Improving the Daylighting and Natural Ventilation of High-Rise Apartments in Hawai'i

Abstract

This thesis argues that the economic and land-use efficiencies of the double-loaded corridor high-rise apartment buildings come at a high cost to building occupants and the natural environment in the form of poor ventilation and daylighting, requiring unnecessary energy use through air conditioning and artificial lighting. While systems such as the single-loaded corridor, double-sided skip-stop, and vertical access arrangement offer potentially improved living environments and reduced energy use, these advantages are offset by significant reductions in built potential. In response, this research examines how double-loaded corridor apartments' daylighting and natural ventilation could be significantly improved without reducing built potential. Digital simulations suggested both ventilation and daylighting values are at their poorest at the rear of most double-loaded corridor apartments. It was hypothesized that rotating 90 degrees and insetting the lanai that usually runs across the front of such an apartment might significantly improve the penetration of fresh air to the rear of the unit, and subsequent analysis showed this to be the case. It was postulated that reducing the depth of a unit by stacking rooms on two levels could potentially benefit ventilation and daylighting. Again, computer simulations showed that the reduction in depth was clearly beneficial to daylighting, and together with the vertical connection of space, it also significantly improved air circulation. Doubling the height of apartments, however, also had unplanned effects. The number of buildable units in height-limited building zones would be halved. To neutralize this, half the double-height unit was placed in front of the other, restoring the built potential to that of an equivalent double-loaded corridor building. Finally, to offset the negative impacts of this change on daylighting and ventilation, the depth of the apartment was reduced by 4ft. The resulting building has the same number of living units as a double-loaded corridor structure of the same height but with greatly improved daylighting, ventilation, and significantly lower energy consumption. Effectively a single-sided skip-stop, it also requires only half the circulation of a double-loaded corridor building, offering significant additional savings in both construction costs and carbon emissions.