Passive Cooling of buildings by night-time ventilation

Nikolai Artmann, Heinrich Manz, Per Heiselberg

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Due to an overall trend towards an increasing cooling energy demand in buildings in many European countries over the last few decades, passive cooling by night-time ventilation is seen as a promising concept. However, because of uncertainties in thermal comfort predictions, architects and engineers are still hesitant to apply passive cooling techniques. As night-time ventilation is highly dependent on climatic conditions, a method for quantifying the climatic cooling potential was developed and the impact of climate warming was investigated. Although a clear decrease was found, significant potential will remain, especially if night-time ventilation is applied in combination with other cooling methods. Building energy simulations showed that the performance of night-time ventilation is also affected by the heat transfer at internal room surfaces, as the cooling effect is very limited for heat transfer coefficients below about 4 W/m2K. Heat transfer during night-time ventilation in case of mixing and displacement ventilation was investigated in a full scale test room at Aalborg University. In the experiments the temperature efficiency of the ventilation was determined. Based on the previous re-sults a method for estimating the potential for cooling by night-time ventilation during an early stage of design was developed.

Original languageEnglish
Place of PublicationDuebendorf
PublisherSchlussbericht. Eidgenössisches Departement für Umwelt, Verkehr, Energie und Kommunikation, UVEK. Bundesamt für Energie BFE
Number of pages44
Publication statusPublished - 2008

Bibliographical note

BFE Projekt-/Vertrag-Nummer 101'308,

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