Analysis of a simple mixed-mode ventilation system in buildings
Authors
Citation
Building journal Hong Kong China, May, 2002, pp. 87-89
Abstract
As a new emerging technology, mixed-mode ventilation systems utilise both natural and mechnical forces to derive air flow in buildings. Mixed-mode systems present new challenges for engineering analysis and design. This paper derives new analytical solutions for a very simple mixed-mode system in a building with two openings and with either supply or exhaust fans. The resulting combined ventilation flow rates are presented. The effects of the two opening areas and the strength of the mechanical fan are studied. We establish the conditions for seitching of the flow direction in one of the ventilation opeining. These new analytical solutions are also used to evaluate the commonly used quadratic superposition method recommended in the existing ASHRAE standard for calculating the combined ventilation flow rate when both natural and mechanical forces exist.
(1) Introduction
(2) Buoyancy-driven natural ventilation
(3) Quadratic superposition formula
(4) A simple mixed-mode system
(5) Analysis and discussion
(6) Conclusions
(7) Acknowledgement
(8) References
Description
Subject
Type
Article
Format
Date
2002
Language
en