Workflow of Duct Sizing Utility
- The first objective is to deliver the building's required airflow rate; the process of designing and selecting a fan and ductwork for this purpose is called duct sizing.
- The second objective of an air distribution system is to minimize life-cycle cost, including initial installation costs (ducts, insulation, acoustic lining, fans, duct-mounted equipment) and operating costs (electrical and heating energy). The process of meeting this objective is called duct optimization.
While an HVAC system is routed and loaded into this utility, with the selection of a starting component, calculations occur, and missing data is highlighted visually distinct. An interactive table populates a view of data complying ASHRAE standards, such as the table of "Total Pressure Loss by Section". This utility allows you to use the interface to "walk-through" the duct system and link components to a mix of detailed design data (such as ASHRAE Fitting number) or estimated data (Loss Coefficient ~ 0.0) and continues the full calculations. Editing in many fields is available to adjust specific data such as loss coefficients for fittings to refine the re-build process. Once promoted the system will rebuild based on the values and restrictions defined within the system grid of the Automated Duct Sizing tool. After the system is balanced and pressure losses are in acceptable range, you can write to model.
Summary of Fittings per Section
While working in Duct Sizing Summary table, you can detail the design by reviewing flow parameters of the fittings in a sub table, named "Fitting Loss Coefficient Summary" (FLC table). Upon recalculate, this table summarizes Loss Coefficient values for all the fittings used in a given route. The Summary of FLC data in the Duct Sizing summary table is manipulated in the FLC Summary where detailing of system is performed. The FLC Summary dialog is accessed via double-clicking in the Summary of FLC column heading. It lists loss coefficient values for each duct component picked from the fitting database. When grouped by Duct Section lists the fitting components per section.
The table also maintains loss overrides and set correction factor for fittings used for duct system sizing computing. The columns can be filtered and narrowed down to view components of certain criteria and be revised in a batch.