Study on Building Engineering with Simulation and Analysis of Outdoor Thermal Environment for a Residential Subdistrict in Hot Summer/Cold Winter Region

2013 ◽  
Vol 700 ◽  
pp. 235-238
Author(s):  
Liu Zhang ◽  
Yong Hong Huang ◽  
Lian Yang
Keyword(s):  
Thermal Environment ◽  
Wall Material ◽  
Heat Island ◽  
Cold Winter ◽  
Simulation Data ◽  
High Rise ◽  
The North ◽  
Outdoor Thermal Environment ◽  
Air Circulation ◽  
Building Engineering

Thermal environmental problems in urban high-rise buildings are prevalent. To analyze the phenomenon, the thermal environment of a typical urban residential subdistrict is simulated by using CFD techniques considering the affects of different type of wall material. The simulation data are carefully analyzed. Some useful results are thus obtained. The direction of the buildings affects air circulation greatly with the north-south orientation having the best effects. Temperature in the subdistrict is about 3~5°C higher than its surroundings because of heat island effects which could be weakened if greening rate of the sbudistrict is increased. Finally, simulation results show that wall materials affect the environment considerably.

Numerical Simulation on Cooling Effects of Greening for Alleviating Urban Heat Island Effect in North China

2014 ◽  
Vol 675-677 ◽  
pp. 1227-1233 ◽  
Author(s):  
Cheng Chen ◽  
Yu Yue ◽  
Wen Jiang
Keyword(s):  
Numerical Simulation ◽  
Computer Simulation ◽  
Urban Heat Island ◽  
North China ◽  
Thermal Environment ◽  
Heat Island ◽  
Island Effect ◽  
Outdoor Thermal Environment ◽  
Urban Heat ◽  
Cooling Effects

As the climate warming up, the effects of the urban heat island have been an insurmountable issue in the urban development. In this paper, taking Tianjin for example, the research combined computer simulation with on-site measurement to evaluate the effects of different greening ratios on outdoor thermal environment. Besides, the accuracy of the simulation model has been verified by calibration. Research results determined that the increase of the greening ratio in the existing environment could improve the outdoor thermal environment in summer. But the limitations of green cooling was also pointed out, namely that the air temperature would infinitely close to a certain value with further increasing greening ratio.

scholarly journals Numerical investigation of the north wall passive thermal performance for Chinese solar greenhouse

2020 ◽  
Vol 24 (6 Part A) ◽  
pp. 3465-3476
Author(s):  
Yiming Li ◽  
Xingan Liu ◽  
Fengsheng Qi ◽  
Li Wang ◽  
Tianlai Li
Keyword(s):  
Solar Energy ◽  
Wall Thickness ◽  
Thermal Performance ◽  
Thermal Environment ◽  
Energy Utilization ◽  
Wall Material ◽  
The North ◽  
Solar Energy Utilization ◽  
Solar Greenhouse ◽  
North Wall

The fully passive solar energy utilization system of Chinese solar greenhouse is efficient for ensuring year-round cultivation of vegetables, owing to the high amount of heat charge and discharge characteristic of the north wall enclosure. In the present research, the thermal performance is investigated using CFD. A 3-D mathematical model has been established to evaluate the wall thickness, layered configuration and material property. The predicted thermal environments are in good agreement with the experimental measurements, indicating the reliability of the established numerical model. The results showed that the increase of north wall thickness could cause the waste of resources due to the thermal masses mainly concentrate in the superficial layer. Constructing layered configuration is rec-ommended for the north wall which uses Styrofoam in the outer layer to reduce heat loss. Nevertheless, the property of north wall material has little effect on the thermal environment. The research results, thus obtained, will give good guidance for completing the Chinese solar greenhouse engineering database and optimizing the solar energy utilization.

Simulation Analysis on Effect of Shading Types on Outdoor Thermal Environment

2011 ◽  
Vol 374-377 ◽  
pp. 1147-1150
Author(s):  
Sha Lu ◽  
Lei Zhang ◽  
Qing Lin Meng
Keyword(s):  
Solar Radiation ◽  
Time Constant ◽  
Simulation Analysis ◽  
Thermal Environment ◽  
Tree Canopy ◽  
Thermal Time ◽  
Heat Island ◽  
Average Heat ◽  
Coverage Ratio ◽  
Outdoor Thermal Environment

Simulating the summer outdoor thermal environment of Exhibition Center in Taizhou with the improved CTTC (cluster thermal time constant) model to quantitatively analyze the effect of shading types on the heat island intensity. The results show that the effect of tree canopy is the most obvious. When the shading coverage ratio is less than 20%, the variations of average heat island intensity with the increased of solar radiation transmissivity is little, and the cooling effect is not significant.

The Effect of Anthropogenic Heat on Local Heat Island Intensity and the Performance of Air Conditioning Systems

2011 ◽  
Vol 250-253 ◽  
pp. 2975-2978 ◽  
Author(s):  
Jing Liu ◽  
Fei Ma ◽  
Ying Li
Keyword(s):  
Air Conditioning ◽  
Thermal Environment ◽  
Local Heat ◽  
Office Building ◽  
Anthropogenic Heat ◽  
Heat Island ◽  
Outdoor Thermal Environment ◽  
Air Conditioning Systems ◽  
Heat Released

Anthropogenic heat released from air conditioning systems is one of the most important factors contributing to the heat island in summer. A model to predicted heat island intensity is built. Using this model, a typical office building cluster is simulated, and the effect of heat released by air condition on outdoor thermal environment and heat island intensity is discussed. Furthermore, the reaction of heat island intensity rising on the performance of air conditioning systems is also investigated.

Analyzing the Factors and Variables of Heat Island Effect in Comprehensive High-Rise Residential Quarter of Mountain City

2011 ◽  
Vol 356-360 ◽  
pp. 980-985
Author(s):  
Jun Lu ◽  
Chun Die Li ◽  
Liang Wang ◽  
Yu Lu Chen ◽  
Xin Hui Zhang
Keyword(s):  
Thermal Environment ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Testing Time ◽  
Heat Island ◽  
High Rise ◽  
Island Effect ◽  
Factors Analysis ◽  
Residential Quarter ◽  
Residential Quarters

In order to guide the planning of urban microclimate, the influencing variables of the heat island intensity (UII) of tall residential quarter in mountain city in spring and summer is quantitatively analyzed. Through experiments and simulations, 6 variables including wind speed(WS), green ratio(GR), impervious ratio(IR), average surface temperature(AST) , shadow ratio(SR), H / W were chosen and summarized as factors by dimension reduction in factors analysis; further, the dominant variables and factors in different time were confirmed through multiple linear regression analysis of the factors/ variables and UII. Results revealed that in the microclimate tests, it is appropriate to make factor analysis when the cumulative contribution rate of a factor is higher than 50%, and the significant correlated factor of UII is horizontal surface factor (HSF) in three fifths of the testing time in July. The variable analysis revealed that the significance of WS on UII is more in cloudy days than that in sunny days; the significance of SR is higher in summer than that in transition seasons and is most in 15:00, it demonstrates that optimal utilization of the building shadings is an effective way to improve the outdoor thermal environment in residential quarters.

scholarly journals Quantitative Study of Using Piloti for Passive Climate Adaptability in a Hot-Summer and Cold-Winter City in China

2018 ◽  
Vol 15 (10) ◽  
pp. 2202 ◽  
Author(s):  
Zeng Zhou ◽  
Qinli Deng ◽  
Guang Yang ◽  
Yaolin Lin
Keyword(s):  
Wind Velocity ◽  
Climate Adaptation ◽  
Thermal Environment ◽  
Three Dimensional ◽  
Winter Season ◽  
Simulation Method ◽  
Cold Winter ◽  
Climate Adaptability ◽  
Outdoor Thermal Environment ◽  
Radiant Temperature

There has been an insufficient study of passive climate adaptability that considers both the summer and winter season for the outdoor thermal environment of hot-summer and cold-winter cities. In this study, we performed a quantitative simulation to research the passive climate adaptability of a residential area, considering piloti as the main method for climate adaptation in a hot-summer and cold-winter city in China. Numerical simulations were performed with a coupled simulation method of convection, radiation, and conduction. A cubic non-linear k–ε model proposed by Craft et al. was selected as the turbulence model and three-dimensional multi-reflections of shortwave and longwave radiations were considered in the radiation simulation. Through the simulation, we found that setting the piloti at the two ends of the building was the optimal piloti arrangement for climate adaptation. Then the relationship between the piloti ratio (0%, 20%, 40%, 60%, and 80%) and the outdoor thermal environment was studied. It could be concluded that with the increasing piloti ratio, the wind velocity increased, the mean radiant temperature (MRT) decreased slightly, and the average standard effective temperature (SET*) decreased to 3.6 °C in summer, while in winter, with the increasing piloti ratio, the wind velocity, MRT, and SET* changed slightly. The wind environment significantly affected the SET* value, and the piloti ratio should be between 12% and 38% to avoid wind-induced discomfort.

scholarly journals Synergistic Influence of Local Climate Zones and Wind Speeds on the Urban Heat Island and Heat Waves in the Megacity of Beijing, China

2021 ◽  
Vol 9 ◽  
Author(s):  
Lian Zong ◽  
Shuhong Liu ◽  
Yuanjian Yang ◽  
Guoyu Ren ◽  
Miao Yu ◽  
...  
Keyword(s):  
Heat Flux ◽  
Wind Speed ◽  
Urban Heat Island ◽  
Rural Areas ◽  
Urban Areas ◽  
Thermal Environment ◽  
Heat Island ◽  
Wind Speeds ◽  
High Rise ◽  
Urban Heat

Large-scale modifications to urban underlying surfaces owing to rapid urbanization have led to stronger urban heat island (UHI) effects and more frequent urban heat wave (HW) events. Based on observations of automatic weather stations in Beijing during the summers of 2014–2020, we studied the interaction between HW events and the UHI effect. Results showed that the UHI intensity (UHII) was significantly aggravated (by 0.55°C) during HW periods compared to non-heat wave (NHW) periods. Considering the strong impact of unfavorable weather conditions and altered land use on the urban thermal environment, we evaluated the modulation of HW events and the UHI effect by wind speed and local climatic zones (LCZs). Wind speeds in urban areas were weakened due to the obstruction of dense high-rise buildings, which favored the occurrence of HW events. In detail, 35 HW events occurred over the LCZ1 of a dense high-rise building area under low wind speed conditions, which was much higher than that in other LCZ types and under high wind speed conditions (< 30 HW events). The latent heat flux in rural areas has increased more due to the presence of sufficient water availability and more vegetation, while the increase in heat flux in urban areas is mainly in the form of sensible heat flux, resulting in stronger UHI effect during HW periods. Compared to NHW periods, lower boundary layer and wind speed in the HW events weakened the convective mixing of air, further expanding the temperature gap between urban and rural areas. Note that LCZP type with its high-density vegetation and water bodies in the urban park area generally exhibited, was found to have a mitigating effect on the UHI, whilst at the same time increasing the frequency and duration of HW events during HW periods. Synergies between HWs and the UHI amplify both the spatial and temporal coverage of high-temperature events, which in turn exposes urban residents to additional heat stress and seriously threatens their health. The findings have important implications for HWs and UHII forecasts, as well as for scientific guidance on decision-making to improve the thermal environment and to adjust the energy structure.

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