016 ASHRAE Journal article on energy modeling
When shouldering your personal pack of life's burdens, bring a pocket full of grit and a bucket full of joy.
__._,_.___
Posted by: Jim Dirkes <jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx
The EnergyPlus web site is found at:
http://www.energyplus.net/
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.