Research On The Impact Of Waterscapes On Outdoor Thermal Environment Of Residential Quarter

With the process of urbanization, urban underlying surface is constantly changing. Increasingly prominent heat island phenomenon increases energy consumption and thermal environment deterioration even seriously affects people’s daily outdoor activities and health. As an important factor in urban planning, waterscape plays an important role in regulating microclimate for its passive evaporative cooling characteristic. Meanwhile, waterscape is widely used in Landscape design in Guangzhou residential quarters as a feature of Lingnan garden, while some unreasonable forms of waterscapes not only cause a waste of resources but also improve the difficulty of operation and maintenance, resulting in some negative effects and contradictions. It adversely affects the thermal environment.Firstly, investigation on the types of waterscape and its design situtions of typical residential quarters in Guangzhou was carried out, and the experience and deficiency of the design and maintenance of waterscape was summarized. Field measurements were carried out to study the effect of different forms of waterscapes on outdoor thermal environment in Guangzhou. The thermal environment parameters like solar radiation, wind speed, air temperature and air relative humidity were measured and the values of the Standard Effective Temperature(SET*) were calculated to evaluate the human thermal comfort. The results show that water plays a role of cooling and humidification and can reduce the SET* slightly compared to other underlying surfaces, while solar radiation still plays a decisive role in influencing air temperature and the SET*. Falling water like waterfalls and fountains can increase the effect of cooling and humidification on air while the exposed surfaces of rockery will absorb solar radiation and deteriorate the microclimate conversely when the waterfalls or fountains are not working or dry up. In the weather condition of weak solar radiation and low wind speed, air temperature at the waterside was significantly lower than other underlying surface and it’s suitable for outdoor activities with the lower SET*. Waterscapes should be combined with shading and ventilation design.The layout of the waters and its suitable size in a residential quarter were optimized through numerical simulation later and the it shows that the degree of improvement by the static water is closely related to the Sky View Factor, wind speed and direction, length-width ratio of the water, area of the water and the relative distance between the water and the buildings. Strategies for designing waterscape in residential quarters were put forward based on the study above to improve the outdoor thermal environment effectively.