Energy Renovation Of Buildings Research Articles

Can distributor system operators play a role in the European Union energy efficiency financing game?

On-bill schemes are innovative financial frameworks for supporting energy renovation based on private capital. Direct intervention of public authorities may not be necessary. The pivotal role is assumed by energy utilities which are the originators of the business and act as market aggregators. On-bill schemes are based on a simple principle, namely the utility supports the energy renovation of final users by providing the upfront capital to repay on the utility bill. This implies that energy supply and renovation services are provided by the same company. This could be a limitation since the user may be obliged to stay with the same energy supplier for all the duration of the on-bill scheme. Even more complications can arise when the dwelling is sold or rent to another tenant. For such a reason it is important to find solutions for the possible decoupling of energy supply and energy renovation services. The present paper introduces an innovative business model which involves Distribution System Operators or other designated entities acting as market facilitators supporting the decoupling between energy supply and building energy renovation services. To characterise precisely the business ecosystem and the relations among the different actors, the Value Flow Model is employed.

Climate Change and Building Renovation: Effects on Energy Consumption and Internal Comfort in a Social Housing Building in Northern Italy

Climate change is becoming a crucial factor to consider within human activities and the building sector is particularly influenced by aspects of internal comfort and energy. In Italy, great attention has been paid to the energy refurbishment of buildings. However, such interventions are mostly focused on reducing heating energy consumption, thus neglecting summer season performance. Moreover, climate change is barely considered during the design phase. This issue is addressed in this work which analyzes some of the most common refurbishment interventions applied to a social housing building in Trieste, while also considering internal comfort during the summer season. A dynamic analysis of the building-plant system is carried out using EnergyPlus. Fanger, UTCI and the adaptive comfort models were used to represent internal health, while three TRY data sets were generated using two GCM–RCM projections to evaluate the influence of climate change. The results show that both building insulation and climatic change affect heating consumption reaching a 70% reduction. However, building insulation does not greatly affect internal comfort, although different models show different behavior to protect against external temperatures. On the contrary, climatic change influences the percentage of hours of discomfort, with a 20% increase for all of the models. The final consideration is that people’s internal health should always be considered when carrying out refurbishment activities.

Streamlining Building Energy Modelling Using Open Access Databases—A Methodology towards Decarbonisation of Residential Buildings in Sweden

The building sector is a major contributor to greenhouse gases, consuming significant energy and available resources. Energy renovation of buildings is an effective strategy for decarbonisation, as it lowers operational energy and avoids the embodied impact of new constructions. To be successful, the energy renovation process requires meaningful building models. However, the time and costs associated with obtaining accurate data on existing buildings make large-scale evaluations unrealistic. This study proposes a methodology to streamline building energy models from open-access datasets for urban scalability. The methodology was tested on six case study buildings representing different typologies of the Swedish post-war construction period. The most promising results were obtained by coupling OpenStreetMap-sourced footprints with energy performance declarations and segmented archetypes for building characterisation. These significantly reduced simulation time while retaining similar accuracy. The suggested methodology streamlines building energy modelling with a promising degree of automation and without the need for input from the user. The study concludes that municipalities and building owners could use a such methodology to develop roadmaps for cities to achieve carbon neutrality and evaluate energy renovation solutions. Future work includes achieving higher accuracy of the generated energy models through calibration, performing renovation analysis, and upscaling from individual buildings to neighbourhoods.

The HOME-Health (HOusing, environMEnt, and Health) Study; Description of a Danish natural experiment, designed as a longitudinal study with repeated measurements, providing internal- and external validity of the study.

The ambient and indoor environment are pivotal to our health. We spend most of our time indoors within our home, why our home is where we are most exposed to indoor pollutants and indoor air quality (IAQ). Populations within social housing areas are more vulnerable due to advanced age, co-morbidity and social economic status. Commonly, studies within social housing are cross-sectional, few Nordic longitudinal studies exist, and fewer studies combine quantitative and qualitative measurements in a mixed method approach. This research proposal provides an extensive detailed description of the design and methodology of the HOME-Health study. The study is a longitudinal study and is a natural experiment employing structured surveys, objective measurements of indoor air parameters, lung function test and qualitative semi-structured interviews. Data collection are conducted seasonally (winter and summer), before and after building energy renovation (BER). The study population before BER (n = 432) was explored and found similar to the Danish social housing population in terms of age, gender, persons per apartment and migration status. Future analyses should be stratified by multi-family apartments and terraced houses. The aim of the HOME-Health study is to provide knowledge about residents' seasonal state of health, perception of indoor enviromental quality (IEQ), IEQ-related behaviours and practices, and objective measurements of IAQ before and after BER. By applying a design with repeated measurement before and after BER, and combining both objective and subjective quantitative as well as qualitative data the study is expected to create in-depth knowledge. Future results will provide evidence of both energy-savings and non-energy savings from different BER projects. Knowledge which are expected to benefit future renovation projects within social housing areas.

Beyond Well-Being: The Assessment of the Energy Renovation in Latvia by the Residents

Abstract Multi-family building renovation represents a key policy area at the same time, predominantly affects the daily life of residents. The paper tackles the energy renovations of multi-family buildings in Latvia. Specifically, it investigates how the renovation process affects the residents’ health and well-being, their perception, and their understanding of the renovation process. To evaluate the residents’ perception, a survey was conducted in thirteen buildings renovated using energy performance contracting to assess the preparation, execution, and impact of the renovation project. The survey revealed the lack of communication between the parties involved and co-design as the roadblocks to upscale the renovation process in Latvia using energy performance contracting. The paper shows aspects of the process that need to be improved to scale up the renovation in Latvia.

Energy renovation of the multi-residential historic building after the Zagreb earthquake – Case study

Historic buildings represent our cultural heritage and identity. Due to their age and building tradition, they are extremely vulnerable to seismic excitations, as confirmed by the recent earthquake in the city of Zagreb. In addition, historic buildings are among the buildings with the worst energy performance and very low indoor comfort. In the scope of this paper, the seismic and energy integrated approach is applied to a typical multi-residential building in Zagreb historical downtown. The main focus of the paper is on building envelope energy efficiency measures. Different variants of thermal insulation (external and internal), secondary windows (maintaining existing ones vs. new efficient ones) and ventilation (natural vs. mechanical with heat recovery) are analysed in terms of building energy performance (3D level). Furthermore, replacement of existing technical systems and installation of RES are also considered. Moreover, the acceptability of the proposed retrofitting solutions for opaque elements is evaluated in terms of thermal bridges (2D level) and long-term hygrothermal performance (1D level). Finally, the results show that it is possible even for a 100-year-old building to meet the current national primary energy requirements for new buildings and provide good indoor environmental quality for occupants while respecting the cultural heritage.

Comparing public- and private-driven one-stop-shops for energy renovations of residential buildings in Europe

Energy efficiency in buildings remains an important priority for the European Union. Towards that direction, therole of the one-stop-shops (OSSs) that will offer integrated renovation services has been further enhanced. Thepaper aims to compare public and private-driven OSSs to increase knowledge regarding the way they operate.The business models of ten OSSs for renovation of residential buildings, operating in six European countries havebeen analysed, and further evaluated for their engagement in the critical moments of the renovation customerjourney. Findings show that the majority of examined OSSs have managed to reach some level of standardizationin the way they deliver their service. Additionally, the examined OSSs appear to be engaged in the critical momentsof the renovation customer journey, which can attract the interest of potential customers. Public-drivenOSSs appear to operate smoother in the renovation market and offer services that are considered crucial for theirpotential customers. Their viability though in the absence of public funding needs to be further examined. On theother hand, private-driven OSSs are called to deal with greater challenges in their effort to consolidate their presencein the renovation market. Providing access to financing remains a challenge for private-driven OSSs, whichto attract more customers resort to value additions to their service, which might affect their viability. The studyprovides valuable information and insights about OSSs in operation that could be useful to stakeholders that areactive in the renovation market or interested to enter it.

Improving the building stock sustainability in European Countries: A focus on the Italian case

COVID-19 pandemic has caused an economic crisis, and also the building sector has suffered consequences. Indeed, an increase in the building energy consumption, mainly in the residential sub-sector, was registered, due to higher energy use. European Union has enacted a strategic plan to combat this crisis by promoting environmental sustainability and giving a key role to the building sector. This study provides an overview of the implementation state from EU countries, of the European policies in terms of building energy efficiency and draws attention to the adopted financial programs and incentives to promote an energy-efficient built environment. It is shown that more than 70% of Member States have transposed the EU Energy Performance of Building Directives and all of them have activated plans or programs to finance the building energy renovation , mainly in the residential sector. A focus is made on the Italian case, by considering the recently introduced tax deduction of 110% (divided into a number of annual rates) that promotes specific energy efficiency measures for existing buildings, in the vein of new requirements provided by the Directive EU 844/2018. In this investigation, three residential buildings are selected, and, by employing both semi-stationary and dynamic approaches, a critical analysis of several passive and active energy efficiency measures is performed. The variability of climatic conditions and building markets are considered in energy and economic evaluations: the building case studies are located in different Italian climatic regions and have different construction ages. Considering the energy, environmental and economic indicators, it is shown how the new Italian funding program can boost the diffusion of energy efficiency interventions which imply the best energy performance, and not the best cost/benefit ratio. The study points out achieved goals, criticalities , and new perspectives after years of energy policies in Europe.

A Sequential Multi-Staged Approach for Developing Digital One-Stop Shops to Support Energy Renovations of Residential Buildings

Buildings account for 40% of the European Union’s energy consumption. Deep energy renovation of residential buildings is key for decarbonization and energy poverty alleviation. However, renovation is occurring at far below the needed pace and depth. In this context, building renovation one-stop shops, which bring all project phases under one roof and provide advice, support, and finance to households, are highlighted as a promising solution. Nevertheless, this model is still absent or under-developed in most European countries and remains understudied in the scientific literature. Therefore, the present research goals are as follows: (i) to provide a critical review of emerging one-stop shop models; (ii) to streamline the deployment of building renovation digital one-stop shops by piloting a sequential multi-staged approach for Portuguese households and proposing it for replication elsewhere; and (iii) to compare case-study insights with other one-stop shops and discuss the notion in the context of the European Renovation Wave. In total, for the Portuguese case-study, five steps were conducted. The first three—stakeholder mapping, expert interviews, and customer journey—aimed to gather intel on the local energy renovation market. The results from these stages informed the design of the platform (fourth step). Finally, a post-launch market consultation survey gathered user feedback (fifth step). Insights from this study suggest that digital one-stop shops, while providing a helpful tool to close information gaps and activate specific audiences, may be insufficient on their own. As such, a more comprehensive set of instruments supporting households is needed to accelerate building renovation.

Dynamic Versus Static Life Cycle Assessment of Energy Renovation for Residential Buildings

Currently, a life cycle assessment is mostly used in a static way to assess the environmental impacts of the energy renovation of buildings. However, various aspects of energy renovation vary in time. This paper reports the development of a framework for a dynamic life cycle assessment and its application to assess the energy renovation of buildings. To investigate whether a dynamic approach leads to different decisions than a static approach, several renovation options of a residential house were compared. To identify the main drivers of the impact and to support decision-making for renovation, a shift of the reference study period—as defined in EN 15643-1 and EN 15978—is proposed (from construction to renovation). Interventions related to the energy renovation are modelled as current events, while interventions and processes that happen afterwards are modelled as future events, including dynamic parameters, considering changes in the operational energy use, changes in the energy mix, and future (cleaner) production processes. For a specific case study building, the dynamic approach resulted in a lower environmental impact than the static approach. However, the dynamic approach did not result in other renovation recommendations, except when a dynamic parameter for electricity production was included.

Mapping the Potential of High-Reflective Roof Coverings in Residential Buildings in Italy

The current warming trend of the earth’s climate is making it increasingly necessary to focus on solutions to improve indoor comfort while reducing energy demand for buildings during the hot season. The use of high-reflective products on the building envelope, and particularly on the roof, has been suggested as a potential solution. The overall impact of using high-reflective products on roofs largely depends on the local climatic conditions and on the characteristics of the building, making it difficult to determine whether the use of these products is beneficial without the use of detailed modelling approaches. In this context, this study aims to propose a method to provide indications for designers and policymakers to make early decisions on the potential benefits of the use of high-reflective products on residential buildings, based on simple and readily-available climatic data of the location. The approach, based on the use of state-of-the-art simulation software, allows researchers to obtain a multi-linear regression of the effect of high-reflective products on roofs as a function of the heating degree days and of the local value of the climate vector. The approach is applied to the case of the Italian territory, where a block-of-flats is selected as the reference building, with features common to a significant part of the national residential stock. The proposed approach allows for the provision of a quantitative estimate of the expected impact of high-reflective roof coverings on the energy performance of residential buildings in all Italian municipalities. The analysis shows that high-reflective products on roofs are likely to reduce the building annual energy demand for heating and cooling in 9% to 25% of Italian municipalities, depending on the building energy renovation state. The proposed approach, whose results are expressed also by means of thematic maps, can be replicated to other geographic areas and can be extended to different energy saving technologies.

Passive Strategies for Building Retrofitting: Performances Analysis and Incentive Policies for the Iranian Scenario

A large amount of the Iranian energy demand is related to the building sector, mainly due to its obsolescence. In this paper, a second-skin system has been implemented as a retrofit action for an office building, evaluating the effect of a tensile material as second-skin in terms of primary energy saving, carbon dioxide equivalent emissions, and simple payback period. The analysis was carried out through numerical simulations across a whole year and for four Iranian cities (Tabriz, Teheran, Yazd, and Bandar Abbas) in four different climates (cold, temperate, hot-dry, and hot-wet), and with the building aligned at either north-south or east-west. Moreover, an economic analysis was carried out suggesting different incentive policies to promote building energy refurbishment. The simulation results highlighted a favorable orientation for buildings in Iran, suggesting a guideline for new constructions. Indeed, the best results were achieved for an east-west orientation of the building (up to a primary energy saving of 13.6% and reduction of carbon dioxide equivalent emissions of 45.5 MgCO2,eq, in Yazd), with a decrease of the annual specific total (cooling and thermal) energy demand of 37.9 kWh/m2/year. The simple payback period values were also lower in the east-west orientation than the north-south one.

Abandoning peat in a city district heat system with wind power, heat pumps, and heat storage

The Finnish Government has established the target of carbon-neutrality by 2035. In Finland, district heating (DH) networks in most cities rely on carbon dioxide (CO2) intensive fuels such as coal and domestic peat. This study assesses the decarbonization of a Finnish city’s DH by employing power-to-heat (P2H) technologies, including heat pumps, an electric boiler, and thermal storage together with an ambitious building energy renovation program. This study also aims to use wind power with a calculated fixed price instead of the market price for the electricity consumption of the deployed P2H units to further support electrification and decarbonization of the DH network. Bilateral contract between the wind producer and the DH operator is examined, as new wind power producers receive no subsidies in Finland. The impacts of storage capacity, electricity tax, building-level renovation, and European CO2 emission allowance (EUA) price on the DH’s optimal operation and break-even price of heat production were evaluated. The optimization routine minimizes marginal production costs. The optimal scenario eliminated the carbon intensive fuel peat with more affordable heat prices, due to P2H technologies, lower electricity tax, higher EUA prices, and the renovation of buildings. Bilateral electricity contract can bring mutual benefits for the DH company and the wind producer.

Investigation of European modular façade system utilizing renewable energy

Abstract The purpose of this investigation is to summarize modular façade construction using renewable energy features in different aspects. Researches done so far primarily focusing on building envelop have shown various constructions of building enclosure without energy usage. This paper mainly focuses on modular façade renovation system programmes of European Horizon 2020 [34] and IEA ECBCS Annex 50 Prefabricated Systems for Low Energy Renovation of Residential Buildings in terms of construction, material, installation and thermal performance. Four aspects of construction, material, installation and thermal performance are adopted to evaluate these practices. Related website, paper and report from European commission constitute the database providing for review. Final results illustrate that all modular façade systems mentioned above could be classified into three layers: interior; module and exterior layer, taking charge of disparate functions. Both insulation and energy usage achieve the innovative envelop constructions manufacture. Integrating the renewable energy resources utilization technique into insulated building façade system is the core of this innovative projects achievement.

The thermal conductivity of the masonry of handmade brick Cultural Heritage with respect to density and humidity

It is very common that the energy refurbishment of buildings of Cultural Heritage is undertaken without considering that their materials and the methods of construction are different from those of modern buildings. Therefore, when seeking the most efficient and effective solutions from an energy point of view, the first step is to understand the thermal characteristics of the materials with which these buildings were constructed. Likewise, as part of this heritage, the fact that many such buildings were constructed using uncoated bricks and with rich voluminous ornamentation or murals must be taken into consideration. This prevents the use of normal construction solutions which consist of attaching a layer of insulating material to the interior or exterior. In addition, the rich surface ornamentation of the walls is not conducive to carrying out tests in situ, so other procedures are needed to determine the thermal behaviour of the facade and thus be able to determine the most appropriate processes for their conservation. To this end, various heat flow tests have been carried out on brick masonry specimens that have characteristics similar to those of the walls of such buildings. This allows an abacus of the approximate thermal conductivity of such brick masonry to be produced with respect to the density of the brick and the moisture content of the wall. The values ​​of this abacus will serve as a reference to guide the energy refurbishment work to be performed on these buildings.

Improving the Energy Efficiency of an Existing Building by Dynamic Numerical Simulation

Nowadays, the enhancement of the existing building stock energy performance is a priority. To promote building energy renovation, the European Committee asks Member States to define retrofit strategies, finding cost-effective solutions. This research aims to investigate the relationship between the initial characteristics of an existing residential buildings and different types of retrofit solutions in terms of final/primary energy consumption and CO2 emissions. A multi-objective optimization has been carried out using experimental data in DesignBuilder dynamic simulation tool.

One-Stop-Shops for Energy Renovation of Dwellings in Europe—Approach to the Factors That Determine Success and Future Lines of Action

Energy renovation of buildings in the European Union would lead to considerable energy savings and a 26% reduction in energy consumption. Despite this and the programmes implemented to promote it in the residential environment in Europe and the United States, the barriers that homes, contractors, and finance companies face to undertake these processes have slowed down the results. The emergence of one-stop-shops (OSSs), promoted by European directives, as integrated management entities to promote the energy renovation of dwellings seems to be a central element in the development of future strategies. This paper looks at experiences of implementing OSSs in Europe, tries to identify the main factors of success, and proposes lines of action to strengthen OSS operation in the long term. To achieve this, documents, regulations, and data on the context were studied, and active cases of OSSs were analysed. Experiences of OSSs that are no longer operating were identified to determine why they had closed down. The results suggested that a lack of structural funding is one reason why activities terminated and that the most successful cases applied an ‘all inclusive’ model and supported families in the entire process.

Uncertainty analysis of climate change potential assessments of five building energy renovation measures in Sweden

The aim of this study is to assess the impact of the uncertainties of life cycle inventory (LCI) data for energy use and materials in life cycle assessments of standard energy renovation measures carried out in multi-family buildings in Sweden. Five energy renovation measures were assessed with regard to their climate change potential. Modules A1–A3 and module B6 were included in the assessment and the functional unit, 1 m2 heated floor area of a renovated building fulfilling the Swedish building regulations and with a calculation period of 20 years, was used. The uncertainty of LCI data for materials and energy were assessed using the Ecoinvent data quality system. This study shows that with two different energy mixes, all renovation measures result in a decrease in the climate change potential. The five renovation measures used in the simulations, with and without consideration to uncertainties, show a lower climate change potential when carried out than when not carried out. It is also shown in this study that the inclusion of the uncertainties of the input data did not have any impact on the overall decisions to renovate or not to renovate. However, this should not be regarded as a general conclusion. If a renovation measure were to have a higher level of material use, or if the “Future energy mix” were to be improved, uncertainty considerations could become much more important from a climate change perspective.Article HighlightsAll assessed energy renovation measures show a decrease in their climate change potential when carried out.The energy renovation measures with the largest decreases of climate change potential are also the measures with largest energy saving potential.When uncertainties are considered, there are no overlaps in the results when carrying out or not carrying out a renovation measure.

Circularity concepts for offsite prefabricated energy renovation of apartment buildings

Deep energy renovation includes the realisation of the full potential of energy performance. A circular deep renovation, which contributes to a circular built environment, is based on 100% life cycle renewable energy, and all materials used within the system boundaries are part of infinite technical or biological cycles with the lowest quality loss as possible. In the current study, the circularity potential was assessed for deep energy renovation from different aspects: circularity of materials, building component and building structure. Careful selection of materials as well as connection, position and disassembly possibilities are needed to increase the degree of circularity. This shows a good possibility to increase energy performance by using circularity principles. The window glass circularity analyse showed that, at best, the thermal transmittance of a new circular product can be more than three times lower than the original. The circular use of materials, components, and structures pose new challenges for the building physic design of building envelope structures.

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

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.