Comparing 2D and 3D Solar Radiation Modeling in Urban Areas

Štefan Kolečanský,Jaroslav Hofierka,Jozef Šupinský,Jozef Bogľarský

doi:10.3390/en14248364

Štefan Kolečanský, Jaroslav Hofierka + Show 2 more

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https://doi.org/10.3390/en14248364

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Abstract

The use of solar radiation in the urban environment is becoming increasingly important for the sustainable development of cities and human societies. Several factors influence the distribution of solar radiation in urban areas, including urban morphology and the physical properties of urban materials. Most of these factors can be modeled with a relatively high accuracy using 2D and 3D solar radiation models. In this paper, the r.sun and v.sun solar radiation models are used to calculate solar radiation for the city of Košice in Eastern Slovakia to assess the accuracy of both approaches for vertical surfaces frequently found in urban areas. The results were validated by pyranometer measurements. The results showed relatively good estimates by the 3D v.sun model and poor estimates by the 2D r.sun model. This can be attributed to an improper representation of vertical surfaces by a digital surface model, which has a strong impact on solar resource assessments. We found that 3D city models prepared in level of detail 2 (LoD2) are not always adequate in case of complex buildings with morphological structures, such as terraces. These cast shadows on facades especially when solar altitude is high and, thus, assessments, even by a 3D model, are inaccurate.

Highlights

The majority of the human population is located in cities, where, in developed countries, about 80% of the population lives [1]
We found that 3D city models prepared in level of detail 2 (LoD2) are not always adequate in case of complex buildings with morphological structures, such as terraces
This contributes to problems associated with dense urban areas, such as urban heat island effects, which lead to a higher energy demand, and to higher production of unwanted exhalants and emissions

Summary

Introduction

The majority of the human population is located in cities, where, in developed countries, about 80% of the population lives [1]. This contributes to problems associated with dense urban areas, such as urban heat island effects, which lead to a higher energy demand, and to higher production of unwanted exhalants and emissions. Solar thermal or photovoltaic applications are very common around the world and have become an important factor in the overall energy production mix in many countries. Solar radiation in urban areas is a key input factor in many urban energy models and sustainable city designs. The changes, associated with rapidly expanding solar benefits in cities, are expected to have disruptive impacts on urban electricity infrastructures and related institutions, and will require tools to evaluate and plan for future changes

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