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Not so cool roofs.

Auteurs : CARTER G., KOSASIH B.

Type d'article : Article, Étude de cas

Résumé

The dialogue in our industry around green, cool and energy-generating roofs has been elevated in recent years yet there are significant shortfalls in our industry knowledge and insufficient tools to fully understand how different roof types affect mechanical system performance. A heat-absorbing roof will warm the air layer above the roof, creating a microclimate that can then bias the roof surface, the ventilation air, and the condensing air temperatures where this equipment is located on the roof. This biasing (urban heat island) effect is ignored by the vast majority if not all load calculation and energy simulation tools our industry uses, thus we fail to account for the full impacts of conventional roofs (at worse we currently undersize AC systems) or the full benefits of cool and green roofs. Parametric three-dimensional computational fluid dynamics (CFD) analysis has been undertaken to characterise the roof microclimate as a function of the convected heat from the roof surface (what absorbs must transmit, radiate or convect), ambient wind speed, roof shape and location on the roof. These results were then used to post-process first order simulation results to estimate the overall benefit of cool roofs relative to conventional roofs. The research outcomes for the Stockland Hervey Bay shopping centre extension are presented, showing that industry simulation tools only account for 25–50% of the full energy benefit of cool roofs for larger roofs. For a conventional Zincalume roof, peak cooling loads and electrical demands are significantly impacted with an estimated 14Wr/m2 increase in cooling load and a 2We/m2 increase in electrical demand across the roof area.

Documents disponibles

Format PDF

Pages : 62-76

Disponible

  • Prix public

    20 €

  • Prix membre*

    15 €

* meilleur tarif applicable selon le type d'adhésion (voir le détail des avantages des adhésions individuelles et collectives)

Détails

  • Titre original : Not so cool roofs.
  • Identifiant de la fiche : 30023860
  • Langues : Anglais
  • Sujet : Environnement
  • Source : EcoLibrium - vol. 17 - n. 3
  • Date d'édition : 04/2018

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