Natural Night Ventilation in Office Buildings: Performance Evaluation Based on Simulation, Uncertainty and Sensitivity Analysis

Sinds 1 januari 2006 is in de Europese Unie de richtlijn betreffende de energieprestatie van gebouwen van kracht. Hiermee beoogt de EU het energieverbruik terug te dringen en aan de Kyotonormen te voldoen. De gebouwsector is immers verantwoordelijk voor 40% van het totale energieverbruik. De energieprestatie van een kantoorgebouw kan o.a. verbeterd worden door energie-intensieve koeling of ‘air conditioning’ te vervangen door nachtelijke natuurlijke ventilatie. Hierbij zorgen wind en het schouweffect ervoor dat koele buitenlucht ‘s nachts doorheen het gebouw stroomt en daarbij de wanden afkoelt waarin de warmte van de vorige dag is opgeslagen. De prestaties van deze koeltechniek kunnen met gebouwsimulatie voorspeld worden. Niettemin bestaat er nog onduidelijkheid over de betrouwbaarheid van deze simulatieresultaten t.g.v. de aannames van de gebruiker in de invoer. Aangezien dit belangrijke gevolgen kan hebben voor het ontwerp- en beslissingproces, wordt in dit doctoraatsonderzoek een methodologie ontwikkeld die de prestaties van nachtelijke natuurlijke ventilatie met gebouwsimulatie evalueert, rekening houdend met de onzekerheden in de invoer. Hierbij worden de prestaties gekenmerkt door het bereikte thermisch comfort in het kantoorgebouw. Om dit comfort te evalueren, wordt een simulatiepakket gebruikt dat tegelijkertijd de temperaturen en de luchtdebieten in het gebouw berekent. Onzekerheids- en gevoeligheidsanalyse bepalen de invloed van de onzekerheden in de invoer. Ze berekenen zowel de variatie op het thermisch comfort als de parameters in de invoer die hiervoor verantwoordelijk zijn. Deze methodologie leidt tot praktische richtlijnen om nachtelijke natuurlijke ventilatie te ontwerpen en dit ontwerp vervolgens te evalueren. Deze richtlijnen worden toegepast op twee kantoorgebouwen in België

Análise de incertezas físicas em simulação computacional de edificações residenciais

Resumo O objetivo deste trabalho é analisar incertezas físicas em simulação computacional de uma edificação residencial e sua implicação no desempenho térmico. O experimento foi elaborado com o método de Monte Carlo, que envolve as propriedades térmicas e físicas dos materiais da edificação. Foi analisada a sensibilidade das variáveis com coeficientes de regressão e correlação. Considerou-se o critério de graus-hora de desconforto por calor e por frio para o clima de Florianópolis, SC, conforme limites de conforto térmico adaptativo. Os resultados mostraram que as incertezas obtidas nos graus-hora são relativamente grandes, sendo de 32% no desconforto por frio e de 53% no desconforto por calor. Grande parte da incerteza é decorrente da temperatura média mensal do solo. Outras variáveis, como a absortância solar da cobertura e o calor específico da argamassa das paredes, resultam em impacto relevante no desconforto por calor, bem como a massa específica da argamassa e o calor específico da cerâmica das paredes no desconforto por frio. Essas variáveis precisam de maior precisão, seja por meio de bases de dados mais confiáveis, ou mesmo por medições em campo e/ou em laboratório

Resilient cooling strategies – A critical review and qualitative assessment

The global effects of climate change will increase the frequency and intensity of extreme events such as heatwaves and power outages, which have consequences for buildings and their cooling systems. Buildings and their cooling systems should be designed and operated to be resilient under such events to protect occupants from potentially dangerous indoor thermal conditions. This study performed a critical review on the state-of-the-art of cooling strategies, with special attention to their performance under heatwaves and power outages. We proposed a definition of resilient cooling and described four criteria for resilience—absorptive capacity, adaptive capacity, restorative capacity, and recovery speed —and used them to qualitatively evaluate the resilience of each strategy. The literature review and qualitative analyses show that to attain resilient cooling, the four resilience criteria should be considered in the design phase of a building or during the planning of retrofits. The building and relevant cooling system characteristics should be considered simultaneously to withstand extreme events. A combination of strategies with different resilience capacities, such as a passive envelope strategy coupled with a low-energy space-cooling solution, may be needed to obtain resilient cooling. Finally, a further direction for a quantitative assessment approach has been pointed out

Female Audit Partners and Extended Audit Reporting: UK Evidence

This study investigates whether audit partner gender is associated with the extent of auditor disclosure and the communication style regarding risks of material misstatements that are classified as key audit matters (KAMs). Using a sample of UK firms during the 2013–2017 period, our results suggest that female audit partners are more likely than male audit partners to disclose more KAMs with more details after controlling for both client and audit firm attributes. Furthermore, female audit partners are found to use a less optimistic tone and provide less readable audit reports, compared to their male counterparts, suggesting that behavioural variances between female and male audit partners may have significant implications on their writing style. Therefore, this study offers new insights on the role of audit partner gender in extended audit reporting. Our findings have important implications for audit firms, investors, policymakers and governments in relation to the development, implementation and enforcement of gender diversity

Resilient cooling strategies – A critical review and qualitative assessment

The global effects of climate change will increase the frequency and intensity of extreme events such as heatwaves and power outages, which have consequences for buildings and their cooling systems. Buildings and their cooling systems should be designed and operated to be resilient under such events to protect occupants from potentially dangerous indoor thermal conditions. This study performed a critical review on the state-of-the-art of cooling strategies, with special attention to their performance under heatwaves and power outages. We proposed a definition of resilient cooling and described four criteria for resilience—absorptive capacity, adaptive capacity, restorative capacity, and recovery speed —and used them to qualitatively evaluate the resilience of each strategy. The literature review and qualitative analyses show that to attain resilient cooling, the four resilience criteria should be considered in the design phase of a building or during the planning of retrofits. The building and relevant cooling system characteristics should be considered simultaneously to withstand extreme events. A combination of strategies with different resilience capacities, such as a passive envelope strategy coupled with a low-energy space-cooling solution, may be needed to obtain resilient cooling. Finally, a further direction for a quantitative assessment approach has been pointed out