Duct System Modeling

Goal Statement:
This task is developing a duct-analysis methodology to be used for benefits analyses in support of the 2008 Title 24 Standards (with recommendations on how to proceed over the long term using EnergyPlus or DOE-2).

Results:
Per our original schedule, there were no expenditures of funds on this task during the first year, awaiting the completion of Ernest Orlando Lawrence Berkeley National Laboratory (LBNL) research on thermal distribution systems under a different (CEC PIER-II) contract (#500-98-026). The final report for #500-98-026 is complete, and a final draft has been submitted to the CEC for comments.

We have begun assessing available simulation tools for modeling thermal losses from duct systems in large commercial buildings. This effort has included a review of past LBNL work that assessed DOE-2 capabilities for this task, a review of a recent doctoral dissertation by E. Franconi that used TRNSYS to model duct thermal losses, and discussions with LBNL and Architectural Energy Corporation staff who are currently developing models to simulate heating, ventilation, and air conditioning (HVAC) system performance for commercial buildings. The purpose of our review is to identify a modeling tool that can be used, with little or no modification, in the benefits analysis task of the Efficient Distribution Systems project. Preliminary indications are that the preferred path is to build on the Franconi efforts using TRNSYS. We have excluded EnergyPlus from our review because it currently has no capabilities to model duct system thermal losses, and modifying it for the benefits analysis is not practical in the short time period that is available.

Downloads and Links:

• "Duct Thermal Performance Models for Large Commercial Buildings", C.P. Wray, LBNL. October 2003. (3.7 MB, 112 pp)
   
• CEC PIER-II contract (#500-98-026)

Contact: Craig Wray, Lawrence Berkeley National Laboratory (LBNL), (510) 486-4021