The effect of airspeed and wind direction on human's thermal conditions and air distribution around the body

Oh, Wonseok; Kato, Shinsuke

doi:10.1016/j.buildenv.2018.05.052

Cited by 51 publications

(16 citation statements)

References 38 publications

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“…Moreover, the heat transfer coefficients of sitting posture in a standard environment in a CFD simulation case were validated using the experimental results from de Dear et al, 48 Sørensen and Voigt, 49 and Oh and Kato. 44 The agreement between the heat transfer coefficient results of sitting postures in standard environment conditions can be found in Figure 4. In order to evaluate the performance of the SV system, two different air supplies with horizontal angles of 0 and vertical angles of 30 were investigated.…”

Section: Model Validationmentioning

confidence: 56%

“…where t sk is the skin surface temperature ( C), q is the sensible heat loss (W/m 2 ), h o is the combined radiative and convective heat transfer coefficient (W/m 2 ÁK) of the human body as determined in a standard environment which was chosen according to our results using a combination of thermal manikin experiments and radiation analysis. 44 Then, the comfort zone diagrams were constructed for a human wearing light summer clothing and was used to analyse human thermal comfort based on the equivalent temperature results for different systems. 43,45 The vertical air temperature difference (DT 1.1-0.1 ) specified for a seated person was measured between the head level at 1.1 m and the ankle level at 0.1 m above the floor, which was calculated for the entire range of ventilation scenarios.…”

Section: Evaluation Indicesmentioning

confidence: 99%

“…Heat transfer coefficient results of sitting postures in standard environment condition between author and other references by de Dear et al, 48 Sørensen and Voigt 49 and Oh and Kato. 44 hc: convective heat transfer coefficient; hr: radiative heat transfer coefficient; ht: total convective; radiative heat transfer coefficient. Figures 6(a) and (b) and 7(a) and (b), both the MV and SV systems are able to keep the calf and foot segments in the acceptable thermal zone with a temperature range of 22 C to 24 C, while in the DV and DPV cases, the calf and foot segments were located in the slightly colder thermal zone with a temperature range of 21 C to 23 C, as shown in Figures 6(c) and (d) and 7(c) and (d).…”

Section: Indoor Air Temperature Distributionmentioning

confidence: 99%

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A comparison of the thermal comfort performances of a radiation floor cooling system when combined with a range of ventilation systems

Liu

Kim

et al. 2019

Indoor and Built Environment

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This study conducted a series of computational fluid dynamics simulations to evaluate the thermal comfort performance of a radiant floor cooling system when combined with different ventilation systems, including mixed ventilation (MV), stratum ventilation (SV), displacement ventilation (DV) and ductless personalized ventilation (DPV). A window temperature of 32°C and three different floor temperatures including 20, 22 and 24°C were set in summer. We used the vertical air temperature differences (VATD) at ankle and head level, the percentage of dissatisfied, the draught rate at the ankle level and the equivalent temperature as our main evaluation indices. Our results show that the VATD in DV system can reach up to about 5°C, compared with about 2°C in MV and SV systems. For the DPV system, there is only a marginal drop in the VATD. For the DV and DPV cases, with a rate of air changes per hour (ACH) of 2.4−1, we recorded a higher draught rate at the ankle level, ranging from 6.55% to 9.99%. The lower equivalent temperature values for the foot and calf segments occur when the floor temperature is 20°C. In all cases, the equivalent temperature values of the whole body indicate an acceptable level of thermal discomfort.

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Section: Model Validationmentioning

confidence: 56%

Section: Evaluation Indicesmentioning

confidence: 99%

Section: Indoor Air Temperature Distributionmentioning

confidence: 99%

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A comparison of the thermal comfort performances of a radiation floor cooling system when combined with a range of ventilation systems

Liu

Kim

et al. 2019

Indoor and Built Environment

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“…In fact, introducing humans as static thermal sources is not an uncommon approach. In the field of building physics, occupants have been simulated in CFD either as simple cuboid geometries [59] and more recently with realistic human shapes [60]. One of the first applications of CFD to model a heritage space is the simulation of the Archaeological Museum of Athens [4], where visitors were accounted for as a source of heat.…”

Section: Sources Of Low Velocity Flowsmentioning

confidence: 99%

Fluid simulations in heritage science

et al. 2019

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This review addresses the use of computational fluid dynamics for the interpretation and preservation of heritage. Fluid dynamic simulations in the heritage field focus mostly on slow air movement in indoor spaces and they usually involve temperature and humidity. Simulations have different roles: they may be exploratory, they may be used to support preventive conservation and occasionally they aid historical or archaeological interpretation. The research questions rarely involve testing or development of new mathematical formulations; instead, existing computational models are used as a means to help solve practical issues. Computationally, the simulations are typically steady-state and they always use a turbulence model. Experimental validations against measured data are uncommon and there is a need for the production of benchmarking cases and the publication of experimental data. Further research is needed in order to explore suitable approximations to the simulation of change in the timescale of months or years, low turbulence flows for which current mainstream turbulence models are ill-suited, and new mathematical formulations for near-wall transport phenomena.

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“…Ceiling fans are cost-effective and energy-efficient comfort cooling approaches commonly used in tropical and subtropical countries, mainly in residential buildings and semi-outdoor spaces. Compared to compressor-based cooling, ceiling fans cool people with less energy consumption [12] by enhancing convective heat transfer [13], and by creating more uniform air temperature distribution through increased air circulation [14,15]. Previous laboratory and field studies on human subjects have shown that using ceiling fans improves perceived air quality, sensation of thermal comfort and productivity [7,10,[16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Detailed experimental investigation of air speed field induced by ceiling fans

Liu

Lipczyńska

Schiavon

et al. 2018

Building and Environment

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Comfort cooling by ceiling fans is cost-effective and energy-efficient compared to compressor-based cooling and fans are commonly used in tropical and subtropical countries. There are however limited data and design tools supporting the design of fan systems, especially for situations where there are multiple fans. In this paper, we investigate airflow profiles induced by a single fan and multiple fans using high spatial resolution air speed measurements (5,760 and 20,160 measuring points for the two cases respectively) in a climatic chamber. To authors' knowledge, this is the first time that interaction between multiple fans has been reported. We developed typical airflow patterns from the measurements and further validated them via smoke visualization. The singlefan results are consistent with previous studies of this configuration, providing additional refinements. For the multiple-fan case, both the difference of fan speed levels and the distance between the fans affect the interacting airflow profiles of the fans in complex ways. When fans are close enough, the combined air speed profile cannot be extrapolated from the profile of a single fan. All the measurement results are open sourced: raw data is included in the supplementary materials and can be visualized via an online platform (single fan, multiple fans). The data and the tool can be used to validate CFD models and inform fan layout design.

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The effect of airspeed and wind direction on human's thermal conditions and air distribution around the body

Cited by 51 publications

References 38 publications

A comparison of the thermal comfort performances of a radiation floor cooling system when combined with a range of ventilation systems

A comparison of the thermal comfort performances of a radiation floor cooling system when combined with a range of ventilation systems

Fluid simulations in heritage science

Detailed experimental investigation of air speed field induced by ceiling fans

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