Experimental investigation of heat transfer during night-time ventilation

Artmann, Nikolai; Jensen, Rasmus Lund; Manz, Heinrich; Heiselberg, Per

doi:10.1016/j.enbuild.2009.10.003

Cited by 62 publications

(33 citation statements)

References 21 publications

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“…This equation has been used by Artmann et al [17] in the previous analysis of the experiments. If the surface emissivities are around 0.8, this method accounts for about 81% of the energy emitted by the surfaces (cf.…”

Section: Establishing the Energy Balance Of The Roommentioning

confidence: 99%

“…The experiments have been performed in the same test room than the one used by Artmann et al [17] for investigating the efficiency of night-time ventilation. The test facility consists of an insulated wooden construction located in a laboratory at Aalborg University, Denmark.…”

Section: Test Roommentioning

confidence: 99%

“…A total of 34 experiments have been performed, with different air change rates (2.3, 3.1, 6.7 and 13 ACH), different ventilation types (mixing and displacement), different types of flooring (normal and low emissivity) and different inlet temperatures ( T 0 varying between 2.9 and 12.7 K, with T 0 difference between the mean temperature at the ceiling before starting the experiment and the mean inlet temperature measured during the last 10 h of the experiment). A first set of experiments has been performed by with the floor made of EPS [17]. In 2009 similar experiments have been conducted using an aluminium floor cover, in order to observe the influence of different surface emissivity on the room heat flow.…”

Section: Procedures For Experimentsmentioning

confidence: 99%

“…In a previous study [17], Artmann et al have investigated experimentally the efficiency of night-time ventilation with different types of ventilation. The results showed that displacement ventilation was more efficient than mixing ventilation for low air flow rates due to the large radiative exchange between the cold floor and the warm ceiling.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigation of convective heat transfer during night cooling with different ventilation systems and surface emissivities

Dréau

Heiselberg

Jensen

2013

Energy and Buildings

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a b s t r a c tNight-time ventilation is a promising approach to reduce the energy needed for cooling buildings without reducing thermal comfort. Nevertheless actual building simulation tools have showed their limits in predicting accurately the efficiency of night-time ventilation, mainly due to inappropriate models for convection. In a full-scale test room, the heat transfer was investigated during 12 h of discharge by nighttime ventilation. A total of 34 experiments have been performed, with different ventilation types (mixing and displacement), air change rates, temperature differences between the inlet air and the room, and floor emissivities. This extensive experimental study enabled a detailed analysis of the convective and radiative flow at the different surfaces of the room. The experimentally derived convective heat transfer coefficients (CHTC) have been compared to existing correlations. For mixing ventilation, existing correlations did not predict accurately the convective heat transfer at the ceiling due to differences in the experimental conditions. But the use of local parameters of the air flow showed interesting results to obtain more adaptive CHTC correlations. For displacement ventilation, the convective heat transfer was well predicted by existing correlations. Nevertheless the change of floor emissivity influenced the CHTC at the surface of interest.

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Section: Establishing the Energy Balance Of The Roommentioning

confidence: 99%

Section: Test Roommentioning

confidence: 99%

Section: Procedures For Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Experimental investigation of convective heat transfer during night cooling with different ventilation systems and surface emissivities

Dréau

Heiselberg

Jensen

2013

Energy and Buildings

Self Cite

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“…Various studies were implemented in the recent parts with the aim to quantify the impact of night ventilation to buildings [6][7][8][9]. The majority of these studies regarded office buildings.…”

Section: Night Ventilationmentioning

confidence: 99%

Numerical assessment of night ventilation impact on the thermal comfort of vernacular buildings

2017

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Night ventilation, is one of the most effective passive cooling techniques that may contribute to the improvement of the occupants thermal comfort conditions. Despite the justified effectiveness of night ventilation, few studies quantified its influence on the thermal comfort of vernacular buildings, especially under warm dominant climates. The aim of this study is the investigation of the impact of night ventilation on the thermal comfort of vernacular buildings under summer dominant environmental conditions. The subjects under investigation was one traditional buildings in the city of Nicosia in Cyprus. In terms of this study numerical analysis regarding the thermal comfort of the investigated buildings was performed by employing Energy Plus and the flow solver of Design Builder. The indoor operative temperature distribution, the indoor air velocity and a thermal comfort related index were identified in selected thermal zones of the examined building using night ventilation. The results of this study quantified the potential temperature decrease that can result on vernacular buildings due to the use of night ventilation and revealed some restrictions with regard to the allowed percentage of the opening sizes towards achieving optimal thermal conditions in space. This study aspires to provide useful insight regarding the importance of humans' behavior in terms of enabling night ventilation to vernacular buildings, as well as to con-tribute to the ongoing scientific discussion on this subject.

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Wall-Attached Night Ventilation Combined with Phase Change Material Wallboard in Hot Summer: An Experimental Study on the Thermal Performance

Yuan

et al. 2022

J. Therm. Sci.

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Experimental investigation of heat transfer during night-time ventilation

Cited by 62 publications

References 21 publications

Experimental investigation of convective heat transfer during night cooling with different ventilation systems and surface emissivities

Experimental investigation of convective heat transfer during night cooling with different ventilation systems and surface emissivities

Numerical assessment of night ventilation impact on the thermal comfort of vernacular buildings

Wall-Attached Night Ventilation Combined with Phase Change Material Wallboard in Hot Summer: An Experimental Study on the Thermal Performance

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