Air turbulence and sensation of draught

Fanger, Povl Ole; Melikov, Arsen Krikor; Hanzawa, Hisashi; Ring, J.

doi:10.1016/0378-7788(88)90053-9

Cited by 436 publications

(236 citation statements)

References 2 publications

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“…The draught rate (DR) higher than 15% is considered unacceptable [43]. Thus, the calculated DR in the meeting room (5.3% for P1 and 7.1% for P2) did not cause local discomfort of the room occupants.…”

Section: Draught Ratementioning

confidence: 99%

Calibrated CFD simulation to evaluate thermal comfort in a highly-glazed naturally ventilated room

Hajdukiewicz

Geron

Keane

2013

Building and Environment

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Section: Draught Ratementioning

confidence: 99%

Calibrated CFD simulation to evaluate thermal comfort in a highly-glazed naturally ventilated room

Hajdukiewicz

Geron

Keane

2013

Building and Environment

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“…However, in real ventilated spaces, airflow in the occupied zone is turbulent and fluctuates randomly. The effect of the velocity fluctuations on the dynamic response of the thermo-receptors in the skin and the draught sensation was identified by Fanger et al (1988). It was found that when the body as a whole remained thermally neutral, high turbulence causes more complaints of draught than low turbulence at the same mean air velocity and temperature.…”

Section: Local Thermal Discomfortmentioning

confidence: 99%

Experimental and numerical investigations of a ventilation strategy – impinging jet ventilation for an office environment

Chen¹

2014

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A well-functioning, energy-efficient ventilation system is of vital importance to offices, not only to provide the kind of comfortable, healthy indoor environment necessary for the well-being and productive work performance of occupants, but also to reduce energy use in buildings and the associated impact of CO 2 emissions on the environment. To achieve these goals impinging jet ventilation has been developed as an innovative ventilation concept.In an impinging jet ventilation system, a high momentum of air jet is discharged downwards, strikes the floor and spreads over it, thus distributing the fresh air along the floor in the form of a very thin shear layer. This system retains advantages of mixing and stratification from conventional air distribution methods, while capable of overcoming their shortcomings.The aim of this thesis is to reach a thorough understanding of impinging jet ventilation for providing a good thermal environment for an office, by using Computational Fluid Dynamics (CFD) supported by detailed measurements. The full-field measurements were carried out in two test rooms located in a large enclosure giving relatively stable climate conditions. This study has been divided into three parts where the first focuses on validation of numerical investigations against measurements, the second addresses impacts of a number of design parameters on the impinging jet flow field and thermal comfort level, and the third compares ventilation performance of the impinging jet supply device with other air supply devices intended for mixing, wall confluent jets and displacement ventilation, under specific room conditions. In the first part, velocity and temperature distributions of the impinging jet flow field predicted by different turbulence models are compared with detailed measurements. Results from the non-isothermal validation studies show that the accuracy of the simulation results is to a great extent dependent on the complexity of the turbulence models, due to complicated flow phenomena related to jet impingement, such as recirculation, curvature and instability. The f v  2 turbulence model shows the best performance with measurements, which is slightly better than the SST k-ω model but much better than the RNG k-ε model. The difference is assumed to be essentially related to the magnitude of turbulent kinetic energy predicted in the vicinity of the stagnation region. Results from the isothermal study show that both the SST k-ω and RNG k-ε models predict similar wall jet behaviours of the impinging jet flow. IVIn the second part, three sets of parametric studies were carried out by using validated CFD models. The first parametric study shows that the geometry of the air supply system has the most significant impact on the flow field. The rectangular air supply device, especially the one with larger aspect ratio, provides a longer penetration distance to the room, which is suitable for industrial ventilation. The second study reveals that the interaction effect of cooling ceiling, heat sources ...

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“…The second strategy achieves better mixing, but often leads to draft, as the air flow is normally turbulent in the occupied zone. Depending on the air temperature and turbulence level, even low air velocities (less than 0.2 d s ) have been shown to elicit complaints from 10 to 20% of the building occupants [15].…”

Section: Short History Of Radiant Cooling Systemsmentioning

confidence: 99%

“…Considering that the density and pressure of the air is constant at a given moment, and neglecting the influences of differences in velocities and potential energy of the air flow domain, the ventilation heat term in the room air heat balance is expressed as [15]: …”

Section: Q-vent-air-roommentioning

confidence: 99%

Radiant cooling in US office buildings: Towards eliminating the perception of climate-imposed barriers

Stetiu

1998

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Air turbulence and sensation of draught

Cited by 436 publications

References 2 publications

Calibrated CFD simulation to evaluate thermal comfort in a highly-glazed naturally ventilated room

Calibrated CFD simulation to evaluate thermal comfort in a highly-glazed naturally ventilated room

Experimental and numerical investigations of a ventilation strategy – impinging jet ventilation for an office environment

Radiant cooling in US office buildings: Towards eliminating the perception of climate-imposed barriers

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