The impact of urban texture on energy system design process

This study evaluates the impact of urban planning decisions regarding building stock on energy system design and operation. Three urban planning scenarios are considered for an archetype neighbourhood in Nablus in Palestine. The distinguishing difference is that they have different albedo values for the building stock. A computational platform that combines building simulation, urban climate and energy system optimization (considering Net Present Value (NPV) and Grid Integration Level) is used to assess the scenarios. The study reveals that the annual or peak energy demand is not sufficient to compare two scenarios; it is important to consider energy demand pattern and the renewable energy potential, where an energy system design tool is important. Therefore, it can be concluded that the energy system design tools will play a major role in sustainable urban planning processes.

Digitalizing the urban landscape. Microclimate, energy systems and comfort

Silvia Coccolo, Dasaraden Mauree, Amarasinghage Tharindu Dasun Perera, Jean-Louis Scartezzini

Urban Green Infrastructures (UGI) play a major role in mitigating the urban climatic conditions, as well as improving people’s health and wellbeing. Indeed, nature has a positive impact both on the pedestrian thermal and psychological perception, increasing productivity and creativity due to their restorative properties. Additionally, UGI mitigate the urban climatic conditions, reducing the energy demand of buildings and affecting the energy systems. The objective of this work is to develop a digital platform to arrive at urban planning decisions considering the impact of greenings on the urban microclimates, thermal perception of the pedestrians and energy infrastructure. The greening module developed within the tool CitySim [1] is coupled with the Canopy Interface Model [2], in order to compute the impact of greening (trees and grass) on the air temperature and wind speed. The study is performed for several urban configurations, focusing on the Lausanne climatic conditions. Greenings are designed as grass (varying their f-factor as function of the water supply), and trees (varying their leaf area index and height). The microclimatic conditions are used to quantify the hourly human thermal comfort, by the bio-meteorological index COMFA* budget. The proposed methodology also integrates energy systems optimizations [3], focusing on the impact of greenings on the renewable energy systems and its influence in smoothing the peak demand. The simulations performed provide the dynamic hourly variation of the wind speed and air temperature within the urban canyon, as function of the greening design (evapotranspiration capacity, geometrical properties of trees). The human thermal comfort is computed, in time and space, showing the positive impact of greening in reducing the “warm” and “hot” thermal sensations during the warmer months. The hourly energy demand of buildings is also computed, and the results are analysed focusing on the renewable energy systems. Results indicate the positive impact of greening in mitigating the urban climatic conditions, as function of the canyon design and the evapotranspiration capacity of the landscape. The important impact on the energy demand of buildings and the energy systems is also presented, providing recommendations for a smart urban systems design. The proposed digital platform provides an interactive display, a common ground of discussion for urban planners, architects, engineers and biometeorologists. Thanks to the work developed, an interdisciplinary knowledge is defined, which will be used as a teaching instrument within the ENAC faculty.

2018

Integrating urban form and distributed energy systems: Assessment of sustainable development scenarios for a Swiss village to 2050

Silvia Coccolo, Morgane Le Guen, Nahid Mohajeri Pour Rayeni, Lucas Mosca, Amarasinghage Tharindu Dasun Perera, Jean-Louis Scartezzini

The integration of renewable energy in the built environment, improving the energy efficiency of buildings, and optimizing distributed energy systems are three interconnected activities that are central for the transition to sustainable cities. Here, a methodology is developed to quantify not only these three activities simultaneously but also link them to the urban form. Two development scenarios (densification and expansion) are proposed for the village Hemberg in Switzerland for the years 2030 and 2050. The results show that, with reference to 2017, global warming increases the cooling demand of the buildings by 70% in 2030 and by 115% in 2050. The results also suggest that renovation is the key element for the future energy management and efficiency improvement in Hemberg because the building insulation has much greater effect on the energy demand than the urban form. Furthermore, the results suggest that a grid-integrated energy hub consisting of wind turbines and PV panels can supply 77% of the annual energy demand in 2050. Also, urban form has great effects on building-integrated PV generation and, in general, on the integration of renewable technologies. The results contribute to efficient energy planning and policy-making for the future energy transition in Hemberg. (C) 2019 Elsevier Ltd. All rights reserved.

PERGAMON-ELSEVIER SCIENCE LTD2019

Redefining energy system flexibility for distributed energy system design

Vahid Moussavi Nik, Amarasinghage Tharindu Dasun Perera, Jean-Louis Scartezzini

A novel method is introduced in this study to consider flexibility taking into account both system design and operation strategy by using fuzzy logic. A stochastic optimization algorithm is introduced to optimize the system design and operation strategy of the energy system while considering the flexibility. GPU (Graphics Processing Unit)-accelerated computing is introduced to speed up the computation process when computing the expected values of the objective functions considering a pool up to 5832 scenarios. Subsequently, a Pareto optimization is conducted considering Net Present Value (NPV), Grid Integration (GI) level (which represents the autonomy level of the energy system) and system flexibility. The case study assesses an energy system design problem for the city of Lund in Sweden. According to the obtained NPV and GI Pareto front, a renewable energy penetration level covering more than 45% of the annual demand of the energy hub (an integrated energy system consisting of wind turbines, solar PV panels, internal combustion generator and a battery bank) can be achieved. However, the flexibility of the system notably decreases when the renewable energy penetration level exceeds above 30%. Furthermore, the results show that poor system flexibility notably increases the risk of higher-loss of load probability and operation cost. It is also shown that the utility grid acts as a virtual storage when integrating renewable energy sources. In this context, a grid dependency level of 25-30% (of the annual energy demand) is sufficient while reaching a renewable energy penetration level of 30% and maintaining the system flexibility.

2019

Digitalizing the urban landscape. Microclimate, energy systems and comfort

Silvia Coccolo, Dasaraden Mauree, Amarasinghage Tharindu Dasun Perera, Jean-Louis Scartezzini

2018