Study On Natural Ventilation Effect Of Cold Alley

Sustainable development is the theme of human society development in the new century, and sustainable development of the buildings plays an important role in the global sustainable development. Under double pressure of saving energy and maintaining good indoor air quality, natural ventilation has become an important component in building energy efficiency. Especially in Lingnan hot-humid areas, natural ventilation is more important than architectural shading and heat insulation. Therefore, enhancing natural ventilation has become an important part of architectural design in Lingnan hot-humid areas. With the function of organizing natural ventilation, cold alley is the essence of traditional architectural design in Lingnan hot-humid areas.In this paper, the traditional architecture with cold alley - Chen Clan Academy has been taken as the research object. The research of cold alley effects on natural ventilation,regional micro-environment and indoor thermal comfort has been carried out by measuring the temperature, humidity, wind speed at different vertical heights in cold alley and simulating the airflow field with software FLUENT. After the research,this traditional technology is hopefully been applied to modern residential buildings so as to enhance the effect of natural ventilation and achieve building energy efficiency. The main conclusion is as follows by the study:First, solar radiation is the key factor of affecting cold alley thermal environment by the contrast test of measuring temperature, humidity, wind speed at different vertical heights in cold alley.Second, thermal insulating property of blue bricks (outer wall material) is good. Obviously, infrared temperature of outside surface on west outer wall in cold alley is lower 5℃than that of north outer wall in courtyard at the same time, and both reach their maximum value around 15:00. Meanwhile, infrared temperature of inside surface on west outer wall is also slightly lower than that of north outer wall, and relatively stable with small temperature difference.Third, indoor PMV value variation is consistent with indoor temperature variation on the whole, but the variation trend of relative humidity is almost opposite. PMV value steadily rises within the scope of 2.0-3.0 during the test, so indoor thermal environment is little poor and relative uncomfortable. Indoor thermal comfort should be satisfied by increasing ventilation components such as windows or strengthening the mechanical ventilation.Fourth, adding height-width ratio and length of cold alley is helpful for natural ventilation by numerical simulation, but the better height-width ratio is less than 36:1. Using the combination method of field test and numerical simulation to study natural ventilation mode of cold alley in Chen Clan Academy, it not only can evaluate effects of cold alley on the regional micro environment, but also has certain reference significance for architectural planning and design.