The International                        UPDATED 22nd May 2011
Journal of Ventilation
Published Quarterly www.ijovent.org.uk          Subscribe to Journal  Online 

June 2011 Edition of the IJV now Published  Call for Papers

IJV now included in the Science Citation Index

Paper 5

Accessing the Thermal Mass above Suspended Ceilings via a Perimeter Gap: a CFD Study of Naturally Ventilated Spaces

Scott Morey, David Coley and Tristan Kershaw

Centre for Energy and the Environment, School of Physics, University of Exeter Stocker Road, Exeter, EX4 4QL, UK

Abstract

There is a growing desire to reduce peak temperatures within non-domestic buildings by accessing the thermal mass of separating floors. These floors are typically formed of concrete and can store reasonable amounts of heat. Unfortunately, they are usually thermally isolated from the room below by a suspended ceiling. Therefore, some architects try to access the concrete by leaving a perimeter gap in the suspended ceiling in each room to allow airflow across the underside of the separating floor. For visual and acoustic reasons, there is the desire to make this gap as small as possible. Using computational fluid dynamics we examine the relationship between gap size and airflow above the suspended ceiling for naturally ventilated spaces.

We show that although the precise details of the airflow depends on the size of the room, levels of incidental gains, ventilation rates and the location of heat sources, in all cases increasing the perimeter width within realistic bounds results in a linear increase in the mean tangential speed of airflow across the underside of the ceiling. This is common for both single sided and cross ventilated rooms and for both single and double raft designs; however, the double raft design performs significantly better.

Key words: CFD, thermal mass, ventilation, suspended ceiling, airflow.

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Contents

Paper 1
A Study on Ventilation Systems for Removing
Indoor House Dust

Paper 2
Principles and Calibration of Solid Phase Microextraction Fibre (Passive Sampler) for Measurements of Airflow and Air Infiltration in Dwellings

Paper 3
Application of CFD in Modelling Wind-Induced Natural Ventilation of Buildings - A Review

Paper 4
Effects of Wall Shape Changes in Indoor Air Circulation - Studies on Concave and Convex Walls

Paper 5
Accessing the Thermal Mass above Suspended Ceilings via a Perimeter Gap: a CFD Study of Naturally Ventilated Spaces

Paper 6 
Use of a Stochastic Regression Model GARCH for Wind Fluctuation Study

Paper 7
Notes on Junction Coefficients