Application of Urban Scale Energy Modelling and Multi-Objective Optimization Techniques for Building Energy Renovation at District Scale

Fahad Haneef,Jérôme Henri Kämpf,Andrea Gasparella,Giovanni Pernigotto

doi:10.3390/su132011554

Fahad Haneef, Jérôme Henri Kämpf + Show 2 more

Open Access

https://doi.org/10.3390/su132011554

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Abstract

Nearly-zero energy buildings are now a standard for new constructions. However, the real challenge for a decarbonized society relies in the renovation of the existing building stock, selecting energy efficiency measures considering not only the energy performance but also the economic and sustainability ones. Even if the literature is full of examples coupling building energy simulation with multi-objective optimization for the identification of the best measures, the adoption of such approaches is still limited for district and urban scale simulation, often because of lack of complete data inputs and high computational requirements. In this research, a new methodology is proposed, combining the detailed geometric characterization of urban simulation tools with the simplification provided by “building archetype” modeling, in order to ensure the development of robust models for the multi-objective optimization of retrofit interventions at district scale. Using CitySim as an urban scale energy modeling tool, a residential district built in the 1990s in Bolzano, Italy, was studied. Different sets of renovation measures for the building envelope and three objectives —i.e., energy, economic and sustainability performances, were compared. Despite energy savings from 29 to 46%, energy efficiency measures applied just to the building envelope were found insufficient to meet the carbon neutrality goals without interventions to the system, in particular considering mechanical ventilation with heat recovery. Furthermore, public subsidization has been revealed to be necessary, since none of the proposed measures is able to pay back the initial investment for this case study.

Highlights

The potential of urban scale energy modeling tools coupled with multiobjective optimization was discussed in the framework of the optimal selection of energy efficiency measures for building energy retrofitting
To cope with the complexity and heterogeneity of urban districts, as well as with frequent issues brought by the lack of complete data inputs, a new methodology was proposed, combining the detailed geometric characterization of urban simulation tools with the simplification provided by “building archetype” modeling, allowing the development of models sufficiently robust for the definition of retrofit interventions at district scale driven by multi-objective optimization
Three goals were considered for optimization, focusing on energy, economic and environmental performances, and expressed in terms of annual energy demand for space heating, net present value and saved CO2 emissions during a 30year period for the whole district and each energy retrofitting alternative

Summary

Introduction

Building Energy Efficiency in the European Framework for 2050 Decarbonization. Cities will continue to expand, leading to a drastic climb in building energy needs. Action is needed to hit the net zero energy targets by 2050. Communities should lead the way and cities should unlock their enormous energy saving potential, especially through building retrofit interventions [3,4]. The transition from the current position to more sustainable, low carbon communities can be achieved following strategies to (i) switch from conventional to renewable energy sources, and (ii) reduce urban energy use [5]. In 2012, the 2012/27/EU Energy Efficiency Directive EED [6] added significant new elements to define a pathway to a “highly efficient and decarbonized building stock by

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