Selective ventilation in large enclosures

Calay, Rajnish Kaur; Børresen, Bjarne; Holdo̸, A. E.

doi:10.1016/s0378-7788(00)00054-2

Cited by 14 publications

(12 citation statements)

References 10 publications

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“…If the Beta distribution applies, it may be possible to quantify the characteristic curves in Figure 1 for various situations mathematically based on the general model of the Beta distribution. This paper first introduces the Beta distribution and its background theory of the order statistics, then validates the findings by the measurement data of the five warehouse and storage spaces, 20 and eleven published studies [5][6][7][8][9][10][11]13,15,23,38 from the literature. This paper also discusses a few practical implications and applications of these findings.…”

Section: Practical Implicationsmentioning

confidence: 69%

“…In buoyancy-driven ventilated spaces including displacement [5][6][7] and/or underfloor ventilation systems, [8][9][10][11][12] and natural ventilation in large spaces 13,14 during cooling seasons; and 3). In buoyancy-driven ventilated spaces including displacement [5][6][7] and/or underfloor ventilation systems, [8][9][10][11][12] and natural ventilation in large spaces 13,14 during cooling seasons; and 3).…”

mentioning

confidence: 99%

“…In large industrial warehouses and storage facilities especially in winter seasons 2-4 ;(ii). In buoyancy-driven ventilated spaces including displacement [5][6][7] and/or underfloor ventilation systems, [8][9][10][11][12] and natural ventilation in large spaces 13,14 during cooling seasons; and 3). In a more extreme stratification case, such as during enclosure fire, buoyancy-driven hot smoke rises to form an upper smoke layer on the top of a cold lower air layer.…”

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confidence: 99%

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Indoor thermal stratification and its statistical distribution

Wang

Zhang

2018

Indoor Air

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Thermal stratification is established when warmer air rises and cooler air descends under thermal buoyancy. It occurs in indoor environment situations including large warehouse‐type buildings, buoyancy‐driven ventilated spaces with displacement, underfloor ventilation, and/or natural ventilation, and enclosure fires with hot smoke layer on top of cold air layer. This paper reports a recent study that thermal stratification of indoor environment follows the statistical Beta distribution so the vertical temperature distribution is the Cumulative Distribution Function of the Beta distribution defined by two shape parameters, Alpha (α) and Beta (β), despite ventilation types, heat source and other details. It is then possible to estimate a complete vertical temperature profile under thermal stratification by four temperature points (ie, 4‐point Beta distribution), or as few as two points (ie, 2‐point Beta distribution) with a slight loss of accuracy. The study was confirmed by the field measurement data of five warehouse‐type buildings, and eleven thermal stratification studies from the literature. A few applications were demonstrated including quantitative characterization of thermal stratification; estimation of mean and spatial temperature uniformities and other key parameters. The dimensionless nature of the methodology may also be potentially applied to other indoor stratification phenomena.

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Section: Practical Implicationsmentioning

confidence: 69%

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confidence: 99%

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confidence: 99%

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Indoor thermal stratification and its statistical distribution

Wang

Zhang

2018

Indoor Air

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“…As mentioned in the previous investigations, 12,13 the thermal stratification often occurs in large open-plan office buildings and storage facilities especially in winter seasons. The heating distribution in these large buoyancy-driven ventilated spaces include displacement, 14,15 under-floor air distribution 16,17 and stratum ventilation systems. 18 In the viewpoint of local personal comfort, discomfort complains typically triggered by draught or low temperature attribute caused by inappropriate airflow designs.…”

Section: Introductionmentioning

confidence: 99%

Mathematical and experimental analysis of the thermal effectiveness of an oscillating jet with side-to-side swing louvers in a cassette split type air conditioner

Fan

2019

Indoor and Built Environment

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The impact of air supply control strategies (louvers movement) on indoor thermal environment were evaluated in this study. The temperature uniformity was evaluated by: (i) the air distribution performance index (ADPI) to determine the air diffusion performance in heating mode; (ii) the air draught rate (DR%) on the face to determine the local discomfort due to cold draught; (iii) the mathematically determined vertical temperature stratification in a room with Beta distributions. A comparison of the conventional type with three different oscillating type airflows (louvers swing angle ±20°, ±40° and ±60°) were experimentally analysed to determine appropriate air supply control strategies. The results indicated that Beta distributions could capture the overall trend of the oscillating airflow, to establish the acceptable thermal uniformity and higher thermal effectiveness. The oscillating airflow as generated by the side-to-side swing type delivery louvers mounted inside a cassette split type air conditioner could shorten heating time by 20% to attain room temperature from 9°C. The data reveal that oscillating airflow can provide a better thermal sensation to feeling warm in the heating mode at both ankle and neck level. The ADPI is approximately 85% in the occupied zone. The actual draught rates on the face ranged 0–35%.

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“…In the final report, they summarized the numerical simulation assisted design and analysis methods of ventilation in large enclosures as well as the improved and new measuring techniques for diagnostics of large enclosure. CALAY et al [7] proposed a new ventilation method which was called "selective ventilation" for large enclosures. Influences of many parameters on the flow patterns with "selective ventilation" were discussed in order to determine design parameters of this new technique.…”

Section: Introductionmentioning

confidence: 99%

Heat and hazardous contaminant transports in ventilated high-rise industrial halls

Wang

Liu

Treeck

et al. 2015

J. Cent. South Univ.

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Performances and efficiencies of displacement ventilation (DV) and partial ventilation (PV) for industrial halls of different configurations as well as the heat and mass transports within the industrial halls were numerically investigated. Three levels of Rayleigh number (5.810 10 , 1.010 12 and 2.110 12 ) and two values of source contaminant flux (5 mg/s and 50 mg/s) were considered. The inlet Reynolds numbers were 210 4 , 510 4 , 1.510 5 and 4.510 5 for DV and 510 5 , 110 6 , 210 6 and 410 6 for PV, respectively. From the results, it is concluded that the above parameters have very complex impacts on the conjugated heat and mass transports. From points of view of acceptable indoor air quality and ventilation efficiency, PV at Re=110 6 with side-located sources and 65% of the supply air extracted through floor level outlets is the best choice when Ra=5.810 10 . However, DVs at Re=510 4 and Re=1.510 5 with center-located sources and floor-mounted air suppliers are the best choices for Ra=1.010 12 and Ra=2.110 12 , respectively. When source contaminant flux reaches 50 mg/s, local extraction as a supplement of general ventilation is recommended. The results can be a first approximation to 3D numerical investigation and preliminary ventilation system design guidelines for high-rise industrial halls.

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Selective ventilation in large enclosures

Cited by 14 publications

References 10 publications

Indoor thermal stratification and its statistical distribution

Indoor thermal stratification and its statistical distribution

Mathematical and experimental analysis of the thermal effectiveness of an oscillating jet with side-to-side swing louvers in a cassette split type air conditioner

Heat and hazardous contaminant transports in ventilated high-rise industrial halls

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