Urban weather generator user interface development : towards a usable tool for integrating urban heat island effect within urban design process

Abstract

Urban Weather Generator (UWG) is the urban design simulation tool that provides climate-specific advice for cityscape geometry and land use to assist the development of energy-efficient cities that are also thermally comfortable. The software enables urban designers to parametrically test built densities for masterplanning and urban planners to advocate zoning regulations such as building height and land use as well as policies for traffic intensity with energy and thermal implications of these interventions. UWG is the first tool publicly available that incorporates microclimatic considerations in urban design and energy simulations. The project succeeds the work of Bueno et al. (2014) to develop a useful and accessible urban design tool to model urban heat island effect (UHI) from measurements at an operational weather station based on neighborhood-scale energy balances. The sensitivity analyses for Boston, MA, USA, and Punggol, Singapore identify as key parameters the building morphologies such as site coverage ratio and fac̦ade-to-site ratio; building surface albedo and emissivity; and sensible anthropogenic heat in the urban canyon. The consistency of results for these cities reduced required user inputs to the model by 46% without decreasing the simulation accuracy. The developed software is available as a stand-alone tool as well as a new plug-in for the Rhinoceros-based urban modeling interface (umi) to integrate the microclimate analysis in the formal design process. The graphical user interface is written in programming language C# in the Microsoft .NET platform and is available free of charge at http://urbanmicroclimate.scripts.mit.edu/uwg.php. The newly proposed workflow for energy- and thermal comfort-driven urban design and planning is demonstrated through a case study of the new 130 thousand square meter development on the MIT East Campus in Cambridge, MA, USA. An IPCC-based climate change prediction is considered along with UHI to evaluate the proposed massing models at each design phase to ensure thermally comfortable urban development along the way.