Floor area density and land uses for efficient district cooling systems in high-density cities

Abstract

Floor area density and land uses are two fundamental parameters of a city's master plan. Both affect the spatial and temporal distribution of the cooling demand in a district. This work studies how floor area density and land use impact the efficiency of district cooling systems in high-density cities and quantifies the impact using five cost indicators. We use the street layout plan of a district of downtown Singapore to generate hundreds of designs by varying density and land uses using Rhino/Grasshopper and the quasi-Monte Carlo Saltelli sampler. Five independent input variables are used for the sampling. The three land uses featured are residential, office, and retail. We assess the cost performance of the district cooling systems for each sample using an urban energy simulation program tool, the City Energy Analyst (CEA). To identify the effects of each design variable on the capital and operational costs of district cooling systems, we perform the Sobol' sensitivity analysis. We find that the district land use ratio is the most dominant parameter, followed by the spatial distribution of density, whereas the spatial distribution of land uses has less influence. Urban planners and designers may use the results of this study of floor area density and land use when designing districts of high-density cities serviced by district cooling systems.