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• Automatic MiC envelopes and layout generation by a novel SSG-MOO method. • Multi-objective optimization formulation for passive MiC design. • A pilot MiC study in Hong Kong produced 5 selected Pareto optima out of 625. • Up to 0.42% energy savings and 9.71% spatial daylight autonomy improvement against the baseline. • A multi-level analysis of results and design strategies for practitioners. Modular-integrated Construction (MiC) is an emerging construction technique promoted in the building sector for high productivity and low waste emission in the construction phase; yet, the standardized modules also bring new challenges, such as balancing passive energy efficiency and spatial daylight autonomy, to the operational phase. This paper proposes a Symmetric Skeleton Grammar-based Multi-Objective Optimization (SSG-MOO) method to formulate parametric MiC envelopes and detailed layout, with the two objective functions being energy efficiency and interior daylight performance in the operational phase. Pareto optima of the SSG-MOO, computed by the Non-dominated Sorting Genetic Algorithm II, are generally verified and analyzed in three levels, i.e., MOO's solution space, SSG layout, and MiC design parameters. A case study of MiC residential building in Hong Kong demonstrated the SSG-MOO method through five new passive MiC designs (i.e., spatial reorganization of three architectural modules, and parameter tuning of the envelops and corridors), achieving up to 0.42% energy savings and 9.71% spatial daylight autonomy improvement compared to the baseline design. The contribution of this paper is two-fold, including a novel and sound SSG-MOO formulation for parametric MiC designs, and offering time-efficient and evidence-based design tactics for MiC designers and industrial practitioners to push boundaries of MiC. [ABSTRACT FROM AUTHOR]

The growing awareness of climate change is constantly moving the attention of designers and policymakers from typical and current scenarios to future layouts. This new approach introduces a degree of uncertainty that should be accounted in the building design process. The multitude of possible scenarios suggests considering dynamic system that can adapt themselves to unpredicted operating conditions. The aim of this study is to test a new approach and a new flexibility metric analysing the behaviour of a high-performance dynamic internal curtain in current and future scenarios. The first part of the paper focuses on the optimization of the dynamic system in the current scenario; this preliminary analysis represents the traditional design approach and is considered the baseline for all the comparisons. Hence, defining a matrix of likely scenarios, this paper explores the behaviour of three different selected control strategies – always off (i.e., no curtain), fixed control, optimized control – in the different scenarios considering possible variations of i) climate, ii) urban context, iii) internal loads, and iv) building use. The main outcomes of the research are, on the one hand, the comparisons of the control strategies and the benefits of the dynamic system and, on the other hand, the definition of a new metric that can properly describe the flexibility of the building systems with reference to the future scenarios analysed. This metric is based on six classes – which describe the statistical distribution of the energy consumptions of all the scenarios simulated in the matrix – and an index called Energy Flexibility Index (EFI) that quantifies the flexibility of the technology considered. The case study analysed highlights how implementing a dynamic shading system, considering the same building use, can increase the EFI of nearly 21% for non-optimized control strategy and up to 23% when optimized. While changing the building use in residential reduces these values respectively, to 6% and 7%. [ABSTRACT FROM AUTHOR]

Reducing energy consumption in buildings and increasing renewable production are key goals of European policies to achieve a sustainable and competitive low-carbon economy by 2020 and beyond. Non-residential buildings constitute a heterogeneity sector characterized by high energy consumption and various building types, sizes and energy characteristics over Europe. This paper presents the overall results of the data collected by the GreenBuilding Programme (GBP), launched in 2006 to promote and improve energy efficiency in new and existing European non-residential buildings. The GPB involved building owners willing to adopt energy efficiency measures to decrease energy consumption of their buildings by of at least 25%. Based on voluntary participation, hundreds of partners joined the project, which collected data from more than a thousand buildings of different age, size, use and type (such as offices, hotels, and industry). This paper provides an overview of the Programme and its main results up to its completion in 2014. The paper focuses on building characteristics, energy performance, efficiency measures and energy savings, which are globally estimated to be around 985 GWh/year. A more detailed focus is then given to office buildings, which represent the most frequent building category in the Programme. Case studies are presented to show best practices in various countries with consolidated energy efficiency policy strategies. The paper categorises the main technological measures related to envelope, appliances and systems. It shows how a wide range of technologies are becoming an integral part of buildings and how technology plays a major role in exploiting the massive potential benefits of reducing building energy consumptions. The analysis of the results generates a reliable snapshot of European non-residential building stock. [ABSTRACT FROM AUTHOR]

Cogeneration (CHP) and Heat Pump (HP) are playing a key role in energy systems due to their high efficiency, especially, in energy refurbishment of buildings and industrial processes. This paper explored the opportunity to couple those two well-established technologies for heating purposes. Basically, the coupling entails limitations and constraints consisting of the mismatch between the power sizes of merchandised machines as well as the deriving technical issues. The main aim of this paper is to analyse the coupling procedure to help HVAC specialists in their job. This paper deals with a simple model formulation, based on the First Law of thermodynamics, for CHP/HP systems rating and off-design operations. Indeed, an analytical method was designed along with the definition of a size factor. Then, a graphical method for coupling CHP and HP was presented so as to be an expeditious tool in designing phase. Finally, two numerical applications were illustrated highlighting the energy performance gains and the high level of operation flexibility. [ABSTRACT FROM AUTHOR]

Energy efficiency standards for household appliances have been adopted in many countries to mitigate negative externalities, reduce emissions, and save energy. Using Chinese provincial-level panel data from 2008 to 2018, this paper builds a difference-in-difference model to examine the mechanism by which energy-efficiency upgrades in China's air conditioners affect urban household electricity usage. The results show that the upgrades have brought about an obvious reverse effect, with urban household electricity usage increasing rather than decreasing. Reducing the unit costs of energy service has enhanced residents' sensitivity to cooling demand. Driven by the substitution and income effects, urban residents may increase the intensity and frequency of their AC use. Additionally, this reverse effect is heterogeneously dependent on the family size and urban residents' age structure rather than their educational level. When families are larger and have more children, the reverse effect is more pronounced. This paper's findings provide useful recommendations for policy-makers to formulate policies that are synergistic with energy efficiency standards for household appliances. [ABSTRACT FROM AUTHOR]

Energy consumption of lift systems is one key issue in modern high-rise buildings, drawing property owners' attention and accounting for 6% of total electricity consumption by end-use in Hong Kong. A Benchmarking Energy Performance Indicator (BEPI), , measured in J.kg−1.m−1 and proposed by the first author of this paper for lift installations is mentioned in the Technical Guidelines of the Building Energy Code , as one emerging good engineering practice. BEPI is a fair parameter for comparing energy performance of lifts irrespective of their brand, model, travel, speed, capacity and control. It considers energy performance due to both the motor drive efficiency and traffic control intelligence. However, one main obstacle to make it statutory is the lacking of a generic monitor able to retrieve three sets of real time data (normally unavailable on an existing lift) to compute the BEPI, namely energy consumption, instantaneous car load and traveling distance, and to collect ample data statistically reliable enough to determine an acceptable threshold value. This paper describes the development of a proof-of-concept prototype BEPI monitor by giving full technical details on the rationale and history of development, the hardware components, software framework, and updated numerical results of one implementation inside the headquarters of Electrical & Mechanical Services Department (EMSD) of HKSAR. Experiences in installing and calibrating those external sensors that make the whole system non-disturbing to normal lift operation, as well as the procedures in computing the BEPI, are discussed in greater details. It has been shown that the BEPI is traffic dependent but the weekly average of it is relatively stable, confirming it may be robust enough for benchmarking purpose. The solution described in this paper may help roll out the monitoring of BEPI for all lifts inside and outside Hong Kong. [ABSTRACT FROM AUTHOR]

Nowadays, aviation industry has been faced with technology challenges and safety requirements. Therefore, aircraft manufacturers give special attention to environmental building capacities regarding to passenger comfort and safety. This paper aims measuring safety and comfortability level of passenger accommodation during the flight. Since the environmental and safety issues could affect humans on a different level significance, this paper is based on the TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) method as a decision making tool for balancing those two inputs. With the aim of defining rank of existing world market aircraft the Saaty scale was used for developing the weight of different criteria whilst the improved TOPSIS method is used for ranking six aircraft: A320, A330, A340, B737, B747, B767 based on cabin environmental efficiency and safety. [ABSTRACT FROM AUTHOR]

[Display omitted] • nZEBs in Eastern Europe lack carbon neutrality metrics and targets. • Performance requirements for nZEBs in Eastern Europe are presented. • Eastern Europe needs strategy and local governance for nZEB market penetration. • EPCs require major reform, and effective monitoring of nZEB performance is needed. • The cost-optimality calculation method must be adopted to ensure cost-effective market uptake. The European Unions' ambition for the construction sector is to be carbon neutral by 2030 for new construction. Since 2021, all new buildings in the EU should have been constructed as nearly zero-energy buildings (nZEB). However, Eastern European countries struggle to implement the 2018 Energy Performance of Building Directive recast requirements. Next to the economic challenges, equally essential factors hinder renovating the existing residential building stock and adding newly constructed high-performance buildings sourced primarily from renewable energy sources. Therefore, this study provides a cross-study to identify the barriers to nZEB implementation in ten Eastern European countries, including Bulgaria, Croatia, Czechia, Estonia, Hungary, Latvia, Lithuania, Poland, Romania, and Slovakia. The study was conducted between 2019 and 2021 and provides an overview of prospects for nZEB in Eastern Europe. The study examines the challenges of nZEB plans faced in those countries and provides constructive recommendations. The regulations and definitions regarding nZEB energy performance, cooling and heating energy demand, thermal comfort, onsite renewables, and construction quality were analyzed. Results show that most Eastern European countries are unprepared to comply with the EPBD guidelines and cost-optimality approach. The paper ranks each country and recommends specific measures to refine the nZEB definitions. The paper provides a thorough comparative assessment and benchmarking of select EU geography that can help shift the identified gaps into opportunities for the future development of climate-neutral high-performance buildings. [ABSTRACT FROM AUTHOR]

This paper recognizes the synergetic relationship and inextricable linkage between conservation and sustainability. Heritage preservation maximizes the use of existing materials and infrastructure, reduces waste, and preserves the historic character of older towns and cities. This paper also presents technical advances in BPS/BES (Building Performance Simulation/Building Energy Simulation), and in co-simulation for energy efficiency optimization, RES integrated historic building's greening and historic neighborhoods, settlements, as well as whole cities urban re-planning. Further, the paper presents initial results of the Aviation Museum in Belgrade preliminary energy refurbishment study focusing results obtained via BPS and co-simulation. Foreseen is the deep energy refurbishment aimed to reach the “total building performance optimization” encompassing multifunctional optimization of building's skin – glazing replacement with the semi-transparent PV glazing and day-lighting control with reference to the artifact preservation, as well as the IEQ (Indoor Environment Quality) control analysis. This study shows that the RES integrated refurbishment can result in the Museum's Zero CO 2 emission and even in the sustainable Energy + status (producing more than using electricity). Finally, needs for most current ICT knowledge use and refurbishment technologies development, as well as integrated design, including particularly relevant benchmarking and rating system development are outlined. [ABSTRACT FROM AUTHOR]

In this paper, a mathematical model is formulated to quantify the social impact an individual has on his/her community when he/she performs any energy efficiency project and transmits that information to his/her neighbours. This model is called the expected power savings model; it combines direct and indirect expected power savings of the energy efficiency project for each individual within the network. The indirect savings are quantified through the social interactions people in the network. The example used in this paper illustrates the effectiveness of the model by identifying the households who should have free solar water heaters installed in their residential houses based on their influence through interactions in their community. Two case studies are considered in this paper, single and multiple sources case studies. In the multiple source case study, the results show that it is not necessarily the people with the highest connections who provide the maximum expected power savings. [ABSTRACT FROM AUTHOR]

The building sector of the U.S. currently consumes over 40% of the U.S. primary energy supply. Estimates suggest that between 5% and 30% of any building's annual energy consumption is unknowingly wasted due to pathologically malfunctioning lighting and comfort conditioning systems. This paper presents analytical methods embodied within useful software tools to quickly identify and evaluate selected faults in air handling units (AHU) that cause large building energy inefficiencies. Algorithm for faults like stuck dampers and leaking dampers have been developed and tested in this particular case study. These damper fault detection algorithms can be applied to outdoor air and return air dampers both. The technical contributions of this work include expert rules that adapt to the Heating, Ventilation and Air-Conditioning (HVAC) equipment scale and operation and methods for sorting fault signals according to user-defined interests such as annual cost of energy inefficiencies. The combination of expert-rule based fault detection combined with first principles thermodynamic modeling is a unique contribution of this work that leads to quicker fault detection with minimal non-intrusive measurements. These contributions are particularly unique in their treatment of models and the careful consideration of user-interests in fault evaluation. As a first step to developing this general framework for fault detection, first-order faults such as stuck dampers and imbalanced airflows within several large air-handling units were targeted. The algorithms focused on detecting faults with minimal data and non-intrusive measurements. An example is presented of the potential energy savings in a large academic building that has been monitored. Real data from an academic building in Boston was collected from the building energy management system (BEMS) for the purpose of this study. Savings of around $3400/month or 18% of the monthly cost when a stuck damper fault occurred over an entire month in an air handler. Another fault that was investigated was that of leaking dampers which lead to savings of approximately $500/month or around 2.5% of the monthly energy expense. The savings would accrue if the fault were corrected; otherwise the occurrence of the fault causes a waste of money and energy predicted. The algorithms developed can be applied to large commercial office buildings, academic buildings, hospitals and other modern buildings in various climates as long as they have data collecting capabilities. [ABSTRACT FROM AUTHOR]

• Development of a new model was developed to estimate the technical potential for net zero energy buildings. • It considers different locations, climates and building types and vintages. • It combines methods for bottom-up energy modeling and geospatial analysis. • Results show a significant energy savings in all regions and building types. With the Paris Agreement coming into force, global efforts will need to maximize opportunities through energy efficiency and renewable energy generation. Zero energy/carbon initiatives are mushrooming worldwide, but it has not been fully understood which building types in which climates and under which conditions can potentially be built to net zero energy standards. In order to inform these efforts, a new model was developed to estimate the technical potential for building—integrated solar energy (BISE, the name of the model) generation in a high resolution regional, climate and building typology breakdown., The BISE model also evaluates the opportunities for potential net zero energy buildings based on the BISE findigns, combining these with the findings of two global low-energy building models. The BISE model has a very high resolution in terms of geographic regions, climate types, building types and vintages. Moreover, the model combines methods for bottom-up energy modeling and geospatial analysis. The thermal building energy demand estimation is based on the 3CSEP-HEB model and the plug load scenarios are based on the BUENAS model. Results are wide, due to intrinsic limitationso of the model detailed in the paper, but it is shown that there is a substantial potential for building-integrated solar energy generation in all world regions, and that the Deep Efficiency Scenario allows significantly more building types to meet net zero energy levels by 2050 in contrast to a scenario when only moderate energy efficiency improvements are implemented. [ABSTRACT FROM AUTHOR]

• Five different energy efficiency alternatives for the building were studied. • A ground-source heat pump and solar PV usually provide the highest profitability. • A household battery has become profitable at the 2022 electricity price. • Dimensioning of a solar PV system massively depends on the electricity price level. • At the 2022 electricity price level, the array-to-inverter ratio can be up to 4.9. Buildings and the construction sector make up about a third of the final energy consumption and energy-related carbon dioxide emissions, offering a significant potential for emission reductions. This paper investigates the conversion of a Nordic oil-heated townhouse into a carbon-neutral one. Five different energy efficiency (EE) alternatives including, for example, different heat pump types and their dimensioning are studied. The electricity demand of the EE alternatives is aimed to be covered as cost-effectively as possible with an on-grid system based on solar photovoltaics (PV) and a battery energy storage system (BESS). The cost-optimal dimensioning of the components is based on the 30-year life cycle cost (LCC), and the work is carried out using an hourly level simulation model developed in MATLAB. To maximize the profitability of the BESS, an intelligent control algorithm based on linear programming is implemented based on a day-ahead electricity spot price for the years 2020–2022 and "perfectly" forecasted power demand and generation data. The data used in the simulation consist of measured electricity consumption, simulated heat generation based on annual oil consumption, and simulated solar PV power generation. It was observed that an about 60% partial-power-dimensioned ground source heat pump together with a solar PV system provides almost always the lowest LCC. However, the BESS was shown to be profitable at the current investment costs for the first time at the 2022 electricity prices, enabling a capacity of 210–230 kWh. On average, the cost-optimized on-grid electricity system was found to reduce the 30-year life cycle costs by 6%, 20%, and 85% with the electricity prices of 2020, 2021, and 2022, respectively. When the price of electricity is exceptionally high, it may be justified to implement more extensive energy efficiency improvements, such as additional insulation of the building envelope. Nevertheless, the impact on the life cycle costs is marginal. In addition, the cost-optimized solar PV capacity has increased more than sevenfold between 2020 and 2022. [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]

• 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]

Providing the occupants with tailored feedback on their energy consumptions can be an effective method to help the users to adopt energy-efficient behaviours. However, in specific contexts such as the social housing, this may be challenging, due to the peculiarities and the economic constraints of the end-users, which make them vulnerable and needing a proper design of the information. Nevertheless, there is a lack of detailed studies in the literature analysing the effects of personalized energy feedback on the space heating consumption and the indoor air temperatures in the social housing sector. This paper aims to evaluate the effects on space heating consumption and indoor air temperature of a personalized feedback campaign delivered in three social housing buildings consisting of 27 apartments in Mediterranean climate. To this end, a personalized feedback campaign was designed and developed, providing for the use of disaggregated energy consumption indicators to show the location of excessive thermal energy consumptions. The daily thermal energy consumptions, as well as the indoor air temperatures of the single dwellings, were monitored daily for over four heating seasons and their variations were analysed before and after the implementation of the personalized feedback. A saving in normalized natural gas consumption of the buildings was found on average equal to −14,8% after the feedback campaign, with no significant variations in the indoor air temperatures. However, some critical issues have been highlighted in the response of individual end-users to the feedback provided. A greater propensity of the occupants to regulate the indoor air temperature through the thermostatic radiator valves in the unoccupied rooms of the house was also observed after the occurrence of the feedback campaign. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has significantly affected people's behavioral patterns and schedules because of stay-at-home orders and a reduction of social interactions. Therefore, the shape of electrical loads associated with residential buildings has also changed. In this paper, we quantify the changes and perform a detailed analysis on how the load shapes have changed, and we make potential recommendations for utilities to handle peak load and demand response. Our analysis incorporates data from before and after the onset of the COVID-19 pandemic, from an Alabama Power Smart Neighborhood with energy-efficient/smart devices, using around 40 advanced metering infrastructure data points. This paper highlights the energy usage pattern changes between weekdays and weekends pre– and post–COVID-19 pandemic times. The weekend usage patterns look similar pre– and post–COVID-19 pandemic, but weekday patterns show significant changes. We also compare energy use of the Smart Neighborhood with a traditional neighborhood to better understand how energy-efficient/smart devices can provide energy savings, especially because of increased work-from-home situations. HVAC and water heating remain the largest consumers of electricity in residential homes, and our findings indicate an even further increase in energy use by these systems. [ABSTRACT FROM AUTHOR]

This paper evaluates through experimental testing a prototype of switchable insulated shading (SIS) systems suitable for windows to optimize solar heat gains in order to maintain indoor thermal comfort. Specifically, the paper describes a laboratory testing procedure and measurement results for SHGC values specific to various SIS designs and operation settings using a box calorimeter set-up. The SIS prototype can modulate continuously its optical and thermal properties including U-value and SHGC using rotating insulation layers controlled through an actuator to a specific slate angle setting. The results of the experimental testing confirm that SHGC value for the SIS prototype is correlated to the slate angle of the insulated layers. This correlation remains applicable for any SIS insulation thickness. The measured data are used to assess the potential energy efficiency benefits from SIS when applied to windows for US homes. In particular, a prototypical housing unit located in three US cities is considered to evaluate the energy efficiency potential for switchable opaque insulated shading systems. The results indicate that SIS systems can achieve up to 8.3%, 11.3%, and 11.4% in annual HVAC energy consumption compared to no-shading cases for dwellings located in Golden, CO (representing a cold climate), Phoenix, AZ (representing a hot climate), and San Francisco, CA (representing a mild climate), respectively. [ABSTRACT FROM AUTHOR]

Abstract Convenience stores are known to have higher Energy Use Intensities (EUIs) than most other commercial building types. However, convenience store energy performance analyses have not been systematically investigated. Moreover, current national convenience store benchmarks are inconsistent from one data base to another due to lack of relevant energy data. This paper assesses the energy performance of more than five hundred convenience stores in the same fleet in Eastern United States. The investigation aims to establish benchmarks for convenience stores with and without gasoline pumping stations. The main factors influencing the actual convenience store building energy use were determined. Multiple regression models were developed to find relationships between annual energy consumption per unit area and gross floor area, customer transaction count, building operating year, etc. The statistically characterized results are meant to serve as a reference data set in comparing the whole-building energy performance index for buildings of similar functionality. The statistical correlation analyses can strengthen the robust prediction of energy performance in convenience stores, enabling proper assessment of energy conservation measurements (ECMs) for convenience store operations, as well as guiding additional such energy performance studies. [ABSTRACT FROM AUTHOR]

Highlights • Non-intrusive techniques are proposed to infer occupancy from existing HVAC sensors. • Reheat energy use is reduced by more than 38% with better nighttime setback schedules. • Derived a comprehensive set of candidate anomalous zones using unsupervised learning. • Proposed approach can be readily applied to any commercial building with a BMS. Abstract The Heating Ventilation and Air Conditioning (HVAC) system of commercial buildings traditionally runs on a fixed schedule that does not take occupancy into account despite its huge variation over space and time, thereby wasting a lot of energy in conditioning empty or partially-occupied spaces. Occupancy information is essential to eliminate wasteful energy use with imperceptible impact on building operations and human comfort. This paper investigates the application of non-intrusive techniques to obtain a rough estimate of occupancy from coarse-grained measurements of sensors that are commonly available through the building management system. Various static and adaptive energy-efficient schedules are developed based on this approximate knowledge of occupancy at the level of individual zones. Our experiments in three large commercial buildings confirm that the proposed techniques can uncover the recurring occupancy pattern of the zones, and schedules that incorporate these occupancy patterns can achieve more than 38% reduction in reheat energy consumption while maintaining indoor thermal comfort. [ABSTRACT FROM AUTHOR]

[Display omitted] The school building sector has a pivotal role to play in the transition to a low carbon UK economy. School buildings are responsible for 15% of the country's public sector carbon emissions, with space heating currently making up the largest proportion of energy use and associated costs in schools. Children spend a large part of their waking life in school buildings. There is substantial evidence that poor indoor air quality and thermal discomfort can have detrimental impacts on the performance, wellbeing and health of schoolchildren and school staff. Maintaining high indoor environmental quality whilst reducing energy demand and carbon emissions in schools is challenging due to the unique operational characteristics of school environments, e.g. high and intermittent occupancy densities or changes in occupancy patterns throughout the year. Furthermore, existing data show that 81% of the school building stock in England was constructed before 1976. Challenges facing the ageing school building stock may be exacerbated in the context of ongoing and future climate change. In recent decades, building stock modelling has been widely used to quantify and evaluate the current and future energy and indoor environmental quality performance of large numbers of buildings at the neighbourhood, city, regional or national level. Building stock models commonly use building archetypes, which aim to represent the diversity of building stocks through frequently occurring building typologies. The aim of this paper is to introduce the Data dRiven Engine for Archetype Models of Schools (DREAMS), a novel, data-driven, archetype-based school building stock modelling framework. DREAMS enables the detailed representation of the school building stock in England through the statistical analysis of two large scale and highly detailed databases provided by the UK Government: (i) the Property Data Survey Programme (PDSP) from the Department for Education (DfE), and (ii) Display Energy Certificates (DEC). In this paper, the development of 168 building archetypes representing 9,551 primary schools in England is presented. The energy consumption of the English primary school building stock was modelled for a typical year under the current climate using the widely tested and applied building performance software EnergyPlus. For the purposes of modelling validation, the DREAMS space heating demand predictions were compared against average measured energy consumption of the schools that were represented by each archetype. It was demonstrated that the simulated fossil-thermal energy consumption of a typical primary school in England was only 7% higher than measured energy consumption (139 kWh/m2/y simulated, compared to 130 kWh/m2/y measured). The building stock model performs better at predicting the energy performance of naturally ventilated buildings, which constitute 97% of the stock, than that of mechanically ventilated ones. The framework has also shown capabilities in predicting energy consumption on a more localised scale. The London primary school building stock was examined as a case study. School building stock modelling frameworks such as DREAMS can be powerful tools that aid decision-makers to quantify and evaluate the impact of a wide range of building stock-level policies, energy efficiency interventions and climate change scenarios on school energy and indoor environmental performance. [ABSTRACT FROM AUTHOR]

• A comprehensive review of urban building energy modeling approaches and methods. • Generalized UBEM frameworks are needed to account for application-specific models. • UBEM domain requires integration with GIS, BIM and cloud-based computing platforms. • Advanced data-driven methods are promising techniques to model building stocks. The world has witnessed a significant population shift to urban areas over the past few decades. Urban areas account for about two-thirds of the world's total primary energy consumption, of which the urban building sector constitutes a significant proportion approximately 40%. Stakeholders such as urban planners and policy makers face substantial challenges when targeting sustainable energy and climate goals related to the buildings' sector, i.e. to reduce energy use and associated emissions. Urban energy modeling is one possible solution that leverages limited resources to estimate building energy use and support appropriate policy formation. Over the past few years, there have been only a few review studies on urban building energy modeling approaches. These studies lack an in-depth discussion of the challenges and future research opportunities related to data-driven, reduced-order, and simulation-based modeling methods. This paper proposes Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis of approaches, methods and tools used for urban building energy modeling. Furthermore, this paper proposes a generalized framework based on existing literature for different urban energy modeling methods. The aim of this study is to assist urban planners and energy policymakers when choosing appropriate methods to develop and implement in-depth sustainable building energy planning and analysis projects based on limited available resources. [ABSTRACT FROM AUTHOR]

[Display omitted] • Development of two benchmark models for post-world war II residential buildings. • Average energy use intensity per household (archetypes A and B) were 166 and 155 kWh/m2/year. • Models validated with four-year monitoring data on energy consumption. • Households are dominated by senior adults and their occupancy profiles are presented. • Findings on energy needs and use intensity are useful in temperate and continental climates. In the context of the European carbon neutrality targets, building benchmarks are a key issue for the renovation of existing buildings. Although there are various benchmark methods for energy efficiency characterization, their application to the residential sector is still limited. This paper developed two building simulation models for post-world war II houses in Belgium based on data from post-occupancy measurements and field survey campaigns. The study reports the energy characteristics and occupancy profiled of detached single-family houses. An analysis of energy consumption (electricity and natural gas) and a walkthrough survey were conducted between 2016 and 2019. The benchmark model's validity has been further checked against public statistics and verified through model calibration and monthly energy bill comparison. Two reference models representing 633.702 post-WWII single-family houses in Belgium were created and validated. The first archetype has an average energy use intensity of 166 kWh/m2/year and represents detached single-family houses built between 1945 and 1969. The second archetype has an average energy use intensity of 155 kWh/m2/year and represents detached single-family houses built between 1970 and 1990. The paper provides a timely opportunity to evaluate the real performance of post-world war II most common archetypes concerning design assumptions and how building professionals can turn the energy performance gap challenge to their advantage. The findings on energy needs and intensity are useful for creating future renovation scenarios for similar archetypes in Western European countries. [ABSTRACT FROM AUTHOR]

Increasing the building renovation rate is a key initiative to drive energy efficiency in the sector and contribute to the European Green Deal. Within this paper, the BIM-based building renovation decision support system RenoDSS is described. RenoDSS (i) automatically generates renovation scenarios based on user preferences and the IFC representation (including second level space boundaries data) of the current building configuration (baseline), (ii) calculates baseline and renovation scenario KPIs, and (iii) identifies the most suitable scenarios by comparing the scenarios' energy, finance, and sustainability KPIs. Validation conducted at two pilot sites shows that RenoDSS reduces the time for (i) identifying potential renovation scenarios, (ii) calculating their energy and LCA/LCC KPIs, and (iii) producing an IFC file for each renovation scenario by around 80% compared to tool-supported manual means. RenoDSS is used by (i) renovation designers that want to optimize the thermal building hull in combination with PV, solar thermal, and HVAC, as well as (ii) decision makers who want to collaboratively identify the most promising renovation option out of the ones generated by RenoDSS. [ABSTRACT FROM AUTHOR]

In this paper, a free running centrifugal fan inside a rectangular duct is investigated via measurements and CFD. A rectangular cuboid-shaped body is mounted downstream of the free running centrifugal fan, covering most of the space next to the fan wheel, leaving only a small channel for the air near the duct walls to pass through. We call this cube a ‘pressure regain unit’ (PRU). The cube increases the fan efficiency by reducing vortices downstream of the fan and tranfering a larger part of the kinetic energy into static pressure. Experiments are conducted with several PRU geometry variations. The measurements show that an increase in efficiency of 10% is possible compared to a free running fan in an empty duct. Subsequently, a numerical analysis is performed to analyze the effect which leads to efficiency increase. Comparing the installation with and without PRU shows that the main difference is a recirculation area behind the fan wheel when no PRU is installed. Higher level of turbulence and strong shear layers in the empty duct cause efficiency losses. The turbulence level and the amount of shear layers are reduced by the PRU. Both experimental and numerical data show an energy saving potential by optimizing the downstream region of the free running centrifugal fan. [ABSTRACT FROM AUTHOR]

With the world rapidly urbanizing, addressing the energy intensive urban built environment is becoming increasingly important. Cities across the United States and the world are turning to energy benchmarking as a means of understanding the relative energy efficiency of their building stock and identifying potential opportunities to reduce energy usage. Benchmarking utilizes building characteristics and energy use data to measure a building’s energy consumption against a performance baseline and derive a level of energy efficiency. Over twenty cities in the United States and many others across the world have passed laws mandating the collection and disclosure of energy use data to enable benchmarking and pinpoint potential energy saving opportunities. However, municipalities are struggling to convert this data into actionable insights and identify which buildings are prime candidates for energy efficiency interventions. Although an extensive body of work exists on benchmarking building energy performance, previous works are limited in their ability to leverage such emerging data streams and conduct analysis at the city scale. Moreover, previous methods are largely based on black-box models that limit the interpretability of results and in turn hinder the ability of policy-makers to employ such models in their policy design and decision-making processes. In this paper, we propose DUE-B, a new Data-driven Urban Energy Benchmarking methodology based on recursive partitioning and stochastic frontier analysis. To test DUE-B, we evaluate its performance using real energy and building data from over 10,000 buildings in New York City, and we compare the results to other common benchmarking models using the Kendall tau-b correlation coefficient. Results indicate that DUE-B is more robust than conventional benchmarking methods in respect to identifying subsets of efficient and inefficient buildings. Furthermore, we highlight how results from DUE-B can be utilized by municipal officials and other policy-makers to target inefficient buildings for energy efficiency interventions, incentives, and programs. Specifically, we indicate how DUE-B can be utilized by municipalities to target the most inefficient buildings for subsidized onsite energy audits and less inefficient buildings for less capital-intensive energy efficiency strategies such as incentives and educational programs. In the end, more robust benchmarking methods like DUE-B have the potential to enhance the efficacy of municipal energy efficiency programs and help transition cities to a more sustainable energy future. [ABSTRACT FROM AUTHOR]

This paper investigates the effectiveness of lighting control systems (LCSs) in 57 individual office rooms of an educational building located in Lund, Sweden. The study uses simulations based on actual occupancy data. The simulations, performed with Daysim via the Honeybee interface, focus on the portion of standby energy use on total lighting energy use considering different combinations of LCSs and lighting power density (LPD). The results show that standby energy use accounts for about 30% of the total lighting energy use, but it can raise up to 55% in extreme cases. The portion of standby energy use increases with lower occupancy rates and lower LPD. As a conclusion, a complete switch-off of systems during unoccupied hours is fundamental to preserve savings from LCSs. In addition, the article argues that, when standby energy use cannot be minimized or eliminated, daylight design and very efficient light sources may reduce the need for complex LCSs in individual office rooms or the like. [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]

This research paper collects the outcomes of an experimental study focused on the energy benefits achieved by coupling an energy efficient building with a sunspace in winter season and Mediterranean climate. Acting as passive Solar heating elements, sunspaces are intended to be a valuable tool among sustainable and energy-efficient constructive and/or retrofitting strategies. In order to assess the energy saving potential of the above-mentioned coupling and relate it to the main design parameters, two operative steps were carried out: the numerical step allowed different simulated configurations to be evaluated in order to identify the optimal one from an energy perspective and physically realize it; the monitoring phase served the double purpose of calibrating the simulation model and provide on-site validated data for subsequent assessments and comparisons. Three main sunspace configurations were tested: irradiative single-glazed, irradiative double-glazed and convective double-glazed. The convective double glazed configuration was found to outperform the others since the daily energy consumption reduction exceeded the 27% (compared to the irradiative, double glazed counterpart) for all weather conditions. Besides, the activation of a mechanical ventilation system was slightly counterproductive in terms of discomfort phenomena since a less stable indoor air temperature was guaranteed. Comparing the two irradiative configurations, it was found that the addition of an extra glass layer was responsible of a quite constant reduction of 1 kW h/day, thus increasing the percent heating energy demand saving achieved through the insertion of the sunspace from approximately 3,3%–8,7%, while minimizing indoor air temperature fluctuations too. [ABSTRACT FROM AUTHOR]

Directive 2012/27/EU on energy efficiency has set the obligation to install individual meters or indirect systems (e.g. heat cost allocators) for heat accounting in multi-apartment buildings supplied by district heating or common central heating. Unfortunately, despite the need of consumers’ protection, neither legal metrology requirements are available for indirect heat accounting systems nor applicable technical standards specify the related on-field maximum permissible errors. In fact, the peculiarity of such systems is the high number of interconnected devices and the influence of installation and operative conditions on their on-field metrological performances should be significant. In this paper, a statistical model to estimate and predict the on-field reliability of heat accounting systems is proposed. The developed model has been applied and validated in three different case studies (i.e. a two-family house, a small building, a large multiple building) showing a good agreement with experimental data. The uncertainty of indirect heat accounting systems in different operating conditions ranges from about 2.7% (i.e. in a large multiple building in optimal conditions) to about 11.7% (i.e. in a two family house in critical conditions). The developed model allows to assess the influence of installation conditions with particular reference to the number and type of radiators and their installation, also in respect with single apartments’ peculiarities and usage. Therefore, the model can be adopted to design appropriate accounting systems in new buildings and to assess the system reliability in the existing ones. [ABSTRACT FROM AUTHOR]

In EU member states, the consumption of electricity per dwelling has remained more or less constant, although the consumption of large appliances has decreased considerably in the last 2 decades. This stabilization is caused by the increased ownership, usage and consumption levels of Information, Communication and Entertainment (ICE) appliances. This paper aims to analyze electrical appliance use in the Dutch housing stock, and identify behavioral patterns and profiles of electricity consumption. The analysis is conducted by applying descriptive, correlation, and exploratory factor analyses on data collected from 323 dwellings in two neighborhoods in the Netherlands. Our results show that behavioral patterns could be found based on actual occupant behavior of lighting and appliance use, especially depending on household activities like cooking, (personal) cleaning, etc. Behavioral profiles could be determined based on household and dwelling characteristics, i.e. household size, income, education, dwelling type, age, hours of working outside. The 4 profiles set up in this research are explained as ‘family,’‘ techie,’ ‘comforty,’ and ‘conscious.’ These profiles showed statistically significantly differences in terms of their electricity consumption levels. [ABSTRACT FROM AUTHOR]

• An overall panorama of the school buildings in Brazil was presented. • Energy billed data and survey evidence were used to build a statistical stock model. • The Weibull distribution was the most adequate to represent the continuous variables. • kWh/student·year was more suitable than kWh/m2·year to model Brazilian school buildings stock. • Thermal performance is an issue to be greatly improved in schools in Brazil. Understanding the actual conditions in school buildings regarding energy usage and environmental satisfaction gives way to the development of consistent building stock modelling. In the Brazilian context, a deep-rooted inefficient structure of energy management implies a lack of mapping the actual conditions of the public schools. Therefore, this paper aimed to assess the actual energy performance of school buildings in Brazil. This paper innovates by integrating questionnaire responses and billed energy data to allow the construction of an evidence-based stock model through a statistical approach, which was never performed for the Brazilian building stock. Moreover, the association of energy use intensity (EUI) with the core aspects of building characteristics, occupancy, environmental satisfaction and necessary improvements mapped the relevance of such aspects in energy usage patterns. Additionally, a discussion of the EUI indicators was addressed. Results showed an unprecedented broad panorama of the school building stock in Brazil and its main features. In terms of statistical analysis, the Weibull distribution was appropriate for representing the continuous variables of the stock. The EUI as a function of the number of students was more suitable than the floor-plan area to achieve a reliable energy performance analysis. Several tests were performed to assess if the energy management, environmental satisfaction and maintenance practices impacted the EUI or not. Finally, the main conclusion was that the stock model obtained was simple and fit the energy management structure in the Brazilian scenario. [ABSTRACT FROM AUTHOR]

In order to achieve greater energy sustainability, the European Union has begun the reform process of the energy policy. Two main lines have been raised: electricity generation with renewable energy and energy saving. The raising cost of energy makes indoor lighting techniques as one of the most important contributors for energy saving in most of the industrialized countries. Therefore, the history of indoor lighting is not exclusively linked to the development of new light sources, having impact on energy saving and sustainability. The aim of this paper was to study and analyse the evolution and milestones of indoor lighting from incandescent bulbs to the modern light-emitting diodes (LEDs) and organic lighting emitting diodes (OLED) going through intermediate milestones like fluorescent lamps (FL) and/or techniques in lighting induction lamps. As main conclusion of this review, it has been found that indoor lighting techniques with their energy efficiency have opened new perspectives for optimizing the energy conversion and this in turn will play a major role in people's quality of life and well-being. [ABSTRACT FROM AUTHOR]

The paper presents cost-optimal energy performance improving measures conducted in deep renovations of typical Finnish (cold climate) brick apartment buildings, built in the 1960’s. The study discusses the effects of different renovation measures on the energy performance and economic viability in a selected building. Energy performance is studied from the primary energy consumption’s perspective and cost-effective renovation measures to meet higher energy performance criteria are also studied. The cost-optimal renovation concepts to meet different energy performance criteria were determined from over 2 billion potential renovation measure combinations by using sophisticated simulation-based multi-objective optimisation (SBMOO) analysis, utilising the advanced Pareto-Archive NSGA-II genetic algorithm, as the main research method. The SBMOO analysis was used to minimise the primary energy consumption and the net present value of life-cycle cost over a 25-year discount period simultaneously. The results indicate that the cost optimum renovation solutions of the brick apartment building stock provide the same energy performance criteria as the current national minimum energy performance requirements of new apartment buildings. According to the study, the investments should be focused on high performance renewable energy production systems, which deliver the best return on investment. External financial support mechanisms are also required to encourage apartment building owners to conduct deep renovations towards nearly zero-energy apartment buildings. [ABSTRACT FROM AUTHOR]

This paper presents a context-awareness system that uses a thermal camera to monitor energy wastage due to user carelessness in a large enclosed space. The users of the system can receive quantitative information of energy use and identify whether to turn an object on or off. The system is composed of a two-axis robotic arm that can manipulate the angle of a thermographic camera and software that can stitch together images received from various angles; and a context-awareness algorithm to identify objects’ situation in stitched thermographic images. The system’s performance was tested for an individual object, more than two objects close to each other, an object at long distance, and the effect of an obstacle. The context-awareness was successful except when obstacles interfered with observations. However, when obstacles interfered, the context-awareness was successful when their heat adsorption was high or when the insulation leaked. The range of spaces and situations that the system can cover will increase if it is combined with an automated device that can move it horizontally. [ABSTRACT FROM AUTHOR]

• An integrated energy-economic analysis of Net ZEB office buildings was proposed. • A thorough discussion on the energy balance was provided for Italian climate zones. • Energy grid integrations, self-consumption, storage and losses were analyzed. • The cost assessment of office buildings was performed and compared to state-of-art. • The energy-economic benefit of a new Net ZEB office in Italy was demonstrated. Recently, the built environment has become one of the leading sectors in the challenge of decarbonization and energy consumption reduction. Because of the specific use and the complexity of the typological, architectural, and technical characteristics, non-residential buildings represent a challenge to overcome the nearly Zero Energy Building standard and to achieve the objective of Zero or Net Zero Energy Buildings. It is desirable that the energy produced in situ from renewable sources totally covers the energy demand (ZEB); alternatively, the amount of energy self-produced and dispatched into the grid must be greater than (or equal to) the energy withdrawn from the grid (Net ZEB). At the same time, it is necessary not to neglect the economic aspects. The aim of this work is to propose an integrated energy-economic analysis to demonstrate the actual feasibility of new Net ZEB offices in different Italian climate zones. Thus, the energy analysis of a reference building, based on consolidated and cost-effective envelope and HVAC systems, has been carried out through dynamic simulations. The photovoltaic field located on the roof provides the energy needed for lighting, appliances, and HVAC. The obtained results are the energy demand and the energy production from renewable sources for the case study in each Italian climate zone. Moreover, the paper discusses the complexity of the annual energy balance, considering contributions such as grid integrations, self-consumption, energy stored and losses. Finally, the cost assessment of the proposed building has been carried out and compared to the state-of-art, pointing out the economic feasibility of the Net ZEB. [ABSTRACT FROM AUTHOR]

The objective of this article is to improve diagnosing and data availability for all stakeholders, including building operators, planners, inhabitants and utility suppliers. This paper presents the results concerning the demand for final and primary usable energy. For each of the buildings a preliminary energy audit was prepared and this was the basis for comparison between the estimated energy consumption in the buildings before and after thermal upgrading. The research was carried out mainly in buildings belonging to the Department of Public Utilities and Housing in Zielona Góra. The group of selected buildings consisted mainly of traditional technology buildings having different functions, i.e. residential, residential-commercial, commercial, and other buildings (schools and boarding houses). Forty buildings were selected for analysis. They were built in different years and had different functions, i.e.: 23 residential buildings, 6 residential commercial buildings, 7 commercial buildings, and 4 buildings had other functions (schools). They are the main energy consumers, which has a considerable impact on the environment. [ABSTRACT FROM AUTHOR]

Buildings have in recent years been the target of a number of energy efficiency improvement strategies given that they are a major energy end-use sector in most countries. Whilst new buildings due to legislations, increasingly address sustainability and improved energy efficiency considerations, the refurbishment process of older buildings still presents a number of challenges. Advancement in Information and Communication Technology, particularly the application of low-cost Wireless Sensors and Actuators Network does however provide the opportunity to harness yet unrealized energy reduction in existing buildings. This paper presents results from an experimental study evaluating the performance and energy saving potentials of such off-the-shelve, low-cost wireless sensors and actuators network in an existing office building for occupancy detection and occupancy-driven lighting control. The study demonstrates that in addition to improved occupancy information obtainable from Wireless Sensors and Actuators Network, worthwhile savings in the energy consumption of the lighting systems can as well be achieved. [ABSTRACT FROM AUTHOR]

The effective and efficient utilization of electrical energy is the outcome of smart energy management system. Moreover, appropriate augmentation of renewable energy alternatives through distributed generation can considerably unburden the power utility system. This paper identifies the scope for the rule based approach to develop an energy efficient utilization model for bulk power consumers. The augmentation of distributed power generation using solar PV has also been proposed which considerably reduces the maximum demand (M.D) of power during peak hours. The distributed generation from solar PV for this case-study uses minimum storage battery as the generation schedule and the load schedule often coincides. The portfolio of energy distribution is formulated based on priority of energy demand. The proposed model can be suitably modified for similar type of load centers including industrial loads. [ABSTRACT FROM AUTHOR]

This paper develops a new process for identifying the lowest cost package of energy efficiency measures (EEM) and hybrid energy system configuration for off-grid homes. Hybrid energy systems, which combine two or more types of energy technologies, often require significant capital expenditure, however, the cost can be reduced by applying EEM to the house to decrease energy demand. The method proposed here, termed Combined Optimization Process (COP), was tested on an off-grid hypothetical case and incorporates an iterative assessment of a building energy and efficiency optimization tool (BEopt) and a hybrid system optimization tool (HOMER). The COP results were compared with the base case where no efficiency measures were applied, and also with a standard process, which involved a selection of best-practice efficiency measures. The COP method yielded net present cost savings of 10% less than the base case, and 5% less than the standard process. The COP method developed in this paper is applicable for existing houses converting to off-grid status as well as for the design stage of off-grid houses. [ABSTRACT FROM AUTHOR]

• Optimized designs for controlled environment agriculture (CEA) facilities are described. • The designs utilize life cycle cost analysis to achieve optimal energy performance. • Energy efficiency and renewable energy measures are part of optimized CEA designs. • Optimal savings of over 65% can be achieved compared to baseline CEA designs. The paper describes a systematic analysis approach to optimize the design of indoor farming facilities considering both energy efficiency and renewable energy systems. The design optimization is based on a life cycle cost (LCC) analysis to account for both capital and energy costs over the lifetime of the facilities. The analysis indicates that LCC-based optimal designs consistently reduce annual energy consumption of the indoor farming facilities compared to the baseline case reaching up to 65%. The most effective energy efficiency measures for indoor farming facilities include high performance heating and cooling systems as well as optimized operational controls. While the heating and cooling system depends on the climate, daylighting controls and temperature settings are found to be consistently suitable for optimized designs in all US locations. The optimization analysis indicates that net-zero energy (NZE) designs for indoor farming facilities, while technically feasible, are typically not cost-effective in most US climates. Only NZE facilities located in Sacramento, CA, can be achieved cost-effectively. [ABSTRACT FROM AUTHOR]

• A new methodology to investigate the impact of thermal mass is defined. • The use of unrepresentative boundary conditions could lead to inaccurate conclusions. • High thermal mass helps to decrease and regulate the internal temperature. • High thermal mass could increase energy use in the summer and winter seasons. • Isolating thermal mass through internal insulation results in better energy performance than external insulation. Contradictory conclusions have been reported on whether thermal mass reduces or increases energy demand in hot and cold climates. A novel approach to measuring the impact of thermal mass on the building's energy consumption is presented. The method aims to better represent reality and applies two different control conditions simultaneously in a numerical model: the first condition, which has been used in past studies, adjusts the internal boundary condition based on the time duration of heating/cooling activation (simulating an occupancy pattern) and the second, which has not been used in past studies, adjusts the internal boundary condition based on both the time duration and the internal temperature (simulating an occupancy pattern and the thermostatic control system). When investigating the impact of thermal mass on the internal temperature in a scenario where no heat is transferred into the building, the high thermal mass outperforms the low thermal mass, showing a time-shifting effect, long time lag, and small decrement factor. However, when modelled using the method presented in this paper, high thermal mass results in greater energy consumption during summer and winter periods in Saudi Arabia. During transition seasons where temperature swings occur on either side of the indoor set-point temperatures, thermal mass reduces thermal transmission. The impact of thermal mass is also investigated for several climatic conditions in Saudi Arabia. Simulation results show that an internally exposed thermal massive wall section results in greater energy consumption when compared to a similar building with isolated thermal mass (i.e. insulated internally). This is due to the fact that even though the internal temperature inside the building is being cooled/warmed up to the set-point, the thermal mass continues to transfer heat that is absorbed by the building's fabric from/to the interior, placing a greater demand on the cooling/heating system. Over the course of a year, however, the impact of thermal mass is negligible when compared to other factors, such as the insulative properties of the building's fabric. [ABSTRACT FROM AUTHOR]

Utility incentive programs are an important channel to support the deployment of energy efficiency in buildings. To date, these programs have largely been limited to single-component strategies. However, many utilities are now motivated to identify and develop multi-component system retrofits to achieve deeper energy savings, which are essential to achieving broader energy and greenhouse gas reduction goals in the buildings sector. In this paper we present the energy savings, demand reductions, and cost-effectiveness of 16 systems retrofit packages in six utility regions in the United States. These results are being used by these utilities to inform and develop incentive programs for systems retrofits. Our analysis shows that packages with proven lighting and HVAC measures can provide 5–22% whole building annual energy savings, and 13–22% annual energy costs savings, using utility incentive program baselines (code and existing building). The packages are reasonably cost effective for replace-on-burnout but generally not for a retrofit scenario prior to end of equipment life. Demand response can increase both the energy savings and energy cost savings, further improving the cost effectiveness of these packages. We analyzed the impact of using existing building vs. code baselines for calculating savings, showing that the choice of baseline in developing utility incentive programs has a substantial impact on the attributable energy savings to a program, with significant implications for the overall viability of a program (generally savings against existing building condition are higher and improve project and program cost-effectiveness). [ABSTRACT FROM AUTHOR]

• Ownership structure of small commercial buildings makes energy retrofits challenging. • Retrofit package for Zero Net Energy small offices in Mediterranean climate. • Energy use and occupant comfort evaluated experimentally, side-by-side, in real time. • 65%-68% energy savings for cooling season; 22%-25% for heating season. • Energy savings are achieved while maintaining visual and thermal comfort. Making buildings zero-net energy (ZNE) is one of the major strategies for achieving carbon emission reduction goals. For this strategy to be successful, it entails a very significant reduction in energy use – 50% or more. In small commercial buildings, however, owners and building management teams usually have limited resources for identifying, analyzing, and procuring appropriate retrofit measures for reducing such use. An approach to overcome this limitation is the development of bundles of energy efficiency measures that can be presented to building owners/operators as a comprehensive package. The research presented in this paper focuses on an experimental evaluation of the impacts of a retrofit package developed for small office buildings in California. Performing this evaluation in a full-scale whole-building integrated systems test facility allowed a side-by-side evaluation in real time, against a reference case, of the impact of the retrofit package not only on energy use but also on visual and thermal comfort. The retrofit package evaluated is comprised of a combination of HVAC, lighting (including daylighting), and plug load measures. The evaluation occurred at different times of the year in order to account for seasonal variations in environmental conditions, including solar angles and weather. The experimental facility allowed testing for two different façade orientations: south and west. Results show that the proposed ZNE retrofit package can save significant amounts of energy for small commercial buildings. During cooling-prevalent periods, total energy savings were 65% for south orientation and 68% for west orientation; during heating-prevalent periods total energy savings were 22% for south orientation and 25% for west orientation. Measurements indicate that the ZNE retrofit package resulted in small but not very significant changes in comfort levels for building occupants. [ABSTRACT FROM AUTHOR]

University campuses can be considered as small towns due to their size, number of users and mixed and complex activities, including numerous actions usually met in urban environments. The energy and environmental impact of universities could be considerably reduced by applying organizational, technological and energy optimization measures. The aim of the present paper is to present an efficient web based energy management system for Campuses which manages in an energy efficient way the Campus buildings and spaces of public use, monitors the energy load and performs energy analysis per building and for the Campus as a whole, as well as it interacts with each building’s BEMS and each user through questionnaires, e-mails and forms. The existing Campus IP infrastructure is exploited by using sensor networks, where nodes communicate their information using Web services, allowing direct integration in modern IT systems. To guarantee the system scalability and respect consolidated and diffused standards, the logical/architectural level of the whole Campus Energy Management System is linked with the existing infrastructure based on Internet Protocol (IP). The overall installation is tested via on line questionnaires to the building users showing a significant increase of the occupants’ satisfaction. Finally, the energy efficiency achieved by the proposed system is almost 20%. [ABSTRACT FROM AUTHOR]

Temperature and humidity independent control (THIC) systems demonstrate promising energy-saving potential compared with the conventional air conditioning systems. One type of THIC systems is proposed to use dual cooling sources with different temperatures since they could be produced easily by traditional vapor compression refrigeration chillers. This paper investigates the applicable condition of the THIC system based on dual cooling sources (DCSTHIC system). It is found that the DCSTHIC system has limited conditions (such as scopes of the heat moisture ratio and the fresh air rate) when applied, otherwise the indoor air temperature and humidity can’t be fulfilled, and further available scope of the heat moisture ratio realized by the DCSTHIC system is disclosed for air conditioned spaces. The minimum realized heat moisture ratio depends on the temperature of low-temperature cooling sources ( t LCS ). A parametric study is also conducted to analyze effects on the energy efficiency of DCSTHIC systems. These parameters include the heat moisture ratio ( ε ) and temperatures of dual cooling sources. Results show that DCSTHIC systems show more significant energy-saving potential in the air conditioned spaces with higher ε . The system COP improvement ranges from 3.1% to 17.5% compared with conventional air conditioning systems when the heat moisture ratio changes from 8000 kJ/kg to 15,000 kJ/kg. This study helps to guide the design and optimization of DCSTHIC systems. [ABSTRACT FROM AUTHOR]

Double skin glazed facades (DGF) are an actual worldwide trend in new and refurbished buildings, even in warm climates with high solar radiation levels as in the Middle East and in Mediterranean climates. In such climates, overheating of indoor spaces and therefore excessive energy consumption are the main problems to be faced. These issues are commonly addressed mostly by thermal simulation or experimental evaluations on small prototypes. However, measurements on real-scale buildings with DGFs are very unusual. This information is crucial to understand and validate the predictions of the thermal behavior of the DGF technology. In this paper, thermal measurements were carried out in an unoccupied office building with a West DGF placed in the Northwest region of Argentina during 3 months in spring/summer. The air temperature exceeded in 10 °C the outdoor air and that indoor temperatures have not exceeded the outdoor levels in the hottest hours. Two correct design decisions were the use of low-e double hermetic glazing and the addition of a screenpainting to the external DGF panel. The experimental data showed that well-designed DGFs can reduce the summer energy consumption of buildings, even using West DGFs, in sunny climates. [ABSTRACT FROM AUTHOR]

• Miscellaneous loads are a major opportunity to save electricity in vacant buildings. • A method for inferring vacancy was developed. • The model generates a continuously updated likelihood of vacancy. • The vacancy inference model requires less ground truth data. • The sensor fusion approach is robust and enables flexibility. Recent events have forced building managers to examine energy use during vacant periods and revealed miscellaneous electrical loads (MELs) as an opportunity for savings. This paper addresses a key step in unlocking these savings, specifically the reliable identification of when a building is vacant. A Vacancy Inference Engine (VIE), using sensor fusion, was developed to identify vacant periods based on outputs from common sensors, historical building vacancy patterns, and expert knowledge. The VIE calculates the confidence that a building is vacant, allowing building managers to balance the capture of energy savings with the possibility of complaints due to powering down MELs. The VIE has the advantage over logistic regression and other models in that it does not require a full set of ground truth for the training process. The VIE successfully predicted vacancy in an office building using input data streams of instantaneous electricity demand, indoor carbon dioxide concentrations, and the number of active Wi-Fi connections. The VIE's ability to predict vacancy was compared to that of logistic regression using a metric based on the Complaint Opportunity Rate and found to be nearly identical (0.94 versus 0.95, respectively). [ABSTRACT FROM AUTHOR]

[Display omitted] • A research topic relatively new but with an increase interest in the last five years. • The largest scientific contribution from China, Australia and Italy. • The main journals in the field Building and Environment and Energy and Buildings. • Three main direction of research: thermal energy performance of buildings, ecological benefits and reducing the urban heat. • The main limitation of using green walls is the high cost of installing and maintenance. The continuous state of development of the human society imply a big effort and demand to generate and use more and more energy to power our lifestyle. The impact of human activity has negative effects on the environment and thus solutions to maintain or increase our development rate but in the same time to decrease the pressure on the environment must be developed. In this context, the purpose of this paper is to investigate if the use of green walls systems can be a solution to decrease the energy demands in buildings. The investigation include a bibliometric literature research, a scientometric analysis and an in-depth discussion. The data used for the research were obtained by interrogating the ISI Web of Science and Scopus databases, were selected using the guidelines of the PRISMA method and processed with the help of VOSviewer and Bibliometrix software. The research results indicate an increase interest in this topic in the last five years and that the use of vegetation in the constructed grey areas can bring a lot of benefits especially from environmental point of view. Green walls can be a solution to decrease the temperature on the wall surface in hot summer days and to prevent heat loses in the winter time, and thus have beneficial effects on the amount of energy required to maintain a proper interior temperature. The main limitation of using green walls is given by higher costs of installing and maintain the vegetation on walls, thus, finding new more economical, systems of green walls must be developed in the future. Considering all of this it can be state that green wall systems have the potential to become good solutions not just to improve the energy efficiency of buildings but also to create more sustainable urban areas. [ABSTRACT FROM AUTHOR]

• The thermo-injection masonry wall drying method was studied. • The behavior of wall samples during drying in a semi-laboratory scale was investigated. • Energy consumption during drying with different parameters was investigated. • The lowest amount of energy was consumed for drying without heating. • Drying with heating showed high moisture removing efficiency and energy consumption. • Two-phase drying showed a good perspective for the optimization of the process. Excessive wall dampness causes damage to buildings, increases energy consumption for heating and cooling, and favors breeding microorganisms dangerous for people's health. In that case, moist walls must be dried and renovated, including making them waterproof. However, present methods for drying are highly time- and energy-consuming and its optimal implementation should be searched. This paper investigates the behavior of wet masonry wall specimens during the drying process in the semi-laboratory scale. The study aimed to examine the influence of different operating parameters of the considered masonry wall drying method on samples' drying rates and propose an optimal drying strategy. Small-scale masonry wall samples made of red ceramic bricks, cement-lime binder, and plaster were considered. Specimens had similar dimensions of approximately 1000×1000×600 mm and a dry mass of roughly 1050–1150 kg. Two types of constructions were studied, i.e., plastered and unplastered. The drying process was conducted by applying the thermo-injection method and using a dedicated device that ventilated and heated the wet sample. Different drying device operating conditions and drying process implementations were tested, i.e., single-phase drying without and with heating for two constant mass flow rates of drying air and two-phase drying initially without and then with heating and with two different mass flow rates of drying air. Moisture mass change in the wet specimen, temperatures in several locations in the sample, relative humidity and temperature of the surrounding air in the room, as well as the drying device electrical parameters, were monitored to have insight into the drying phenomenon and assess the energy efficiency of the process. In both tested constructions, the lowest amount of energy was consumed during drying with ventilation mode on and without heating. However, much less moisture was removed from samples in these implementations than for drying implementations with heating. The drying with heating mode activated showed the highest moisture removal efficiency, but energy consumption increased significantly. The drying strategy with a two-phase drying process, i.e., initially without and later with heating of the specimen, showed promising efficiency and a good perspective for the future optimization of the process. [ABSTRACT FROM AUTHOR]