ASHRAE 90.1 2013 Section 11 ECB Supporting document (to be used in conjunction with the 90.1 2013 PRM navigator)
The intent of this document is to outline and provide guidance regarding workflow when using the ASHRAE 90.1 – App. G PRM and ECB Navigator to complete analysis for ASHRAE Standard 90.1-2013 Section 11 Energy Cost Budget (ECB) method.
Because the PRM (Appendix G) and ECB (Chapter 11) ASHRAE rule sets are similar, using the PRM & ECB Navigator will streamline either of the PRM or ECB energy modeling exercises. In order to work effectively with this navigator to develop an ECB model, it is important to be aware of the differences between the two energy modeling rule sets. The following describes, in brief, what should be considered when implementing the ECB Method through the use of this navigator.
1. Selection of the ECB method for ASHRAE 90.1 Workflow Navigator
Action: Click the “Select ASHRAE standard” navigator action item and select the option for “ASHRAE 90.1-2013 ECB”. This will automatically cause the auto-generation of the ECB Budget model later, within this Navigator workflow and auto-generate the ECB Budget model reports.
2. A single baseline (Budget) model for ECB Method.
For the ECB method, the baseline model is referred to the Budget model and is generated and simulated only at the same orientation as the proposed. There is no option to analyze the Budget model at 4*rotated baseline models in the ECB Method. This is only available in the PRM method.
3. ECB HVAC systems
Action: Autosized prototype systems have been developed with reference to table 11.5.2-1 to accommodate the ASHRAE 90.1-2013 ECB HVAC Systems. When the “Edit current Baseline” navigator workflow is selected the relevant ECB budget system should be selected from the “ECB systems” prototype library.
4. Thermal Mass for ECB Budget Model Opaque Construction Assembly
Budget model Opaque assemblies including roofs, floors, walls, and doors are modeled using performances parameters (assembly U-value, insulation R-value, etc.) in ASHRAE 90.1 Tables 5.5 (same as PRM); however the budget assemblies are automatically modeled with the same heat capacity or thermal mass as the proposed building assemblies. This ECB approach differs from the PRM in that table G3.1 specifies the type of constructions that should be used (steel frame wall etc.).
See example below with proposed wall vs. the automatically generated and automatically assigned ECB Budget wall constructions. Note varying U-values and differing Thermal Mass.
5. Automated Reports for ECB Compliance
The 90.1-2013 Navigator automatically produces reports for ECB Compliance, as per official ASHRAE templates.
