Impact of Urban Characteristics on Microclimatic Conditions and Cooling Loads In a Newly Developed City
1Texas A&M University at Qatar, Qatar; 2Concordia University, Montreal, Canada
The microclimate of a dense urban environment is highly dependent on the form, structure, and material configuration of the buildings at the concerned site. In this study, we estimate the impact of urban characteristics on the micro-climatic condition of a district in a newly constructed city. Lusail is a new city which is being built just north of Doha, Qatar. The city buildings are required to be built with the local sustainability assessment tool called the Global Sustainability Assessment System (GSAS) kept in mind. A minimum GSAS 2 rating is required in all buildings. However, it is up to the contractors to further increase the sustainability perspectives of the building. To evaluate how variation in design characteristics affect the local microclimatic conditions and in turn, cooling loads, we assess the local conditions using the Urban Weather Generator and Openstudio simulation tools. Simulation results are obtained by varying building types, i.e., ‘mid-rise apartment,’ ‘large office’ and ‘standalone retail,’ with further variation in microclimatic conditions estimated through changing urban road pavement thickness and fraction of urban ground covered in grass and trees. Results are shown through the Urban Heat Island Effect with temperature and humidity deviations revealing fluctuations in the microclimate. A diurnal behavior in temperatures can be seen compared to rural weather readings, with urban heat effect raising night-time temperatures more than daytime temperatures. The updated microclimate data are then further used in a residential building model in Openstudio to see the microclimate impacts in terms of cooling load requirements.
Variation in Cooling Loads Based on Location of Apartments in High-Rise Buildings in Extremely Hot and Humid Climate
1Texas A&M University at Qatar; 2Concordia University, Montreal
In the extremely hot and humid climate of the Middle East, cooling loads in the residential buildings consume more than half the total electricity consumption. Having recently experienced swift growth in the construction industry because of the rapid population and economic growth, Qatar has seen an increase of more than two folds in its entire apartment buildings over the past two decades. These apartment buildings are ventilated and cooled by central chiller units, including the rooftop unit and, more recently, district cooling systems. Cooling loads vary significantly based on the zone location in tall buildings, as these loads are dependent on the direct and indirect impact of sunlight. Furthermore, cooling also varies depending on the floor level as various parameters, including wind speed, atmospheric temperature, and pressure changes depending on the height. Considering that some of the apartment stakeholders of high-rise buildings charge a flat rate for cooling, this study aims to assess the impact of zone location on space cooling consumption in an extremely hot and humid environment. To estimate the differences based on apartment location, this study evaluates a 16 storied residential building in Lusail city, located just north of Doha, Qatar. An energy model of the building is simulated through the Openstudio simulation environment. Cooling loads are measured for apartments located North, South, East, and West of the building. Furthermore, the impact of height is also assessed by comparing the cooling required in the first and top floor apartments.