| Urban heat island effect and severe high temperature weather seriously threaten people’s health and increase heat-related morbidity and mortality,especially for the elderly.In order to alleviate the negative impact of urban heat island and urban local overheating,a series of effective improvement measures have been proposed,including retroreflective materials,green vegetation,cool roofs and so on.Although these technical measures show a certain cooling effect,the rapid cooling effect of passive cooling on specific areas is small,the significance is low,and the transient benefit is not obvious enough.However,unlike passive measures,spray cooling system has been proposed as a promising active cooling technology.In order to verify the feasibility of the spray system in the summer outdoor bus waiting area,and to ensure the effective improvement of the outdoor thermal environment and the improvement of human thermal comfort,this paper makes an in-depth study on the improvement and optimization of the thermal environment of the spray system in the traffic waiting area.(1)Firstly,the influence of the spray system on the regional thermal environment of the traffic waiting area and the effect of improving the thermal sensation and thermal comfort of the human body are explored.The acceptance of the spray system installed in the traffic waiting area is investigated.The conclusions of the experiment are partially insufficient,and then the optimization strategy is proposed to improve the spray effect and further improve the thermal comfort of the outdoor human body in summer.(2)Secondly,after exploring the feasibility of the spray system in the traffic waiting area,the spray cooling system can significantly reduce the air temperature in the waiting area,but it also increases the relative humidity,which can seriously cause the pedestrians humidity and discomfort.Therefore,on this basis,an optimization experiment of different spray volumes was designed.By comparing different spray volumes(Case1 v=20ml/min;Case2 v=30ml/min;Case3 v=40ml/min)the coupling relationship between temperature and humidity and outdoor environmental factors(air temperature,relative humidity,wind speed,solar radiation)on the cooling effect of the spray system.At the same time,the subjective investigation and analysis of participants ’ thermal sensation,humidity and comfort under different spray volumes were carried out.Based on the subjective temperature and humidity parameters and objective investigation results,the spray volume most suitable for traffic waiting area was selected,which provided a research basis for improving human comfort.(3)In order to explore the effect of spray cooling under different initial water temperatures,a comparative experiment was carried out by reducing the initial water temperature,and the temperature and relative humidity under different nozzles were monitored and compared.Under different working conditions(Case1 ΔT= 0°C;Case2ΔT=-5°C;Case3 ΔT=-10°C;Case4 ΔT =-15°C),the questionnaire survey is carried out to summarize the thermal sensation,moisture sensation and thermal comfort of the human body.Through comprehensive comparative analysis,the best scheme is selected to further improve the thermal environment of the outdoor traffic waiting area and improve the thermal comfort of the human body.(4)By adding different low concentration alcohol in water,the heat transfer efficiency is improved,the evaporation process is accelerated,and the heat of the surrounding air is absorbed to achieve the cooling effect.The comparative experiment is carried out to detect the different working conditions(Case1 Vol=0%;Case2 Vol=2%;Case3 Vol=4%;Case4 Vol=6%),The temperature and relative humidity of the working are compared and analyzed,and the questionnaire survey is carried out to summarize the thermal sensation,humidity and thermal comfort.Comprehensive comparative analysis,and then select the best solution,so as to further improve the outdoor traffic waiting area thermal environment thermal comfort.In this paper,the whole experimental process is introduced in detail,and the future research directions and noteworthy problems are clarified.The research in this paper provides a theoretical basis for the spray cooling system to improve the thermal environment and thermal comfort of outdoor areas.It provides theoretical and technical support for the improvement of regional thermal environment when people travel in summer and wait for buses,and effectively promotes the development and application potential of spray cooling system. |
