Studying comfort and energy usage for different room arrangements using a simplified flow pattern for highly-cooled and conventional operations

Abstract

Simulations are carried out on 2-D models representing rooms having different supply/return arrangements with flat and curved ceiling. The velocity and temperature fields are used to assess comfort and energy usage. A simplified flow pattern is deduced from the flow field. This pattern describes the flow as a main stream travelling from the inlet to the exit adhered to walls along its path, thus collecting the load directly from these walls. This main stream induces an eddy that collects the load from the rest of the boundaries and transfers this load to the main stream. When this main stream passes directly through the occupied zone, the large velocity disturbs comfort. The larger the portion of load carried directly by the main stream, the lesser is the energy use. When the inlet and exit are on the same wall, the main stream might follow a short-cut beyond certain supply angles. Curving the ceiling is seen to retard the onset of the short-cut. Keywords: Comfort, Air diffusion performance index ADPI, Effective draft Temperature CFD, Cold air system, Curved ceiling