Quantifying the impact of urban climate by extending the boundaries of urban energy system modeling

Abstract

Rapid growth of cities, concerns on global warming and depletion of fossil fuel resources call for sustainable energy solutions for cities. Distributed energy systems such as energy hubs offer promising solutions in this context. Evaluating the energy demand at urban scale is vital to support the design of energy hubs. However, most of the recent studies are based on bottom-up models and do not consider the energy demand in detail. More specifically, the influence of the urban climate on urban energy demand has not been considered so far in the energy system design process. In order to address this research gap, a novel computational platform is developed in the first part of this study, combining an urban climate model with a building simulation tool and an energy system optimization model. The second part of the manuscript is devoted to quantifying the impact of urban climate on energy system design and assessing the consequences of neglecting this specific aspect on energy system performance. Three case studies are conducted considering three building densities for the city of Nablus (building density at the periphery, center and future center of the city) in Palestine. Three scenarios representing 1) standalone buildings (present practice) 2) shadowing and longwave reflection (radiation heat transfer from the walls and the roofs of the buildings to the urban climate and to the sky) of neighboring buildings and 3) urban climate are considered for each case study when computing the energy demand. Subsequently, the energy system is optimized considering Net Present Value (NPV) and system autonomy level as the objective functions (Pareto optimization). The results of the study reveal that the urban climate has a notable impact on the energy demand and energy system design. More importantly, it is shown that the influence of urban climate results in higher fluctuations in the energy demand, which in turn results in a notable increase in the NPV (by up to 40%). This further magnifies the increase in annual or peak demand. The study reveals that neglecting the influence of urban climate in the energy system design process can result in a performance gap in NPV, grid integration level, and greenhouse gas emissions and can impose reliability issues. The design tool introduced in this study can be used for urban planning to mitigate the aforementioned adverse effects.

A review of assessment methods for the urban environment and its energy sustainability to guarantee climate adaptation of future cities

“…Perera et-al. [117] extended the boundaries of the urban energy system model to incorporate the influence of urban climate. They showed that the urban climate is having a considerable impact on both the design and operation of the energy system.…”

“…As explained in Section 3, both models were developed as an urban modelling platform that includes integrated custom modules for modelling microclimatic effects, transient heat flow, plants and equipment as well as occupant presence and behaviour. CitySim has furthermore been extended with the coupling with CIM and the energy hub tool to design urban energy systems [117]. Table 5 underlines the tools that are already available and their capabilities.…”

An Urban Energy Atlas and Engineering Model for Resilient Cities

“…Studies on Urban-Scale Energy Modeling (USEM) have shown the importance of morphological characteristics for the energy consumption of buildings [7]. The influence of urban form is considered important to optimize an energy system, together with the impact of the microclimate in built-up areas [8] and the characteristics of the outdoor environment [9]. These models also investigate the interaction between individual buildings and the urban context.…”

Optimal Operation Modes of Virtual Power Plants Based on Typical Scenarios Considering Output Evaluation Criteria

“…Considering the limitation and negative impact of fossil fuels, renewable energy has become the focus of the global energy industry. Distributed energy systems (DES) offer promising solutions in this context, and their impact on urban power grids has drawn the attention of scholars [1,2]. Distributed generation (DG) has developed rapidly owing to its advantages, such as low pollution, high efficiency, and cost savings in power transmission and transformation infrastructure [3].…”