Application study of the awning measure to obstruct solar radiation in permafrost regions on the Qinghai-Tibet Plateau

With globe warming, road safety will change dramatically, especially within the Qinghai-Tibet Plateau permafrost regions. Because of higher elevation and better almospheric transparency, the Qinghai-Tibet Plateau has stronger radiation than other regions, which can change the daily variation of ground surface temperature on the Plateau. The awning measure （shading board） is one of the actively protected permafrost measures, which was adopted along the Qinghai-Tibet railway and highway and the Qing-Kang Highway in China. Field test results show that embankment surface month mean net radiation is 60-130 W/m2, but the value is below 20 W/m2 under the shading board, and the reducing level of naRn-al net radiation is 80%-90%. The shading board reduced the heat flow entering into the embankment by 80%,90% or more, with heat entering into the soil on the common embankment, but emitting from the embankment under the shading board. At the same time, ground surface temperature under the shading board is 6-8 ℃ lower than the exposed embankment. Test results show that the shading board measure can rapidly and effectively reduce net radiation and heat flow into the embankment, decrease embankment surface and interior temperature, effectively delay increase rate of soil temperature under globe warming, ensure stability and safety of the embankment, and guarantee unblocked road projects in cold and permafrost regions.

Study on the influence of retroreflective materials on the“secondary reflection”on the room above the horizontal sunshade

Existing studies on horizontal sunshade systems mainly focus on the influence of the sunshade on the room under or inside the sunshade systems.Meanwhile,the top surface of horizontal sunshade,especially those with mirror surface or made of metal,reflects solar radiation into the indoor and surroundings,resulting in“secondary reflection”.This paper mainly focuses on the influence of secondary reflection on the room above the sunshade,using DesignBuilder software to conduct numerical simulation analysis and building architectural model for field measurement.Results from simulation and field measurement both prove that mirror materials increase secondary reflection reflected into the indoor.Moreover,results from experiments show that retroreflective materials decrease secondary reflection reflected into the indoor.At low latitude,the application of retroreflective materials on the top surface of horizontal sunshade effectively reduces the adverse influence of secondary reflection on the room above the sunshade.

Research on Landscape Energy-Saving Integrated Water Curtain System

Aiming at the serious heat and cold loss of the building glass curtain wall in the field of amusement and tourism,and the need to meet the landscape requirements of the building facade,this paper put forward the idea of integrating the shading and consumption reduction of glass curtain wall with the landscape requirements,that is,the water curtain was set outside the glass curtain wall to form a landscape energy-saving integrated water curtain wall system,while meeting the needs of landscape and shading.By establishing the numerical calculation model of the system,the corresponding relationship between the thickness of water film and the weakening of solar radiation intensity was revealed,as well as the influence of wind speed and wind direction on the nozzle exit angle and velocity selection;and the synergistic law of air flow rate and air temperature drop amplitude.The results showed that the water film thickness at 3-4 cm can reduce the solar radiation by 65%-80%.The temperature of the air layer between the water film and the curtain wall decreased as the air flow rate decreased,when the thickness of water film was 2 cm and the air velocity was 0.5-1.5 m/s,the air temperature dropped to 2.47-3.6°C.Finally,through the analysis of the actual project-ICE World&WATER Park,the system can reduce 66.8%of solar radiation,and reduce the air layer temperature by 3.9°C.