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• Combining several different heating devices in a hybrid installation is possible. • The RES share in heat production in hybrid installation may be significant. • The passive cooling mode of heat pumps is highly energy-efficient. • The efficiency of the ground heat pump in heating mode ranged from 3.5 to 3.8. The article presents long-term results of experimental tests of a hybrid installation (HI) consisting of four heating devices, three of which use renewable energy sources (RES). The HI is operating in a residential and retail building located near Kraków, in southern Poland. There is little experience with the operation of such installations, therefore, the purpose of this paper is to discuss significant aspects related to the implementation and operation of HI in a moderate, transitory climate. The research was carried out from 2011 to 2017. The share of solar collectors in annual heat generation ranged between 7.4% and 12.5%, with an average annual efficiency to 38%. The annual performance of a ground-source heat pump in the heating mode ranged from 3.5 to 3.8, and in the passive cooling mode, it reached up to 11.87. The annual efficiency of a gas condensing boiler was from 77.5% to 82.2%. Annually, the largest amounts of heat were supplied by a biomass boiler i.e. from 30% to as much as 50%. The paper disclosed clearly that it is possible to reach in HI high level of RES share in heat generation. A key issue requiring further research is the development of appropriate algorithms in the control systems of HI. [ABSTRACT FROM AUTHOR]

[Display omitted] • A wireless-energy green city concept integrating WPT, renewable energy, and infrastructure is proposed. • Security-electrification, digitization, and intelligence are bolstered by the incorporation of WPT into urban settings. • The SDGs are advanced by the wireless-energy green city's energy, environment, and social economy benefits. The significance of energy stability in urban development has increased as the use of intelligent devices continues to expand and extreme weather poses a threat to the integrity of electric networks. Wireless power transfer technology is well-known for its dependability, security, and adaptability, and has reached billions of market share in China alone in the cell phone and electric vehicle sectors over the past decade, with the electric vehicle wireless charging market expected to grow at a compound annual growth rate of over 30% by 2023. Combining WPT with renewable energy, electric vehicles, and recharge infrastructure is a promising new application for smart city development. This paper examines the history, characteristics, and six classifications of WPT technology through the lens of urban development, in addition to its successful implementations in seven contexts, such as portable devices and transportation, based on a survey of 161,425 papers. We propose a dependable and efficient research-to-application life cycle for high-power WPT operations, which is capable of achieving efficiencies of approximately 90 percent at approximately 50 percent of the original cost. In addition, the significance of incorporating WPT technology, renewable energy sources, and urban infrastructure into the design of sustainable cities is highlighted. This study determined that WPT is advantageous for promoting the construction of space and ground photovoltaic plants, as well as photovoltaic rooftops, and also serves to accelerate the promotion of electric vehicles, smart devices, and charging roads. The findings of this study cast light on three problem areas and six future prospects of WPT, as well as its multifaceted benefits in terms of energy, the environment, and the social economy of sustainable cities. [ABSTRACT FROM AUTHOR]

As the built environment is among the main contributing sectors to climate change, it is needed to investigate new paradigms to push decarbonization efforts towards the ambitious objectives defined internationally. It is a shared understanding that shifting the perspective from the single building to the district perspective is required to fully take into consideration the complexity of all interactions undergoing within the built environment, thus the concept of Positive Energy District emerged as a district with annual net zero energy import and net zero CO 2 emission working towards an annual local surplus production of renewable energy. In this framework, this paper explores the investigation of the potential for achieving the level of Positive Energy District in a group of non-residential buildings in Balaguer, Catalonia, Spain. These buildings, occupying 8,825 m2 in the city centre, require significant refurbishment for improved energy performance. The analysis includes building energy modelling and simulation, renovation studies, several alternative balance calculations, and carbon emissions assessment. The paper also considers mobility and embodied energy and their impact on energy/carbon balances. The results show that Positive Energy Districts carbon and primary energy balances are not met with rooftop PV installations when retrofitting an existing district towards the Positive energy target but further significant PV areas (roughly + 50%) are required to meet merely the use stage balances: negative results are traced when mobility and embodied energy are computed. A formulation alternative to the simple mathematical balance to facilitate the diffusion of Positive Energy District as catalyst of urban decarbonisation could be needed, including context factors and alternative systems (e.g., rating systems). [ABSTRACT FROM AUTHOR]

Increasing use of volatile renewable energy sources causes challenges in balancing supply and demand. Therefore, demand-side flexibility has rising importance for system operators and balancing authorities. Flexibility management methods are needed to integrate loads like ventilation systems of different buildings (e.g., residential and commercial) into flexibility service. However, the available methods described in research papers require further development for implementation in practice. Heating and cooling systems have received much attention from researchers, but the potential of ventilation systems has been left out of focus. Therefore, this paper provides a complete set of novel flexibility management methods for ventilation systems created from an aggregator's viewpoint. The flexibility is quantified through capacity (e.i. the amount of power consumption that can be altered), forced ventilation rate duration, and the tendered price for the service. The proposed methods were tested on a building model constructed and simulated in IDA ICE. The data processing and flexibility management methods were applied in MATLAB. Two types of ventilation systems with different sensor configurations were considered: constant and variable air volume. Forced ventilation rate duration is calculated using energy and mass balance analysis where the root means squared error was 10 to 33 min, depending on the system type, measured parameter, and sensor location. The flexibility service pricing model was tested on the 2022 years' manual frequency restoration reserve (mFRR) activation and balance energy market data. [ABSTRACT FROM AUTHOR]

Highlights • The state-of-the-art research of energy demand flexibility of demand responsive building is reviewed. • The energy demand flexibility measures range from renewable energy to HVAC, energy storage, building thermal mass, appliances, and customer behavior are introduced. • Systematic methodology framework to evaluate energy demand flexibility in buildings are developed. Abstract This paper classifies and discusses the energy flexibility improvement strategies for demand responsive control in grid-interactive buildings based on a comprehensive study of the literature. Both supply and demand sides are considered. The flexibility measures range from renewable energy such as photovoltaic cells (PV) and wind to heating, ventilation, and air conditioning (HVAC) systems, energy storage, building thermal mass, appliances, and occupant behaviors. Currently, owing to the highly developed smart appliances and sensing communication techniques, DR is considered as an essential measure for improving energy flexibility in buildings without much additional investment. With the help of advanced demand response (DR) control strategies and measures, buildings can become more flexible in terms of power demand from the power grid. In this way, buildings achieve a better ability to balance differences in energy supply and demand. Furthermore, a synergistic approach with various measures is advisable, e.g., the use of energy storage technologies with PV and passive DR methods. This paper summarizes the measures for improving the flexibility of commercial and residential buildings, and develops a systematic methodology framework to evaluate energy demand flexibility in buildings. [ABSTRACT FROM AUTHOR]

With ever increasing energy generation diversity and energy storage becoming affordable, distribution networks are becoming more complex than ever before. This complexity can be utilized to benefit the distribution networks as well as end consumers in the form of controlled Microgrids. Microgrids are not simply distributed generation and energy storage systems; solar systems and battery banks, rather a complete design of hardware and software for specific uses and users. All the different elements need to be designed to work together to provide stable, efficient and sustainable power delivery to the end user. An experimental Hybrid-Microgrid testing facility is presented in this paper that implements high-efficiency distribution architectures combining both AC and DC networks. This testing facility provides a research testbed for investigating different aspects of Microgrid systems, employing a total of 15.5 kW of reconfigurable Solar PV and 80 kWh of lithium energy storage on a 145 kVA commercial building load located at Griffith University. Implementation results along with control system simulation results are presented in this paper for distributed renewable generation, Static Synchronous Compensators, advanced control methodologies and forecasting methods for energy management purposes. [ABSTRACT FROM AUTHOR]

As demand response and energy flexibility are often suggested as key principles to facilitate high levels of renewable energy sources into energy markets, different studies evaluated the potential impact of energy flexibility in buildings. Nonetheless, due to differences in definition and quantification methodologies for energy flexibility, comparing results between such studies is difficult. With a review and applied evaluation of existing definitions and quantification methodologies this paper aims at assessing the applicability, benefits and drawbacks of each quantification methodology. The conducted review shows that energy flexibility definitions found in the literature have their particularities despite sharing the same principle that energy flexibility is the ability to adapt the energy profile without jeopardizing technical and comfort constraints. The survey of quantification methodologies reveals two main approaches to quantify energy flexibility. A first approach quantifies energy flexibility indirectly using past data and assuming a specific energy system and/or energy market context. The second approach directly predicts the energy flexibility that a building can offer to the energy system in a bottom-up manner. While applications for both approaches were identified, this paper focuses on the latter. By applying methodologies that follow this second approach to a common case study, three common properties of energy flexibility were observed: i) the temporal flexibility; ii) the amplitude of power modulation; iii) and the associated cost. [ABSTRACT FROM AUTHOR]

The development of control strategies is a challenge for optimal use of low-temperature heat in complex energy systems. In the energy system of the considered building, several different combinations of active system components lend themselves to supply a given energy demand. Within preceding research, we transformed the considered building into a multi-functional test bench for control techniques that offers optimal conditions for the demonstration and evaluation of control strategies. This paper describes a control strategy for the complex heat pump system based on operation modes. It enables us to integrate a geothermal field into the system with respect to exergetic principles. The paper presents results of the control strategy's first year of operation. It correlates between active operation modes and the respective electrical consumption of the building. We derive the potential of the implemented operation modes for demand response applications. A mode-based control strategy enables the robust and efficient operation of complex building energy systems. We show that the integration of renewable energy sources becomes easy and flexible. [ABSTRACT FROM AUTHOR]

The seawater source heat pump (SWHP) is a renewable energy utilization system. The beach well infiltration intake system (BWIS) effectively improves the stability, reliability, and energy efficiency of SWHP systems in cold climate areas. BWIS research requires a multidisciplinary approach that involves both hydrogeology and heat transfer theory. There are many factors influencing the energy consumption and life-cycle costs of the systems, with each factor having many possible values. This paper aims to determine the degree of influence of ten representative factors of BWIS: specific heat capacity of rock-soil, rock-soil density, thermal conductivity of rock-soil, void fraction of rock-soil, rock-soil permeability, beach well radius, site length, site width, row number of beach wells, and column number of beach wells. In this paper, a BWIS seepage and heat transfer model is established. Based on the model, an orthogonal design optimization method is presented and analyses are conducted for heat pump unit energy consumption, seawater pump energy consumption, and economic cost for various conditions using MATLAB code. The results indicate that a greater number of beach wells is not always better and the number and placement of beach wells should be scientifically and objectively optimized by the orthogonal design method. The optimization method can scientifically guide engineering design for BWIS and offset the design deficiency that results from the current practice of only using a hydrogeological report of randomly selected test wells. [ABSTRACT FROM AUTHOR]

Nowadays the concept of intelligent homes and smart technologies are spreading out and becoming a vital strategy to optimize the energy performance. Specially that the internet is available to all our life aspects including educational system, health care, banking, commercial, industries, mobile applications, etc. The energy sector is one of the important domains to use the internet in the supply and demand sides. As the buildings consume two third of electricity globally, the real-time monitoring, by using the internet, is one of the key factors to manage the energy consumption and to optimize the buildings’ performance. Accordingly, the buildings’ systems have utilized the information technology’s revolution in the last decade in several manners. One of the very interesting synergies is that developing relationship between the energy monitoring and the Internet of Things (IoT) for most of buildings’ sensors, energy meters and building automation systems. These new technologies interact effectively with the Smart Home Energy Management System. It increases its value and ensures securing tangible benefits. As shown through the findings of this study, the level of buildings intelligence will significantly contribute the improvement of energy performance. Not only, the energy demand and the use of energy will be smartly efficient. As a result, the renewable energy systems in such smart homes will be a cost-effective option and the probability to build a net zero energy home becomes materialized and affordable economically. This paper reviews the latest technologies and telecommunication techniques that used in the homes to monitor energy performance. It also discusses a case study in Riyadh – Saudi Arabia about smart home’s technologies, and the impact of using the renewable energy to improve the energy performance compared to the energy benchmark. The main focus will be on the smart technologies; interface and integration of the meters, sensors and monitoring systems with the home energy management system (HEMS). The findings of this paper outline that the smart home in practice provides the ability to the house to be net zero energy building. Especially that it reduces the power demand and improve the energy performance by 37% better than ASHRAE standards for family villas sector. [ABSTRACT FROM AUTHOR]

This paper mainly analyses two systems in Shanghai. A Building Attached Photovoltaic (BAPV) system of 3 kWp and a Building Integrated Photovoltaic (BIPV) system of 10 kW. This BAPV system is the first practical application of grid-connected roof-mounted BAPV systems in China. It has great significance to the research of BAPV systems and the development of China renewable energy. The output yields, monthly performance ratio (PR), and monthly system efficiencies of the two systems of the two systems are illustrated. This paper used net present value (NPV) and the payback period (P d ) to analyze system benefits. PV SOL is used to simulate these two systems combined with three load profiles. The simulation results including economic and performance states are illustrated in this paper. Moreover, energy payback time (EPBT) and greenhouse-gas payback time (GPBT) are used to evaluate environmental impacts. EPBT of the two systems are 4.2 years and 3.1 years, for GPBT they are 1.3 years and 0.4 years. The economic benefit of contaminating emission reduction of the two systems is also assessed to promote the development of PV industry. [ABSTRACT FROM AUTHOR]

Domestic electricity load profile is essential for energy planning and renewable energy system design. This paper presents analysis of domestic electric load characteristics and a method to model domestic and regional load profile. Multiple Gaussian functions are used to express the load characteristics in the proposed model. This is done by associating the Gaussian function parameters with the peak load changes, e.g. changing height parameters to reflect the peak magnitude. The result of the load curve represented with multiple Gaussian functions allows the model to generate a regional load profile using the number of homes, the number of bedrooms (Nr) and the number of occupants (Np). The proposed model simulates domestic load profile by its load demand change characteristics instead of its appliance ownership and use pattern, etc. Data requirement for the proposed method is significantly lower than the previous top-down and bottom-up approaches. Seasonal change is not included in the present paper, but the method is capable of including seasonal changes if each season’s load demand changes in relation to Np and Nr is available. A demonstration of modelling England and Wales’s national hourly load profile in 2001 and 2011 is presented in this paper. Comparison is made of the proposed method with two other published domestic load profile models. Results show that the proposed method improves the mean percentage errors by at least 5.7% on average hourly load profile. [ABSTRACT FROM AUTHOR]

Demand-side management methods are expected to play a key role in future energy systems. These methods are making energy demand adaptive to fluctuations inherent to intermittent renewable energy sources. In order to develop feasible demand-side management solutions, a better understanding of the temporality of the energy demand is needed. This paper contributes to this by focusing on the daily load profiles of energy demand for heating of Danish dwellings with heat pumps. Based on hourly recordings from 139 dwellings and employing cluster and regression analysis, the paper explores patterns (typologies) in daily heating load profiles and how these relate to socio-economic and technical characteristics of the included households. The study shows that the load profiles vary according to the external load conditions. Two main clusters were identified for both weekdays and weekends and across load segments; a main cluster with a relatively constant load profile and a minor cluster with a more distinct variation during the day. The difference between the clusters is primarily correlated with building characteristics like floor area, building year and type of space heating distribution system, while the existence of children and teenagers in the household were the only significant socio-economic variables. [ABSTRACT FROM AUTHOR]

In order to fully exploit the potential of renewable energy resources (RERs) for building applications, optimal design and control of the different energy systems is a compelling challenge to address. This paper presents a two-step multi-objective optimization approach to size both thermal and electrical energy systems in regard of thermo-economic performance indicators to suit consumer and grid operator interests. Several utilities such as storage, conversion systems, and RERs are hence modeled and formulated through mixed-integer linear programming. Simultaneously, the algorithm defines the optimal operation strategy, based on a model predictive control structure, for each deterministic unit embedded within the energy management system of the building to meet the different comfort and service requirements. The developed design framework is successfully applied on several energy systems configuration of typical Swiss building types. Different component sizes are analyzed, regarding the present investment cost and the self-consumption share. In addition, this paper presents a novel optimal design criteria based on the maximum cost benefits in the view of both the consumer and the distribution network operator. [ABSTRACT FROM AUTHOR]

This paper presents a residential energy hub model for a smart multi-carrier energy home consisting of plug-in hybrid electric vehicle (PHEV), combined heat and power (CHP), solar panels, and electrical storage system (ESS). The energy hub inputs are electricity and natural gas that provide electrical and heat demands at the output ports. In this paper, an optimization-based program is proposed to determine the optimal operation mode of the energy hub, to manage the energy consumption of responsive appliances, to schedule charging/discharging of PHEV and the storage system, and to coordinate solar panels operation with household responsive demand in response to day-ahead time-varying tariffs of electricity. The objective function is to minimize customer payment cost considering vehicle to grid (V2G) capability. Different case studies are conducted to probe the effectiveness of the proposed method and study the impacts of different electrical time-differentiated tariffs on the optimization results on daily and yearly basis. [ABSTRACT FROM AUTHOR]

In this paper, a new methodology has been discussed on economical power management of a grid-connected CHP system which consists of a wind turbine, photovoltaic array, polymer exchange membrane fuel cell and an electrolyzer. Hence, the paper also attempts to present the thorough modeling of energy management of the hybrid system in the form of a nonlinear optimization problem; through which offline energy management is regarded to use the available options in order to determine the role of each generator in producing heat, power and hydrogen in the system under study. In addition to this, variable tariffs of daily exchange with local grid have been taken into account in different operation conditions so as to reach real utilization requirements. Based on these facts, choosing the most suitable model for each element of the hybrid system has been considered in regard to their dynamic behavior. The proposed hybrid system is to supply the electrical and thermal demands of renewable energy laboratory of Shahid Bahonar University of Kerman (SBUK). The economical energy management is comprehensively studied and surveyed in the form of various scenarios while the hybrid system is connected to the grid. [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]

• 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]

Trigeneration systems based on renewable energies are useful solutions to provide heat, cooling and electricity in buildings and industries. According to the International Energy Agency, more than 30% of the world population has a profile demand requiring heating and cooling and this percentage is above 70% in many developed countries. This paper experimentally evaluates the energy performance of a trigeneration system based on a solar PVT-assisted heat pump installed in an industrial building. The heat pump is a vapor compression air-to-water type, with a nominal capacity of 16 and 10.5 kW in heating and cooling respectively. The PVT solar field consists of unglazed PVT collectors with a total area of 13.6 m2. Results indicate that this type of system is effective to provide heat, cooling and electricity, using mainly solar energy. The PVT solar thermal fraction is significant to provide domestic hot water, but it is less representative in heating production. On the other hand, solar electrical production gets high representative contributions to feed the heat pump compressor. Different performance indicators were calculated to evaluate the system performance. Besides, a comparison with a reference system, that uses a PV instead of a PVT technology, was also evaluated. [ABSTRACT FROM AUTHOR]

Planning and managing energy production, transmission, and distribution face new challenges as renewable energy sources become more widely used. These sources enhance existing issues of grid operation due to their unpredictability and intermittency. As a result, sophisticated energy system control techniques and technologies that offer novel flexibility solutions to the inelastic demand side are necessary to ensure the power system's stability. This paper reviews the feasibility of demand response as a tool for effective grid management and a measure for properly sized renewable energy systems (RES) capacities, both of which could accelerate the phase-out of fossil fuels. Research also focuses on tapping into the building stock's demand response capacity in an effort to decrease operational CO 2 emissions. In this line of approach, current status and goals of the respective European policies are analyzed. The role of market based decarbonization is studied and presented along with the status of demand response market implementation in several countries. [ABSTRACT FROM AUTHOR]

Decarbonization goals in the United States electricity sector are increasing the levels of renewable energy generation in the electricity supply system, and are driving increased attention to building electrification, which will increase the magnitude and shift the timing of the electricity system peak. These changes are motivating new approaches to coordinate building electricity demand with low-carbon renewable generation, elevating the importance of demand flexibility (DF) in buildings and the need to quantify the temporal impacts of DF. In this paper, we first characterize the hourly predictive accuracy of six commonly used baseline models in an application context of quantifying building-level load shift. Our analysis revealed insights such as hours of the day (afternoons), periods of the week (weekends), and seasons (summer) that were predicted with more accuracy than other time periods. In addition, the analysis showed tendencies toward overprediction or underprediction of load. Secondly, we provide the first published investigation of baseline erosion from repeated dispatch of building load shifting. We observed that as the baseline period is pushed back further from the prediction day, the distribution of errors across baseline model predictions increases, with notable inflection points near the three-week erosion point for two of the three models. [ABSTRACT FROM AUTHOR]

• Different renovation intervention levels are evaluated. • The technoeconomic feasibility by itself does not explain the actual renovation rates. • Existing social, material and legal barriers are key for a comprehensive analysis. • Measures should be taken to boost district/building level interventions. Building is one of the main sectors in which significant energy savings can be achieved with a consequent reduction in emissions. This paper assesses the large-scale renovation of buildings, exploring the quantitative and qualitative factors that determine their replicability potential from three different perspectives, namely dwelling, building and district intervention level. Different passive and active measures are assessed, covering energy saving measures, the improvement of energy supply systems and the integration of renewable energy sources. Different scenarios are defined for each intervention level, which are evaluated using the methodology developed in the IEA-EBC Annex 75 project. The methodology is applied to a residential district located in Bilbao (Northern Spain). The analysis is based on the results obtained from the simulation of 41 combinations of different renovation options, obtained by simulation in the Design Builder software. The assessment is carried out from the evaluation of different key performance factors, including annualised cost and annual primary energy consumption, as well as the CAPEX and OPEX requirements. The results show that energy renovation of buildings offers a great opportunity for energy reduction at affordable investment costs, obtaining the cost optimal values when the intervention focus on the energy system and reaching net NRPE values close to zero when the intervention is carried out in a comprehensive way, considering energy systems and thermal improvement of the envelope. Additionally, the different energy reduction scenarios show that, while interventions at district level offer the greatest potential for minimising annual costs and primary energy consumption levels, intervening at building level offers only slightly worse results. However, there are other issues which can better explain the current low rate of renovation works in the urban environment. Thus, if the additional existing social, material and legal barriers and constraints are included in the analysis, it becomes clear why renovation from a district perspective is not actually leading the race. Given this situation, some measures and policies are proposed to realise the true potential of large-scale building renovation. [ABSTRACT FROM AUTHOR]

This paper proposes a distributed feedback-based optimization method, based on the principles of approximate dynamic programming, aiming for the optimal management and energy efficient operation of grid connected buildings. Modern building management faces multiple challenges, aiming for, energy efficiency, RES integration, EV operation, cost reduction and of course user comfort. Therefore, this paper adopts a multi-criterion cost objective, where minimum energy costs are required without sacrificing user preferences and satisfaction. Different type of loads are presented, including both thermostatically controllable loads (simulated and modelled in Energy Plus), and controllable electric vehicles (EV) and energy storage systems (ESS). Extensive simulations showcase the effectiveness of the proposed method introducing comparisons with different strategies by exploiting renewable energy integration, varying pricing tariffs and the stored energy of EVs and ESS units. A robustness evaluation of the proposed method is presented, validating the performance under different conditions. Finally, the paper demonstrates that the proposed strategy can be utilized for the management of real-world problems and buildings. [ABSTRACT FROM AUTHOR]

Abstract: Directive 2010/31/EU adopted that by the end of 2020 all new buildings should be nearly Zero-Energy Buildings (nZEB) and Member States should achieve cost-optimal levels by ensuring minimum energy performance requirements for buildings. This paper discusses how low should be the energy required by a nZEB, in the context of housing energy consumption in a Mediterranean climate (Lisbon). For selected houses built after 1990, the calculated primary energy loads for regulated uses – heating, cooling and domestic hot water – are found to be below 90kWh/(m2 year). Applying the cost-optimal solutions of thermal insulation and glazing type and considering energy efficiency improved systems, this study concludes that housing energy loads are ‘low’ for the indicative range of 70kWh/(m2 year) for regulated uses or 100–110kWh/(m2 year) for total uses, taking primary energy indicators (PEI) from EN 15603. Assuming PEI from Passive House Planning Package or those to be assumed in Portugal for 2013, the threshold decreases to 60kWh/(m2 year) for regulated uses or 90–100kWh/(m2 year) for total uses. Only the first nZEB condition is explored by this paper. The second condition requires that the nZEB energy load is covered by a ‘significant’ part of renewable energy sources produced on-site or ‘nearby’. [Copyright &y& Elsevier]

Abstract: Photovoltaic (PV) connected systems are experiencing rapid market growth. This is due to the continually downward trend in PV cost together with government support programs. A scenario has been assumed to analyse the geographical market of PVs. The results provide clear evidence of the influence that some variables have on the profitability of PV investments. This study presents a model for minimising investment risk and maximising the return of a renewable energy portfolio in Italy. The value of the paper is in showing that the energy and CO2 reduction potential that can be reached through consumer-oriented policy measures, but the paper also looks at the effectiveness and social implications of such measures. Private households possess immense unused potential for energy reductions (and climate protection) that could be realised through gains in energy efficiency, behavioural changes, and extended use of low-emission energy. The focus of energy policy has been on businesses rather than on private households, which are only partly captured by direct policy measures. To achieve the goals of climate policies, the current political and scientific discussion increasingly considers measures that aim to reduce energy consumption in the private sector. Quantitative estimates are presented for economic indicators and will show the various effects of policy measures on the implemented household types. [Copyright &y& Elsevier]

Abstract: This paper reviews crucial role of building performance simulation (BPS) – dynamic analysis of the inextricable linkage of building''s energy demand for HVAC and other building''s technical systems sustainable energy supply and renewable energy sources (RES) availability to reach building''s zero energy status. Reviewed are BPS advances in buildings energy efficiency optimization, solar, geothermal and other renewable energy sources integrated implementation, as well as hybridization and mixed distributed energy generation, co- and tri-generation for building''s greening and sustainable neighborhoods, settlements, as well as “high performance” Zero Energy Cities Planning. As an introduction, outlined is the intrinsic harmony of the traditional village houses balanced use of renewable materials and energy sources and presented are feasibility study results on the sustainable Zero Energy ECO Settlement at the Mediterranean Sea proceeded by the description of the site''s sustainability''s constrains assessment. Architectural design and building''s dynamic behavior and energy efficiency optimization resulting in minimization of thermal and lighting loads, precede to the multidisciplinary engineering investigation and preliminary design of sustainable Zero Energy Buildings confirming feasibility of settlement''s sustainable energy and water supply by the reliable implementation of solar PV and wind technologies, including PV powered sea water desalination. Further, interwoven with presentation of a few case studies, paper outlines advances in BPS and Co-simulation. Reviewed are optimization of mixed, natural and mechanical ventilation via CFD integrated with architectural modeling; BPS and Co-simulation approach to the “total building performance optimization” encompassing multifunctional facades, day-lighting, IE&AQ and HVAC systems operation offering an enormous potential for energy saving by residential/municipal RES integrated renovation. Stressed has been that it is impossible to reach sustainability without harmonious interdisciplinary interacting, without balance between materiality and spirituality, science and art, technology development and cultural and other human values improvement, without ethics of sustainability. [Copyright &y& Elsevier]

• Examination of a typical classroom in Greece and its installed power for an artificial lighting profile from 1970 until today (type and number of luminaires, installed power per classroom, consumed annual energy kWh/m2). • Calculation of potential energy savings for customizing installed power LED with AC and DC supply aiming for the illuminance target values from the European Norm 12464–1, 2011. • Measurements of dimming curves of LED luminaires with AC and DC supply (consumed energy versus lighting output) and measurements of power of typical photosensors. • Estimated energy savings, CO 2 reduction and cost optimal analysis due to various scenarios (different luminaire technologies and daylight harvesting techniques). • Calculation of the final energy consumption for potential power supply from renewable energy sources using DC LED luminaires and photosensors. The energy consumption for the artificial lighting in school buildings is one of the main consumers of electricity. In Greece, there is a large number of school buildings with quite old lighting systems using luminaires with T8 and sometimes T12 fluorescent lamps and degradated translucent diffusers. Due to the economic crisis, the public sector failed to invest in LEDs and although daylight is adequate during the year, the adoption of control technology is rather slow. The paper, using a typical classroom of a Greek public school, examines a number of lighting technologies (with AC and DC supply) together with two daylight harvesting systems. The first one uses one stand-alone photosensor per luminaire while the second one sensor per control zone, in an effort to calculate energy savings and light adequacy. The dimming curves of the DC LEDs were measured along with the installed power of the photosensors. The results show that the existing 90.5 kWh p /m2 of annual lighting primary energy consumption can be reduced to 0.55 kWh p /m2. The maximum annual reduction of CO 2 emissions was 32.44 kgr/m2 for classroom areas, which is translated to 201929 tn for the whole country. It is evident that the path to Zero Energy School Buildings goes through the mandatory use of daylight controls. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Abstract European renewable energy developments have so far focussed on electricity generation, with relatively modest progress in renewable heating. Partly this is due to the temporal mismatch between solar irradiation availability and residential heating demand profiles. Seasonal thermal energy storage (STES) has been proven in several pilot projects and is market ready, albeit not currently economical. This paper sets out to assess the potential contribution of STES to increasing the renewable heating fraction in residential buildings. An existing mixed integer linear program (MILP) is extended to consider STES and applied to optimize the energy supply system for a typical residential district with efficient new-build apartment buildings, in the context of five contrasting scenarios. Achieving 100% renewable heat supply requires significant capacities of seasonal storages and is associated with substantially (14%) higher cost than in the reference scenario. To achieve a 60% renewable heat supply fraction under today's framework conditions, the cost increase compared to the reference scenario is only marginal (1%). The results in three future scenarios reflecting possible conditions in 2030 demonstrate that even higher levels of renewable heat supply could soon become economical. Overall the recommendation is to aim for renewable heat supply levels of around 60–80% combined with demand side measures such as improved insulation. Further work should focus on more systematically exploring the relationship between the grid renewable electricity fraction, available solar collector area and the optimal renewable heat integration strategy. [ABSTRACT FROM AUTHOR]

Abstract Since the launch of the Sustainable Energy for All initiative in 2011, renewable off-grid energy systems have attracted increasing attention as means to break the vicious circle of poverty and improving living conditions in rural areas of developing countries. The extensive diffusion of decentralised renewable energy technologies, while harvesting international positive reactions, is scarcely understood in the context of livelihood strategies and micro-level analysis of remote villages located in protected areas of the Amazon forest. The scope of this paper is to explore the impacts of energy use in two decentralised systems, from renewable and non-renewable sources, on livelihood diversification in the Brazilian Amazon. Empirical research gathering qualitative and quantitative data was conducted in two isolated sites in the state of Amazonas. To understand the multidimensional factors influencing poverty reduction and income generation in relation to renewable and non-renewable energy use on livelihoods, this study used the Sustainable Livelihood Framework as conceptual framework. The main findings of this research show that while energy from solar PV mini-grid encourages the productivity of existing home-based off-farm income, the system does not meet future demand for either new income generating activities, demographic growth or migration. [ABSTRACT FROM AUTHOR]

Abstract The power grid has seen record demand for frequency regulation capacity in recent years due to the increased employment of renewable energy resources worldwide. Building thermal loads are flexible and thus, can be used as regulation reserves with proper control strategies. Previous studies have shown that building HVAC equipment can provide high-quality power grid regulation service with PJM performance scores of up to 0.98 and buildings' participation in the regulation market could bring significant economic benefits for building owners. However, the power flexibility in buildings is not persistent and the available HVAC regulation capacity has significant hour-by-hour variation due to building load and other operating constraints. This paper presents a regulation capacity reset strategy for HVAC regulation control that identifies the available regulation capacity and baseline power on the fly with real-time load and operation data. The strategy relies on a steady-state HVAC performance model derived from manufacturer performance data and implements a pseudo-optimization that seeks the maximum regulation capacity while respecting all operating constraints. The proposed strategy was implemented on a variable-speed rooftop unit (RTU) and validated with laboratory tests in psychrometric chambers. The test results show that the proposed reset strategy is effective in providing consistent high-quality regulation service with negligible impact on the indoor temperature control; the zone temperature deviation from the setpoint was within 0.3°C for all the performed tests. The reset strategy was also simulated with a prototypical building diurnal load model to quantify the integrated regulation capacity for a typical summer day. Simulation results indicate the integrated HVAC regulation capacity throughout a summer day equals approximately 1/4 of the daily electrical energy use; and the estimated daily regulation credit can offset up to 26% of the daily HVAC electricity cost based on PJM historical prices. [ABSTRACT FROM AUTHOR]

Abstract In the energy strategy of the European Union, the end-user is envisioned as a key participant in the future electricity market (European Commission, [16]). Current market designs and business models lack incentives and opportunities for regular electricity consumers (e.g. residential buildings) to become prosumers and actively participate in the market. Incentives should include economic and behavioural motivation beyond subsidised flat feed-in tariffs. Opportunities should allow for active participation of prosumers with relatively modest generation volumes but significant flexibility. In this paper, we propose a framework to integrate prosumer communities into the existing day-ahead and intraday markets. Using a two-stage stochastic programming approach, we incorporate the sequenced decision-making in the wholesale system under uncertainty of renewable generation and spot prices. We focus on the value of peer-to-peer (P2P) trading in the integration of prosumers in the day-ahead and intraday markets and investigate how residential battery storage contributes to local demand side flexibility in an integrated market setting. To this end, we introduce the Smart elecTricity Exchange Platform (STEP) that represents the interface between the wholesale electricity markets and the prosumer communities, and coordinates the community's operational supply-demand decisions. A study on residential buildings in London show that both P2P trade and battery storage by themselves each induce a reduction of electricity bills by 20%–30%. Combined, P2P trade and battery storage may lead to savings of almost 60%. In other words, we find that peer-to-peer trade and flexibility options such as local storage generate higher levels of the community's self-sufficiency. [ABSTRACT FROM AUTHOR]

Highlights • Road-stacked piezoelectric energy-harvesting units are designed and fabricated based on technical requirements and actual mass production requirements. • The preparation process and detailed structure of the units are optimized. • The applicability of the units in pavements is effectively improved. Abstract The exploration and research of pavement piezoelectric energy harvesting technology provides new ideas for the collection and application of road green energy. To improve the applicability of the piezoelectric energy-harvesting units in road environment effectively, based on technical requirements of energy-harvesting units for pavements, this paper compares two processes for preparing stacked piezoelectric energy-harvesting units and evaluates their application performance in terms of electromechanical conversion performance and structural strength; and the optimal preparation process for the units is determined as well. Two detailed structure optimization schemes of U-shaped interlayer copper foil electrode structure and lateral lead electrode structure are designed, which are tested and evaluated from the three perspectives of energy output performance, working durability and material properties, and the optimal electrode structure is determined. The results indicate that at 0.7 MPa–10 Hz, the parallel connected units prepared based on the multilayer adhesive process can increase the terminal voltage by 28.0 V and the output power by 22.80 mW, which are superior than units prepared by the monolithic co-firing process. In addition, the multilayer units exhibit good structural stability and weatherability. Under the same load condition, the optimal load resistances of the units with the U-shaped interlayer copper foil electrode and the lateral lead electrode can reach 20 kΩ with comparable energy outputs. Subsequently, mechanical testing is conducted after 50,000 simulation (MTS) cyclic loading, the structural performance of the U-shaped interlayer copper foil units is relatively durable and stable: the open-circuit voltage is attenuated by 4.4 V, the output power is attenuated by 3.30 mW, and the average capacitance of a single unit is only attenuated by 3.4 nF. Finally, future research plan is discussed. [ABSTRACT FROM AUTHOR]

Abstract: An experimental system was developed and tested in order to investigate the exergetic performance of a solar photovoltaic system (PV) assisted earth-to-air heat exchanger (under ground air tunnel) that is used for greenhouse cooling at the Solar Energy Institute, Ege University, Izmir, Turkey. This system was under operational conditions successfully during the 2010 summer cooling season. This paper provides the experimental results obtained between 18th of August and 26th of August of in 2010. Exergy destruction in the system was calculated and presented in this paper using a reference temperature of 15°C. Results are discussed and interpreted in the paper for various performance metrics, such as the effect of climatic conditions and operating conditions on the system performance. Results show that the system may be satisfactorily used for greenhouse cooling in the Mediterranean and Aegean regions of Turkey. [Copyright &y& Elsevier]

Abstract: The success of modeling the sustainable performance of the residential building envelope will be to a great extent associated to the sustainable energy performance indicators used. The sustainable energy performance indicators that these building assessment models are developed around should be chosen by taking into account the targeted objectives. However, it is very common to find building performance assessment models that do not take into account these considerations and therefore have a limited capability and scope. This leads to inadequate aggregate indicators for the actual assessment of the sustainable performance of the building envelope for a sustainable energy efficient building. The focus of this paper is to investigate the principal sustainable energy performance indicators for modeling the sustainable performance of the residential building envelope and develop an approach for determining the most appropriate sustainable energy performance indicators. In doing that, this paper provides an overview of previous research on sustainable energy performance indicators and discusses conceptual framework for developing sustainable energy performance indicators. In order to identify these indicators that influence the capability of building performance assessment models, a comprehensive survey of construction industry professionals was conducted using questionnaire survey technique while the data was analyzed using correlation analysis techniques. [Copyright &y& Elsevier]

Abstract: This paper demonstrates how Linear Programming (LP) can be applied to assist in the choice of renewable energy technologies for use in buildings to meet CO2 emissions reduction targets. Since there are many possibilities for combining different renewable technologies, the capital costs associated with the installation of one or more renewables can vary widely. In terms of capital investment the preferred solution will be the one at least cost, and LP provides an effective way to find this minimum through the so-called “objective function”. This project has used “lp_solve”, a free-source Mixed Integer Linear Programming solver that has been embedded in a Microsoft Excel application called Carbon emissions And Renewables for Building OPtimisation Toolkit (CARB-OPT) developed by RES Ltd in collaboration with London South Bank University (Renewable Environmental Services Ltd. (RES) is the environmental consultancy of Long and Partners Engineering Group. RES is currently involved in a Knowledge Transfer Partnerships (KTP) project in conjunction with the Faculty of Engineering, Science and the Building Environment (ESBE) at London South Bank University). This paper reports the application of this LP optimisation process for an office building case study with four alternative combinations of renewables. The process showed the technology mix that would lead to the smallest investment needed to comply with UK Building Regulations requirements and regional planning targets. In addition, the process offers a robust methodology to test the impact that the key assumptions may have upon the optimum solution. [Copyright &y& Elsevier]

Abstract Sustainable energy technologies are frequently considered for use with buildings in order to reduce their environmental impact. However, each technology will come with its own associated embodied carbon, which might potentially represent a significant proportion of a building's total embodied carbon impact. There is a need for further studies on the embodied carbon or CO 2 equivalent (CO 2 e) impact of sustainable energy technologies and it is important to understand how they contribute to the total CO 2 e budget of a building. Life Cycle Assessment (LCA) is used for the CO 2 e calculations and this paper has reviewed a significant number of existing studies. The results show that LCA methodologies can and do present information which has a significant degree of inaccuracy. Furthermore, the impact of some technologies can significantly increase the embodied CO 2 e impact of modern low to zero energy buildings. Considering the whole life CO 2 e impact of each aspect of a building is crucial for the successful creation of a truly low to zero carbon building. Many current studies omit the CO 2 e impact from sustainable energy technologies. This leads to results which are under representative and misleading. [ABSTRACT FROM AUTHOR]

Abstract Determining the economic benefits of building asset retrofitting has been a difficult task due to the paucity of reliable data and the inherent limitations of existing life-cycle costing models. For example, most life cycle costing models do not accommodate revocability (i.e. the economic impacts of reversing a decision previously made on a building configuration). Thus, the impact of revocability in the life cycle appraisal of a retrofit building project is assessed in this paper. Using a case-study approach, the economic impact of revocability is appraised using a real-options framework. The flexibility and non-flexibility of life cycle options are evaluated and compared. It is revealed that the cost of revocability may be as high as 27% in retrofit buildings. Flexible options have up to 50% chance of exceeding the performance of non-flexible retrofit options when fabric insulation measures and smart control installations are considered. The incorporation of renewable energy may undermine the performance of flexible options due to their inherent uncertainties in the cost and evolution in the future. There is, however, a need to develop holistic lifecycle option appraisal approaches for scenario feasiblility assessments to optimise the value of retrofit interventions in buildings. [ABSTRACT FROM AUTHOR]

Abstract: The electric-driven seawater source heat pump district heating system is a renewable energy utilization system, but this cannot guarantee the energy-saving effect of the system. The static energy-saving judgment between this system and the conventional boiler house district heating system was provided in a former research paper. However the static method has proved to be a very rough evaluation method and may lead to misjudgment as well. So a quasi-dynamic method, taking the total energy consumption during a whole heating season into consideration, is established in this paper. The energy-saving index turns out to be the expression of the lower limit of the average COP of the seawater source heat pump unit throughout the heating season (COP h,mc ). Then a case study is presented to show how the index of COP h,mc and the actual average COP of the heat pump unit throughout the heating season (COP h,ma ) are calculated. The calculation results show that the quasi-dynamic method improves the calculation accuracy dramatically, and thus provides a better solution to the quantitative energy-saving evaluation of the electric-driven seawater source heat pump district heating system. [ABSTRACT FROM AUTHOR]

The paper focuses on the experience with research of combined building-energy systems such as energy roofs, ground heat storage and active thermal protection. The EB2020 experimental house was largely designed in accordance with the patented ISOMAX system (SK 284 751, author: Dipl.-Ing., Phys. Edmond D. KRECKÉ), which represents a high potential for the use of renewable energy sources. When designing the experimental house EB2020, we eliminated the problem of this system by designing top heat sources, whose heat sources are exclusively solar and geothermic energy. The investigated building is designed with the following heat sources and energy systems: energy roof, low-temperature gas boiler, fireplace with hot water exchanger, ground heat storage, storage water heat storage with electric reheating, active thermal protection, large-area radiant low-temperature heating / high-temperature cooling, liquid cooling circuit in the ground outside the building, recuperative air handling unit and air ground heat exchanger. In this paper we describe the theoretical procedure for calculating the efficiency of the energy roof, comparison with a classic solar collector, experimental measurements of the energy roof during one season and evaluation of the measured data. The application of an energy roof requires lower investment costs than conventional solar collectors, but experimental measurements have shown that the energy gain and the achieved temperatures of the working substance at the outlet are significantly lower. For higher efficiency energy roof, it is worth considering installing a dark roofing and installing more circuits with a suitable orientation according to cardinal directions. This may be the subject of further research. [ABSTRACT FROM AUTHOR]

• Limited generation capacity and penetration of renewables need demand response. • Energy-storing water heaters are suitable for demand response with scheduling. • Artificial intelligence potentially suited due to patterned hot water usage. • Review of scheduling techniques and machine learning for optimal scheduling. • Machine learning clear advantages over classical control strategies. A high penetration of renewable energy sources such as wind power generation and photovoltaic generation causes some problems in power systems such as the duck curve and unreliability due to environmental variability. An effective solution to this problem is Demand Response (DR). Electric Water Heaters (EWHs) are considered ideal candidates for DR due to their energy storage capability. Due to the benefits, control strategies or techniques for EWHs have received considerable academic attention. The energy sector has recently tapped into the disruptive artificial intelligence world to learn, among other related priorities, how to enhance operations, maintain energy resilience and improve consumer service. Consequently, this paper reviews the use of machine learning (ML) for optimization and scheduling of EWHs. The main contributions of this review paper are, firstly, to identify state of the art of energy optimization and scheduling of EWHs. Secondly, to review the current ML models for energy optimization and scheduling of EWHs in smart grids and smart building environment. While classical control strategies may deliver substantial improvements, optimum efficiency may not be reached. ML has demonstrated clear advantages over classical control. Based on these conclusions, recommendations for further research topics are drawn. [ABSTRACT FROM AUTHOR]

Abstract: Constructing an indicator to measure the effectiveness of energy management is important for energy agencies and authorities. This paper uses multiple linear regression method and data envelopment analysis to examine the effectiveness of energy management. First, the regression method using environmental factors is used to calculate the predicted energy usage intensity of each evaluated building. Data envelopment analysis is then employed to calculate overall energy efficiency, using the predicted energy usage intensity as output and the observed energy usage intensity as input. Data envelopment analysis can be further applied to measure the overall energy efficiency in details by examining environmental factors and management factors. Finally, the energy consumption of buildings can be measured to evaluate the effectiveness of energy management. Buildings examined as a case study in this paper are government office buildings in Taiwan. The results show that most of the buildings evaluated to report a higher predicted energy usage intensity have successfully used efficient energy management methods in energy saving. [Copyright &y& Elsevier]

Abstract: Heating/cooling cost allocation is of growing concern in many countries because it contributes much to the energy conservation of central air-conditioning system. This paper intends to summarize the current studies and techniques on the heating/cooling cost allocation and discuss about the key problems to them. The contents mainly include the following parts: (1) probing into the methods of heating/cooling measurement; (2) establishing the calculation model for thermal billing; (3) presenting several typical systems for heating/cooling cost allocation. The significance of the paper is to help the engineers in this field have a good idea of the current development of heating/cooling cost allocation and promote the application of the relevant technologies to practice. [Copyright &y& Elsevier]

Abstract: This paper presents the performance analysis on a hybrid air-conditioning system according to the hybrid building energy system of the green building demonstration project in Shanghai, in which a 150m2 solar collector is used to power two 10kW adsorption chillers, a vapor compression heat pump is used to cool air in the evaporating end while the condensing heating at about 80°C is fully used to regenerate a liquid desiccant dehumidification system. In the hybrid system, the sensible cooling to the air is treated mainly by solar adsorption cooling and vapor compression cooling, whereas the latent heat is treated by the liquid desiccant dehumidification system with regeneration from the condensing heat of the heat pump. The results show that the performance of this system is 44.5% higher than conventional vapor compression system at a latent load of 30% and this improving can be achieved by 73.8% at a 42% latent load. The optimal ratio of adsorption refrigerating power to total cooling load for this kind of hybrid systems is also studied in this paper. [Copyright &y& Elsevier]

Abstract: This paper discusses the future development of efficient energy policies with respect to building sector, using a new simulation computer model called INVERT. The building sector incorporates supply side systems (heating, domestic hot water (DHW) and cooling systems) and Demand Side Management (DSM) measures. Simulation runs have been carried out up to 2020 for the Greek island of Crete based on sensitivity analyses for different building types, heating/cooling technologies and DHW systems. Promotion schemes for renewable energy sources (RES) and rational use of energy (RUE) are also implemented in the simulation model, since they have a strong impact on long-term financial investment strategies. Transfer costs and CO2 emissions of various hypothesis scenarios about new or additional promotion schemes for energy conservation in residential buildings have been compared with a reference scenario for the island of Crete. The outcome of this case study is presented and discussed in this paper. [Copyright &y& Elsevier]

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]

Heat recovery devices can help ventilation systems conserve energy; However, they cause a pressure drop in the system, and hence the system incurs an electricity consumption. In the present paper, the maximum allowable pressure drop of the recovery units is achieved from thermodynamic and economic points of view. The novelty of the research is that, unlike the existing criterion which does not differ for different cities, the introduced criteria can be calculated for each city with individual weather, economic, power plants, and energy conditions. Although the methods presented to calculate the criteria consider a broad range of effective parameters, there is no need to use complex energy simulation methods. Moreover, for each city, four types of criteria are introduced, which allows the city authorities to choose the best ones according to their city conditions, and then calculate the chosen criteria by the data of the city. In order to gain the criteria, modified enthalpy-hours and bin method variables are introduced to calculate sensible and latent energy consumption due to ventilation. The criteria are numerically calculated for Kerman city in Iran, and the results show that the recovery type and the chosen viewpoint has a considerable effect on the allowable pressure drop. The sensitivity of the results to different variables is analyzed in the end. [ABSTRACT FROM AUTHOR]

Actual national and international energy strategies generally encourage the use of renewable energy sources. Thermal energy storage (TES) offers various opportunities in the design of renewable energy systems. Thermochemical heat storage has gained popularity among researches because of higher energy density and lower heat loss compared to sensible and latent heat storage. On the other side solar energy has been recognized as one of the renewable energy sources with the most potential. This paper reviews thermochemical heat storage technologies and systems with emphasis on systems involving solar energy utilization in buildings. The studies are reviewed based on used storage materials, system configuration as well as models to predict and optimize system performance. [ABSTRACT FROM AUTHOR]

The continued growth in variable renewable energy sources (VRES) has created increased focus on the use of office buildings for power flexibility activities. Office buildings uniquely present opportunities for relatively easy control adaptation during power flexibility activities given their large thermal inertial and existing building automation. Though a number of studies have outlined the potentials of office buildings for power flexibility, however only few studies have clearly outlined associated critical performance characteristics as it relates to comfort. Subsequently, this paper uses structured literature survey to outline critical performance characteristics that should be considered when using office buildings as power flexibility resources. Understanding the performance characteristics that are critical for using office buildings as power flexibility resources is important not only for their effective control and coordination but also to avoid compromising the core role of office buildings which is the provision of a comfortable and productive environment for business transactions. [ABSTRACT FROM AUTHOR]

A Net Zero Energy Building (NZEB) is a term, subject to ambiguity, that could be used to describe a building with characteristics such as equal energy generation to usage, significantly reduced energy demands, energy costs equalling zero or net zero greenhouse gas (GHG) emissions. Despite lacking an authoritative definition of NZEBs, this relatively new emerging concept in Australia provides significant opportunities to reduce GHG emissions, energy usage and operational energy costs for buildings owners. This paper aims to explore the existing NZEB models, assess the progression of NZEB literature, identify key policies encouraging NZEB development and recognise potential areas of NZEB research. [ABSTRACT FROM AUTHOR]