Analysis of the urban heat island effects on building energy consumption

Abstract

Urban areas usually experience higher temperatures when compared to their rural surroundings. Several studies underlined that specific urban conditions are strictly connected with the Urban heat island (UHI) phenomenon, which consists in the environmental overheating related to anthropic activities. As a matter of fact, urban areas, characterized by massive constructions that reduce local vegetation coverage, are subject to the absorption of a great amount of solar radiation (short wave) which is only partially released into the atmosphere by radiation in the thermal infrared (long wave). On the contrary, green areas and rural environments in general show a reduced UHI effect, that is lower air temperatures, due to evapo-transpiration fluxes. Several studies demonstrate that urban microclimate affects buildings’ energy consumption and calculations based on typical meteorological year could misestimate their actual energy consumption. In this study, two different sets of meteorological data are used for the calculation of the heating and cooling energy needs of an existing university building. The building is modeled using TRNSYS v.17 software. The first set of data was collected by a weather station located in the city center of Modena, while the second set of data was collected by another station, located in the surrounding area of the city, near to the studied building. The influence of the different meteorological situations described by the two weather stations are analyzed and assumed to be representative of the UHI effect. Furthermore, the effects of UHI mitigation strategies on the building energy needs are evaluated and discussed

Assessing the urban heat island and its energy impact on residential buildings in Mediterranean climate: Barcelona case study

“…The analysis performed for Boston (MA) [65] showed, instead, a smaller impact of the UHI on the residential cooling demand; however, the climate of Boston is colder compared to Barcelona, so the cooling need is less relevant. Finally, the impact of the UHI intensity on the cooling needs is found to be greater on residential buildings compared to office buildings [38,44,45], whose energy needs are more related to the internal heat gains rather than outdoor temperature variation.…”

“…A methodology already employed in several studies has been adopted [17,27,38,44,45,49,50]; this consists of using temperature data collected at urban and rural sites as input data for a set of energy simulations of a sample building. The difference between the results obtained with the two set of climate data is assumed to be due to the UHI effect.…”

“…With the same methodology, Magli et al [45] estimated the impact of the UHI on the cooling loads of a university building in Modena (Northern Italy), finding an increase of about 10% for the urban situation compared to the suburban one.…”

University energy planning for reducing energy consumption and GHG emissions: the case study of a university campus in Italy

“…The University owns professional weather stations in both Modena and Reggio Emilia [15][16]. The hourly weather data include global radiation on horizontal, dry bulb temperature, wind speed and relative humidity.…”

The Impact of Albedo Increase to Mitigate the Urban Heat Island in Terni (Italy) Using the WRF Model

“…The intensity of the UHI depends strongly on the urban characteristics, the synoptic conditions, the local meteorological features, the type of urban materials and the presence (or lack) of green areas [3]. Urban warming has serious energy and environmental impacts on cities and its residents [4][5][6][7][8][9]. The UHI may increase the energy consumption of a reference building and leads to a rise of CO 2 equivalent annual emissions for a cooling of up to 7% [10].…”