Urban heat island in Boston – an evaluation of urban air temperature models for predicting building energy use

The Urban Heat Island (UHI) effect is a well-documented phenomenon, in which the air-temperature in an urban area is elevated relative to the regional air-temperature.  This paper evaluates two recently developed methods for generating urban weather files from a rural station that account for microclimatic impacts on dry-bulb temperature and relative humidity.  The two methods examined are computationally inexpensive.  The first method is the urban weather generator (UWG) a model developed by Bueno et al. and the second is a temperature alteration scheme developed by Crawley (Bueno et al., 2012; Crawley, 2008).  Actual weather data is used to validate the modeled urban data.  Actual and modeled weather data is used in simulation of a typical single-family and small office building to quantify model output in terms of combined heating and cooling energy use intensity (EUI).  The difference between urban and rural EUI actual is 13% and 17% for the small office and single family building, respectively.  The UWG reduces this difference to 8% and 13%. The Crawley scheme reduces this difference to 9 % and 14 % (ΔDB = 1°C) or -9% and -4% (ΔDB = 5 °C).