Study On Integrated Model Of Green Fa?ade In Building Transitional Space In A Hot-humid Climate Area Based On Thermal Environment Adaptation

As a countermeasure to the high-density urbanization and urban heat island(UHI),urban green infrastructure(UGI)has been promoted as an approach to improving human health and adapting to climate change.However,after rapid development in recent years,some high-density areas even lack green space in neighborhoods.In response to the limitation of green land and soil condition in some extreme urban space,green fa?ade(GF),which plant the climbing plants strategically in both urban and building environment,reveals a potential for increasing canopies and optimizing the pedestrian thermal comfort.GFs and living wall system(LWS)are two technologies of the green wall(GW).Compare to the LWS,the GFs are much more simple and low-cost technologies constituting a training or guiding structure.This paper focuses on the integrated building design with GF and transitional space in a hot-humid climate area.From the perspective on the foliage layer,fa?ade layer,and the typology of space,this paper takes a systematic and procedural study on GF to provide some design strategies on the integrated building design with GF.This paper includes a series of chapters:1. Via a systematic review on green walls,chapter 1 figures out that the significant effects of GF on the climatic response and urban ecological environment.Basing on this,an analysis of the integrated strategy of GF with building fa?ade and building transitional space is given and supports the research on GF models.(Chapter 2)2. Via field measurements on typical GF projects and scenarios,results reveal that the GF has a positive effect on the thermal environment.However,the change in temperature is limited in a distance.Comparing on the typology,the LWS performs a better optimization effect than the GF.Comparing to the time,the GF performs a better optimization on summer daytime.The results show that the PET of the transitional space with GF was decreased by 7.63?comparing to the outdoor environment and by 1.43?comparing to the unshaded area.Furthermore,an analysis of measurement data reveals the thermal environment in the transitional space was much more affected by the solar irradiation,which was reduced by 73.4%in the shaded area.The measurements also figured out that the leaf area index(LAI)of the GFs was 1.56-3.61and the foliage coverage ratio(FCR)was 49.7-92.9%.Two indices presented a high correlation coefficient(R~2>0.8).The measurements support the setting of parameters on the GF model.(Chapter 3)3. A GF model in a building transitional space and a standard simulation coupling with computational fluid dynamic(CFD)and a radiation model are built up and evaluated based on the literature review and field measurements data.Properties of a GF were also tested and results revealed that the optimization on temperature will increase with the increase of thickness of foliage layer.The result reveals that the thickness of the foliage of 0.3-1.2 m will decrease the temperature of a corridor by 0,15-1,2?.However,when the thickness is over 0.6 m,the wind velocity was decreased near 0 m/s.Adding an air layer between the foliage layer will increase the area of evapotranspiration effects.The increase of LAI and FCR will increase the abilities of optimization in the thermal environment as well.(Chapter 4)4. A series of shading models of GFs was built up and compared with the shading devices.Results reveal that a fully shading model of GF presented a most significant effect on thermal comfort and the PET of a corridor was decreased by 2.0?.Considering a balance on temperature,wind velocity,and PET,model V3 and H1 could be the secondary choices,whose PET was reduced by 1.9?and 1.6?.Comparing with the aluminum shading devices(solid models),the results reveal that the vertical shading form of solid models presented better performance than the GF model,while the horizontal shading form of solid models and GF models present almost no difference.An analysis of simulation data also revealed that a high correlation coefficient existed between the foliage volume and thermal indices.Furthermore,PET values present a higher correlation with MRT than temperature and wind velocity.(Chapter5)5. A series of scenarios of transitional spaces were tested basing on the standard model coupling with GFs.Results reveal that the upper floor corridor model,the arcade model,and external corridors presented similar results on thermal comfort and the fully shaded model presents the reduce on PET by 1.6-1.7?.In the balcony model,the front shading models(FA,F1,and F2)presented better optimization on thermal comfort and the average PET were reduced by 1.9-3.2?.In the cross ventilated model,the side shading GF could reduce the solar irradiation and keep the ventilation ratio so that a better performance on thermal comfort was given and the average PET was reduced by 0.1-0.7?.(Chapter 6)6. Basing on the field measurements,simulation studies,and application factors,an integrated model of GFs was built up.A hierarchy of foliage layer,fa?ade,and space and a procedure including objects analysis,design strategies,model building,performance evaluation,and model optimization was set up.The availability and feasibility of the design procedure were testified in the above step-by-step studies accompanying the setting GF models.(Chapter 7)Concludingly,this paper testified the optimization of GF on thermal comfort in the transitional spaces in a hot-humid climate area.The main factor is the reduction in solar irradiation by the GF and the second factor is the wind disturbing on evapotranspiration cooling power.Therefore,the layout of GFs should be considered on shading forms as well as on ventilation modes.This study provides guidelines on a climatic responsive design on GFs and supports the research on urban heat island mitigation.