Abstract
Rapid urbanization and associated land-use changes in cities cause an increase in the demand for electricity by altering the local climate. The present study aims to examine the variations in total energy and cooling energy demand in a calibrated building energy model, caused by urban heat island formation over Delhi. The study used Sentinel-2A multispectral imagery for land use and land cover (LULC) of mapping of Delhi, and Moderate Resolution Imaging Spectroradiometer (MODIS) imagery for land surface temperature (LST) mapping during March 2018. It was observed that regions with dense built-up areas (i.e., with built-up area greater than 90%) had a higher annual land surface temperature (LST), i.e., 293.5 K and urban heat island intensity (UHII) ranging from 0.9 K–5.9 K. In contrast, lower annual values of LST (290K) and UHII (0.0–0.4 K) were observed in regions with high vegetation cover (53%). Statistical analysis reveals that a negative correlation exists between vegetation and nighttime LST, which is further confirmed by linear regression analysis. Energy simulations were performed on a calibrated building model placed at three different sites, identified on the basis of land use and land cover percentage and annual LST. Simulation results showed that the site located in the central part of Delhi displayed higher annual energy consumption (255.21 MWh/y) compared to the site located in the rural periphery (235.69 MWh/y). For all the three sites, the maximum electricity consumption was observed in the summer season, while the minimum was seen in the winter season. The study indicates that UHI formation leads to increased energy consumption in buildings, and thus UHI mitigation measures hold great potential for energy saving in a large city like Delhi.
Highlights
Industrialization and economic growth cause urbanization, which brings about significant modifications in the land use and land cover (LULC) of a local region [1,2]
For the purpose of simulation, we identified three different sites based on their land surface temperature (LST) values, urban heat island intensity (UHII), availability of hourly air temperature data, and the percentage of LULC classes for these sites
Su et al [49] examined the relationship between LULC classes and LST, and found higher LSTs in the densely built-up areas compared to vegetative areas
Summary
Industrialization and economic growth cause urbanization, which brings about significant modifications in the land use and land cover (LULC) of a local region [1,2]. High rise buildings with complex geometries in urban areas reduce the sky view factor, thereby reducing the efficiency of radiation loss in the longwave region [4,5] This causes a significant decrease in the rate of cooling of urban surfaces compared to their rural counterparts [6,7,8,9]. Hwang et al [31] simulated the building model under different UHII magnitudes in the central Taiwan region They found that a linear correlation exists between the rise in cooling energy demand and the magnitude of UHI intensity in urban areas. Investigated the impact of UHI on energy consumption in residential buildings in Barcelona, Spain, by using Energy Plus as a simulation engine They reported that UHI intensity (1.7–2.8 ◦ C) in urban areas could increase the sensible cooling load by 18%–28%.
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