Experimental investigation of convective heat transfer for night cooling with diffuse ceiling ventilation

Guo, Rui; Heiselberg, Per; Hu, Yue; Johra, Hicham; Zhang, Chen; Jensen, Rasmus Lund; Jønsson, Kim Trangbæk; Pei, Peng

doi:10.1016/j.buildenv.2021.107665

Cited by 7 publications

(3 citation statements)

References 37 publications

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“…The research was carried out in two real free-standing residential buildings, differing only in the thermal capacity of the walls, whereas most research in this area has been carried out in free-standing experimental facilities, usually much smaller and sometimes close to real facilities [52][53][54], or in climatic chambers in a fully controlled environment [51,55]. Such rooms do not fully reflect real conditions, as their thermal performance depends not only on their thermal capacity but also on the thermal capacity of the whole building, which is much higher.…”

Section: Novelty Of the Workmentioning

confidence: 99%

Cumulative Multi-Day Effect of Ambient Temperature on Thermal Behaviour of Buildings with Different Thermal Masses

Staszczuk,

Kuczyński

2023

Energies

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In most studies, the effect of the thermal capacity of the building envelope on changes in internal temperatures is reduced to a 24 h period. During this period, daytime heat gains are balanced by nighttime heat losses. The maximum indoor temperature, the diurnal variation of the indoor temperature and the time lag between the occurrence of the maximum daily temperature determine the effect achieved. The aim of the article was to show that the effect of the thermal capacity of a building on the indoor temperature is not limited to 24 h but accumulates over a period of several days, mainly depending on the temperature and solar radiation history of the previous days. As a result, contrary to what some studies have suggested, the bedrooms of heavier buildings remained significantly colder at night during periods of prolonged high outdoor temperatures. The results obtained may fundamentally influence the perception of the effect of using the high thermal capacity of the building envelope to reduce high indoor temperatures in hot weather.

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Section: Novelty Of the Workmentioning

confidence: 99%

Cumulative Multi-Day Effect of Ambient Temperature on Thermal Behaviour of Buildings with Different Thermal Masses

Staszczuk,

Kuczyński

2023

Energies

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“…Three types of DCV panels are discussed in literature and these differ on specifications of pressure drop across the false ceiling and consequently the airflow characteristics in the ventilated room, see [3,24]. Experimental and numerical studies have explored DCV [32][33][34][35], while other studies have explored integration of other building technologies and strategies to enhance building ventilation performance [36][37][38][39]. Overall, DCV has several benefits over conventional duct-based ventilation.…”

Section: Introductionmentioning

confidence: 99%

On the Performance of Diffuse Ceiling Ventilation in Classrooms: A Pre-Occupancy Study at a School in Southern Sweden

Ogbuagu

Linden

MacCutcheon³

et al. 2023

Sustainability

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The implementation and application of diffused ceiling ventilation (DCV) is gradually gaining momentum, especially in Denmark, Finland, and the Netherlands. In countries such as Sweden, the application is limited despite the favorable conditions for implementation. The current study investigates the performance of DCV and mixing ventilation in a pre-occupancy field study for newly renovated classrooms in Southern Sweden. Two classrooms at the school were installed with diffuse ceiling ventilation while the rest had mixing ventilation. The objective of the study was to compare and evaluate the ventilation performance in terms of indoor environmental quality parameters such as thermal comfort, air quality indexes, airflow, and temperature distribution. Pre-occupancy measurements were performed in two classrooms with similar room characteristics, with one room running under mixing ventilation and the other under DCV. Constant temperature anemometers, thermocouples, and INNOVA thermal comfort were used to measure the indoor air speeds, temperature, and thermal comfort, respectively. Tracer gas measurements, with SF6, were performed to assess air quality. Additionally acoustic measurements were conducted to assess the acoustic benefits of DCV on reducing ventilation noise. The results demonstrate that DCV offers similar indoor environmental conditions to mixing ventilation but has better acoustic performance especially on reducing the ventilation noise. Indoor environmental conditions were very homogeneous under DCV with mixing ventilation showing tendencies for short circuit ventilation. This study demonstrates that DCV has a potential for implementation in Swedish schools with minimal system modification on existing ventilation and air distribution systems.

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“…Chao and Hu [16] discussed that classroom occupants can be exposed to harmful concentrations because emissions may accumulate without proper ventilation during the unoccupied periods. Earlier research shows that night ventilation has been typically used to enhance indoor thermal conditions [17][18][19][20][21][22]. Even though many standards and guidelines have been provided for health-based ventilation [10,23,24], different night ventilation methods have been relatively rarely studied regarding organic pollutant levels in the mornings at the beginning of space use.…”

Section: Introductionmentioning

confidence: 99%

Effects of Night Ventilation on Indoor Air Quality in Educational Buildings—A Field Study

et al. 2021

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Night ventilation methods have been used in educational buildings to guarantee indoor air quality at the beginning of occupied periods. A typical method has been to pre-start ventilation 2 h before the space usage. Another selection has been to ventilate a building continuously during the night with a minimum airflow rate that can dilute material emissions. In this study, the pre-started, continuous, and intermittent ventilation methods were compared by assessing indoor air quality in field measurements. The daytime ventilation was operating normally. The test periods lasted for 2 weeks. Indoor air quality was assessed by measuring the total volatile organic compounds and microbial concentrations using the quantitative polymerase chain reaction method. Additionally, the thermal conditions, carbon dioxide, and pressure differences over the building envelope were measured. The results show that the night ventilation strategy had negligible effects on microbial concentrations. In most cases, the indoor air microbial concentrations were only a few percent of those found outdoors. The averaged concentration of total volatile organic compounds was at the same level with all the night ventilation methods at the beginning of the occupied periods in the mornings. The concentrations reached a minimum level after 2-h ventilation. The concentrations of total volatile organic compounds were higher during the day than at night. This reveals that space usage had the largest effect on the total volatile organic compounds. Generally, the results show that continuous night ventilation does not significantly affect the biological and chemical contaminants. Consequently, a 2-h flushing period is long enough to freshen indoor air before occupancy.

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Experimental investigation of convective heat transfer for night cooling with diffuse ceiling ventilation

Cited by 7 publications

References 37 publications

Cumulative Multi-Day Effect of Ambient Temperature on Thermal Behaviour of Buildings with Different Thermal Masses

Cumulative Multi-Day Effect of Ambient Temperature on Thermal Behaviour of Buildings with Different Thermal Masses

On the Performance of Diffuse Ceiling Ventilation in Classrooms: A Pre-Occupancy Study at a School in Southern Sweden

Effects of Night Ventilation on Indoor Air Quality in Educational Buildings—A Field Study

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