The Indoor Humidity Environment Of Huizhou Traditional Vernacular Dwellings

As one of the most typical climatic traditional dwellings,Huizhou traditional vernacular dwelling is not only a valuable historical and cultural heritage,but also possesses amount of distinct strategies of ecological adaptability,drainage and moisture proof that have a vital influence on the indoor humidity environment.The parameter of air humidity plays an significant role in the indoor thermal environment,which is closely relevant to many issues like thermal comfort and human health,etc..Therefore,it is imperative to focus on the study of indoor humidity environment.The study aims to figure out the status quo and the formation mechanism of humidity environment of Huizhou traditional vernacular dwellings.It is also expected to design the passive dehumidification strategies in order to solve the indoor humidity concerning problems effectively.It was carried out a one-year field measurement of air temperature,relative humidity,wall surface temperature in a typical Huizhou traditional vernacular dwelling compared with a modern dwelling on the same condition.The results show that the level of indoor humidity environment is at ‘wet' and ‘very wet' in Huizhou traditional vernacular dwelling.It the major problem that the high indoor humidity contributes to the indoor thermal discomfort.Specifically,the proportion of comfort time discreases a lot during autumn due to the moist condition compared with a diserable thermal comfort during spring.There are more than 50% of period of summer distribute in moist,muggy during summer.It is uncomfort during winter with a period of clammy time.The indoor humidity environment is mainly influenced by the outdoor humidity environment in the hall due to the transparent structure of the traditional vernacular dwelling.There is a comparatively strong relationship with the indoor and outdoor humidity environment in the wing-room during mild seasons while the dependency weakens slightly during summer and winter.Moreover,the diurnal amplitude of indoor humidity is relative small in the wing-romm due mainly to the air-exchange through hollowed-out windows and the moisture buffering effect of the internal wooden wall.Therefore,the indoor humidity environment is more stable and comfort in the wing-room compared with the hall.There is also a risk of moisture condensation on the ground of the hall in the morning and at night whilst the suspended wooden floor in the wing-room has a good effect of thermal insulation and anti-condensation during the mild seasons.moisture ondensation on of the hall morning nd night hilstsuspended ooden oor in the ing-room has ood of thermal nd nti-condensation du ing t mild seasons.There are amount of factors influence the indoor humidity environment of Huizhou tradtional vernacular dwelling,e.g.outdoor climate,indoor air distribution,internal moisture source and moisture buffering effect of envelope materials.It is built a balance equationof the indoor air humidity in Huizhou tradtional vernacular dwelling.The major influencing factor is the moisture transmission by natural ventilation after the analysis of various moisture t concerning items.It is expected to apply the dehumidification by natural ventilation to improve the indoor humidity environment in order to take full advantage of the climate resources.It is devided into three period of the yearly ventilation in Huizhou tradtional vernacular dwelling,which are 222 d of available ventilation period accounting for 61%,28 d of limiting ventilation period accounting for 8% and 114 d of unavailable ventilation period accounting for 31%.The indoor moisture excess is taken away by bringing the adequate outdoor fresh air during the available ventilation period while adpopt intermittent ventilation during the limiting ventilation period.When in the unavailable ventilation period,it is supposed to improve the building air-tightness and thermal insulation.The available ventilation period in Huizhou tradtional vernacular dwelling mainly distributes in spring,summer and autumn.It is analyzed with the software of Fluent that the dehumidification efficiency in various ventilation conditions(opening door and windows,only opening door,only opening windows,opening new windows in northern wall).The simulation results show that the dehumidification efficiency of only opening windows is higher than only opening door during spring and summer.The dehumidification time of only opening door is relative short while the homogeneity of indoor humidity is undesirable.The optimization design of new openings on the north wall forming a indoor cross ventilation could shorten the dehumidification time effectively and avoid a high humidity with the increase of opening area.