Research On Cooling And Energy Saving Effect On Climbing Vertical Greening In Guangzhou Area

In the process of urbanization,it is necessary to make full use of vertical greening of buildings to increase urban greening and reduce building energy consumption.For a long time,there have been many studies on the thermal performance of traditional vertical green faade(Direct green fa?ade),but few studies on Double-skin green faade(Double-skin green fa?ade).Climbing vertical greening depends on the support structure on external side of that wall,which makes the air layer between the vegetation layer and the wall form.It has the advantages of low cost and easy popularization,and has great potential of development and research.In this paper,evergreen climbing plant Pyrostegia venusta were selected and planted on the left side of the western wall of the comparative laboratory.Through theoretical research on vertical leaf area index and its measuring instrument,experimental verification of VLAI value measurement scheme and statistical analysis of data,a suitable method for measuring vertical leaf area index is obtained,and the VLAI value of 20 cm thick Pyrostegia venusta is 4.51 ± 0.033.Then the simplified energy and heat balance equation is obtained by theoretical analysis of heat and mass transfer in vertical greening of outer climbing.According to previous studies,the transpiration latent heat of plants generally accounts for about 50-60%,indicating that the physiological and thermal effects of plants can play a great role.The transpiration coefficient(TC)was 501.66,and the net photosynthetic heat effect was 3.13% of the transpiration latent heat,so the net photosynthetic latent heat should be about 1.565-1.878%.The net photosynthetic latent heat could not be considered in the allowable error range of energy and heat balance calculation.Finally,through the experiments of cooling and energy saving in the self-built comparative laboratory,the following conclusions are drawn: to the inner and outer surface of RW’s wall,GW’s temperature can be highliest reduced by 6.55°C and 15.38°C;respectively,the temperature of the indoor air in GW’s can be highliest reduced by 3.80°C.In the outdoor environment,the maximum reduced temperature of black globe in the air layer of vertical greening inner can be 12.30°C compared with bare wall;the temperature of black globe in the middle of greening layer can be reduced by 11.00°C;and it can also be reduced by 2.70°C on the outer side of greening.Under the condition of air conditioning,the indoor air temperature of the comparative laboratory room is controlled at 24°C.In a certain period of time,compared with RW room,GW room can save 16% of the electricity consumption.It can be seen that the outer climbing vertical greening has a good cooling and energy saving effect.Through the study of leaf area index,physiological heat effect and cooling energy saving of vertical greening with outer climbing,it lays a foundation for further study of its thermal performance,and it can also provide test methods and basic data for the application of vertical greening in landscape architecture.