The heating and air-conditioning energy demand of skyscrapers with atria between buildings is explored. Radiation, conduction, convection, and ventilation were evaluated to determine annual heating and cooling energy demands for a 100-building city located in Provo, Utah. Spreadsheets models were developed and calibrated with a computational fluid dynamics model. Three spreadsheet model cases were examined: a baseline no-atrium case, a conditioned atrium case, and an unconditioned atrium case. The energy demands and atrium temperatures were compared between the different cases. The research concludes that atria can be used between buildings to reduce the heating and cooling energy demands. The exposed surface area of the city was reduced by 73.7%. This resulted in a 49.7% reduction in heating and cooling energy consumption for the unconditioned atrium case and a 16.0% reduction in energy consumption for the conditioned atrium case.

This thesis presents an investigation of a new three-dimensional urban form where walking distances are less than a half-mile and congestion is minimal. The car-free urban form investigated herein is a city composed of skyscrapers massively interconnected with skybridges at multiple levels. The investigation consists of optimizing space use arrangement, skybridge presence or absence, and elevator number to simultaneously minimize total travel time, skybridge light blockage, and elevator energy usage in the city. These objectives are evaluated using three objective functions, the most significant of which involves a three-dimensional, pedestrian-only, three-step version of the traditional four-step planning model. Optimal and diverse designs are discovered with a genetic algorithm that generates always-feasible designs and uses the maximum fitness function. The space use arrangements and travel times of four extreme designs are analyzed and discussed, and the overall results of the investigation are presented. Conclusions suggest that skybridges are beneficial in reducing travel time and that travel times are shorter in cities wherein space use is mixed vertically as well as horizontally.