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Paper-based materials, due to their availability, environmental benefits and high thermal properties, have already been implemented in several building envelope designs. However, most of them either did not optimise the use of the material or did not provide sufficient thermal insulation for use in permanent buildings. The presented research analyses six original paper-based building envelope core proposals, suitable for use in permanent buildings in temperate climate of Europe, in terms of thermal and environmental efficiency. Proposals include cores with embedded paper tubes structural elements, timber-cardboard studs and sandwich designs. The heat transfer coefficient of the envelopes was obtained for repeatable modules via 2D computer simulations (ThermCAD software), and the environmental impact was assessed for a representative square metre of the envelope via LCA analysis, based in ecoinvent 3.8 database. All analysed designs showed high thermal insulation properties and met the requirements for U max = 0.20 W/m2K, did not cause the risk of surface condensation, nor have excessive thermal bridges. The analysed building envelope designs based on embedded frame wall structure showed environmental superiority over conventional envelopes (timber frame and SIP panels). The research may serve as a proof of concept, for using paper-based building envelopes in sustainable architecture. [ABSTRACT FROM AUTHOR]

In times of great transition of the European construction sector to energy efficient and nearly zero energy buildings (nZEB), a market observation containing qualitative and quantitative indications should help to fill out some of the current gaps concerning the EU 2020 carbon targets. Next to the economic challenges, there are equally important factors that hinder renovating the existing residential building stock and adding newly constructed high performance buildings. Under these circumstances this paper summarises the findings of a cross-comparative study of the societal and technical barriers of nZEB implementation in 7 Southern European countries. The study analyses the present situation and provides an overview on future prospects for nZEB in Southern Europe. The result presents an overview of challenges and provides recommendations based on available empirical evidence to further lower those barriers in the European construction sector. The paper finds that the most Southern European countries are poorly prepared for nZEB implementation and especially to the challenge/opportunity of retrofitting existing buildings. Creating a common approach to further develop nZEB targets, concepts and definitions in synergy with the climatic, societal and technical state of progress in Southern Europe is essential. The paper provides recommendations for actions to shift the identified gaps into opportunities for future development of climate adaptive high performance buildings. [ABSTRACT FROM AUTHOR]

• Wind-driven rain (WDR) quantification experimentally on 2 case buildings. • Effect of WDR on hygrothermal conditions in internally insulated masonry studied. • Numerical simulations to determine WDR effect on hygrothermal performance. • WDR models were found to overestimate WDR deposition. • Direct influence of WDR events on RH behind insulation was not detected. An inevitable measure when energy retrofitting historic buildings in Europe, is the reduction of building envelope heat loss. On preservation-worthy facades where external insulation is not an option, installation of internal insulation is gaining pace. The historic buildings in Denmark are often constructed with solid masonry facades and wooden decks. The internal insulation may, however, entail potential hygrothermal risks in walls and embedded wood. Measures such as vapour barriers and capillary active insulation materials are continuously evolving and the subject of much current research. The hygrothermal conditions are of great importance for the durability of the building constructions, and for the health and wellbeing of occupants. Wind-driven rain (WDR) is a central factor contributing to water penetration and moisture loads of the exterior walls. Numerous studies have shown that WDR loads influence the moisture conditions in masonry walls and embedded wooden beams, and can even affect interior relative humidity. In the present paper WDR loads on existing façades in a cold temperate climate were determined by measurements and compared to a semi-empirical model. Simultaneously, the hygrothermal conditions within internally insulated walls with exposed brick and embedded wooden beams were monitored. Furthermore, numerical simulations were implemented for clarification of WDR impact. Hygrothermal simulations and previous studies, inevitably show that high WDR loads result in higher moisture content behind the interior insulation. Results from the field measurements of WDR however, cannot directly be referred to the moisture content measured in walls behind interior insulation or beam ends. However, fluctuations in external air humidity proved to be influential on condiditons in the construction. Implementation of a semi-empirical model for calculations of WDR agreed with previous studies in predictions being too conservative when compared to measured WDR. [ABSTRACT FROM AUTHOR]

Conceptually, many energy poverty studies to date have been narrowly focused on inadequate indoor heating, paying little attention to other domestic energy services. Yet there are indications that a growing number of households in Europe are struggling to achieve adequate levels of indoor cooling, with adverse consequences for their health, well-being and productivity. This situation is exacerbated by changing global weather patterns, with many countries facing increases in the frequency and intensity of extreme heatwaves. There is limited understanding of the ways in which households respond to extreme heat, and consequently how this might create greater demand for indoor space cooling and air conditioning, and the consequences for increased stress on power grids and conflicts with carbon reduction goals. Using custom-built survey data collected from 2337 households in Gdańsk (Poland), Prague (Czech Republic), Budapest (Hungary) and Skopje (North Macedonia), along with in-depth qualitative fieldwork with 55 households in the same cities, this paper presents novel evidence on the issue of summertime energy poverty and space cooling difficulties. We identify the driving forces of household vulnerability to excessive indoor heat, in terms of risk of exposure, adaptive capacity, and sensitivity, and explore the implications for addressing energy poverty. [ABSTRACT FROM AUTHOR]

• An LCA tool for non-LCA experts building practitioners in Latin America is presented. • It meets several of literature requirements for LCA tools for first design phases. • A screening LCA of a bioclimatic building showed 30% reduction in carbon footprint. • Using local databases and a BIM-LCA integration are some of the tool's main features. • A carbon footprint benchmark for the Mexican housing use phase has been proposed. Several Life Cycle Assessment (LCA) tools have been generated seeking to facilitate its application in buildings. However, most of them are focused on Europe or the US, leaving aside the Latin American region. This paper presents the EVAMED (Building Environmental Assessment tool) framework, a new tool developed mainly for Latin America, aimed at non-LCA expert users. It is analyzed how this software addresses the requirements established in the literature for LCA tools in early design phases. A screening LCA of a bioclimatic project is presented as a case study. A validation has been made by comparing the results obtained with those of a commercial software. The difference between both tools does not exceed an average of 40% considering various environmental impact categories. The results show EVAMED covers several of the requirements established for LCA tools for buildings early design stages, like the use of regional and international databases, the BIM (Building Information Modeling)-LCA integration and its versatility during project configuration and results visualization. Bioclimatic strategies achieve a 30% reduction in the carbon footprint of the case study. The use phase has improved its rating in the Mexican housing carbon footprint benchmark, going from E (78.8 kgCO 2 e/m2-year) to C (54.7 kgCO 2 e/m2-year). [ABSTRACT FROM AUTHOR]

• The new solution for the façade integrated photovoltaic system, En-ActivETICS was proposed and described in detail, including technical recommendations. • The calibrated numerical model was used to determine hygrothermal performance and identify the most crucial issues of En-ActivETICS. • The positive effect of PCM and diffusion channels was revealed based on a numerical study using calibrated thermoelectrical and hygrothermal models. • The En-ActivETICS was investigated considering local climatic and economic conditions among 38 European countries. • The roadmap 2030 for the En-ActivETICS advancement was developed and presented. The main goal of the European building market transformation regards the reduction of CO 2 emissions and energy demand in the built environment towards net zero carbon buildings. This drives research and building practice to search for economically justified solutions that contribute to achieving these objectives. The work presented in this paper is concerned with the technological and economic context. The original solution of photovoltaic integration with the external thermal insulation composite system named the En-ActivETICS was developed, tested and analysed. The energy potential of the En-ActivETICS across Europe, considering south oriented façade is from 88.3 to 195.8 kWh/(m2⋅a), with the efficiency of solar energy conversion of around 13–14%. The problem of system overheating was solved by applying PCM mortar beside the PV panel, which allowed to keep the PV temperature below 70 °C. The risk of moisture load (from driven rain or water vapour condensation) was avoided by diffusion channels pressed in the mortar. Furthermore, the economic analysis of system implementation in Europe is also promising. Considering the availability of solar energy and electricity prices around Europe the payback time of the En-ActivETICS varies between 12 and 44 years for analysed countries. According to the presented roadmap for the En-ActivETICS advancement a payback period of <10 years is possible with a maximum cost of the system <275 EUR/m2 and electricity price >0.25 EUR/kWh. [ABSTRACT FROM AUTHOR]

• Long term field evaluation of forecast control of heating. • Easy integration with existing installations in buildings. • Widely applicable measure for energy savings around 10%. • Payback time below one heating season. The priority for reaching carbon neutral buildings by 2050 is to first increase energy efficiency in existing buildings by use of easily and widely applicable measures that are verified based on long-term field research. One such solution is a forecast control of heating systems, which can be quickly and easily integrated to existing weather based controls. However, there are still no long-term field evaluation and detailed analyses of the main features of such a system, which would provide a clear picture about the system's energetical and economical features and thus increase their wide application in existing buildings. This paper provides the data from a long term field evaluation of an innovative forecast control of heating systems (forHEAT), which can be easily installed (in less than 2 h) and integrated with existing installations in millions of existing buildings in Europe and throughout the world. The energy consumption for heating was evaluated in seven residential buildings and three public office buildings before and after the installation and use of the forecast control. The resulting energy savings averaged 13.4% in the residential and 10.7% in the public buildings located in continental European climate, with very cold winters. The payback time averaged a 0.6 heating season and in most case studies does not exceed a single heating season. [ABSTRACT FROM AUTHOR]

Building hygrothermal performance, indoor air quality and energy consumption depend heavily on envelope airtightness. Over the last three decades, single-family dwellings have been amply studied in this respect by researchers in North Europe, the United States and Canada. However, very few studies have been conducted on airtightness in multi-family housing in warm climates such as Mediterranean Europe. This paper aims to enhance the understanding of building airtightness in early twenty-first-century multi-family buildings in southern Spain. Blower Door tests were conducted in 45 units in seven such buildings. The main airtightness parameter values found are reported and compared to the data for other buildings in southern Europe. The paper includes a statistical analysis of the findings, characterises building types and describes the protocol used to identify and quantify air leakage pathways. The conclusion drawn is that although a rough predictive model can be developed, the results are widely scattered due to the impact of the random component of manual construction, even in buildings with identical construction characteristics and types. The values recorded are nonetheless consistent with the findings for other European surveys. [ABSTRACT FROM AUTHOR]

Highlights • Lack of a clear path in the fight against energy poverty across the European union. • Energy poverty related to the residential sector allows new solutions to be developed. • Current energy poverty indicators provide an incomplete analysis of vulnerability. Abstract The term energy poverty (EP), mostly used to capture problems related to an inadequate access to energy suppliers in developing countries, and that of fuel poverty (FP), commonly employed when households suffer from insufficient monetary resources to pay for their basic energy needs, are used interchangeably by many researchers. Energy poverty and/or fuel poverty are considered to be an indication of domestic energy deprivation or energy vulnerability and remain a global problem that has been accentuated in Europe due to the economic crisis. This work has made a comprehensive review of the current concepts and indicators of FP, and of current initiatives to tackle this issue, across Europe, thereby raising the discussion of how energy vulnerability factors fit FP situations: available infrastructure, energy efficiency, social and economic poverty, and wellbeing and health. In this context, the first weak spot of the FP indicators and initiatives analyzed is that most factors that influence the everyday activities of a household are not considered (comfort, health, and wellbeing), resulting in an incomplete analysis if these are used in an isolated way. This paper provides a multiple-indicator approach to understand an FP situation beyond its traditional definition, thereby establishing a starting point for the reflection of vulnerability in policy decisions and methodological implications. [ABSTRACT FROM AUTHOR]

This paper summarises the results of a study to identify and quantify the potential impact of measures and policies to reduce the energy consumption of air conditioning in European countries over a 10-year period. The market penetration of air conditioning in Europe has increased steadily over several decades. On a “business as usual” basis, its energy consumption would increase by over 50% by 2020. Measures to restrict this increase are therefore important, but the savings potential straddles several overlapping areas which are subject to different constraints including those imposed by the replacement rates of systems and products, and the refurbishment rates of existing buildings. This work reported in this paper is based on the use of information from a variety of sources in a highly disaggregated model to assess the “realisable” savings over a 10-year period, taking into account relevant constraints. The paper summarises results at a European level, focussing on those cases that generate the greatest realisable savings. Savings are possible in three areas: improved equipment and system efficiency, reduced cooling loads, and more effective operation. The cases that offer the largest savings provide the basis for recommendations for policy measures, often using existing policy instruments. In addition, areas where further work is needed are identified. More detailed results and information about the study and additional recommendations can be found at http://www.bre.co.uk/searchresults.jsp?category=5&q=energy+management [1] . [ABSTRACT FROM AUTHOR]

This paper proposes a novel Case Based Reasoning (CBR) application for intelligent management of energy resources in residential buildings. The proposed CBR approach enables analyzing the history of previous cases of energy reduction in buildings, and using them to provide a suggestion on the ideal level of energy reduction that should be applied in the consumption of houses. The innovations of the proposed CBR model are the application of the k -Nearest Neighbors algorithm (k-NN) clustering algorithm to identify similar past cases, the adaptation of Particle Swarm Optimization (PSO) meta-heuristic optimization method to optimize the choice of the variables that characterize each case, and the development of expert systems to adapt and refine the final solution. A case study is presented, which considers a knowledge base containing a set of scenarios obtained from the consumption of a residential building. In order to provide a response for a new case, the proposed CBR application selects the most similar cases and elaborates a response, which is provided to the SCADA House Intelligent Management (SHIM) system as input data. SHIM uses this specification to determine the loads that should be reduced in order to fulfill the reduction suggested by the CBR approach. Results show that the proposed approach is capable of suggesting the most adequate levels of reduction for the considered house, without compromising the comfort of the users. [ABSTRACT FROM AUTHOR]

A large share of the buildings in Europe are old and in need of renovation, both in terms of functional repairs and energy efficiency. While many studies have addressed energy renovation of buildings, they rarely combine economic and environmental life cycle analyses, particularly for office buildings. The present paper investigates the economic feasibility and environmental impact of energy renovation packages for European office buildings. The renovation packages, including windows, envelope insulation, heating, cooling and ventilation systems and solar photovoltaics (PV), were evaluated in terms of life cycle cost (LCC) and life cycle assessment (LCA) through dynamic simulation for different European climates. Compared to a purely functional renovation, the studied renovation packages resulted in up to 77% lower energy costs, 19% lower total annualized costs, 79% lower climate change impact, 89% lower non-renewable energy use, 66% lower particulate matter formation and 76% lower freshwater eutrophication impact over a period of 30 years. The lowest total costs and environmental impact, in all of the studied climates, were seen for the buildings with the lowest heating demand. Solar PV panels covering part of the electricity demand could further reduce the environmental impact and, at least in southern Europe, even reduce the total costs. [ABSTRACT FROM AUTHOR]

• Modelling energy savings of renovations in the Dutch non-profit housing stock. • Assessment of 1.6 million dwellings, 21 building features and 3 empirical models. • Empirical models outperform the theoretical building energy model. • Shortcomings exist when predicting effects of specific energy-saving interventions. In Europe, the energy performance of dwellings is measured using theoretical building energy models based on the Energy Performance of Buildings Directive (EPBD), which estimates the energy consumption of dwellings. However, literature shows large performance gaps between the theoretically predicted energy consumption and the actual energy consumption of dwellings. The goal of this paper is to investigate the extent to which empirical models provide more accurate estimations of actual energy consumption when compared to a theoretical building energy model, in order to estimate average actual energy savings of renovations. We used the Dutch non-profit housing stock to demonstrate the results. We examined three empirical models to predict the actual energy consumption of dwellings: a linear regression model, a non-linear regression model, and a machine learning model (GBM). This paper shows that these three models alleviate the performance gap by giving a good prediction of actual energy consumption on sectoral cross-sections. However, these models still have shortcomings when predicting the effects of specific renovation interventions, for example newly introduced heat pumps. The non-linear and machine learning model (GBM) outperform the theoretical model in terms of estimating energy savings through renovation interventions. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents evidence for the role of building energy certificates as a behaviour change tool that drives improvements in the energy performance of public buildings. Findings are presented from an evaluation of a large-scale voluntary building labelling campaign, CYBER Display®. Energy-Cities, the European association of local authorities, launched its Display® Campaign in 2001 aimed at encouraging authorities to publicly display the energy and environmental performances of their buildings. Over 500 local and regional authorities in Europe participated in producing over 22,000 certificates. The database contains over 10,000 buildings and provides an excellent opportunity to produce an overview of the broad energy performance trends of buildings in Europe. Common technical factors are identified that lead to improved energy performance. Evidence from a comprehensive survey also reveals a further set of common factors in terms of communication activities that appear to lead to improved energy performance. The paper concludes that whilst building energy certificates are no panacea for the problem of increased emissions from public buildings, producing and displaying building energy certificates such as the Display® Poster can act as a catalyst for behaviour change. [Copyright &y& Elsevier]

Windows are central for the development of liveable nearly zero-energy homes and require careful consideration. Various studies have indicated that the effect of windows on energy consumption may change significantly with improved building insulation levels. Current guidelines on windows may therefore not apply in very well-insulated buildings, and more up-to-date information is needed about window solutions that are appropriate for the new conditions. This study maps the effect of multiple combinations of window size and basic glazing—and frame properties on energy, daylighting and thermal comfort in nearly zero-energy houses located in the European cities Rome and Copenhagen. The aim was to identify options that can support the easy and robust design of future homes with typical use of roof and façade windows. Hourly daylight levels were calculated in DAYSIM, while space heating demand and operative temperatures were calculated in EnergyPlus. The results support previous findings on the limited ability of nearly zero-energy buildings to utilise solar gains. It was found that U -values are becoming increasingly important for the energy performance of windows. The paper sketches the increased flexibility and related possibilities that may appear with improved roof window frame constructions and glazing U -values far lower than currently standard levels. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present the development and evaluation of neural network based identification algorithms for the prediction of outdoor air temperature using acquired data from four European cities (Ancona – Italy, Chania – Greece, Granada – Spain and Mollet – Spain). Different neural network topologies (feed forward, cascade and elman) have been tested to identify the most suitable for each city. The efficiency of the prediction is validated by comparing predicted and measured outdoor air temperature. Furthermore, statistical tools such as R 2 , and root mean square error (rmse) are used to evaluate the annual performance of the neural network. The comparison of measured and predicted outdoor air temperature ( R 2 > 0.9, rmse <2 °C) confirms the accurate training of the neural network for all four European cities. All work has been contacted using Matlab's environment. [ABSTRACT FROM AUTHOR]

• We use a machine learning (ML) approach to study energy poverty (EP) risk in Europe. • We produce an EP risk classifier with accuracies ranging from 60% to 75%. • Through ML we identify three EP predictors: income, household size, and floor area. • We suggest the presence of universal predictors complemented by contextual ones. • Increasing data collection efforts in Europe can improve EP policy research insights. In this paper we identify drivers for energy poverty in Europe using machine learning. The establishment of predictors for energy poverty valid across countries is a call made by many experts, since it could provide a basis to effectively target energy-poor households with adequate policy measures. We apply a "low income, high expenditure" framework that classifies households as being at risk of energy poverty to a dataset from a survey conducted at the household-level in 11 European countries with vastly different economies, cultures, and climates. A gradient boosting classifier is successfully trained on a set of socio-economic features hypothesized as predictors for energy poverty in this diverse set of countries. The classifier's internal model is analyzed, providing novel insights into the intricacies that underlie energy poverty. We find that besides the main driver - income - floor area and household size can be confirmed as predictors. Our results suggest the presence of universal predictors that are valid across Europe, and contextual ones that are governed by local characteristics. To facilitate advanced research into energy poverty in Europe, we recommend to increase and streamline household data collection efforts, both at the country- and EU-level. [ABSTRACT FROM AUTHOR]

Extreme weather conditions in urban areas have a serious impact on the quality of life, energy consumption and health of urban citizens. In addition energy poverty has a serious impact on the quality of life of low income households. The aim of the present paper is review the actual housing status of low income population in Europe and discuss issues related to the impact of urban overheating and extreme weather phenomena on the specific energy consumption, indoor environmental conditions and health. Finally advanced low cost mitigation and adaptation technologies developed during the last years that offer a serious potential for energy and environmental improvements which can contribute to improve the quality of life of low income population are presented. [ABSTRACT FROM AUTHOR]

This paper reports on the electrical system design and development of Home Energy Management System (HEMS) of a solar house, named “Omotenashi House”, which was entered in the Solar Decathlon Europe 2012 (SDE2012). Completed solar houses were judged on a number of factors; in particular, the electrical energy balance, and whether it is possible to achieve comfort conditions along with normal house functioning using electrical power generated solely from the solar panels. Therefore, it was necessary to use efficient battery storage for electrical power at night, as well as modern energy-saving home electrics, appliances, and electronics, and high-performance thermal insulation from vacuum panels. Sensors monitored temperature, humidity, light quality, and other factors to measure the comfort conditions. We decided the requirements of the electrical system and HEMS for SDE2012, and we planned the electrical system and HEMS. The test process and schematic diagrams and hardware and software components were explained in figures and tables. The solar house we constructed at SDE2012 did not perform to our expectations because of some electrical problems, but HEMS functionality was verified. In Japan, standardization of HEMS is proceeding due to the Echonet Consortium, a group of Japanese electronics manufacturers. [ABSTRACT FROM AUTHOR]

• The environmental performance of PU-gypsum ceiling tile and standard gypsum ceiling tile has been investigated. • Several forms of environmental impact have been analysed. • A comparative cradle-to-grave LCA of two gypsum ceiling tiles has been carried out, the PU-gypsum ceiling tile having better results. • The LCA includes the production and construction phases, use and end of life, the production stage being the main contributor to the environmental impact. In this paper, the LCA of two gypsum ceiling tiles is compared, the first one is a traditional gypsum tile and the second is a new eco ceiling tile in which polyurethane foam waste has been incorporated. Both tiles were made at one of the largest gypsum tile factories in Europe. The life cycle assessment has been considered from cradle to grave for which the corresponding production stages have been defined. This includes the extraction and transportation of raw materials, the manufacturing process, transportation to the client, the use of the product and the end of its useful life. The results show that the tile with polyurethane has a better environmental performance than the standard commercial ceiling tile. This is quantified as a 14% reduction in energy consumption, a 14% reduction in CO 2 emissions and a 25% reduction in water consumption compared with the standard tile, all the while maintaining the technical performance. An analysis of the results suggests that the new eco product has a competitive advantage on the market thanks to its environmental improvements and good technical performance. [ABSTRACT FROM AUTHOR]

• The Solar Decathlon successfully tackles the triple: design, build, operate. • Competition houses demonstrate net energy positive buildings. • All energy supply systems are based on PV and air heat pumps. • Houses with battery storage provide flexibility in building grid interaction. • Online knowledge platform provides building information and monitoring data. • The competition format can be linked to building science. The Solar Decathlon is a competition for universities from all over the world to design, build and operate small experimental solar powered houses. Its first edition took place in the US in 2002. Since 2010 it is in practice in Europe with four competitions and 65 net zero or net energy plus houses build and tested in 10 disciplines (decathlon). This paper provides an overview and analysis on the European edition of the competition. The work was carried out within the framework of Annex 74 "Competition and Living Lab Platform" of the International Energy Agency and an EC funded project named "Solar Decathlon Europe - Analysis of the Results". The analysis was based on the development of a web based knowledge platform, providing a large set of information and monitored data from past competitions. Based on the availability of information and data, the comparative evaluation is centred on the building energy supply systems and their performance. Starting with very large PV systems, the latest competitions rules trigger the teams to apply systems sized comparable to small buildings in net zero energy building practice. As a result not all houses succeed in a positive energy balance. Due to the wider introduction of batteries the self-consumption of the solar yield and the degree of self-sufficiency increases. New developments of the competition rules stimulate the energy flexibility in operation with the power grid. Modifications for the rules and the monitoring procedure for the next edition intend to further link the competition to building science. [ABSTRACT FROM AUTHOR]

Abstract: Energy efficiency in buildings is essential for economic, social, and environmental reasons. Under current European legislation, buildings have to be certified with an energy efficiency index. To provide a fair comparison of the energy performance in buildings we need a global and unified representation. In this paper we propose the Energy Efficiency Ontology (EEOnt) to provide a foundation upon which this requirement can be built. EEOnt extends the applicability of other ontological models of buildings incorporating energy efficiency data and knowledge that can be calculated with high spatial and temporal resolution in what we call an Energy Efficiency Landscape (EELB). These EELB''s provide significant information which allows a detailed diagnosis of the energy efficiency within the building. Consequently, EEOnt is capable of representing buildings and energy efficiency in a unified way. Furthermore, it supplies a tool for managing the energy efficiency in buildings and constructing national inventories. These two features link the global and particular needs of governments and users, thus becoming key to both improve the energy efficiency in buildings and to implement viable certification schemes. [Copyright &y& Elsevier]

Abstract: The age of European existing building stock and the very low growth rate make energy retrofit a critical issue at the moment. The spreading of good practices is strongly hampered by their cost effectiveness. National legislation thermal requirements for retrofitting works play a fundamental role. If they are too strict, the initial economic investment could be too high if compared with energy savings achievable. The paper refers to a case study of improving fabric thermal performance of stone masonry buildings located in Cagliari – Italy. They were built in 1950s. The economic feasibility of different energy efficiency retrofits is evaluated. Two different scenarios are analyzed: the former according to the earlier Italian legislation (valid from 2006 to 2008), the latter according to the latest and strictest measures (valid from 2010). The results show that heavy thermal performance upgrades, even though compulsory, are not completely cost-effective in a mild Mediterranean climate area as far as payback time is concerned. National subsidy policies can improve the economic return on the investment. The impact of present Italian incentives has also been evaluated. [Copyright &y& Elsevier]

Abstract: Cool roof technology is an energy efficient, financially viable and sustainable solution for mitigating heat islands and reducing building energy consumption for cooling. An EU supported project called Cool Roofs has achieved to promote this technology in the EU by the implementation of an Action Plan. The work is developed in four axes, technical, market, policy and end-users. The Action Plan is steered by the development of the European Cool Roof Council that brings together all related stakeholders. The main results of the project include the creation of the European Cool Roof Council (ECRC), five cool roof pilot studies, a database of cool roofing materials, a handbook and a toolkit to assist the better understanding of the technical aspects of the technology, a market promotion plan, a proposal for a successful strategy to overcome possible policy barriers and engage with key stakeholders who could support and accelerate the creation of an EU policy and regulatory friendly environment to cool roofs, the organization of workshops and seminars and other actions of dissemination. This paper presents the main achievements at EU level regarding the establishment of cool roofs as heat island mitigation strategy and a measure for reducing cooling loads. [Copyright &y& Elsevier]

Abstract: A big amount of final energy in Europe is used in buildings (about 50%). Thermo insulating investments in the building sector can have a great impact on the improvement of the energetic efficiency of buildings and the reduction of the use of final energy in this sector. In the paper there were presented properly modified indicators for the economic assessment of the investments which is based on the thermal insulation of external walls of the building, such as: net present value, profitability indicator and payback period. For the ecological assessment the following indicators were introduced: ecological net present value, ecological indicator of profitability and ecological payback period. LCA technique was used in ecological indicators. For different variants of external walls, sources of heat and thermo insulating materials, the assessment of investments due to economic and ecological indicators was conducted. Ecological payback periods were obtained within 0–6 years. [Copyright &y& Elsevier]

Abstract: Indoor air pollution has a negative impact on human health, comfort and productivity. Emissions, however, are often related to essential functions of the indoor environment and cannot be eliminated with source control. Ventilation is then used to dilute these pollutants to acceptable concentrations. Due to recent crises in the energy markets and the subsequent quest for higher efficiency in energy use, heat recovery ventilation has gained capstone status in sustainable building concepts. However, along with a reduction of ventilation heat loss, operating a heat recovery unit increases the pressure drop and fan power consumption in the system. These aspects are rarely traded off against each other and even more scarcely for a broad range of operating conditions. This paper addresses this trade-off based on primary energy, carbon dioxide emission, household consumer energy price and exergy frameworks for the different climates in Europe. The results presented here demonstrate that, for the moderate climate region of middle Europe, natural ventilation, simple exhaust mechanical ventilation and heat recovery ventilation have no clear advantage over each other as far as operating energy is concerned. Realistically low specific fan power will make heat recovery ventilation advantageous in virtually all tested conditions. [Copyright &y& Elsevier]

Abstract: Elevators and escalators have received little attention from an energy efficiency perspective in the past. To close this gap, this paper analyses energy efficiency potentials and suggests policy measures for the European elevator and escalator market. As a precondition, the electrical energy demand of elevators and escalators in the European market is analyzed, based on expert estimations and the results of a monitoring campaign. The estimated current demand is compared to scenarios where the implementation of best available technology for the relevant equipment is assumed and the savings potentials thereof are calculated. The results indicate that considerable technical efficiency potentials exist for elevators (more than 60%) and escalators (around 30%). However, various specific barriers impede the diffusion of these energy-efficient technologies. They include issues like a lack of awareness and relevant information as well as split-incentive problems. The technological analysis is therefore complemented by an investigation of how to overcome these barriers, leading to a set of recommendations on how to improve energy efficiency in the elevator and escalator market. Suitable measures could be implementing standardized methods for electricity measurement, introducing a labeling system and including elevators and escalators in the legislative framework. [Copyright &y& Elsevier]

Abstract: Granaries (hórreos) are bioclimatic conservation structures with various forms that have been used for over 2000 years in different countries across Europe and Asia. Galician raised granaries built upon “staddle stones” (pillars with a rodent-proof cap) are specialised barns. The importance of airflow in the preservation of stored grain is based on the use of air as an energy exchange fluid for exchanging heat or water with the grains. The preservation system is based on continuous ventilation inside the bin. Some granaries do not have a wooden slatted floor with gaps, although they should. The gapped, slatted floor particularly influences the thermodynamic behaviour, which is powered by solar radiation, improving ventilation efficiency and internal temperature regulation. This paper shows the important influence of floor grooving on improving grain conservation via better ventilation and limiting the rise in the internal temperature when the granary is subjected to solar radiation. [Copyright &y& Elsevier]

Abstract: Across Europe domestic electricity consumption is on the rise. In an attempt to counter this increase, various initiatives have been introduced to promote the replacement of less energy-efficient appliances with more efficient ones. Whilst the likely aggregate effect of such measures over long time periods has been modelled extensively, little is known about the affect that a change to higher efficiency appliances will have on the electrical demand profile of individual households at higher temporal resolutions. To address this issue a means by which established approaches to detailed electrical demand modelling can be adapted to simulate the improvements in the efficiency of appliances is elaborated in this paper. A process is developed by which low-resolution empirical appliance demand data can be transformed to produce high-resolution electrical demand data for different periods in the year, factoring in improvements in appliance performance. The process is applied to simulate the effects a changeover to more energy-efficient appliances would have on the minute resolution demand profiles of a group of households. Results indicate that improving the energy-efficiency of appliances in households leads to a significant reduction in electrical energy requirements but does not appear to have a significant affect on the peak electrical demand. [Copyright &y& Elsevier]

Abstract: The reliable estimation of buildings energy needs for cooling is a crucial issue in the implementation of the EPB Directive 2010/31/EU (formerly 2002/91/EC), especially in central and southern Europe climates. On this purpose one of the main topics is to predict the behavior of the opaque envelope subjected to variable boundary conditions. The EN ISO 13786:2007 technical standard assumes sinusoidal boundary conditions and introduces dynamic thermal characteristics. The aim of this paper is to assess the deviation arising by the use of different approaches for the calculation of the dynamic thermal characteristics of an opaque envelope element under periodic non sinusoidal boundary conditions. The EN ISO 13786 procedure has been firstly applied by decomposing the external forcing temperature by means of the Fast Fourier Transform (FFT) analysis. A comparison with different approaches, such as Finite Difference Methods (FDM) and Transfer Function Methods (TFM), has been carried out. The predictions of the EN ISO 13786 with a sinusoidal forcing temperature (i.e., standard approach) have also been assessed, comparing the results to the ones obtained through the FFT analysis. Furthermore, corrections to the periodic thermal transmittance and to the time shift have been proposed, in order to improve the explicative worth of those parameters. [Copyright &y& Elsevier]

Abstract: The paper discusses an assessment tool, used for the energy, economic and environmental evaluation of Thermal Insulation Solutions (TIS). The results of the assessment undertaken with this tool can take the form of a simple rating system in order to enable users to perform comprehensive comparisons amongst various building materials and TIS. A ranking expressed by A, B and C classes is used for energy, environmental and economic parameters. By evaluating the materials, the tool supports the users to make decisions, depending on preferences or priorities such as the energy efficiency achieved, the total cost and the environmental performance. The assessment tool is applied for the double cavity wall and the External Thermal Insulation Composite Systems (ETICS) as they are used throughout Europe, both in new constructions and in the renovation of existing buildings. [Copyright &y& Elsevier]

Abstract: A Window Energy Rating System (WERS) provides a simple, approximate method to compare the energy performance of the various windows and to determine the different potential savings for the various weather conditions. The main aim of this paper is to obtain a WERS for two climatic zones in Spain. For this purpose, the heating loads and energy savings of a residential building with different types of windows were obtained by three ways. Firstly, the energy through the window was evaluated considering only the climatic conditions. Secondly, the study was performed taking into account the energy useful for the heating system considering the climate and the type of building. Finally, the different cases were simulated using TRNSYS16 and WINDOW5. This study was performed for different European climates. The WERS proposed here is based on the second method. It takes into account the U factor of the window, U factor of the frame, absortivity of the frame, solar heat gain of the glazing and infiltration. [Copyright &y& Elsevier]

In the UK, heating systems in the built environment consume a substantial proportion of its total energy and are responsible for about 25% of the total carbon emission. A similar pattern is also exhibited in many other European countries. Despite the enormous effort made over the last decades to improve the energy efficiency of these heating systems, a huge potential for further energy saving still persists. This paper investigates the potential for energy saving in heating systems that can be achieved through improving boiler controls. This investigation was carried out through surveys, simulation and experimental study. Through the surveys, typical boiler control schemes widely used in current practice were identified. The performance of some systems surveyed was monitored through the survey. The data obtained is used to demonstrate the problems associated with the control of boilers in heating systems. These typical control schemes identified through surveys were studied using a simulator that had been rigorously validated. An experiment was carried out to demonstrate how the overall performance of a heating system could be improved by using a better boiler controller. The result shows that improving boiler controls can lead to up to 20% of energy saving and a significant improvement in thermal comfort. [Copyright &y& Elsevier]

• A new retrofitting strategy by using prefabricated elements window machine. • Minimization of the renovation costs and speeding up the retrofit action. • A potential in energy saving and improving the Indoor Environment Quality. • Further significance in retrofit and healthy home office working environments. The renovation of existing residential buildings across Europe has become a key factor for energy saving and the improvement of Indoor Environment Quality (IEQ). This paper presents an investigation of IEQ for a typical 1960s single-family house in Germany before and after a new retrofitting strategy (prefabricated element with integrated ventilation and new thermal envelope). In-situ measurements were applied to investigate the energy efficiency and IEQ improvement for the new retrofitting strategy in temperate winter regions of Europe. The simulation model replicates the measured data to be closer to reality and simulates a home office (COVID-19) scenario. The in-situ measurements showed that our retrofitting strategy increases the indoor air temperature during the heating period by up to 2.5 °C, decreases relative humidity by up to 3.8% and increases CO 2 by up to 24 ppm than before. As the simulation results shows, the retrofitted home office scenario allows a reduction in heating energy of up to 77%, an increase in CO 2 concentration of up to 41.8 ppm, 0.5% less relative humidity and 1.6 °C higher indoor air temperature than that without retrofitting. The new approach to retrofit residential buildings thus showed a potential in energy saving and improving the IEQ. [ABSTRACT FROM AUTHOR]

The paper analyses effects of changes in temperatures on heating and cooling demands in Europe until 2050. Specifically, the study addresses changes in trends (10-year mean) and extremes (10-year min/max). The analysis is based on two GHG emission climate scenarios (RCP2.6 and RCP4.5) and eight high-resolution regional climate models and results are provided as relative and absolute changes on grid and country scales. Population density is used as proxy for spatial distribution of demands. Projected future temperatures are proportional with RCP scenario and distance into the future and the highest relative changes occur towards north-eastern Europe and for high-altitude areas. The temperature changes lead to general decreased heating demands and corresponding increased cooling demands. In general, higher spreads are seen between demand change ratios for individual models when addressing extremes as opposed to trends: The general 2010–2050 change ratios for heating between countries are 0.85–95 for model means and average 0.69 for the extreme analysis. For cooling, corresponding ratios are 1.25–1.5 for model means and average 2.76 for model maxima. For absolute demand changes, some countries are projected to experience significant changes e.g. exceeding a doubling in cooling demands. The results are suggested as a basis for energy system analyses. [ABSTRACT FROM AUTHOR]

The Life Cycle Assessment (LCA) represents a suitable methodology to evaluate quantitatively the environmental impact related to a product or a process and it can be used as a guiding tool to make effective environmental sustainability choices. While the LCA-based methods are more and more diffused in the assessment and selection of materials for new constructions, they are still scarcely applied in the field of conservation and repair of historical buildings, although these buildings, especially in Europe, represent a high percentage of the building stock. In the present paper, the LCA method was applied to the field of the restoration, with particular reference to cleaning technologies and materials, in order to investigate if LCA can be applied in this field. The analysis of results pointed out the different environmental impact of the cleaning methods investigated (ascribed to different impact categories), but also the shortcomings and proxies arising from the lack of specific database. The impact of the waste treatment stage was also analysed, in order to highlight the main impact spots related with the end of life of materials and equipment. Results showed that, for some cleaning methods, the impacts related to manufacturing and disposal are very similar, which emphasizes the importance of performing LCA including the end of life scenarios. Finally, an evaluation of externalities was performed, to provide a monetary value of the environmental damage. [ABSTRACT FROM AUTHOR]

Many studies have investigated different aspects in the decarbonisation of the European housing stock. However, a comprehensive quantitative analysis of the literature on the diffusion of energy efficiency technologies is still missing. We conducted a bibliometric analysis to better understand the knowledge base in the field energy efficiency technology diffusion in the European residential building stock. After the scanning and screening process, we identified 954 scientific articles pertinent to this topic. Through a co-citation network analysis, we generated a visual knowledge structure of the field and by the further investigation of the bibliography we were able to synthesize the state-of-the-art and answer to our initial research questions. Results of the co-citation network show a scattered and fragmented field in many domains. The descriptive analysis highlights this fragmentation, especially on a cross-country level among EU country members. Findings from this study contribute to map the scientific knowledge base in relation to technology diffusion in European residential building projects, identify relevant topic areas, visualize the links between the topics, as well as to recognize research gaps and opportunities. The methodology utilized in this paper proved to be viable approach to map and characterize the knowledge base within a field and can, therefore, be replicated in upcoming studies with analogous ambitions. [ABSTRACT FROM AUTHOR]