Coupled analytical modelling of long-wave radiation and convection in rooms to enable better prediction of the thermal stratification
Author(s)
Gong, Pu
Hughes, Graham O
Burridge, Henry C
Type
Journal Article
Abstract
Indoor environments are continuously subject to the effects of thermal radiation: short-wave radiation that brings in solar heat, and long-wave radiation that acts to redistribute heat. However, the effects of the latter are often overlooked. To fully understand and predict the effects of long-wave radiation indoors, spatial variations in indoor temperature must be considered. This paper develops an analytical framework to describe coupled radiative and convective heat transfers within simple representations of thermally stratified rooms, a minimal description requiring only five thermally active bodies. The model, termed ‘AR5B’, predicts the coupled heat fluxes from each thermal body, enabling the effects of long-wave radiation to be simply mimicked within ventilation flow models. Data from six full-scale experiments show that predictions from AR5B are of suitable accuracy. Moreover, when the AR5B results are then used to mimic the effects of radiation within a simplified ventilation flow model, the resulting thermal stratification is reasonably predicted. We show this to be in stark contrast to comparable cases but without accounting for the effects of long-wave radiation – this finding underscores that long-wave radiation plays a significant role in determining indoor environments and should be incorporated more routinely in predictive models.
Date Issued
2026-01-01
Date Acceptance
2026-04-07
Citation
Flow, 2026, 6
ISSN
2633-4259
Publisher
Cambridge University Press
Journal / Book Title
Flow
Volume
6
Copyright Statement
© The Author(s), 2026. Published by Cambridge University Press. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
License URL
Identifier
10.1017/flo.2026.10050
Subjects
analytical model
indoor thermal stratification
long-wave radiation
Publication Status
Published
Article Number
E14
Date Publish Online
2026-06-03