Space heating models for residential buildings and the influence of urban variables

Proceedings of the workshop Ispra, 12-14 September 2016. The aim of this second workshop was to discuss different approaches and methodologies to assess energy efficiency measures as well as energy usage and monitoring of energy flows at building, urban and regional level, representing an opportunity to share information, integrate stakeholders’ views and set the ground for mutual collaboration. Eleven invited leading organisations and EU projects were invited to take part in this workshop sending experts to present their projects and discuss how to assess synergies and how to arrive to a coherent approach for assessment of energy use in the built environment. Another twelve people from JRC, experts on energy efficiency, energy performance, geospatial data modelling and processing participated to the workshop. Guglielmina MUTANI presented an energy consumption model at urban scale that includes the impact of the urban context on buildings' energy consumption. The model is combining a top-down approach (statistical model at municipality scale) and a bottom-up approach (simplified energy-use model for space heating, hot water production and electrical use). It is based on previous research results on mapping energy consumption and renewables sources and uses the CitySim simulation tool for the description of the buildings (and of their energy needs). The urban context is modelled through an urban context factor. The tool has been applied to the city of Turin

L'analisi del fabbisogno di energia elettrica e termica del parco edilizio esistente attraverso un sistema informativo geografico open source

Questo lavoro parte da un'analisi delle banche dati esistenti sulle caratteristiche del parco edilizio della Città di Torino con una correzione informatizzata dei dati, principalmente geometrici. Alcuni dati sono relativi al singolo edificio, altri, invece, si riferiscono alle sezioni di censimento, altri ancora vengono ricavati indirettamente dai dati esistenti. Vengono descritti i modelli di riferimento per il calcolo del fabbisogno termico ed elettrico che poi si applicano per poter effettuare delle valutazioni sul risparmio energetico sugli edifici. L'obiettivo di questo lavoro è quello di realizzare una procedura che possa poi essere estesa su tutto il territorio provinciale con un livello di approssimazione che dipende dalla disponibilità e qualità dei dati di partenza. Il software di georeferenziazione open source non verrà utilizzato solo per rappresentare dei dati ma anche per elaborare nuove informazioni, su cui poter condurre anche analisi statistiche. Ciò consentirà di poter valutare l'impatto delle politiche di risparmio energetico sul territorio

An Urban Energy Atlas and Engineering Model for Resilient Cities

Increasing energy efficiency in buildings is a crucial topic, especially in those EU countries where almost 50% of the final energy consumption is used for space heating and cooling, of which 80% is used for buildings. This study presents a model and a tool that can be used to evaluate energy consumption and to identify retrofitting strategies and renewable energy sources with the aim of reaching energy and climate targets in order to improve energy security, competitiveness and sustainability in a territory. In a previous research, a ‘top-down engineering’ model was applied for a number of 1 km2 districts in the city of Turin (IT) to evaluate the residual potential of buildings that could be connected to the district heating network. In this work, the energy-use model has been improved by considering applications to urban areas of different dimensions, and an urban energy atlas for the Turin building stock has been defined with the support of a Geographical Information System. The model has been validated by comparing the results of an energy balance calculation with energy consumption data of three consecutive heating seasons over an area of about 40 km2 in which 500,000 inhabitants live

Roof-Integrated Green Technologies, Energy Saving and Outdoor Thermal Comfort: Insights from a Case Study in Urban Environment

Green urban infrastructures have a significant impact on urban climate mitigation, on indoor and outdoor thermal comfort and on energy performance of buildings. In this paper, outdoor thermal comfort conditions and energy saving for space heating and cooling were investigated before and after the use of roof-integrated green technologies. Existing urban energy and climate models and tools were applied to an urban area located in a Turin (Italy). CitySim, ENVI-met and SOLWEIG tools and a GIS-based model were used to evaluate the mean radiant temperature and the thermal comfort of outdoor spaces before and after the use of vegetated roofs and green surfaces such as the predicted mean vote (PMV), the physiological equivalent temperature (PET) and the universal thermal climate index (UTCI). A GIS-based engineering model and CitySim tool were used to evaluate the energy saving and energy independence index for space heating and cooling after the use of green roofs and solar technologies. According to the shape and the suitability of rooftop elaborated with GIS tools, some roofs were identified as potential green roofs other as potential solar roofs for installing solar thermal collectors and photovoltaic panels. According to the results it is possible to confirm that the use of green roofs and urban greenery can decrease the mean radiant temperature until about 10℃ during summer season, improving outdoor thermal comfort conditions and energy savings with a reduction of 12% for space cooling energy consumption

GIS-based urban energy modelling and energy efficiency scenarios using the energy performance certificate database

The EU building stock is 97% not energy efficient and the promotion of energy retrofitting strategies is a key way of reducing energy consumptions and greenhouse gas emission. In order to improve the energy performance of buildings, the European Union released the Energy Performance of Buildings and the Energy Efficiency Directives. The certification of the energy performance of a building is a central element of these Directives to monitor and promote energy performance improvements in buildings, with the aim of increasing their energy efficiency level, thereby reducing greenhouse gas emissions. This work evaluates the energy performance of existing residential buildings using the energy performance certificate database and identifies the more effective retrofitting interventions by applying an urban-scale energy model. The novelty of this study is that a new retrofitting database is created to improve the results of a building energy model at urban scale taking into account the real characteristics of the built environment. The here presented GIS-based monthly engineering model is flexible and easily applicable to different contexts, and was used to investigate energy efficiency scenarios by evaluating their effects of city scale. An urban energy atlas was designed for an Italian city, Turin, as a decision-making platform for policy makers and citizens. This energy platform can give information on energy consumption, production and productivity potential, but also on energy retrofitting scenarios. The results of this work show that it is possible to obtain energy savings for space heating of 79,064 MWh/year for the residential buildings connected to the district heating network in the city of Turin; these interventions refer mainly to thermal insulation of buildings envelope with windows replacement and allow a reduction in greenhouse gas emissions of 12,097 tonCO2eq/year

Low-Carbon Strategies for Resilient Cities: A Place-Based Evaluation of Solar Technologies and Green Roofs Potential in Urban Contexts

The use of smart green technologies such as solar panels or green roofs on the top of buildings are identified as low-carbon infrastructure strategies. This work examines the roofs’ potential in a densely built-up context, analyzing the effects of smart green technologies on energy savings and thermal comfort conditions at district scale. The methodology presented can be used to accurately estimate solar energy potential and green roof potential on existing building stock at national, municipal, district and building level, with direct application in energy efficiency policy design. With the support of a place-based approach, the methodology was applied to a district in the city of Turin (Italy). A 3D model was created, some scenarios have been investigated, and priorities of interventions have been established mapping the spatial distribution of different parameters. From the results, it is emerged that there is a significant potential in Turin, and the use of green technologies especially in critical areas with solar technologies can promote a more sustainable development of the city. Solar modules and green roofs have been used alternatively to maximize the benefits. The applicability of these technologies can be integrated in the Municipal Energy-Environmental annex of the Building Regulations of the city of Turin

Boosting energy efficiency and RES in urban contexts: from the plan to the project

The breakdown by end-use energy shows a high incidence of buildings sector with a share of 35% of the total in 2010, a sharp increase compared to previous years and higher than the transport sector (31%) and industry (23%) [Bertini et al. 2012]. In high populated places, such as cities, there is a close correlation between the choices of spatial planning and the use of renewable energies and energy-saving strategies. Aiming at optimizing the use of energy in our cities is crucial. The European Directive 2010/31/EU on energy efficiency gives recommendations in order to increase services to the energy market; the spread of tools for the calculation of the feasibility of building’s renovation can help to measure, differentiate and optimize the use of energy sources even in urban areas. The implementation of spatial information through GIS tools can be important to manage energy demand changes and maximize the energetic potential of the territory. This works, developed within the Cities on Power project, co-financed by the Central Europe program, aims to integrate the energy efficiency and RES processes in residential buildings, with an holistic approach, giving to the municipalities some instruments to pilot correctly the energy transition

Social energy e produzione distribuita in ambiente urbano: nuova vocazione e nuovo business per gli spazi pubblici. Il caso della piccola centrale idroelettrica Michelotti del Comune di Torino

L'articolo discute il tema della produzione di energia da fonti rinnovabili per mezzo di piccoli impianti distribuiti sul territorio. Si riflette sul ruolo di queste infrastrutture nel più ampio fine di costruire un paradigma urbano in grado di offrire risposte concrete al progetto di smart city, con un coinvolgimento, anche economico, dei cittadini, e un possibile bilancio energetico "distrettuale". A tal fine si riporta il caso della piccola centrale idroelettrica Michelotti che verrà costruita a Torino, su un tratto del Po prossimo alla zona centrale della città

Environmental High Performance Urban Open Spaces Paving: Experimentations in Urban Barriera (Turin, Italy)

The aim of this paper is to describe the experimentation on environmental high performance urban paving for open space re- design in Urban Barriera program framework in Turin (Italy). Urban Barriera is a program designed to trigger a process of improvement of the “Barriera di Milano” area, the historical neighborhood in the northern part of the city. It was supported by the City of Turin, the Piedmont Region and the European Community, in order to operate on physical, economic, social aspects of the city by encouraging collaboration and proactive interaction between all actors and beneficiaries of urban redevelopment. Particular attention is given to the issue of re-design of urban open spaces, as an instrument for regeneration of the district also from the social point of view. The phase of competitive tender was preceded by a research on environmental high performance paving characterized by good properties related to solar absorption/reflection and permeability, selecting one of this materials for the redevelopment of public open space. In this work, the microclimate conditions of three urban areas were compared, with similar characteristics of morphological urban shape of buildings’ surround but different paving materials. The experimentation started with microclimate monitoring to evaluate outdoor thermal comfort; interviews on citizens and the calculation of thermal comfort indexes completed the analysis. Some of the thermal comfort indexes used are intended for outdoors spaces, but others were developed starting from indoor indexes. A first investigation on the correlation between outdoor thermal comfort indexes and subjective thermal perception have been conducted. The results of this paper analyse thermal comfort conditions during summertime with different paving materials and compare thermal comfort indexes with the subjects’ response. Some considerations on procedural aspects of an ordinary competitive tender concluded the study

Optimization of Costs and Self-Sufficiency for Roof Integrated Photovoltaic Technologies on Residential Buildings

It is common practice, in the production of photovoltaic energy to only use the south-exposed roof surface of a building, in order to achieve the maximum production of solar energy while lowering the costs of the energy and the solar technologies. However, using the south-exposed surface of a roof only allows a small quota of the energy demand to be covered. Roof surfaces oriented in other directions could also be used to better cover the energy load profile. The aim of this work is to investigate the benefits, in terms of costs, self-sufficiency and self-consumption, of roof integrated photovoltaic technologies on residential buildings with different orientations. A cost-optimal analysis has been carried out taking into account the economic incentives for a collective self-consumer configuration. It has emerged, from this analysis, that the better the orientation is, the higher the energy security and the lower the energy costs and those for the installation of photovoltaic technologies. In general, the use of south-facing and north-facing roof surfaces for solar energy production has both economic and energy benefits. The self-sufficiency index can on average be increased by 8.5% through the use of photovoltaic installations in two directions on gable roofs, and the maximum level that can be achieved was on average 41.8, 41.5 and 35.7% for small, medium and large condominiums, respectively. Therefore, it could be convenient to exploit all the potential orientations of photovoltaic panels in cities to improve energy security and to provide significant economic benefits for the residential users