A study of the relationship between daylight performance and height difference of buildings in high density cities using computational simulation

Daylight design for “extremely” obstructed urban environment is a relatively uncharted area of scholarship. The reason might be that the problem has not been critically important. No city in the world has an urban density as high as Hong Kong. Deisgning and providing adequate daylight into buildings is a difficult challenge. A key question designers often ask is: If there is a need to build a high density city, what should it look like? What one should or should not do? There are many design variables. This study examined one of them: building heights. It attempted to determine what one could gain by optimizing it; and to understand what is the relationship between height difference of buildings in a city and the daylight performance. The study utilized computational lighting simulation as a study tool. Simplified cityscapes of various degrees of height differences are studied. They are plotted against the Vertical Daylight Factor (VDF) available to the building envelop. It has been found that, given the same high density, better daylight availability to the lower floors of buildings could be achieved by varying buildng heights.