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This paper investigates conversion of a Nordic oil-heated townhouse into carbon-neutral by different energy efficiency (EE) improvements and an off-grid system including solar photovoltaics (PV), wind power, and battery and hydrogen energy storage systems (BESS and HESS). A heat-pump-based heating system including waste heat recovery (WHR) from the HESS and an off-grid electrical system are dimensioned for the building by applying models developed in MATLAB and Microsoft Excel to study the life cycle costs (LCC). The work uses a measured electrical load profile, and the heat generation of the new heating system and the power generation are simulated by commercial software. It is shown that the EE improvements and WHR from the HESS have a positive effect on the dimensioning of the off-grid system, and the LCC can be reduced by up to €2 million. With the EE improvements and WHR, the component dimensioning can be reduced by 22%–41% and 13%–51% on average, respectively. WHR can cover up to 57% of the building's annual heat demand, and full-power dimensioning of the heat pump is not reasonable when WHR is applied. Wind power was found to be very relevant in the Nordic conditions, reducing the LCC by 32%. [Display omitted] • Energy efficiency improvements notably reduce dimensioning of system components. • Waste heat from FC and electrolyzer covers up to 57% of the annual heat demand. • A full-power-dimensioned GSHP does not reduce the fuel cell dimensioning. • Seasonal storage on a small scale makes the system not economically viable. • Small-scale wind power is expensive, but it significantly reduces the system LCC. [ABSTRACT FROM AUTHOR]

This study analyzes the impact of green finance and renewable energy on energy efficiency in E−7 economies. We analyzed the nonlinear and asymmetric effects of green finance and renewable energy on energy efficiency. We collected data from 1985 to 2017 and applied the NARDL and 2SLS methods. The results reveal that the differences in green finance development in the E−7 region are as follows: China (0.61), Brazil (0.55), India (0.53), Indonesia (0.49), Mexico (0.37), and Russia (0.39). In 2019, the Gini coefficient was the largest in Russia (0.57), followed by Turkey. Based on empirical findings, the largest barrier to green energy efficiency is insufficient private and governmental investment in the energy sector to improve access to power, to increase energy security and promote economic growth in an environmentally sustainable manner. The findings point to a promising but vulnerable future for renewable energy and energy efficiency deployment in E−7 countries. This paper emphasizes that green financing and renewable energy policy limitations must be addressed to realize the funding potential of energy efficiency in E−7 countries. • We have analyzed the barrieres for renewable energy and energy efficiency. • Non-linear and asymmetric effects is observed on energy efficiency. • We have applied NARDL model to examine the relationship among variables. [ABSTRACT FROM AUTHOR]

This paper investigates the sustainability of Tabriz City focusing on its decarbonization. Statistical, quantitative, and comparative research methods are used to analyze the total energy consumed, conversion of primary energy, final exergy, and losses analysis according to the renewable and carbon-based energies. Then, the renewable resource potentials of the city are simulated using Grasshopper plug-in-Rhino simulator, THERM, PVSyst photovoltaic software, and ArcMap. In terms of the socio-economic assessment, non-oil Per Capita GDP, emissions, and energy intensities are analyzed concerning the B2DS scenario by 2050. The per capita GDP of the city is 71% of the country's average value. Tabriz's real GDP growth averaged −1.11% per year, primary energy demand increased by an average of 6.1%, CO 2 emissions from energy use grew by an average of 6% annually and the emission intensity of the economy increased by a total of 52.02%, in the period from 2011 to 2019. Finally, it is shown that the city consumes 58050 GWh/year of different carbon-based resources that only produced 20110 GWh/year of useful work with 5.63 MT CO 2 emissions, while the same work could locally be supplied by 30000 GWh/year RE with a minimum rate of 0.18 MT CO 2 emissions. The city Landfill receives 1000 tons/day of MSW, but two-thirds of this amount can be recycled. Regarding different sectors, buildings produce half of the CO 2. The cement industry with dual pollutants (17%) is the most polluting factory. Carbon-based electricity (66%) is the most polluting form of energy. In terms of carbon sequestration requirements with trees, shifting from fossil fuels toward green energies, EE, and recycling MSW can plunge required trees from 81.9 to 1.16 million trees. This paper highlights the importance of electrification of transportation based on RE, energy performance of buildings, and all sectors. • Large city decarbonization strategies • Application of RE according to geographic and climatic factors. • Electrification of sectors based on RE locally. • MSW recycling and sequestration by trees for decarbonization regarding the LULC and NDVI analysis. • Conversion and storage efficiencies of carbon-based fuels vs RE. [ABSTRACT FROM AUTHOR]

The aim of this paper is to analyze through simulation how the energy efficiency of a single electrolysis stack at various loads is affected by shunt currents and to determine the energy-optimal load distribution between lines in a multiline electrolysis system under various magnitudes of shunt current losses. A dynamic energy and mass balance model of an industrial 3 MW , 16 bar alkaline water electrolyzer (AWE) process was developed using MATLAB. The optimization goal is to determine the power supply for each AWE line so that it can meet any hydrogen demand while minimizing the global specific energy consumption (SEC). The Particle Swarm Optimization (PSO) algorithm is used to minimize the objective function. According to the results of the single stack investigation, shunt current reduction could significantly improve the energy efficiency of partial-load operation. In addition, the optimization study revealed that whenever two or more lines are required to run in order to satisfy the hydrogen demand, the global SEC is minimized when the lines operate at equal loads. [ABSTRACT FROM AUTHOR]

This study aims to unveil the heterogeneous impacts of import product diversification and institutional factors for achieving energy efficiency in Organization for Economic Co-operation and Development (OECD) countries. In doing so, the study employs robust econometric techniques such as Fully modified ordinary least squares (FMOLS) co-integration, pooled Ordinary Least Squares (OLS), Feasible Generalized Least Squares (FGLS), pool mean group regressions, fixed effects, and random effects for panel data from 1990 to 2015 for selected OECD countries. The detailed empirical outcomes suggest that import product diversification is conducive to reducing the energy and carbon intensity (improvement in energy efficiency) in OECD countries. The empirical conclusions provide various guidelines to achieve cleaner and greener growth and align with various Sustainable Development Goals (SDG 7: Affordable and clean energy, SDG 9: Industry, innovation, and infrastructure, and SDG 13: Climate action) of OECD countries. The paper elaborates fruitful policy suggestions regarding the diversification of imports and energy use-carbon emission-nexus for the OECD member nations. Based on the findings, policymakers and environmental scientists should strengthen the trade-energy and import portfolio policies to attain energy efficiency. [ABSTRACT FROM AUTHOR]

As the world's largest energy consuming country, it is important to study the mechanisms of improving renewable energy and energy efficiency to achieve green economic growth in China and globally. Therefore, this study investigates the impact of environmental regulations on green economic growth and renewable energy development in China, respectively. First, this study measures the level of green economic growth in Chinese cities by the Metafrontier-Global-SBM super-efficient data envelopment analysis (DEA) model from the perspective of energy efficiency. And the environmental regulation intensity was measured using an improved fuzzy comprehensive evaluation method. Second, a spatial econometric model based on longitudinal data was constructed to examine the non-linear effects of environmental regulations on green economic growth and its spatial spillover and feedback effects. The results indicated a U-shaped non-linear effect of energy efficiency-related environmental regulation on green economic growth as well as a spatial spillover effect and spatial feedback effect. Finally, the impact of environmental regulation on renewable energy development was investigated. The results show that renewable energy development, an important component of green economic growth, is equally dependent on the implementation of environmental regulation policies and that environmental regulation makes a significant contribution to renewable energy development. The findings of this paper provide a basis for the realization of green economic growth and the formulation of renewable energy policies in China. • Impact of environmental regulation on renewable energy development was investigated. • A spatial econometric model of 286 Chinese cities from 2003 to 2018 was constructed. • Environmental regulation has a significant U-shaped effect on green economic growth. • Non-linear effects include spatial spillover and spatial feedback effects. • Environmental regulation promotes green growth earlier in resource-based cities. [ABSTRACT FROM AUTHOR]

Energy efficiency interventions in Water Supply Systems (WSSs) need a precise evaluation of the available water flow rates for energy recovery interventions; however, flow meters are generally too costly for being installed in all the gravity adduction pipelines of a WSS. This paper presents a methodology for predicting flow rates in gravity adduction pipelines based on the electricity bill consumption. In this study, the predicted average flow rate is 0.0300 m3∗s−1, being 1.64% lower than the real one. A Pelton turbine has been chosen as energy recovery unit for supplying electricity to a pumping station of a preloading tank where the water is treated to make it drinkable. An energy saving of 475.26 (MW∗h)∗year−1 is achieved, which can be also expressed as 88.87 saved Tonnes of Oil Equivalent (TOE) and 204.36 ktCO 2 not released into the atmosphere. The gross economic saving due to the installation of the Pelton turbine is equal to 94.29 k€∗year−1 and it can be further increased up to 116.51 k€∗year−1 if the energy efficiency certificates issued by the Italian Authorities are considered. The Payback Period (PBP) of the intervention corresponds to 3 years, and a Net Present Value (NPV) after twenty years is approximately 1.4 M€. • A methodology to assess the energy recovery in Water Supply Systems is presented. • The methodology is used in gravity adduction pipelines linked to preloading tanks. • Measured flow rates have been used for validating the proposed methodology. • A Pelton turbine was used as energy recovery unit in a Water Supply System. • The achievable energy recovery potential in this study is 475.26 (MW∗h)∗year-1. [ABSTRACT FROM AUTHOR]

In this paper, a model based on the first and second laws of thermodynamics is developed in MATLAB R2020a Simulink software and is utilized in thermodynamically optimizing a bismuth telluride based solar thermoelectric generator (STEG) while estimating all system irreversibilities. This study aims at presenting a cheaper and simpler method of optimizing the performance of traditional STEGs without using segmentation or cascading. This is achieved by studying the effects of operating thermal and electric parameters such as load-resistance ratio (LRR), optical concentration ratio (OCR), thermal concentration ratio (TCR), hot junction temperature (T h), cold junction temperature, current and voltage on STEG power output, energy and exergy efficiencies, respectively. The results obtained are validated with experimental and numerical data from previous studies. Results indicate that for an OCR of 30, a STEG exergy efficiency of about 6.5% is obtained from a conventional bismuth-telluride single-stage module. Also, a means of maximising STEG performance while reducing system irreversibilities to the barest minimum is presented. The results obtained herein will provide useful information in the maximisation of conventional and complex STEG systems employing segmentation or cascading. • A solar thermoelectric generator yielded an exergy efficiency of 6.5%. • Device performance is maximised with minimum irreversibilities. • The critical optical concentration ratio of the solar concentrator is obtained. • A cheaper and simpler means of maximising device performance is presented. [ABSTRACT FROM AUTHOR]

As climate warming intensifies, reducing greenhouse gas emissions has become a national consensus for many countries. Green finance plays an important role in promoting energy efficiency and lowering such emissions, but there is scant literature that analyzes the impacts and mechanisms of green finance on energy efficiency. Based on China's provincial panel data from 2010 to 2018, this research measures the green finance index using the panel entropy weighting method and systematically evaluates the relationship between green finance and energy efficiency using the fixed-effects model. The results show the following. (1) Green finance significantly contributes to energy efficiency and remains the same after a series of robustness tests such as endogeneity treatment, replacement of explanatory and interpreted variables, and replacement of regression models. (2) Green technology innovation and energy structure optimization are the transmission mechanism of green finance for energy efficiency, which means that green finance improves energy efficiency by promoting green technology innovation and energy structure optimization. (3) There is regional heterogeneity, temporal heterogeneity, and industry heterogeneity in the impact of green finance on energy efficiency. The positive effects of green finance on energy efficiency are more pronounced in resource-dependent regions, regions with irrational industrial structure, north regions, industrial sectors, and after 2013. The conclusions of this paper offer some policy recommendations, including promoting the development of green finance, building a cooperation platform for green finance and technological innovation, enhancing the depth and breadth of renewable energy utilization, and building differentiated green finance strategies according to local conditions. [ABSTRACT FROM AUTHOR]

Ground-source heat pump (GSHP) systems contribute significantly to the reduction in energy consumption and CO 2 emissions. The vast territory, abundant geothermal sources, and different climatic zones of Southwestern and Northwestern China provide significant opportunities for the application of GSHP technologies. In this study, a statistical study was performed to assess the general performances and identify the existing problems of GSHP systems located in the abovementioned areas. Twenty-eight GSHP projects, including groundwater heat pumps, soil-source heat pumps, and surface water heat pumps were selected. Water temperature, energy consumption, coefficient of performance (COP), energy efficiency ratio (EER), and thermodynamic perfectibility were analysed. The energy efficiency of GSHP systems were assessed according to the national standard. In addition, barriers and problems in GSHP applications are discussed herein. It is concluded that the average cooling COPs of SSHP, GWHP and SWHP units are 4.9, 4.7, and 4.2, respectively, with SSHP unit being the highest. The average heating COPs of SSHP, GWHP and SWHP units are 4.3, 4.2, and 4.2, respectively with SSHP unit being the highest. The SSHP has the best performance in both seasons amongst three GSHP types. Furthermore, though 89% of the systems can meet the requirements of national standard, more than 50% of them work at the lowest allowable energy efficiency value. This paper attempts to provide essential clues for the adoption feasibility and technical guidelines of GSHPs in the target areas. • 28 GSHP projects including GWHP, SSHP and SWHP were selected in this study. • The field performance and thermodynamic perfectibility of the GSHPs were analysed. • The energy efficiencies of GSHPs were assessed according to the national standard. [ABSTRACT FROM AUTHOR]

In this paper, the thermal characteristics of an evacuated tube solar collector for different volumetric flow rates of the fluid (10, 30 and 50 l/h) was experimentally improved by using copper oxide/distilled water (Cu 2 O/DW) nanofluid, and parabolic concentrator. Moreover, the effect of different volume fractions of the utilized nanofluid on the fluid properties, such as convective heat transfer coefficient, Nusselt number, and the useful gain of the collector was experimented. Finally, three artificial intelligence (AI) techniques namely, multi-variate adaptive regression spline (MARS), model tree (MT) and gene-expression programming (GEP) have been employed to predict the energy efficiency ( η І ) and inlet-outlet water temperature difference (ΔT). The input variables were volume of the storage tank (V), volume fraction of the nanofluid (VF), and mass flow rate of the fluid (M ˙). The proposed AI methods presented robust formulations for prediction of η І and ΔT with an acceptable level of precision. The statistical results of AI models demonstrated that the MARS method can make a more accurate prediction of the collector performance than GEP and MT. It was also concluded that increase in both flow rate, and concentration of the nanofluid, lead to an increase in the thermal performance of the solar collector. • Experimental evaluation of the evacuated tube solar collector with coil inside. • Using Multi-variate Adaptive Regression Spline method for performance prediction. • Utilizing Gene-Expression Programming method for the thermal performance prediction. • Applying Model Tree method to performance prediction of the tubular solar collector. • Presenting new formulas for the energy efficiency and water temperature difference. [ABSTRACT FROM AUTHOR]

In order to support the growth of grid-tied photovoltaic power plant implementation in the Saharan environment. A detailed assessment analysis of 28 kWp photovoltaic (PV) system installed on the rooftop of Research Unit for Renewable Energies in Saharan region (URER/MS), located in southern Algeria (Adrar), has been carried out and presented in this paper. The monitoring data of the PV system over 12 months (March 2017 to February 2018), are used to evaluate both energy efficiency and the output power losses. The collected experimental data reveal that the environmental parameters variation has a direct effect on the performance of both the energy conversion efficiency and the system losses. From the monitoring data and the performance assessment, it was found that the highest final yield is 5.3 h/day while the irradiation and the ambient temperature are 518 W/m2 and 37.9 C° respectively. The annual production injected to the grid is 45.12 MWh, with 2.4 MWh energy losses are attributed to the grid voltage rise, 1.57 MWh energy is lost due to the array and thermal capture losses and system losses. The yield values of maximum/minimum monthly average reference and array yield values were; 6.7/5.4 h/day and 5.5/3.2 h/day respectively. The annual average PV module, inverter and system efficiencies reached; 11.37%, 96.46% and 10.99%, respectively. Some parameters of measured data; are used to calculate the harvested energy and performance ratio, and then compared with other PV systems installation located in different geographical regions worldwide. Finally, we have studied the impact of the grid voltage rise on the grid-connected photovoltaic system performance on both energetic and economical levels. • The assessment of 28 kWp photovoltaic (PV) system installed in the desertic weather condition in Sahara of Algeria. • The most appropriate and relevant performance indices were used to analyze the PV system performances. • The system disconnection losses have an important influence on the PV systems performance. • Performance analysis exhibit high losses in PV system due to environmental factors. [ABSTRACT FROM AUTHOR]

The implementation of load management and demand response programs is motivating utilities to propose demand-side management to incentivize customers to modify their energy consumption during critical events, providing energy flexibility to the grid. With the widespread use of distributed energy resources, energy aggregators have grown significantly to manage the portfolio of residential buildings. This paper presents a control-oriented implementation to define the energy flexibility potential of a portfolio of residential buildings within the same energy aggregator. The data-driven methodology combines the resistance-capacitance thermal network model of the households with building integrated photovoltaics/thermal and air source heat pump models to assess the modification of the baseline of power demand at the energy aggregator level. The optimization is performed through a model predictive control (MPC) framework for day-ahead predictions. Parametric analysis and scenario investigation are exploited to define the optimal configuration for both the households and the grid operator. The presented methodology provides insight for energy efficiency and flexibility about the operating and design of energy aggregators in a demand response program. A Canadian virtual community is used as a case study to estimate the performance of the presented methodology. The optimization of load management at the aggregator level is presented for a representative demand response (DR) event during the winter season for two different energy pricing structures. Numerical results show the potential of the proposed methodology to guide the design and operation of virtual clusters integrating renewable technologies towards energy efficiency, showing a reduction of 40% in total energy consumption and a peak reduction of around 32%. [ABSTRACT FROM AUTHOR]

Abstract The coupling between heat pumps and renewable energy sources is a recognized strategy to reduce primary energy consumption at the household level. This paper contributes to the present-day discussion concerning solar-assisted heat pumps for heating/cooling and to produce domestic how water. In particular, this study presents the results of a field study concerning a novel solar-assisted dual-source multifunctional heat pump, installed in a detached house in Milan. The proposed system couples hybrid photovoltaic/thermal (PVT) panels with a multifunctional and reversible heat pump. The heat pump is equipped with " air-source " and " water-source " evaporators, connected in series and operated alternatively, based on the ambient conditions, system parameters and operating modes. In addition, the PVT panels are used, by employing two storage tanks, to produce domestic hot water and to provide a heat source to the " water-source " evaporator. The proposed system has been tested experimentally, showing interesting and promising results: the system has been able to maintain high efficiencies in the different seasons and has been able to use the solar energy to support the production of domestic hot water. It was found that the use of the " water-source " evaporator allowed to significantly increase the performance of the system and to avoid the defrost cycles. Highlights • We present a novel solar-assisted dual source multifunctional heat pump. • We summarize the results of a field trial. • We provide seasonal performances of unit installed in a detached house. • We provide daily performances of unit installed in a detached house. • We relate seasonal and daily performances. [ABSTRACT FROM AUTHOR]

Ground heat exchanger takes the soil underground as heat source or sink to supply cooling or heating. It has been widely used in building heating and cooling systems due to high efficiency and environmental friendliness. This paper reviews the latest research on ground heat exchangers from several new perspectives and demonstrates their potentials in achieving zero energy buildings. Firstly, ground heat exchangers are classified into water-based and air-based ones based on the heat transfer medium. They can be used in a passive or active approach. Associated research and projects for each approach are introduced and analysed. Then the integration of ground heat exchangers with various cooling and heating technologies and related studies are reviewed. These technologies include solar thermal collectors, cooling towers, nocturnal radiative cooling technology, solar chimney, etc. Finally, a technical route for ground heat exchangers to help realize zero energy buildings is presented, which provides a promising solution to improve energy efficiency of buildings. [ABSTRACT FROM AUTHOR]

This work shows a technical review for two promising technologies and two commercial systems that can be applied in Hybrid Wind Systems —also known as Extraction Water from Air Systems (EWAS) — for the special weather conditions presents in Brazilian northeast. Additionally, a full description of the main components for the innovative technologies and for commercial solutions are explained. An energy consumption analysis for each one of these systems is made for comparison purposes. Water extraction capacity and energy efficiency are evaluated (for two commercial EWAS) for a theoretical operation point in the middle of the North–eastern semi–desert region. This point is obtained by means of the well–known humid air diagram. Important information about minimum environmental conditions for Membranes and Coils are also considered. Three main types of electric generators are described, including its advantages and disadvantages, for the estimation of the power ratio to generating electricity and water. For all above, the right sizing of the future Brazilian EWAS prototype and its possible application in a semi-arid region is the objective of this paper. [ABSTRACT FROM AUTHOR]

An unprecedented expansion of household photovoltaic (PV) systems coincided with a marked decline in household electricity demand in several jurisdictions around the world. This was driven by falling PV prices and the installation of more energy efficient residential appliances (EE). However, existing net metering arrangements value self-consumption of PV far more than PV exports to the grid. As a result, energy savings from EE that considerably reduce household PV self-consumption could also reduce the value of PV systems. Since PV exports generally utilise only part of the distribution grid, ‘local generation network credits’ (LGNCs) have been proposed to increase the value of PV exports. LGNCs also have the potential to improve the combined value of PV and EE. Given the large variability of the household PV generation and load and the time-varying structure of LGNCs, an empirical probabilistic method is proposed in this paper in order to assess the combined PV-EE value with the LGNC arrangements. The results show how simplistic feed-in tariffs have an adverse impact on the combined PV-EE value and how LGNCs can assist in removing barriers to the combined uptake of these two key clean energy technologies. [ABSTRACT FROM AUTHOR]

Renewable energy is a significant input for environmental, economic and social development. The wind energy has become the quickest thriving renewable energy resource. It is worth noting that wind power has the least emissions and lowest water consumption, but it has comparatively high costs. Thus, making wind energy station planning decision requires an operation of balancing various technical, economic, ecological, and environmental aspects over time and space. This paper is constructed to choose a convenient turbine from various perspectives for developing a wind energy station. For 2 MW, the best wind turbine brands are listed based on expert interviews and literature review and they are used to establish a decision-making model with four main criteria consisting technical, economic, environmental, and customer attributes with various sub-criteria. Determining the related criteria and grouping them in main categories is the novel approach provided by this research. The constructed model can be solved by various multi-criteria decision making techniques. The selection of the best wind turbine is determined by using AHP technique. The results are significant both from engineering and economic perspective as the applied methodology is practically implementable and commercially viable. Accurate and up-to-date data are obtained from leading companies in the industry. [ABSTRACT FROM AUTHOR]

Due to environmental effects of extensive use of energy, solar collectors are being installed on a large scale in many countries. The accurate determination of its efficiency by a test laboratory strongly affects the system performance prediction, cost-benefit valuations, technology introducing in public policies and certification programs. In this context and considering that indoor efficiency tests using solar simulators are increasingly used by test labs, this paper presents an assessment of uncertainty associated with usual flat plate solar collector efficiency tests performed with solar simulator. For this purpose, tests were performed according indoor method in order to estimate uncertainty associated with efficiency determination. Uncertainty evaluation included the contributions of instrumentation, temporal stability of environmental test conditions and statistical regression used to determine collector's efficiency curve. Additional tests and evaluations were also carried out to investigate solar simulated irradiance and air speed influence on estimated uncertainty and to validate the results from comparison with uncertainties derived from two other laboratories. [ABSTRACT FROM AUTHOR]

Abstract: Prince Edward Island (PEI) is the smallest province in Canada measuring about 5700 km2 in area with a population of around 130,000 people. Small family farm operation is part of the Island's way of life. However, the dairy industry in North America is undergoing significant structural change. Statistics show a significant decline in the small dairy farms industry, while the number of large operations has been increasing. Advantages for large operations include purchasing energy in large quantities with better price margins and the inherent economy of scale created by such breaks. One strategy for small-scale farms to become competitive is to reduce their energy-related operational costs and greenhouse gas emissions. This can be achieved through taking energy efficiency steps, reducing overall energy consumption and generating energy through renewable energy resources and technologies. This paper uses a case study of a small dairy farm in Oyster Bed Bridge, PEI to gain insight into the direct use of energy within small dairy farms. An energy audit methodology is used to determine the energy intensity of the farm as well as energy efficiency opportunities. The paper also assesses the feasibility of meeting part of the energy demand of the farm with renewable energy generation. Energy efficiency recommendations for the case study farm include lighting retrofitting and regular maintenance of refrigeration condenser units. Renewable energy generation findings include the potential use of an anaerobic digester or a 25 kW wind turbine to generate the majority of the operation's energy. [Copyright &y& Elsevier]

Due to high cost, solar Photovoltaic (PV) systems are not an attractive option for places where energy buyback programs are not available. Mostly because small scale PV systems are incapable of operating legacy high-powered electrical devices such as room air conditioners, induction motors and other compressor-based devices on renewable energy. This is because these devices show either capacitive or inductive behavior which results in a high transient power during their startup cycle, not accommodable by small-scale PV systems. Solutions to solve this problem such as Variable Frequency Drives (VFDs) are expensive and restrictive in their applicability. In this paper, we propose an approach to operate high-powered legacy electrical appliances on small-scale solar PV. Our proposed method involves a real-time algorithm which detects the onset of a transient and shifts the appliances from PV to the utility during the transient duration. Upon reaching back to a stable state after the transient, the device is shifted back to PV. We have evaluated our transient detection algorithm on a two publically available datasets as well as on a specifically designed testbed system. Our evaluations show that for most common high-powered devices, the transients are detected fast enough to shift the load from PV to the grid and vice versa. [ABSTRACT FROM AUTHOR]

This study discusses the consequences of recent European Regulations concerning the integration of water and/or space heating systems within the framework of the European Directives for Energy Labelling and Ecodesign. This development undoubtedly creates a completely new environment for the production and commercial distribution of solar thermal products, for the benefit of both producers and distributors of heating-energy handling appliances, as well as for the end users of those devices. This paper will first outline the requirements of the relevant regulations and highlight the critical parameters affecting the classification of products in energy classes. Specific failures, ambiguities and deficiencies related to the proposed procedures are indicated and discussed, noting that these factors can potentially undermine the objectivity, impartiality and effectiveness of the products' evaluation. It will conclude by proposing specific corrective measures which could be considered through the periodic revision anticipated in the Regulations. [ABSTRACT FROM AUTHOR]

Two different analyses of the energy behavior of dwellings in Santa Rosa city (36°27′ S, 64° 27′ W, 182 m above sea level), in central Argentina, are presented. Firstly, a retrospective analysis of the operating energy -electricity and gas- of 10 compact housing in a period of 50 years is presented. Periods with missing data were fulfilled through predictive statistical models. Then, a “case study” was used to study different retrofitting strategies and to make a prospective analysis for future weather conditions calculated through the CMIP5-Coupled Model Intercomparison Project-Phase 5. The results indicate that the addition of thermal insulation in walls and roofs is highly beneficial, but the increase of glazed areas seems to be counterproductive. The energy demands for 2010 and 2039, for both the conventional and the retrofitted dwelling, show a decrease in winter and an increase in summer. We conclude that it is necessary to revise the dimensions suggested for the glazed areas, in order to deal with present and future indoor overheating. This paper presents the integration of past, present and future, towards a better comprehension of the challenges to be faced in the next decades. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports the outcome of the project on “Capacity building in formulating harmonized policy instruments for the promotion of Renewable Energy and Energy Efficiency in the ASEAN member countries”. With the growing concerns about green house gas (GHG) emission and consequent climate change, renewable energy sources have become more attractive option for electricity generation around the world. Studies have been made on the status of renewable energy potential and utilization, major barriers in promoting renewable energy in ASEAN countries, major energy policies to overcome barriers, and existing renewable energy and energy efficiency policies in ASEAN countries. Paper concludes that ASEAN has not utilized its renewable energy resources anywhere near to the potential. Analysis found that the key factor that has to be amended is “policies and regulations in renewable energy and energy efficiency” at both country level and regional level. But, ASEAN is not yet ready for the full harmonization of the policies. However, it recommends that, with the project outputs it is possible to focus on the specific policy instruments common to most of the member countries, such that it could use to augment ASEAN Plan of Action for Energy Cooperation (APAEC) initiatives. [Copyright &y& Elsevier]

Abstract: Within recent years, energy policies have imposed a number of targets at European and national level for rational use of energy (RUE), renewable energy sources (RES) and related CO2 reductions. As a result, a wide variety of policy instruments is currently implemented and hence the question arises: how can these instruments be designed in a way to reach the maximum policy target with the minimum public money spent? The objective of this paper is to derive a methodology for obtaining efficient policy portfolios promoting sustainable energy systems depending on the policy target and show corresponding results from case studies in Austria, Germany and Poland. The investigations were carried out by application of Invert simulation tool, a computer model developed for simulating the impacts of various promotion schemes for renewable and efficient energy systems. With this tool, the CO2 reductions and related public expenses have been calculated for various policy mixes. In the building-related energy sector, it turned out that in all investigated regions support schemes for supply side measures are the most cost-efficient instruments. However, their potential is restricted and for achieving higher levels of CO2 reduction, promotion of demand side measures is indispensable. The paper shows that for a comprehensive comparison of policy portfolios, there are always two dimensions to be considered: efficiency and effectiveness. The more effective, i.e. the higher the implementation rate of a scheme, the more essential becomes the efficiency criteria. [Copyright &y& Elsevier]

A very large percentage of the European residential building stock is ageing and does not comply with current energy regulations. The need to complete short-term energy upgrading on these buildings in order to improve performance and meet current regulations poses a considerable challenge. Consistent energy methodologies are needed for mass application of suitable technologies in sensitive points such as the façade, saving time by guiding designers on use of preferred climatic design strategies for each situation and with economic feasibility. The paper presents a methodology with integrative approach between energy and economic aspects, using an inference system to overcome uncertain or unknown information found at the start of the project. Components used in the analysis are studied from a programmatic point of view (input, decision process and output). The methodology is suitable for early stages of the design process and its products enable continuation into more advanced ones. The methodology can form the basis for a software program using either its own databases or integrated energy simulation engines. This work is based on research for a European project concerning energy retrofit of residential building facades, but can be extended to other zones or end-uses having similar approaches. [ABSTRACT FROM AUTHOR]

The performance of a building integrated photovoltaic system (BIPV) has to be commendable, not only on the electrical front but also on the thermal comfort front, thereby fulfilling the true responsibility of an energy providing shelter. Given the low thermal mass of BIPV systems, unintended and undesired outcomes of harnessing solar energy - such as heat gain into the building, especially in tropical regions - have to be adequately addressed. Cell (module) temperature is one critical factor that affects both the electrical and the thermal performance of such installations. The current paper discusses the impact of cell (module) temperature on both the electrical efficiency and thermal comfort by investigating the holistic performance of one such system (5.25 kWp) installed at the Centre for Sustainable Technologies in the Indian Institute of Science, Bangalore. Some recommendations (passive techniques) for improving the performance and making BIPV structures thermally comfortable have been listed out. [ABSTRACT FROM AUTHOR]

Abstract: Community-based social marketing (CBSM) has shown to be very effective at inducing behavioural change due to its pragmatic approach. It has been found that nonintegrated intensive approaches towards changing individual's behaviour, such as education and economic self-interest are not successful. This paper will explain how a large urban electricity meter replacement program can achieve a reduction in peak demand and overall energy consumption through the use of advanced metering infrastructure (AMI or ‘smart meters’) coupled with CBSM, which in turn enables the progression towards a ‘smart grid’. In order to measure success the following targets were set: [•] Peak demand reduction (peak lopping) of 20% from the households participating in the Behaviour Change Programs (BCPs). [•] Peak demand shifting (load shifting) to reduce energy consumption during ‘super peak’ by 10% in BCP participating households. [•] Average total energy use reduction of 10% in BCP participating households. The energy efficiency actions discussed with householders during eco-coaching, and other feedback communications, are identified by utilising the information regarding barriers and benefits generated from the research phase prior to coaching. These actions can include referral to other initiatives such as the provision of reduced cost solar PV power systems, direct load control devices for domestic air-conditioners, the time-of-use pricing product, the provision of in-home-displays (IHD) and other devices necessary for development of a ‘smart grid’. [Copyright &y& Elsevier]

Abstract: Energy is released when feed waters with different salinity mix. This energy can be captured in reverse electrodialysis (RED). This paper examines experimentally the effect of varying feed water concentrations on a RED system in terms of permselectivity of the membrane, energy efficiency, power density and electrical resistance. Salt concentrations ranging from 0.01 M to 5 M were used simultaneously in two stacks with identical specifications, providing an overview of potential applications. Results show a decrease of both permselectivity and energy efficiency with higher salt concentrations and higher gradients. Conversely, power density increases when higher gradients are used. The resistance contribution of concentration change in the bulk solution, spacers and the boundary layer is more significant for lower concentrations and gradients, while membrane resistance is dominant for high concentrations. Increasing temperature has a negative effect on permselectivity and energy efficiency, but is beneficial for power density. A power density of 6.7 W/m2 is achieved using 0.01 M against 5 M at 60 °C. The results suggest that there is no single way to improve the performance of a RED system for all concentrations. Improvements are therefore subject to the specific priorities of the application and the salt concentration levels used. Regarding ion exchange membranes, higher salinity gradients would benefit most from a higher fixed charge density to reduce co-ion transport, while lower salinity gradients benefit from a thicker membrane to decrease the osmotic flux. [Copyright &y& Elsevier]

Abstract: This paper describes the analysis of a real case of multiple Aquifer Thermal Energy Storage systems. The Hague, the capital city of the province of South Holland in the Netherlands, is densely populated with many ATES systems. A total of 19 ATES systems are installed in an area of 3.8 km2 with a total of 76 functioning wells. The analysis focuses on the development of a coupled groundwater flow and heat transfer model over a period of 10 years. Results are then post-processed to evaluate efficiency of each individual well and system. Efficiency of the ATES systems has ranged between 68% and 87%. The analysis showed that efficiency tends, in general, to increase over time and stabilize at an asymptotic value after few years. Analysis of interference among individual wells of an ATES system and wells of other systems showed that interference could, in fact, have a positive impact on the efficiency of a well/system. Interference can increase efficiency of an ATES system since it can help in trapping energy (cold or warm) within the capture zone of all operating ATES systems. In the study area, the interference phenomenon affects efficiency, in general, positively where it increases the efficiency of individually operating wells by a maximum of 20%. However, the phenomenon also affects efficiency of some wells negatively where it reduces the efficiency of individually operating wells by a maximum of 25%. In average, systems in the study area are positively affected by interferences among each other with an overall average of 3.2% for all wells (over the 10 years operation period). [Copyright &y& Elsevier]

Abstract: In a building market oriented toward ever greater energy efficiency, the improvement of European Directive 31 at the national and regional levels accelerates Europe''s transition to near zero and zero energy buildings. Because the directive''s rules and definitions are still subject to discussion and debate at the international level, the implementation and the monitoring of pilot experiments can provide useful information to manage the complexity inherent in this new generation of buildings. This paper, by starting out with an examination of state of the art near zero- and zero energy buildings, describes a pilot certification scheme promoted by the Province of Milan (Italy) and implemented in Italy in collaboration with the local builders association. A case study of the application of this new procedure, which uses a quality-driven approach, is then described and discussed. The certification process proposed highlights the fundamental role of contribution of renewable energy sources in achieving high performance standard of zero energy buildings. [Copyright &y& Elsevier]

Abstract: Energy efficiency is a primary consideration when designing off-grid renewable energy systems including portable micro-grids. This study focuses on characterizing the potential benefits associated with using energy efficient exterior area lighting commonly associated with remote installations. Light emitting diode (LED) luminaires are becoming more commercially available, and this study compares two LED products designed for exterior lighting to traditional metal halide lamps. The characterization focuses on the use of a diesel generator, battery bank, and a bank of ultra capacitors (UCAPs) to power the lights because these systems are also used to generate or store energy at renewable energy-powered micro-grids. This field-based study quantifies the illuminance provided by each lighting system, diesel consumption rates associated with powering the lights and/or charging the batteries and UCAPs, and the time of operation for each lighting system when powered by a single discharge cycle of the batteries and UCAPs. The energy efficiency benefit of the LED luminaires is offset by their lower illuminance. However, a comparison of lighting standards for specific purposes such as security lighting indicates that LEDs may be appropriate for applications where a metal halide system would provide significantly more illumination than required at a much higher energy cost. For those purposes where higher levels of illuminance are required, the data presented in the paper may be useful in designing a renewable energy-powered micro-grid that uses multiple LED fixtures to illuminate an exterior area that is currently illuminated by a single metal halide light stand. [Copyright &y& Elsevier]

Abstract: An energy efficiency and control analysis is given for application of a transparent electric curtain for dust mitigation on a solar panel. The electric curtain technique has been proposed by NASA as an effective active method for dust removal from solar panels in planetary and lunar exploration, and this method also has potential for mitigation of dust build-up on terrestrial solar panels in dry environments. Since energy expenditure rate required for electric curtain operation can be significantly higher than the energy capture rate from a solar panel, a control scheme for activation and deactivation of the electric curtain is necessary to achieve optimal net energy capture. The control method examined in the current paper is one in which the electric curtain is activated when the panel output voltage decreases to a fraction of the clean panel output voltage and deactived when the output voltage exceeds a second output voltage fraction . A combination of theoretical and computational approaches is used to determine how the energy efficiency changes with change in the threshold voltage ratios. A scaling analysis is developed that identifies a single key dimensionless parameter that influences the efficiency results. Optimal values of turn-on and turn-off voltage ratio are determined in terms of this parameter, and it is demonstrated that the efficiency decreases rapidly as the turn-off voltage ratio is raised above the optimal value. All of the efficiency predictions for a given mitigation velocity profile are collapsed onto a single curve with appropriate choice of the scaling parameters, which is then used to develop an optimal control criterion. [Copyright &y& Elsevier]

Abstract: Increasing requirements for energy performance in new buildings mean the cost of incorporating energy-saving in buildings is also increasing. Building designers thus need to be aware of the long-term cost-effectiveness of potential energy-conserving measures. This paper presents a simplified and transparent economic optimisation method to find an initial design proposal near the economical optimum. The aim is to provide an expedient starting point for the building design process and more detailed economic optimisation. The method uses the energy frame concept to express the constraints of the optimisation problem, which is then solved by minimising the costs of conserving energy in all the individual energy-saving measures. A case example illustrates how the method enables designers to establish a qualified estimate of an economically optimal solution. Such an estimate gives a good starting point for the iterative design process and a more detailed economic optimisation. Furthermore, the method explicitly illustrates the economic efficiency of the individual building elements and services enabling the identification of potentials for further product development. [Copyright &y& Elsevier]

Abstract: This work presents an experimental comparison of two algorithms developed in order to maximize the output power from a photovoltaic (PV) system for the same given set of conditions. The maximum power point tracking (MPPT) methods proposed in this study are two extended algorithms: Perturb and Observe and Incremental Conductance. The numerical modelling of the PV system shows the MPPT interest and then the extended MPPT algorithms are highlighted. In this paper, a PV system based on a boost converter as MPPT device is considered. A programmable DC electronic load is fed by two identical PV systems in which the MPPT control converter algorithms are different. This experimental platform operates under the same conditions such as changing solar radiation and cell temperature. The experimental results obtained with a dSPACE controller board show the MPPT energy efficiency of the proposed algorithms. [Copyright &y& Elsevier]

Abstract: Commercialization efforts to diffuse sustainable energy technologies (SETs 1 [1] The SETs can be viewed as a portfolio of technologies, which are expected to use renewable energy resources as input to produce modern energy carriers. ) have so far remained as the biggest challenge in the field of renewable energy and energy efficiency. Limited success of diffusion through government driven pathways urges the need for market based approaches. This paper reviews the existing state of commercialization of SETs in the backdrop of the basic theory of technology diffusion. The different SETs in India are positioned in the technology diffusion map to reflect their slow state of commercialization. The dynamics of SET market is analysed to identify the issues, barriers and stakeholders in the process of SET commercialization. By upgrading the ‘potential adopters’ to ‘techno-entrepreneurs’, the study presents the mechanisms for adopting a private sector driven ‘business model’ approach for successful diffusion of SETs. This is expected to integrate the processes of market transformation and entrepreneurship development with innovative regulatory, marketing, financing, incentive and delivery mechanisms leading to SET commercialization. [Copyright &y& Elsevier]

Abstract: Over 1 year, private swimming pools in Australia will typically consume 1680GWh of electricity, producing 2130kt of CO2. Redesigning a pool''s filtration system and using it more efficiently can reduce the energy use, and hence the CO2 production, by a significant amount. This paper describes experimental measurements carried out on a new design of pool pump system. Initial experiments using a variable frequency drive (VFD) with a standard, single phase pump/motor system have achieved energy savings of 40%. Utilising a VFD and a three phase pump/motor energy savings of 61% have been achieved, without degrading the system performance. [Copyright &y& Elsevier]

Abstract: Energy use in the built environment is globally recognized as a key issue for sustainable urban development. In tempered-cold arid regions with a generous solar resource, adequate design and technology can substantially reduce the energy demand for space and water heating in urban buildings. This study assessed the solar potential of low-density urban environments in the city of Mendoza, Argentina. The results of the study will be used to develop technical guidelines for urban and energy planning agencies and professionals involved in the production of habitat. The study included the following successive steps: (i) selection of a representative sample of analysis units (city blocks); (ii) selection of a series of urban and building variables; (iii) definition of indicators accounting for solar masking, building''s potential use of the solar radiation on the whole urban area, and availability of adequate collecting areas to satisfy high percentages of the energy demand in low-density urban environments; and (iv) insolation of potential collectors simulated by a graphic-computational model developed in the R+D unit. Only the results for solar space heating are presented in this paper. The results, direct and statistical, indicate that it is technically feasible to meet the target solar fractions. At the same time, by means of the solar recycling of existing building stocks, it is possible to considerably reduce the environmental impacts due to the extraction of materials from, and the disposal of solid wastes into, the ecosystem. [Copyright &y& Elsevier]