Convective heat loss from computational thermal manikin subject to outdoor wind environments

Zou, Jiwei; Liu, Jianlin; Niu, Jianlei; Yu, Yichen; Lei, Chengwang

doi:10.1016/j.buildenv.2020.107469

Cited by 26 publications

(5 citation statements)

References 24 publications

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“…It can be observed that the hc of the present prediction is higher than the experimental results of de Dear et al [3]at the reported TI between 4%-8%, averaging about 19% higher. At the same TI of 8%, the result of the present study was lower than the prediction https://doi.org/10.1051/e3sconf/202235603001 E3S Web of Conferences 356, 03001 (2022) ROOMVENT 2022 of Zou et al [8], with a maximum difference of 23% in the wind range of 4m/s. Meanwhile, the result at high wind speeds is similar to those of Yu et al [7], while differing in the lower wind speed range, up to 24% difference at 0.5m/s.…”

Section: Comparison Of Experimental Results With Other Studiescontrasting

confidence: 85%

“…Based on the experimental results, not considering TI would lead to deviations in the true hc. The observed results are similar to those of Yu et al [7] and Zou et al [8]. In the range of TI measured in this experiments, the difference in hc between high and low TI groups can be up to 15% at the same wind speed.…”

Section: Data Processingsupporting

confidence: 92%

“…in 2020 showed that ignoring TI may result in underestimating the wind effect on pedestrian thermal sensation by up to 50%. Subsequently, this underestimation effect was also confirmed by Zou et al using CFD simulations [8]. In their study, the turbulence integral length scale was added as an influencing factor and regression equations were proposed to predict hc.…”

Section: Introductionmentioning

confidence: 64%

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Measurement of the convective heat transfer coefficient of the human body in the lift-up design

Zhou

Niu²

2022

E3S Web Conf.

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So far, the research on the convective heat transfer coefficient (hc) in outdoor thermal comfort has mainly employed CFD simulation and wind tunnel experiments, which are difficult to fully restore the complex microclimate wind environment. In the traditional thermal comfort model, the influence of turbulence intensity (TI) on the hc might be underestimated. This study aims to measure the hc of the human body surface in the outdoor environment. A thermal manikin was placed in a lift-up building. The ambient wind speed ranged from 0.5m/s to 4m/s, with the TI ranging from 4% to 55%. The experimental results show that under the same wind speed, the difference in hc between high and low TI can be up to 15%. Based on that, the regression formula for predicting hc related to wind speed and TI was proposed. This experimental study supplements the lack of field measurement of hc in outdoor thermal comfort research, which is helpful to improve the accuracy of the outdoor thermal comfort model.

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Section: Comparison Of Experimental Results With Other Studiescontrasting

confidence: 85%

Section: Data Processingsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 64%

See 1 more Smart Citation

Measurement of the convective heat transfer coefficient of the human body in the lift-up design

Zhou

Niu²

2022

E3S Web Conf.

Self Cite

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“…𝑇𝑇 𝑎𝑎 is the evaporator temperature (the serpentine tube)°𝐶𝐶 𝑇𝑇 𝑎𝑎 is the ambient temperature°𝐶𝐶 𝑆𝑆 𝐿𝐿,𝑎𝑎 is the lateral surface of the geometrical form composed of the serpentine tube and the storage 𝑚𝑚 2 𝜋𝜋 is the radius of the geometrical form composed of the serpentine tube and the storage 𝑚𝑚 ℎ is the height of the geometrical form composed of the serpentine tube and the storage 𝑚𝑚 ℎ 𝑤𝑤𝑤𝑤𝑤𝑤𝑎𝑎 is the heat exchange coefficient that describes the losses of solar energy by wind convection expressed by correlation [49].𝑊𝑊. 𝑚𝑚 −2 .…”

Section: Description Of Heat Exchanges Through the Evaporator-absorbermentioning

confidence: 99%

Mathematical Modeling of the Heat Generated through an Evaporator-Absorber Accompanied by Thermal Storage for the Solar Energy Applications

Latrache

Hammouch

Lamnaouar

et al. 2023

JERA

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An evaporator-absorber geometry allows the absorption of incident solar radiation andconverts it into thermal energy useful for the evaporation of a working fluid. The evaporator-absorberworks with two fluids: a heat transfer fluid transmitting heat to a working fluid, which, circulatesalong the thermal circuit composed of an evaporator, a turbine, a condenser and a pump. The aim ofthis research work is to analyze the heat transfer through the evaporator-absorber and to extract themathematical equations model the heat exchange process between the component elements of theevaporator-absorber: a serpentine tube, a working fluid and a cylindrical tube. In this case, theworking fluid is water, and the heat transfer fluid is air, which is heated by the thermal energyconverted from solar energy. The mathematical equations describing the heat transfer are extractedby using the nodal method and discretized by the finite difference method. Afterwards, the presentwork estimates the outlet temperature of each element of the evaporator-absorber and studies thestorage capacity of the cylindrical tube. Then, the water temperature distribution on the geometry ofthe evaporator and the required quantity of water and the number of spires to have a high outlettemperature of the water vapor are determined. As a result, the mathematical modeling estimated thatthe outlet temperature of the serpentine tube is higher than the outlet temperature of the water.Additionally, the temperature of the storage tube maintains its increase throughout the day. Thequality of the heat transfer in the serpentine tube is improved by placing the tube in a vertical positionand by adopting a lower volume of water compared to the maximum volume, which is supported bythis tube.

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“…Previous studies mainly focused on the effect of the single influenced parameter, air temperature or relative wind speed (the combined result of air velocity and working speed) on h c , including ISO 7933. 22,23 Few studies considered airspeed and temperature gradient simultaneously in the estimation of h c . 19 Still, no one has established a quantitative relationship between h c and the interaction between walking speed and temperature gradient, which is a critical factor for calculating boundary heat transfer of clothing surface, especially in the walking state.…”

mentioning

confidence: 99%

The predicted heat strain model considering wet and dynamic thermal insulation for thermal protective clothing: Modification and validation analysis

Zhang

Huang

Wang

et al. 2022

Textile Research Journal

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For guiding the setting of working time, it is necessary to develop a realistic clothing model with accurate thermal physical properties including the effects of human body activities and environments in the predicted heat strain model, especially for the high thermal insulation clothing ensembles and high-temperature conditions. In this study, realistic clothing models, including clothing wet thermal insulation ( Icl_w), dynamic thermal insulation ( Icl_vw), and convective heat transfer coefficient considering the temperature difference and walking speed ( hc_vw), were established. Then, we validated the modified predicted heat strain models combined with realistic clothing parameters. The results revealed that the core temperature of the predicted heat strain model combined with Icl_w, Icl_vw, and hc_vw (deviation of 0.1°C) was significantly more accurate than the original predicted heat strain model (variation of 1.5°C) in the environment of 40°C within 65 min of heat exposure. Our study emphasizes the necessity of ensuring the accuracy of clothing thermal physical properties in the predicted heat strain model to improve validity for the specific conditions investigated.

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Convective heat loss from computational thermal manikin subject to outdoor wind environments

Cited by 26 publications

References 24 publications

Measurement of the convective heat transfer coefficient of the human body in the lift-up design

Measurement of the convective heat transfer coefficient of the human body in the lift-up design

Mathematical Modeling of the Heat Generated through an Evaporator-Absorber Accompanied by Thermal Storage for the Solar Energy Applications

The predicted heat strain model considering wet and dynamic thermal insulation for thermal protective clothing: Modification and validation analysis

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