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• The paper has a focus on energy consumption habits and trends using statistical methods. • Occupants' behavior is monitored using smart metering system and awareness surveys. • The impact of a serious game on occupant's behavior is evaluated. The paper has a focus on energy consumption habits, trends and intervention strategies in residential buildings, mainly through the serious game approach with a combination of direct consumer feedback through smart metering. More than 150 homes in France and Spain have been involved in the research experiment and the consumption habits of approximately 50 homes were deeply analyzed. The applied methods, processes, results and findings of the monitoring data analysis are presented in the paper with two aims. First, consumption profiles and trends were determined for apartment homes with regard to heating, domestic hot water and electric consumption. Second, the impact of a serious game experiment was assessed comparing energy consumption, indoor air temperature and users' habits (based on questionnaires) before and after launching the experiment. [ABSTRACT FROM AUTHOR]

Hospitals present a widely recognized margin for energy conservation due to their elevated final energy use intensity. Specifically, operating rooms are among the functional areas with greatest energy demand in hospitals, given the stringent indoor conditions for patients and surgical staff. However, energy efficiency in surgical facilities has traditionally been overlooked by the scientific literature in favor of guaranteeing adequate air quality conditions. This paper assesses the potential energy savings that could be achieved in a surgical suite in a Spanish hospital by lowering the current ventilation rates to the lowest energy-demanding values recommended by the proper Spanish standard and other international codes. Likewise, the paper assesses the actual hygrothermal and ventilation conditions in the suite based on the results of a continuous monitoring campaign performed for a period of 12 days. Simulations undertaken with a dynamic energy model specifically developed and calibrated for this work revealed that the average energy intensity of the suite is 1021 kWh/m 2 /year (1685 kWh/m 2 /year for operating rooms), with 80% of the total annual thermal demand corresponding to periods of inactivity. In addition, energy savings between 40% and 80% are possible while complying with both national and international standards. [ABSTRACT FROM AUTHOR]

• Energy Communities analysis and review in Europe and, more specifically, in Spain. • Promoting energy poverty reduction and cooperation through Energy Communities. • Real case study focused on reducing energy poverty in the city of Getafe (Spain). • Selection of public buildings to implement energy community in two neighborhoods. • Significant electricity bill reductions for energy poverty households. Advancements in renewable energy technologies, a growing awareness of the need for sustainable energy solutions, and the emergence of new business models in the energy sector, have contributed to the growth of Energy Communities. Public entities can find in energy communities today an opportunity to tackle energy poverty, to increase the cooperation among citizens and to empower them to be a more active player within the energy sector. This paper analyzes energy communities in Europe and focuses specifically on Spain; considering the three beneficial aspects previously mentioned. It aims to obtain ground truth about the applications of these new citizens' arrangements. A citizen-led initiative at the city of Getafe (Madrid, Spain) is included and discussed in detail. This case study focused on reducing energy poverty of its participants. An energy community was designed and implemented as a collective PV solar self-consumption infrastructure. The roofs of various public buildings in the two case study neighborhoods were selected for locating the PV installations. Real metered data were used to evaluate the solution. A public building was selected for the energy community, considering generation on roof and dwellings proximity. The results provided that out of the 77% PV generations could be used to contribute to the demand of 100 residences; while the resulting 23% would provide approximately 60% of the energy demand of the public building. The setting up of the Energy Community not only had the technical part but also included workshops seminars and information sessions, to ensure that people prone to benefit and maximize its impact. [ABSTRACT FROM AUTHOR]

The low energy efficiency of the European building stock is both a social and environmental issue. However, plans and studies on energy retrofitting interventions do not usually evaluate the impact of these measures on households' energy affordability. This paper analyses and compares the effect of alternative retrofitting strategies on thermal energy services' affordability in Spanish vulnerable households. This analysis was carried out by applying the Required Thermal Energy Expenditure model proposed in previous studies to several 2030 residential building stock scenarios, setting 2020 as a baseline. Therefore, this work proposes a methodological approach to assess the impact of the considered energy efficiency interventions on energy poverty in winter (WEP) and summer (SEP) and carries out both a 'social cost' and a cost-benefit analysis. The dwelling's thermal-enclosure retrofitting stands out as a very WEP-reduction and social-cost effective measure. Instead, replacing old thermal systems with more efficient ones would have a higher impact on SEP. Combining both kinds of retrofitting measures could reduce heating and cooling required expenditures by, respectively, 49% and 59%, and decrease the WEP and SEP share, correspondingly, by 35% and 63%. These results might inform policymakers to enhance the targeting and design of energy efficiency programs. [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]

Designing a low energy building requires to evaluate a large number of parameters: design combinations, element thermal characteristics, HVAC systems efficiencies, etc. All of them determine the space heating and space cooling energy demands, energy consumptions, and life cycle cost over the lifetime of the building. This paper presents the achievements of SEDICAE research project consisting on a new methodology based on a tabu search and a simplified method to calculate energy consumptions. The methodology is designed to estimate the annual energy demand, life-cycle cost and energy rating. A second process is included to select the HVAC system is developed for the building designed with this methodology. In general, builders should look for low energy, but investment in building design is a limiting factor. This paper show the relationship between energy efficiency index and investment in optimized residential building. Furthermore, the best energy rate is obtained applying the HVAC systems in the integrated optimization method for residential buildings. This methodology reduces investment, reduce the energy demand and selects the best construction materials, allowing to study the cost in different economic scenarios. In this paper, a building design case study is studied in 2028 scenarios in 12 climatic zone in Spain. [ABSTRACT FROM AUTHOR]

This paper evaluates a parametric analysis towards compliance with the nZEB standard, which in Spain is defined by the latest update of the Technical Building Code. This regulation is critically assessed regarding its ability to promote the concept of cost optimization, promote renewable energy sources and minimize primary energy consumption in the residential sector. To this end, a virtual building was defined and multiple designs were evaluated using DesignBuilder software. A set of 170 alternative scenarios was established and parametrically evaluated for five cities representing the five climatic zones of inland Spain (Bilbao, Burgos, Seville, Madrid and Almeria). The results were evaluated focusing on cost-cost effectiveness and primary energy consumption values for the different scenarios, evaluating them in relation to the minimum requirements set by the regulation. The great potential of photovoltaic energy is highlighted, which allows negative values to be obtained for the two Equivalent Uniform Annual Costs due to the cost avoided through self-consumption. This fact makes the optimal designs tend to electrification, specifically through air and ground source heat pumps. It is worth mentioning that the new Code has only established a minimum target for renewable self-consumption in the residential sector, which should be reinforced in future updates. [ABSTRACT FROM AUTHOR]

The aim of this paper is twofold: to investigate the applicability of a building-stock modelling methodology to assess the potential of Energy Conservation Measures (ECMs) and their associated effects on carbon dioxide (CO 2 ) emissions for a building stock in a South European climate, with Spain being used as an example; and to analyse the technical potentials and costs of the ECMs when applied both individually and as packages of multiple ECMs for the entire Spanish building stock, including residential and non-residential buildings. The modelling methodology, which has been designed to be applicable to any European country, is fully dynamic and based on an aggregated description of the building stock. This paper updates and validates the methodology to account for the climate and technical characteristics of the region under study. Applying all ECMs as a package gives a potential technical reduction in final energy demand of 55% and a 65% reduction in CO 2 emissions, while the corresponding techno-economical potentials are 33% and 37%. Nevertheless, the market potentials estimated are substantially lower (5–10%), which indicate that policy shifts are needed if the techno-economic potentials identified in this work are to be realized. [ABSTRACT FROM AUTHOR]

This paper presents a study of the thermal performance of a single-family house located in a coastal city in northern Spain that was built according to Spanish standards during the 1990s. The study estimates an annual energy demand of around 95 kWh/m 2 and a thermal power rating of the heating system of around 16 kW. The potential energy savings that would be obtained by implementing different retrofitting measures frequently used nowadays are also quantified: installing a ventilation system with heat recovery, improving the insulation of opaque construction elements, replacing the existing windows with high-thermal performance windows, and reducing air infiltration rates. These integrated actions on the house would reduce the annual energy demand below the requirements of both the Technical Building Code (24.24 kWh/m 2 year for this case of study), which is the regulation currently in force in Spain, and the well-known Passivhaus standard (15 kWh/m 2 year), which is one of the most widespread building standards in Europe. Compliance with these requirements means that the annual energy demand and the size of the heating system would respectively be potentially reduced by 81% and 57% of the present values. [ABSTRACT FROM AUTHOR]

• Self-consumption in residential sector is studied under Spanish regulatory framework. • An average-day model versus a whole-year model is benchmarked. • Scheduling household appliances is analysed in a residential building. • Ex-ante and ex-post renewable energy sharing is investigated. Studies on self-consumption in residential use are constantly evolving, and society claims new solutions in response to changes to new paradigms. This paper aims to optimise the sizing of a self-consumption installation for collective self-consumption in a residential building under the Spanish regulatory framework. The study considers the current price volatility in the retail electricity Spanish market and focuses on the techno-economic analysis of self-consumption in a building consisting of 12 dwellings using photovoltaic energy and the possible support of a storage system. The three aspects analysed are the sizing of the self-consumption facility, the use of smart appliances to shift their consumption to more cost-effective times and the sharing of the renewable energy generated by the facility among the consumers participating in the collective self-consumption. This study employs two models, an average-day model and a whole-year model. The techno-economic analysis yields that between the two self-consumption modalities for residential consumption, the modality with surplus simplified compensation is more profitable than the one without surpluses. Finally, the study focuses on sharing the total renewable energy generated among the participants. The results indicate that both ex-ante and ex-post dynamic sharing brings few benefits. [ABSTRACT FROM AUTHOR]

The Spanish residential building stock built between 1940 and 1980 period presents a high energy saving potential as it represents a significant percentage of the total housing stock and it was built without any regulation regarding energy efficiency. Accordingly, the first aim of this paper was to quantify the energy saving potential and the related reduction in CO 2 emissions of the housing stock in those years. The work focuses on the Mediterranean climate of the Comunitat Valenciana Region, therefore the energy efficiency strategies proposed are passive and deal with the envelope of buildings. On the basis of the results obtained, several scenarios with intervention periods of 10, 20 and 30 years were calculated. The conclusion was that with the current rate of annual building renovation, it will be nearly impossible to reach the goals established by the EPBD. Only a deep transformation of the building fabric within this sector could help in achieving them. Finally, it should be noted that the proposed methodology can be applied to other areas with different climates, particularly in Spain. [ABSTRACT FROM AUTHOR]

The paper shows the results of measurements of carbon dioxide concentrations conducted in the school buildings located in two different climates: Białystok (Poland) and Belmez/Córdoba (Spain). CO 2 concentration in first 45 min met requirements of regulations, but with medium occupation of places in classrooms, then the recommended values were excided. We developed a model for CO 2 level estimation. This model allowed us to simulated the CO 2 concentration for full occupation of classrooms in both countries. In these cases CO 2 concentration would exceed maximum value (1000 ppm) during the first hour. Furthermore required air change rates were calculated: for actual occupation they should be in a range 2.5–5 h −1 to maintain IDA2 and carbon dioxide concentration below 1000 ppm, while in case of full occupation even 6–9 h −1 . Finally, surveys of student satisfaction were performed in situ during the measurements of CO 2 level to obtain the dependence of student comfort perception on this concentration. [ABSTRACT FROM AUTHOR]

• A DCE is conducted to assess households' willingness to insulate their homes. • Determinants for the adoption of façade thermal insulation are identified. • The investment cost required in the existing building stock is below the obtained WTP. • The required subsidy level is lower than the grants set by existing aid programs. • Increased tax rebate has greater incentive effect than soft financing. This paper assesses Spanish households' willingness to thermally insulate their homes and the drivers that influence such a decision-making process. Stated preference data were collected through a discrete choice experiment (DCE). The final sample of 191 respondents and 1,145 observations was analysed by the use of a mixed logit model, weighing the factors that encourage homeowners to carry out façade energy renovations or not. The model enables the quantitative estimation of renovation adoption rates depending on the households' characteristics and public support instruments in place. The results show that homeowners are extremely interested in increasing the thermal insulation of their homes. The actual investment cost required in the existing building stock is lower than the obtained willingness-to-pay. Furthermore, it was found a relevant effect of a variety of household features on renovation choice (income, age, heating system, etc.), which should be contemplated in the energy efficiency policy design. Additionally, a case analysis is performed which comprises 3 household categories. The results reveal that the required subsidy level is different in each case, sometimes even unnecessary, although all of them lower than the grants set by existing aid programs. Thus, to reduce the free-riding effect, a closer perspective would enable targeted support mechanisms towards each household category. Moreover, the policy performance can be improved by combining subsidies with other measures such as low-interest loans or increased tax rebates, which could contribute to improving the cost effectiveness of the public expense associated with direct grants. Overall, an increased tax rebate is preferred to soft financing, although the influence of the latter increases in low-income households. [ABSTRACT FROM AUTHOR]

• Cost-effective and sustainable energy systems retrofit for buildings. • 2nd life Li-Ion batteries in polygeneration systems for buildings. • To cut off the natural gas consumption at affordable cost. The building sector represents around one-third of the energy related to the EU CO 2 eq emissions, which makes it a crucial sector for achieving the EU's energy and environmental goals. Thus, the EU has established a legislative framework to foster, among others, the modernisation of the existing building stock through a better energy system integration. In this sense, bearing in mind the needs of energy system retrofit of the public buildings in Spain, this paper carried out a thorough analysis of different trade-off solutions obtained from the multiobjective optimization of a polygeneration system for the TR5 building of the Polytechnic University of Catalunya. The results highlight the selection of PV panels, cogeneration modules and 2 nd life Li-Ion batteries, among others, to achieve cost-effective and sustainable energy systems. By covering the available area, 2000 m 2 , the PV panels attend about 23% of the electricity required for the building. On the other hand, considering the current geopolitical tensions, it presents a potential configuration that allows to cut off the natural gas consumption reducing about 6% the current cost. The study was carried out by using a Mixed Integer Linear Programming model maximizing the Net Present Value of the project considering the environmental impact. [ABSTRACT FROM AUTHOR]

• Building stock modelling is implemented through a bottom-up method. • Dynamic simulations are applied through calibrated and parameterized stock models. • Optimal retrofit solutions under a 2050 future weather scenario are proposed. • Results are provided for four different climatic regions in southern Spain. • Results can be interactively accessed by stakeholders and the general public. Retrofitting the existing building stock is widely accepted as a crucial factor to reaching 2030 and 2050 climate and energy targets, given that the building sector is among the top three most dominant energy consumers. This paper presents a bottom-up study which uses calibrated and parameterized energy stock models (building archetypes), while also incorporating building stock information from a large database. The thermal performance of the existing social housing stock of southern Spain is assessed through dynamic simulation under present and future climate change scenarios. Subsequently, several passive and low-cost operation-related strategies are numerically optimized through genetic algorithms to determine the best retrofit solutions, taking into consideration global warming scenarios. A multi-objective decision analysis is carried out by optimizing annual overheating hours (%), annual undercooling hours (%), and investment costs (€/m2). Among the conclusions reported, it is important to note the feasibility of implementing low-cost retrofit strategies considering investment costs of up to around 200 €/m2, which would lead to average annual overheating and undercooling hours below 55 % and 45 %, respectively. However, retrofit solutions exclusively based on passive and low-cost operation measures were proven to be significantly limited to improve thermal comfort results in the social stock. [ABSTRACT FROM AUTHOR]

The building sector is well known to be one of the key energy consumers worldwide. The renovation of existing buildings provides excellent opportunities for an effective reduction of energy consumption and greenhouse gas emissions but it is essential to identify the optimal strategies. In this paper a multi-criteria methodology is proposed for the comparative analysis of retrofitting solutions. Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) are combined by expressing environmental impacts in monetary values. A Pareto optimization is used to select the preferred strategies. The methodology is exemplified by a case study: the renovation of a representative housing block from the 1960s located in Madrid. Eight scenarios have been proposed, from the Business as Usual scenario (BAU), through Spanish Building Regulation requirements (for new buildings) up to the Passive House standard. Results show how current renovation strategies that are being applied in Madrid are far from being optimal solutions. The required additional investment, which is needed to obtain an overall performance improvement of the envelope compared with the common practice to date, is relatively low (8%) considering the obtained life cycle environmental and financial savings (43% and 45%, respectively). [ABSTRACT FROM AUTHOR]

The total energy demand of data centres has experienced an important increase in the last years. This is why data centres industry and researchers are working on implementing energy efficiency measures in data centre portfolio. The cooling system of these unique infrastructures can account for 40% of the total energy consumption. Therefore, air management plays an important role to reduce operating costs and to increase overall cooling system efficiency. In order to improve and optimize the energy consumption and thermal management in data centres, appropriate metrics are imperative to evaluate their efficiency and performance. The present paper examines the air management of a real data centre by the use of the most promising air metrics. Noticeable air recirculation and hot spots were observed in the facility. Dynamic modelling was used to evaluate the benefit of air inefficiency mitigation. The combination of air management improvement with increasing the supply air temperature and reducing the air flow rate would allow important energy reduction in the cooling system. [ABSTRACT FROM AUTHOR]

In this paper, an experimental and numerical approach to the characterization of thermal bridges is presented. The need for this characterization was found within an experimental study in a 2 floor high façade. This façade was constructed with 3 concrete elements which were placed in it to produce a similar thermal bridge effect to the one created by floor slabs traditional building construction in Spain. Commonly applied thermal assessments perform one-dimensional heat transfer analysis over planar elements such as the façades studied in this experiment. However, it is well known that thermal bridges are locations in buildings where one-dimensional heat transfer analysis cannot be applied. This problem was approached by creating a numerical 2D thermal model which was calibrated against experimental data from several temperature and heat flux sensors which were located at specific points in the thermal bridge elements. [ABSTRACT FROM AUTHOR]

The European SHERPA project aims to share knowledge for energy renovation in buildings by public administrations. The EU Energy Performance in Buildings Directive (EPBD) recast, indicates the necessity of transforming EU buildings into Nearly Zero Energy Buildings (nZEB). Each Member State transposes differently the EPBD, usually based on European norms like Spain did. The generated knowledge about improving performance and transforming public buildings into nZEBs, is applied here to schools, according to the Spanish transposition. SHERPA, among other buildings, has audited four schools sited in the Valencia Region (Spain, Southern European Country). The paper starts describing, briefly, the general auditing protocol devised by SHERPA. Particularly, one school was chosen out of the four to illustrate the protocol and was converted into a nZEB. This school led to the most unexpected and outstanding results, although the trends were shared among all the audited schools. Finally, based on the results, the paper suggests some recommendations to the policy makers about the practical definition of nZEB and financial instruments to engage this nZEB challenge for schools. [ABSTRACT FROM AUTHOR]

• A systematic literature-approach to classify retrofitting is proposed. • An overview of Spain's previous guidelines on residential retrofits is presented. • A review of financial and subsidies mechanisms in Spain to renovate buildings is introduced. • A literature-based matrix on retrofitting actions is presented. • A classification of energy efficiency strategies for retrofitting is proposed. The building sector is responsible for more than 40% of final energy consumption in Europe; consequently, retrofitting existing buildings can significantly contribute to mitigate greenhouse emissions. Nevertheless, although the European Union has introduced relevant policy instruments, up to now the annual retrofit rates are considerably low with an average of 0.2% at European level. Understanding the past would support the success of the new strategies, such as the recent ones launched through the New Green Deal, which reinforces the importance of renovating existing buildings stock, as the main aim of the renovation wave. As a starting point for assessing the main challenges to allocate the Recovery funds, this paper provides a review of Spain's relevant literature to clearly define the characterization of the existing building stock, which actions have been typically considered under the scope of retrofits, and which strategies have been implemented until now, considering both, private and public initiatives and public financial schemes. The present work has a strong focus on energy-related strategies, although other interrelated actions are mentioned, such as accessibility measures and interior refurbishment of dwellings. Differences and similarities within these approaches are presented through the analysis of 27 relevant references of retrofitting actions and 52 references of financial mechanisms. As in Spain 93% of multifamily buildings were constructed prior to the national transposition of the first Energy Performance Building Directive (EPBD), and therefore are in need of deep energy renovations, the retrofitting of multifamily buildings topic has been widely addressed, even though often in a disjointed manner. The study suggests that although historically there have been several recommended strategies, few are conceived as integral actions, only 15% of the intervention packages refer passive and active energy-related measures and renewable energy incorporation. Furthermore, considering the antiquity of the building stock and the advantage of addressing the topic through clusters, only 63% of the resources directly refer these actions to specific clusters among the six distinctive periods, although in most cases focusing their recommendations on buildings constructed before 1980 where the worst energy performance buildings are concentrated. Concerning public financial and funding instruments, the research illustrates that there has been a substantial increment of programs over the last years promoting energy-related measures, renewable energy and other complementary aspects such as accessibility and interior renovations, mainly for older clusters. Nevertheless, the funds constitute only 8% of the necessary declared investments, which along with the dispersion between the different procedures and the complexity of the processes, have significantly reduced the global impact of these actions without generating robust and oriented market dynamics. Despite the several resources found, both financial instruments and guidelines tend to describe in more detail strategies related to heating demand and consumption and not delve into other relevant actions for warmer climates, fact associated both to the dynamics coming from other countries, and to a vision of the past in which people do not consume refrigeration. This clear focus on heating loads rather than cooling could present limitations for warmer regions in the near climate-change future. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a regression analysis of energy consumption in the banking sector. In our case study, the target area is the Spanish banking sector, for which we divide the available data into a prediction and a validation subset. Power models were developed using test data from 55 banks. From the analysis, three models were obtained; where the first proposed model can be used to predict the energy consumption of the whole banking sector, while the rest of the models estimate the energy consumption for branches with low winter climate severity (Model 2) and high winter climate severity (Model 3). Models 2 and 3 differ from the first model in that they need independent variables measured in situ. As a result, the uncertainty of the response variable in the function of the independent variables is reduced by 56.8% for the first model and by 65.2% and 68.5% for the second and third proposed models, respectively. The validation of the first model, which is the model with the lowest determination coefficient, shows that this model is appropriate for predicting the energy consumption of bank branches with good energy consumption performance and detecting inefficiencies in bank branches with poor energy consumption performance. [Copyright &y& Elsevier]

Abstract: Energy consumption in buildings accounts for a significant percentage of total world energy utilization. Great efforts have been made in order to reduce fossil energy consumption and mitigate its depletion by means of energy efficiency directives. The national transposition of such directives generates regional regulations that might be counterproductive if it is not clear which one is more restrictive. The main goal of this paper is to evaluate the potential of energetic savings of the dwellings in Catalonia and its economic impact, according to different scenarios of efficiency that have been defined according to current regulations at state and autonomic level. To achieve this objective, thirteen typologies of dwellings have been defined in order to categorize the stock of buildings in Catalonia. Simulations with LIDER software have been carried out in order to obtain the heating and cooling demand for each typology of dwelling in different climatic zones and orientations. The economic impact of each scenario has been stated as well. We show that the best normative scenario is not the regional but the national one, and only when full limitations imposed by the state regulations are fulfilled. Following the latter 6.4% reduction in CO2 emissions would be achieved, whereas following the former gives us only 2.8% reduction for year 2015. These results have been obtained considering a base case scenario without any energetic measures implemented for the same time line. [Copyright &y& Elsevier]

Abstract: Numerous computer programs are available to calculate the energy efficiency of buildings. Many are based on the use of a reference building to determine the degree of efficiency. However, this methodology presents a major constraint when assessing a building after construction and during the use stage. To assess the energy efficiency of buildings, this paper proposes new indices based on energy consumption during different periods; as well as other parameters of the buildings such as construction area, number of users, and air-conditioned volume. Results are presented as an application for various buildings on the campus of the Universidad Politécnica de Valencia. [ABSTRACT FROM AUTHOR]

Abstract: The significant and continuous increment in the global electricity consumption is asking for energy saving strategies. Efficient control for heating, ventilation and air-conditioning systems (HVAC) is the most cost-effective way to minimize the use of energy in buildings. In this framework, an energy management and control system (EMCS) has been developed to schedule electricity end-uses in the campus of the Universidad Politécnica de Valencia (UPV), Spain. This paper presents an evaluation performed by using the EMCS of different control strategies for HVAC split systems. It analyzed the effect of different schedules for a common air-conditioning device and demand response strategies are tested in several situations. The economic saving is calculated taking into account the electricity contract clauses. Finally, a test is made for the control of a group of similar devices in order to reduce the maximum peak power in consumption and to obtain a flexible load shape with the HVAC loads. The studies are then extrapolated to a larger system, the whole University campus, for which energy and economic savings are quantified. [ABSTRACT FROM AUTHOR]

Abstract: Trigeneration systems, also known as Combined Heat, Cooling and Power (CHCP) systems, are interesting alternatives to supply different energy services in urban districts and in large buildings, particularly in warm areas such as Mediterranean countries. These systems can provide substantial benefits from economic, energetic, and environmental viewpoints, since the cogenerated heat can be used for heating in winter as well as cooling in summer with an absorption refrigerator. This paper develops an optimization model using Mixed Integer Linear Programming (MILP) to determine the type, number and capacity of equipment in CHCP systems installed in the tertiary sector as well as to establish the optimal operation mode for the different plant components on an hour-by-hour basis throughout the year. The objective function to be minimized is the annual total cost. The optimization model considers the legal constraints imposed to feed the surplus autogenerated electricity into the grid at a regulated feed-in tariff. The optimization model is applied to design a system providing energy services for a hospital located in the city of Zaragoza (Spain). The effects of the financial market conditions and energy prices in the optimal structure of the system are analyzed. [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]

Abstract: The main requirements of European Directive 2002/91/EC on the energy performance of buildings (EPBD) are the application of minimum energy performance requirements for new buildings and certification of the energy performance of buildings. Its transposition into the national law of member states of the European Union has signified the appearance of new and more onerous requirements in terms of construction quality from the point of view of energy performance, and in terms of the procedure for certification of the energy performance of buildings. In both cases, the levels required tend to be based on climatic conditions, fundamentally in countries such as Spain, where the climatic variability is very pronounced. This paper presents a methodology developed for the climatic zoning of the localities not included in the above-mentioned regulations in order to facilitate their application. By way of example, the method is shown which was used to generate the climatic files and carry out the subsequent climatic zoning of all the municipalities of the region of Andalusia in southern Spain. [Copyright &y& Elsevier]

Abstract: This paper studies a new innovative concrete with phase change materials (PCM) on thermal aspects. The final objective is to develop a product which would achieve important energy savings in buildings. The work here presented is the construction and experimental installation of two real size concrete cubicles to study the effect of the inclusion of a PCM with a melting point of 26°C. The cubicles were constructed in the locality of Puigverd of Lleida (Spain). The results of this study show the energy storage in the walls by encapsulating PCMs and the comparison with conventional concrete without PCMs leading to an improved thermal inertia as well as lower inner temperatures. [Copyright &y& Elsevier]

• A methodology to assess energy flexibility of building clusters in a GIS framework. • Building clusters become energy prosumer by deep renovation and renewable energies. • It aims to integrate a wider spatial decision tool for environmental public policy. • Comfort thermal indexes quantify energy flexibility to measure peak load reduction. • Cluster design approach may help reduce investment costs and reach cost optimality. Natural resource depletion, global warming and pollution pose substantial threats in prioritizing environmental policy, both for private organizations and for governments. Half the EU building stock is prior to energy efficiency standards, thus making it an urgent challenge for the EU to aim at decarbonized cities by 2050. Urban energy retrofitting at cluster level represents a major opportunity, as its current rate is lower than an annual 1%, 3% being the EU desirable rate. This paper presents a bottom-up methodology to assess energy flexibility of building clusters within a Geographic Information System (GIS) framework, applied on a district scale. Energy performance certificates and GIS-based data permit diagnosis and neighborhood selection. The methodology evaluates building cluster energy flexibility via energy demand reduction and PV production. The results show the building cluster hourly load profile for heating and cooling, and thermal comfort indexes. It is expected that this GIS-based methodology will become part of a wider spatial decision support tool for environmental public policies contributing to building stock transformation, from energy consumer to prosumer through deep renovation and renewable energy use. Finally, this methodology is adaptable to other climates, particularly within Spain. [ABSTRACT FROM AUTHOR]

• Listed dwellings of southern Spain were monitored in winter to evaluate IEQ and EP. • Lengthy high rates of IRH were observed. • High levels of CO 2 concentration were recorded in bedrooms at night. • Thermal comfort is only achieved through a constant use of the heating systems. • Heat losses are entirely building-driven. Although European heritage buildings are excluded from energy efficiency targets, it would be beneficial to include the largest group, that of listed housing, in energy retrofit plans, in order to encourage its occupation and contributing to the sustainable maintenance of historic cities. This requires reliable experimental studies, which have been rare so far, in order to establish energy rehabilitation plans that do not jeopardize the conservation of their values. This paper aims to contribute to addressing this gap. It evaluates the energy performance and indoor environmental quality of dwellings within listed buildings of the conservation area of Seville, Spain, in the Mediterranean climate zone, under actual winter use and occupation conditions. An experimental campaign was conducted, generating energy models and measuring rates of indoor air temperature to validate them. The findings highlight important health and environmental issues: despite the mild winters of southern Spain, intensive use of the heating system is needed to maintain thermal comfort indoors, increasing polluting emissions; CO 2 concentration in bedrooms is usually excessive overnight and, regularly, indoor relative humidity remains too high; heat losses depend entirely on the physical condition of the constructive elements (walls, roofs, air leakage and glazing) which occupants cannot easily improve. [ABSTRACT FROM AUTHOR]

• Effects of multi-zone heating systems in residential buildings are assessed. • Data obtained from 336 scenarios in Mediterranean climates are evaluated. • Results are evaluated under economic and energy criteria. This paper explores the effects of multi-zone heating systems in residential buildings in different Mediterranean climates. The aim is to evaluate their potential in residential sectors to provide a general basis from the results (from the energy and economic point of view). In addition, if feasible, a further detailed evaluation of this management strategy for optimising the energy use in residential buildings would also be carried out. To do so, the effects of two different zoning controls in different types of apartment, occupancy patterns, building characteristics and locations in Spain, have been assessed. Different combinations of these parameters have resulted in 336 different scenarios that have been dynamically simulated using Design Builder software. The obtained energy results have been analysed in detail. Moreover, an economic analysis of these results has also been carried out to evaluate the economic feasibility of these systems in residential buildings located in temperate climates. This has been calculated by evaluating the maximum investment that can be assumed in each scenario to achieve different payback periods (namely 10 and 20 years). The results obtained show that these systems could be a cost-effective strategy aimed at reducing the energy consumption in residential buildings, not only in cold climates, such as is shown in the literature (the majority of the studies found are located in the UK and northern countries), but also in more temperate climates, such as that of Spain. Savings of around 20% were obtained in the most usual scenarios in Spain (coherent with results obtained in previous studies in the UK found in the literature), showing that in several cases, the initial investment in zone-controlled systems could be paid off in less than ten years, especially in large apartments and the coldest weather conditions. [ABSTRACT FROM AUTHOR]

• Optimal design approach for carbon-neural residential communities is outlined. • The design approach is applied to residential communities in Barcelona, Spain. • Energy efficiency measures combined with wind turbines are found to provide cost-effective options. This paper investigates the optimal retrofit solutions for residential communities to be carbon neutral in Barcelona, Spain. In particular, three different sizes for the residential communities are considered depending on the number of housing units: small, medium, and large. First, the best cost-effective energy efficiency measures (EEMs) have been determined and applied to all the buildings of the communities, in order to reduce their overall energy demand. The retrofit optimization results demonstrate that combinations of passive and active strategies would achieve source energy use saving and electrical peak demand savings up to 57% and 29%, respectively. Then, a variety of renewable energy generation systems has been explored to determine the optimal grid-connected technologies for meeting the electricity demands while achieving annual carbon neutral conditions for the residential buildings. The analysis shows that wind turbines can reduce the cost of electricity generation up to 21.5% compared to the current utility prices (LCOE value as 0.247 €/kWh) and electricity sell back policies. The results indicate that for PV systems to compete with wind turbines, their capital costs need to be lower by at least 40% compared to the current level costs. [ABSTRACT FROM AUTHOR]