Urban heat islands and electrical energy consumption in a Brazilian city

Widely known as urban heat island (UHI) phenomenon, urban air temperatures tend to be higher than rural temperatures,due to the thermal performance of building materials and urban geometry, together with the productionof anthropogenic heat. Although the UHI phenomenonis worldwide studied, still just too few works deal with the relationship between heat islands and electricalenergy consumption. Furthermore, just a few tools that could actually support urban designers and decisionmakers are currently available. In order to develop a methodology and tools that could help in this field, this study proposes the development of thermal and energyconsumption maps to generate suitable planning information. The proposed methodology applies a GIS environment to store, analyze and cross-examine data of an urban thermal environment and its energy consumption.First of all, a residential neighbourhood in a medium sized city was selected as the study area. In this area forty points were taken as urban reference points, where air temperatures at the pedestrian level were collected.At the same time, rural temperatures made availableby the city meteorological station, were registered. Data of electrical energy consumption of the building units (houses and apartments) were collected through a household survey that was also designed to identify the users income levels. Then, by applying GIS tools, maps were developed so that the configuration of urban heat island and electrical energy consumption could be visualized, compared and analyzed. For the neighbourhoodstudied, the results showed that the income level was the most important variable influencing electrical energy consumption. However, a strong relationship of the consumption with the thermal environment was also observed. By comparing the maps created, it was possible to observe that the highest energy consumption areas tend to occur within areas of highest urban heat island intensity.