Design optimization of air distribution systems in non-residential buildings

In the present study, the effect of bend angle on pressure drop and flow behavior in a small-diameter corrugated duct is numerically investigated and experimentally validated under a fully developed flow condition. The large eddy simulation, together with the proper orthogonal decomposition (POD) method, is employed to study the pressure drop, mean flow pattern, and unsteady flow evolution for a corrugated duct with various bend angles. The results show that the pressure drop exhibits a monotonic increase with increasing bend angle. Specifically, as the bend angle increases from $$0^{\circ }$$
 to $$90^{\circ }$$
 , the pressure drop of the corrugated duct experiences a striking increase of about 43%. Accordingly, a larger bend angle is found to induce the occurrence of stronger Dean cells or larger swirl intensity downstream the duct bend. Meanwhile, as for larger bend angles, the main turbulent properties of the Dean cells could be, to some extent, governed by the first few POD modes, which appear to be featured with one or a few large-scale vortices. Generally, the larger bend angle causes stronger swirl intensity and wave-like structures, thus rendering severer pressure drop or larger pressure loss coefficient in the corrugated duct.

The effect of bend angle on pressure drop and flow behavior in a corrugated duct

Reducing the drag of midpoint lateral orifices of exhaust air ducts by shaping them along vortex zone outlines

Comparison and analysis of energy loss and flow characteristics of T-junctions via secondary flow and entropy production

Pressure loss reduction in ventilation ducts by shape optimization of the removable profiled components

Automated design procedure for duct layout has potential for further improving system efficiency. Currently, duct layout is often based on the discretion of the designer and might miss possible areas for energy improvement or meeting system targets, for example, minimal pressure drop, temperature uniformity, and contaminant removal, just to mention a few. Since the initial duct layout design can be considered as a topology problem, topology optimization methods have great potential to advance green building efficiency and design. Topology optimization has been successfully applied to various physics problems, such as structural, heat conduction, and fluidics, yet its application for the built environment, HVAC&R and its subsystems, remains highly unexplored. In the current article, the applicability of topology optimization for determining optimal duct layout is presented. A survey of successfully applied fluid topology optimization cases is presented in the article with outlooks of its applicability to i...

Ming Chang

Papers

Optimal duct layout for HVAC using topology optimization