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• Analyzes South Asia's energy trilemma balancing energy access, security and sustainability. • Focuses on four major regional countries: India, Pakistan, Bangladesh, and Sri Lanka. • Identifies major challenges as lack of energy access, unreliable gird, and unaffordable prices. • Explores the prospects of renewable energy as the key toward a sustainable energy transition. • Presents stakeholder perspectives on crucial dynamics of energy transition. To address the faced challenges – i.e. rapidly growing energy needs, depleting fossil fuel reserves, surging energy prices, risks to security of supplies, and climate change – the World is targeting a sustainable energy transition. This energy transition is primarily propelled by a global decarbonization drive. South Asia, a developing region housing over 23% of the global population, faces the additional challenge of serious energy deprivation. The subject of energy transition has not been explored in the South Asian context in terms of drivers, challenges, and prospects. This paper investigates the prospects of sustainable energy transition in South Asia in terms of resources, consumption trends, and challenges encountered by countries in the region, particularly India, Bangladesh, Pakistan, and Sri Lanka. It also examines the sustainable and renewable energy options for the region. An original stakeholder survey provides salient behavioral insights into awareness, attitudes and opinions shaping societal response to energy transition. The findings of the study highlight the serious energy security issues faced by the region in terms of lack of access, inconsistent supplies, unreliable grids, and high energy prices. Renewables like solar energy, wind power, and hydropower have the potential to propel regional countries to energy and environmental sustainability. "Lack of consistent policies and regulations", "lack of political will" and "lack of investment" are found to be the three most important challenges to the energy transition. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present an improved way of collection and compilation of data about solid biomass consumption in households in order to improve accuracy of official energy statistics data. The accurate, timely and reliable energy data significantly contribute to the consistency in national energy statistics, energy balance, as well as for many other obligatory reporting procedures which are requested and prescribed by national and international standards. When compiling energy statistics, statistics on renewables, particularly biomass consumption, it is often the most questionable as little or no available official data exists in the country. According to the international standards and definitions, solid biomass covers organic, non-fossil material of biological origin which may be used as fuel for heat production or electricity generation. In households, the most commonly used biomass are fuelwood and wood residues. In the process of compiling national energy statistics, national institutions responsible for official energy statistics usually estimate biomass consumption based on the reports on fuelwood cuts in state forests and official biomass production, although it is known that consumption is much higher. Over the past two decades, Energy Institute Hrvoje Požar worked intensively on the energy consumption data collection and particularly on the development of the tailored-made surveying methods for different final energy consumption sectors, particularly for the household sector. The similar methods were recommended to national statistics institutes in the countries in the region when providing technical assistance in developing energy statistics. This paper describes the survey results and methods applied for the determination of energy consumption in households and particularly biomass consumption in three selected countries: Croatia, Bosnia and Herzegovina and Macedonia, and recommendations for the further improvements. [ABSTRACT FROM AUTHOR]

A vital element in making a sustainable world is correctly managing the energy in the domestic sector. Thus, this sector evidently stands as a key one for to be addressed in terms of climate change goals. Increasingly, people are aware of electricity savings by turning off the equipment that is not been used, or connect electrical loads just outside the on-peak hours. However, these few efforts are not enough to reduce the global energy consumption, which is increasing. Much of the reduction was due to technological improvements, however with the advancing of the years new types of control arise. Domestic appliances with the purpose of heating and cooling rely on thermostatic regulation technique. The study in this paper is focused on the subject of an alternative power management control for home appliances that require thermal regulation. In this paper a Model Predictive Control scheme is assessed and its performance studied and compared to the thermostat with the aim of minimizing the cooling energy consumption through the minimization of the energy cost while satisfying the adequate temperature range for the human comfort. In addition, the Model Predictive Control problem formulation is explored through tuning weights with the aim of reducing energetic consumption and cost. For this purpose, the typical consumption of a 24 h period of a summer day was simulated a three-level tariff scheme was used. The new contribution of the proposal is a modulation scheme of a two-level Model Predictive Control’s control signal as an interface block between the Model Predictive Control output and the domestic appliance that functions as a two-state power switch, thus reducing the Model Predictive Control implementation costs in home appliances with thermal regulation requirements. [ABSTRACT FROM AUTHOR]

At the early stage of photovoltaic plants feasibility study, the assessment of the power production and the technology performances is a necessity. To do so, engineers usually use software’s and prediction models. Plenty of models are available in the literature, nevertheless, the selection of the most suitable one to be use in a specific climate is a hard task since no study deals with the inter-comparison of the existing PV production models. In this paper, the output of 12 -from the most used- PV production models were evaluated, and their accuracy has been assessed versus one-year of ground measurements from a PV module at different time resolutions. Results show that the models developed by Twidell, Yamawaki and Nishioka -or M1, M2 and M3 as sited in the manuscript- are the most adequate to simulate the PV performances under semi-arid and hot climatic conditions, with an hourly nRMSE of 7.07% during spring, 4.23% during summer, 7.56% in autumn and 10.11% in winter. Furthermore, and based on site measurements, Mid-south of Morocco can be considered as a very good location for PV plants with a PR higher than 80% and an average efficiency of 16%. [ABSTRACT FROM AUTHOR]

• The study investigates HRES sizes to achieve NZEB status for a hotel building. • An optimization analysis of a hotel's grid-connected HRES is presented. • The PV/wind grid-connected system has the lowest NPC and LCOE. • The electricity price of the proposed HRES, at 2.1 ¢/kWh. • The Egypt's retail electricity prices of 6.9 ¢/kWh. The tourism sector is a key source of national income, and the use of renewable energy resources promotes green and sustainable tourism. In addition, ensuring a reliable supply and efficient use of clean energy is a primary objective of Egypt's Vision 2030, as it has a significant impact on the sustainable development and growth of the tourism sector in Egypt. Net-zero energy buildings (NZEBs) are a promising decarbonization effort as they reduce energy consumption while increasing the share of renewable energy. Therefore, it is worth investigating the opportunities for NZEBs applications in tourism sector. This paper presents an optimization analysis of a hotel's grid-connected hybrid renewable energy system (HRES) based on its technical, economical, and environmental prospects. Seven scenarios are considered for on-site generation to match the energy requirements of the specific hotel building. The proposed hybrid systems incorporate photovoltaic (PV), wind turbine (WT), and biogas generators into a grid-connected system for supplying power to a tourist hotel. The size of the microgrid system is optimized to decrease the net present cost (NPC) and levelized cost of electricity (LCOE). The results reveal that the PV/wind grid-connected system, with renewable energy generators consisting of 143 kW of photovoltaic modules and one 20 kW wind turbine with a hub height of 18 m, has the lowest NPC and LCOE. This hybrid energy system has a net present cost of 388 k$, which is significantly lower compared to the electricity grid's cost of 873 k$. The electricity price of the proposed HRES, at 2.1 ¢/kWh, is highly competitive with Egypt's retail electricity prices of 6.9 ¢/kWh. Moreover, grid-connected HRES can lower the pressure on the electricity grid arising from the feed-in of electricity from HRES. Furthermore, the proposed HRES will help slow climate change by reducing GHG emissions and fossil fuel usage. Finally, this study will provide valuable guidance for the practical application of NZEBs in Egypt as well as similar global zones. [ABSTRACT FROM AUTHOR]

The present paper aims to evaluate the performance of a solar district cooling system in typical Middle East climate conditions. A centralized cooling station is supposed to distribute chilled water for a residential compound through a piping network. Two different solar cooling technologies are compared: two-stage lithium-bromide absorption chiller ( 2sABS ) driven by Parabolic Trough Collectors ( PTCs ) vs. single-stage lithium-bromide absorption chiller ( 1sABS ) fed by Evacuated Tube Collectors ( ETCs ). A computer code has been developed in Trnsys® (the transient simulation software developed by the University of Wisconsin) to simulate on hourly basis the annual operation of the solar cooling system, including building thermal load calculation, thermal losses in pipes and control strategy of the energy storage. A solar fraction of 70% was considered to size the solar field aperture area and the chiller capacity, within a multi-variable optimization process. An auxiliary compression chiller is supposed to cover the peak loads and to be used as backup unit. The two different solar cooling plants exhibit strongly different performance. For each plant configuration, the model determined the optimal size of every component leading to the primary cost minimization. The solar district cooling configuration based on 2sABS and PTCs shows higher performance at Riyadh (KSA) climate conditions and the overall cost is 30% lower than the one of the single-stage absorption chiller plant. [ABSTRACT FROM AUTHOR]

Refrigeration systems are crucial in retail food stores to ensure appropriate merchandising of food products. This paper compares four different CO 2 refrigeration system configurations in terms of cooling performance, environmental impact, power consumption and annual running costs. The systems studied were the conventional booster refrigeration system with gas bypass (reference system), the all CO 2 cascade system with gas bypass, a booster system with a gas bypass compressor, and integrated cascade all CO 2 system with gas bypass compressor. The weather conditions of London, UK, and Athens, Greece, were used for the modelling of energy consumption and environmental impacts to represent moderate and warm climatic conditions respectively. The control strategies for the refrigeration systems were derived from experimental tests in the laboratory on a conventional booster refrigeration system. The results from the analysis showed that the CO 2 booster system with gas bypass compressor can provide best performance with 5.0% energy savings for the warm climate and 3.65% for the moderate climate, followed by the integrated cascade all CO 2 system with gas bypass compressor, with 3.6% and 2.1% savings over the reference system for the warm and moderate climates respectively. [ABSTRACT FROM AUTHOR]

Parameters identification of photovoltaic (PV) models based on measured current-voltage characteristic curves is significant for the simulation, evaluation, and control of PV systems. To accurately and reliably identify the parameters of different PV models, an improved JAYA (IJAYA) optimization algorithm is proposed in the paper. In IJAYA, a self-adaptive weight is introduced to adjust the tendency of approaching the best solution and avoiding the worst solution at different search stages, which enables the algorithm to approach the promising area at the early stage and implement the local search at the later stage. Furthermore, an experience-based learning strategy is developed and employed randomly to maintain the population diversity and enhance the exploration ability. A chaotic elite learning method is proposed to refine the quality of the best solution in each generation. The proposed IJAYA is used to solve the parameters identification problems of different PV models, i.e., single diode, double diode, and PV module. Comprehensive experiment results and analyses indicate that IJAYA can obtain a highly competitive performance compared with other state-of-the-state algorithms, especially in terms of accuracy and reliability. [ABSTRACT FROM AUTHOR]

• Forecast analysis of the behavior of air source heat pumps for the next 50 years for all climate zones. • The winter heating season is expected to shorten and the summer season to lengthen. • Winter operating hours will increase in very cold climates and decrease in temperate climates. • Rising temperatures will force air source heat pumps to work in extreme conditions for longer periods in hot climates. • Under extreme winter conditions, exceeding the TOL (operating limit temperature) occurs for an increasing number of hours. Climate change will impact the building sector, but the related consequences are not fully known, especially at energy system level. This paper investigates the effect of a changing climate on heat pumps, worldwide recognized as one of the most promising technology to decarbonize the building sector. Being highly dependent on outdoor temperature, the research aims to understand how air-source heat pumps (ASHPs) will perform within climate change depending on locations and scenarios. ASHPs are considered in several locations around the world selected to cover the climate variability of the Köppen-Geiger climate classification. Future projected climate scenarios to the years 2030, 2050, and 2070 are studied under three Representative Concentration Pathways (RCPs: 2.6, 4.5, 8.5) that reflect an increasing climate change severity. The forecast analysis is conducted in terms of ASHPs seasonal coefficients of performance, working hours, seasonal and annual energy consumption. Results show how a rising average temperature facilitates, in winter, the energy transition to the use of electric heat pumps to replace fossil fuels. However, differences are found among locations, scenarios, and RCPs. The research illustrates how the two effects of heating decrease and cooling increase offset or whether one seasonal consumption prevails and where this occurs. The general trend foresees a noteworthy reduction of winter energy consumption in all climate zones. Higher decreases are found for RCP 8.5 compared to RCP 2.6 and RCP 4.5 scenarios, for both radiant floor panels and fan coils, with most variations in Hanoi (-48,24 % in 2070) and Cairo (-39,59 % in 2070). Concurrently, a major rise is estimated in cooling consumption in almost each climate zone, with wider differences within RCP 8.5. In this scenario, the increase in summer energy consumption is more extreme, ranging from a minimum in Singapore (+4.20 %) and Mombasa (+4.66 %), to a maximum in Anchorage (+87.31 %), Reykjavik (+49.89 %) and Lethbridge (+56.53 %). This increase is only partly offset by the reduction in winter energy consumption, with an overall net increment in the forecasted building's energy consumption. [ABSTRACT FROM AUTHOR]

The energy demand for cooling and air conditioning systems is increasing worldwide, especially in regions with high solar radiation intensity. One of the reasons for this is the increase of comfort demands worldwide. The most cooling and air conditioning systems are the conventional electrically driven one type such as compression refrigeration machines and air conditioning systems. Through the huge electricity consumption for cooling and air conditioning, the environmental problems get bigger and bigger, because of carbon dioxide (CO 2) and other pollutant emissions. One of the possibilities to reduce the primary energy consumption is through the use of solar energy for driving the thermal driven absorption or adsorption refrigeration systems, or desiccant cooling. Another possibility is using solar energy to produce electrical energy and this can be used to drive the conventional refrigeration systems. Many research and developmental efforts in the last years have been done to enforce the spreading of solar-driven cooling systems. This paper will illustrate the state of the art about the energy consumption for cooling and air conditioning systems, available solar-driven cooling systems and the potential of the utilization of such systems in comparison to the conventional ones. Moreover, this paper highlights some different methods of optimization, which used to maximize the performance and minimize the cost. [ABSTRACT FROM AUTHOR]

Initially pushed by the European Union (EU) through the Europe 2020 strategy, the development of renewable energies is a strategic action aiming to limit climate changes and cut greenhouse gas emissions. National subsidies favored the diffusion of this new kind of energy sources, even if there are interesting economic opportunities also in non-subsidized markets. Renewable energy (RE) is a sustainable choice, but its management requires a proper analysis, both from political and operational levels. The aim of this paper is the assessment of European renewable energy source (RES) trajectory towards 2020, starting from historical values and through common scientific methods. In addition, a new reference framework is proposed, in order to evaluate RESs performances in Europe. The framework is based on three indicators: (i) share of energy from RESs in gross final energy consumption, (ii) REs primary production per capita and (iii) gross final consumption of REs per capita. Results could have practical implications for the decision makers involved in the management of energy sources throughout Europe and could be used for the comparison on a global scale. [ABSTRACT FROM AUTHOR]

Enhanced dissemination of information regarding energy saving and climate change targeted toward property owners is considered to be an important strategy in order to reach the Swedish national target of energy efficiency in the building sector by 2050. Here the municipality energy advisors and the national register for energy performance certificates can facilitate the mitigation of energy use in the building stock. So far few studies have focused on the practical road map to the national target of energy use on the city/district level and to the communication aspects with stakeholders in the creation of energy city models. In this paper a city energy model is developed based on the requests and need for visualization from a group of energy advisors. Six different scenarios are studied in order to analyze the possibility of reaching the energy targets specified by the government in the town of Kiruna. The results show that: (1) it is possible to automatically create city energy models using extract, transform and load tools based on spatial and non-spatial data from national registers and databases; (2) city energy models improve the understanding of energy use in buildings and can therefore be a valuable tool for energy advisors, real estate companies and urban planners. The case study of Kiruna showed that the proposed energy saving measures in the energy performance certificates need to be implemented and new buildings in the urban transformation must be of high energy standard in order to reach the national target in Kiruna. [ABSTRACT FROM AUTHOR]

One way to improve the efficiency of solar powered systems is to maximize the energy harvesting from the photovoltaic module by using a maximum power point tracking algorithm. The latter must be simple for implementation, fast and accurate to cope with fast changing atmospheric conditions and partial shading operations. The paper presents a new maximum power point tracking method based on Golden-Section Optimization technique for photovoltaic systems. The proposed method converges to the Maximum Power Point by interval shrinking. Initially, two points are selected from the search space whose boundaries are known, evaluated then a new point is accordingly generated. At given iteration the algorithm has a new narrowed interval bounded by the new point and one of the initial points according to the evaluation results. The algorithm stops iterating (interval shrinking) when the interval becomes small enough and the photovoltaic system is forced to operate at the average value of the last found interval without perturbing either the voltage or the duty cycle. This makes the photovoltaic system converges rapidly to the maximum power point without voltage or power oscillations around the maximum power point thereby lower energy waste. A comparison results with recently published work are provided to show the validity of the proposed algorithm under fast changing conditions and partial shading. [ABSTRACT FROM AUTHOR]

Energy consumption in heating and cooling around the world has been a major contributor to global warming. Hence, many studies have been aimed at finding new techniques to save and control energy through energy efficient measures. Most of this energy is used in residential, agricultural and commercial buildings. It is therefore important to adopt energy efficiency measures in these buildings through new technologies and novel building designs. These new building designs can be developed by employing various passive cooling systems. Earth pipe cooling is one of these which can assist to save energy without using any customary mechanical units. This paper investigates the earth pipe cooling performance in a hot humid subtropical climate of Rockhampton, Australia. A thermal model is developed using ANSYS Fluent for measuring its performance. Impacts of air velocity, air temperature, relative humidity and soil temperature on room cooling performance are also assessed. A temperature reduction of around 2 °C was found for the system. This temperature reduction contributed to an energy saving of a maximum of 866.54 kW (8.82%) per year for a 27.23 m 3 room. [ABSTRACT FROM AUTHOR]

While the climatic conditions of the Canary Islands (Spain) are highly favourable for wind and solar energy exploitation, the low freshwater reserves are a problem when considering the implementation of hydro-based systems. For this reason, the pumped hydro storage (PHS) systems that have been proposed on the islands and which aim to exploit the available freshwater include an additional seawater desalination process. Given this drawback, this paper proposes an original alternative: a reversible PHS facility which directly uses seawater with the system in this case located on the coast of Gran Canaria island. This facility would be used to manage and better integrate the energy generated by a wind farm into a weak insular electrical system. An analysis is also undertaken of the economic benefits the proposed wind-hydro system would entail for the island’s electrical system. As a result of the incorporation of the hydraulic unit, the contribution of the wind-hydro system in satisfying electricity demand is 29% higher than if a wind-only system is used. The electrical energy generation cost of the wind-hydro system amounts to 95.34 €/MW h, entailing an annual saving for the electrical system of 7.68 M€/year. [ABSTRACT FROM AUTHOR]

Ground source heat pumps (GSHP) have attracted increasing attention because of their high energy efficiencies. The aim of this paper is to study the performance of (GSHP) in future climate conditions (2040–2069) by using projected future hourly weather data of selected representative cities in the US to estimate future ground temperature change. The projected hourly weather data and estimated ground temperatures are input to an hourly simulation tool (TRNSYS and eQuest for this research), which provides reliable coupling of GSHP system and building performance. The simulation results show that global warming will decrease the energy efficiency of GSHP in US residential buildings because a rise in inlet and outlet water temperature is predicted for GSHP systems during the cooling season and because buildings will become more cooling dominated in the future. For office buildings, although the cooling performance of GSHP will not drop significantly under future climate, the overall energy efficiency for the system will decrease due to the increasing energy consumption of the ground loop pump. In the future, considering the significant ground heat imbalance for GSHP operation, GSHP will become less competitive both economically and technically than it is now in the context of US climate zones. [ABSTRACT FROM AUTHOR]

Architects and urban planners have been relying on geometry-based indices to design more energy efficient buildings for years. The advantage of such indices is their ease of use and capability to capture the relation of a few geometric variables with the building’s performance. However, such relation is usually found using only a few simple building models and considering only a few climate regions. This paper presents the analysis of six geometry-based building indices to determine their adequacy in eight different climate regions in Europe. For each location, three residential building design programs were used as building specifications. Two algorithms were employed to randomly generate and assess the thermal performance of three sets of 500 alternative building models. The results show that geometry-based indices only correlate with the buildings’ thermal performance according to specific climate regions and building design programs. [ABSTRACT FROM AUTHOR]

The accurate prediction of direct solar irradiance is essential in many solar energy applications, particularly those relying on concentrating solar technologies. The present paper is aimed at a detailed assessment of a large range of clear-sky solar radiation models under Algerian climate to select the more accurate one for estimating the performance of solar power projects where meteorological and radiometric measurement stations are not available. To this end, seventeen models have been reviewed and their performance compared to measured irradiance of Ghardaia (Southern Algeria). The validation methodology presented herein is very helpful for ranking the models. A new statistical accuracy indicator has been originally introduced to find out the most accurate ones. A thorough analysis of selected models has shown that the more complex models, that seem at first sight more sophisticated, are not necessary the most accurate; while simpler models depending on a limited number of parameters are more suitable. In other words, the suitability and accuracy of a model do not necessarily improve with an increase in the number of its parameters. This important finding is in good agreement with the previous published studies. This fact is important to take into account, in the case where measured data are not available, for the selection of the most suitable locations for the installation of the future concentrating solar power plants in Algeria or even in other countries. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) is a high-potential renewable energy technology for Kuwait to pursue due to high daily irradiation, and has garnered local attention in recent years due to the growing energy demand and concerns over climate change. As yet, no data are available regarding the actual performance of PV systems in Kuwait’s harsh environment. This paper presents a 12-month-long performance evaluation of the first 85.05 kW p and 21.6 kW p copper indium gallium selenide (CIGS) thin film, grid-connected PV systems on the rooftops of two schools. The schools’ monthly energy consumption and PV generation profiles, the actual performance of the PV plants, the effectiveness of automated cleaning systems on the power output, and the benefits of PV implementation in schools were analyzed and evaluated. Data analysis was applied to filter and normalize the data in order to identify the actual performance parameters. The findings of the study, based on solar irradiation collected, the performance of the module technology and the effectiveness of the automated cleaning systems, show that the performance ratio was maintained between 0.74 and 0.85. Furthermore, the minimum monthly energy yield of the PV systems was about 104 kW h/kW p . The annual average daily final yields of the PV systems in this study were 4.5 kW h/kW p /day. The results provided insight into the performance of CIGS grid-connected PV systems in Kuwait, and those data will be beneficial to the PV research community worldwide. School buildings, particularly for the rooftops, are a unique and important asset for urban PV system implementation, because they provide a combination of relatively large, unused, suitable areas, which would make distributed and effective solar power generation possible on the national level. [ABSTRACT FROM AUTHOR]

PV/T solar collector is an energy system designed to provide both thermal and electrical energies at the same time. In this paper, the dynamic simulation of a photovoltaic thermal collector is presented. The effect of different parameters, such as meteorological, design and optical parameters are investigated. Furthermore, evaluation and comparative economic analyses among different designs of PV/T sheet-tube collectors, conventional thermal solar collector and PV module is conducted under Monastir (Tunisia) climatic conditions. Numerical results show that the thermal and electrical efficiencies significantly depend on the studied parameters. It is also found that, in terms of economy, the uncovered PV/T collector yield the best performance among others. [ABSTRACT FROM AUTHOR]

Accurate mid-term electricity demand forecasting is critical for efficient electric planning, budgeting and operating decisions. Mid-term electricity demand forecasting is notoriously complicated, since the demand is subject to a range of external drivers, such as climate change, economic development, which will exhibit monthly, seasonal, and annual complex variations. Conventional models are based on the assumption that original data is stable and normally distributed, which is generally insignificant in explaining actual demand pattern. This paper proposes a new semiparametric additive model that, in addition to considering the uncertainty of the data distribution, includes practical discussions covering the applications of the external variables. To effectively detach the multi-dimensional volatility of mid-term demand, a novel piecewise smooth method which allows reduction of the data dimensionality is developed. Besides, a semi-parametric procedure that makes use of bootstrap algorithm for density forecast and model estimation is presented. Two typical cases in China are presented to verify the effectiveness of the proposed methodology. The results suggest that both meteorological and economic variables play a critical role in mid-term electricity consumption prediction in China, while the extracted economic factor is adequate to reveal the potentially complex relationship between electricity consumption and economic fluctuation. Overall, the proposed model can be easily applied to mid-term demand forecasting, and produce accurate and stable forecasts. [ABSTRACT FROM AUTHOR]

A photovoltaic-thermal (PVT) module is a combination of a photovoltaic (PV) panel and a thermal collector for co-generation of heat and electricity. An integrated collector-storage solar water heater (ICSSWH) system, due to its simple and compact structure, offers a promising approach for the solar water heating in the varied climates. The combination of the ICSSWH system with a PV solar system has not been reported. In this paper, simulation of an enhanced ICSSWH system combined with the PV panel has been conducted. The proposed design acts passive. Therefore, it does not use any photovoltaic driven water pump to maintain a flow of water inside the collector. The effects of the solar cell packing factor, the tank water mass and the collector area on the performance of the present PVT system have been investigated. The simulation results showed that the high solar cell packing factor and the tank water mass are caused to the high total PVT system efficiency. Also, larger area of the collector is resulted to lower total PVT system efficiency. [ABSTRACT FROM AUTHOR]

The thermal environment in outdoor public spaces and their level of use are strongly connected. The design of outdoor spaces, especially in urban areas, is very critical in Southern Europe due to their extended use during summertime where the urban heat island phenomenon deteriorates the microclimatic conditions. In this paper the main outcomes of outdoor spaces field surveys are presented, which were carried out in four different urban open spaces in Crete. On site measurements were implemented and a questionnaire was used in order to estimate the thermal comfort of visitors. Thermal indices like Predicted Mean Vote, Physiologically Equivalent Temperature, Standard Effective Temperature, Wet Bulb Globe Temperature are used to evaluate the features of urban microclimate and then are being compared in order to find the most suitable for the Mediterranean microclimate. This suggests another way of approach to the researcher and provides essential tools to the designer. [ABSTRACT FROM AUTHOR]

Driven by the security of supply and climate change concerns, decarbonisation of energy supply has become a priority for many countries. This study focuses on Mexico, the world's 14th largest economy, and considers the environmental implications of decarbonising its electricity supply. Eleven scenarios are considered for the year 2050 with different technology mixes and GHG reduction targets, ranging from stabilisation at the year 2000 level to a reduction of 60-85%. Unlike most energy scenario analyses which focus mainly on direct CO2 or GHG emissions, this paper presents the full life cycle impacts of electricity generation in 2050 considering ten environmental impacts which, in addition to global warming, include resource and ozone layer depletion, acidification, eutrophication, summer smog, human and eco-toxicity. The results indicate that continuing with business as usual (BAU) would double the current life cycle GHG emissions, even if annual electricity demand growth was reduced to 2.25% from the current 2.8%. Switching from the current fossil fuel mix to a higher contribution of renewables (55-86%) and nuclear power (up to 30%) would lead to a significant reduction of all ten life cycle impacts compared to the current situation and up to an 80% reduction compared to BAU. [ABSTRACT FROM AUTHOR]

The subject of publicly disclosing Greenhouse Gas (GHG) emissions by companies and organizations is gaining momentum and a variety of so called 'GHG Registries' have been developed in countries around the globe, while specific requirements are being adjusted to local circumstances and needs. Different GHG Registries are currently operating worldwide, either as mandatory or as voluntary programs. Israel launched a voluntary initiative in 2010 known as the Israel GHG Reporting and Registering System. The Israel GHG Reporting Protocol was prepared by the Ministry of Environmental Protection and the Energy and Environment cluster at the Samuel Neaman Institute, in cooperation with a wide range of stakeholders, including other governmental ministries, industry and local government representatives as well as non-governmental organizations. The Israel GHG Protocol is largely based on the World Resources Institute/World Business Council for Sustainable Development (WRI/WBCSD) corporate accounting standard and ISO 14064. While the decision to join the GHG registry in Israel is currently voluntary, once an organization has joined the registry it commits to calculate and report GHG emissions according to the registry's protocol and methodology guidance to allow for consistency in the reported data and for accurate comparison of the results. The Israeli program is intended to help develop capacities and tools for organizations, industry and various other private sector entities to manage their GHG emissions by annually calculating and submitting their emission inventories which will also help them to estimate the potential for emissions reduction. This paper focuses on the analysis of the GHG emission reports submitted for 2010, 2011 and 2012 by participating companies and organizations and on how these data enable the reporting organizations to develop their databases, improve their risk management capabilities and identify opportunities for energy and process efficiency improvements that could lead to GHG emissions reduction. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, comparative analysis of different type of photovoltaic thermal (PVT) air collector namely: (i) unglazed hybrid PVT tiles, (ii) glazed hybrid PVT tiles and (iii) conventional hybrid PVT air collectors have been carried out for the composite climate of Srinagar (India). The comparative study has been carried out in terms of overall thermal energy and exergy gain, exergy efficiency and carbon credit earned by different type of hybrid PVT air collectors. It has been observed that overall annual thermal energy and exergy gain of unglazed hybrid PVT tiles air collector is higher by 27% and 29.3% respectively as compared to glazed hybrid PVT tiles air collector and by 61% and 59.8% respectively as compared to conventional hybrid PVT air collector. It has also been observed that overall annual exergy efficiency of unglazed and glazed hybrid PVT tiles air collector is higher by 9.6% and 53.8% respectively as compared to conventional hybrid PVT air collector. On the basis of comparative study, it has been concluded that CO2 emission reduction per annum on the basis of overall thermal energy gain of unglazed and glazed hybrid PVT tiles air collector is higher by 62.3% and 27.7% respectively as compared to conventional hybrid PVT air collector and on the basis of overall exergy gain it is 59.7% and 22.7%. [Copyright &y& Elsevier]

Abstract: This paper deals with an experimental investigation of the effect of the working fluid inventory on the performance of the gravity assisted solar heat pipe. Measurements of solar flux and the temperature in different positions over the heat pipe have permitted us to evaluate the performance of the system for different working conditions. Results prove that the optimum performance is observed when the 2/3 of evaporator volume is filled with methanol. [Copyright &y& Elsevier]

Abstract: The coupled heat, air and moisture transfer between building envelopes and indoor air is complicated, and has a significant influence on the indoor environment and the energy performance of buildings. In the paper, a model for predicting coupled multi-zone hygrothermal-airflow transfer is presented. Both heat and moisture transfer in the building envelope and multi-zone indoor airflow are simultaneously considered; their interactions are modeled. The coupled system model is implemented into Matlab–Simulink, and is validated by using a series of testing tools and experiments. The new program is applied to investigate the moisture transfer effect on indoor air humidity and building energy consumption in different climates (hot-humid, temperate and hot-dry climates). The results show that not accounting for hygrothermal effects in modeling will result in overestimation of energy costs for hot and humid climate situations and possible over sizing of plant leading to inefficient operation. [ABSTRACT FROM AUTHOR]

Abstract: A great fraction of worldwide energy carriers and material products come from fossil fuel refinery. Because of the on-going price increase of fossil resources, their uncertain availability, and their environmental concerns, the feasibility of oil exploitation is predicted to decrease in the near future. Therefore, alternative solutions able to mitigate climate change and reduce the consumption of fossil fuels should be promoted. The replacement of oil with biomass as raw material for fuel and chemical production is an interesting option and is the driving force for the development of biorefinery complexes. In biorefinery, almost all the types of biomass feedstocks can be converted to different classes of biofuels and biochemicals through jointly applied conversion technologies. This paper provides a description of the emerging biorefinery concept, in comparison with the current oil refinery. The focus is on the state of the art in biofuel and biochemical production, as well as discussion of the most important biomass feedstocks, conversion technologies and final products. Through the integration of green chemistry into biorefineries, and the use of low environmental impact technologies, future sustainable production chains of biofuels and high value chemicals from biomass can be established. The aim of this bio-industry is to be competitive in the market and lead to the progressive replacement of oil refinery products. [Copyright &y& Elsevier]

Abstract: Deep ocean storage of CO2 could help reduce the atmospheric level of greenhouse gas as part of a climate change mitigation strategy. In this paper, a multiphase flow model of CO2 sequestration into deep ocean sediments was designed associated with the formation of CO2 hydrates. A simplified assumption was proposed to predict the critical time of CO2 leakage from marine sedimentary strata into seawater. Moreover, some principal parameters, which include the permeability, anisotropy, total injection amount, and length of the injection part of wellbores, were investigated by numerical simulations. The numerical estimates are used to assess the feasibility and effectiveness of CO2 storage in deep ocean sediments. Accurately predicting the actual fate of liquid CO2 sequestered into the marine sedimentary strata at depths greater than 500m is complicated by uncertainties associated with not only the chemical–physical behavior of CO2 under such conditions but also the geo-environment of disposal sites. Modeling results have shown some implications that the effectiveness of CO2 ocean sequestration depends mainly on the injection conditions (such as injection rate, total injection amount, and the depth of injection), the site geology (such as permeability and anisotropy of disposal formations), and the chemical-physical behavior of CO2 in marine environment. [Copyright &y& Elsevier]

Abstract: This paper focuses on the potential upcoming impacts of climate change in the 21st century on electricity demand at regional/national levels for regions where topography and location result in large differences in local climate. To address this issue, a regional climate model, PRECIS, has been used to predict future climatic conditions under different emissions scenarios (namely A2 and B2 of the IPCC special report on emissions scenarios (SRES)) as an input to a multiple regression model of the sensitivity of electricity demand in the Greek interconnected power system to climate and socio-economic factors. The economic development input to the multiple regression model follows the same storylines of the SRES scenarios upto 2100 and includes sub-scenarios to cover larger and smaller economic development rates. The results of the analysis indicate an increase of the annual electricity demand attributable solely to climate change of 3.6–5.5% under all scenarios examined, most of which results from increased annual variability with substantial increases during the summer period that outweighs moderate declines estimated for the winter period. This becomes more pronounced if inter-annual variability, especially of summer months, is taken into consideration. It was also found that in the long run, economic development will have a strong effect on future electricity demand, thus increasing substantially the total amount of energy consumed for cooling and heating purposes. This substantial increase in energy demand with strong annual variability will lead to the need for inordinate increases of installed capacity, a large percentage of which will be underutilized. Thus, appropriate adaptation strategies (e.g. new investments, interconnections with other power systems, energy saving programmes, etc.) need to be developed at the state level in order to ensure the security of energy supply. [Copyright &y& Elsevier]

This paper outlines a methodological framework for the economic evaluation of CO2 emissions abatement policies and measures in the residential sector, taking into consideration both economic and social costs/benefits. The approach includes two stages: first, the measures under consideration are evaluated on the basis of a cost effectiveness analysis, which takes into account only the related net financial costs, thus highlighting win–win actions (i.e. measures presenting an economic benefit for end users without the provision of any economic subsidies or other similar policies); and second, the measures are re-evaluated using an integrated cost benefit analysis (where both the private and external costs/benefits are taken into account). The economic performance of the measures examined incorporates the effects of a variety of parameters, such as the region’s climate, size and age of buildings, etc., which significantly affect the resulting ranking. The implementation of this framework in the Greek residential sector identified and prioritized a significant emissions reduction potential, which could be achieved with win–win measures and/or interventions that present a net social benefit. Measures with negative economic cost but positive net social benefit for the majority of the buildings examined include: (i) regular inspection of central heating boilers, (ii) use of thermostats in central heating boilers, (iii) sealing of openings, (iv) installation of solar collectors for hot water etc. The monetization of environmental benefits is shown to provide a powerful tool for highlighting priority actions in the context of a climate change mitigation policy. [Copyright &y& Elsevier]

Climate change issues and building energy use implications in subtropical Hong Kong were examined. A total of 40 years (1961–2000) of measured hourly temperature data were gathered and analysed. Three different parameters were examined, namely mean temperature, cumulative frequency of occurrence and cooling degree days (CDD). It was found that there was an underlying trend of temperature rise in recent years. Such temperature increase tended to occur more frequently during the winter period and mid-season than the summer months. The slight increase in CDD during the last 20 years suggested that cooling requirements and, hence, energy use for air conditioning might be affected if the trend persisted. The frequency of occurrence analysis, however, revealed no significant changes in the outdoor design conditions, and peak building cooling loads were expected to remain unchanged. This paper presents the work and discusses the energy use implications. [Copyright &y& Elsevier]

Emissions reduction in industrial processes, i.e. clean production, is an essential requirement for sustainable development. Fossil fuel combustion is the main emission source for gas pollutants, such as NOX, SO2 and CO2, and coal is now a primary energy source used worldwide with coal combustion being the greatest atmospheric pollution source in China. This paper analyzes flue gas cleaning by ammonia scrubbing (FGCAS) for power plants to remove gaseous pollutants, such as NOX, SO2 and CO2, and presents the conceptual zero emission design for power plants. The byproducts from the FGCAS process can be used in agriculture or for gas recovery. Experimental results presented for SO2 removal from the simulated flue gas in a continuous flow experiment, which was similar to an actual flue gas system, showed that the effectiveness of the ammonia injection or scrubbing depends on the temperature. The FGCAS process can effectively remove SO2, but the process temperature should be below 60 °C or above 80 °C for SO2 reduction by NH3 scrubbing. [Copyright &y& Elsevier]

• ERA5 reanalysis and multi-ensemble EURO-CORDEX models are used for simulating onshore and offshore wind power output. • All wind speed models show significant bias that imposes a method for bias-correction. • Wind turbine improvements are evaluated. • Wind power intermittency and spatial-decorrelation effects are analyzed and quantified. • Climate change has little impact on the wind power output and even the sign of the change varies among climate models. Wind power is developing rapidly because of its potential to provide renewable electricity and the large reduction in installation costs during the past decade. However, the high temporal variability of the wind power source is an obstacle to a high penetration in the electricity mix as it makes difficult to balance electricity supply and demand. There is therefore a need to quantify the variability of wind power and also to analyze how this variability decreases through spatial aggregation. In the context of climate change, it is also necessary to analyze how the wind power potential and its variability may change in the future. One difficulty for such objective is the large biases in the modeled winds, and the difficulty to derive a reliable power curve. In this paper, we propose an Empirical Parametric Power Curve Function (EPPCF) model to calibrate a power curve function for a realistic estimate of wind power from weather and climate model data at the regional or national scale. We use this model to analyze the wind power potential, with France as an example, considering the future wind turbine evolution, both onshore and offshore, with a focus on the production intermittency and the impact of spatial de-correlations. We also analyze the impact of climate change. We show that the biases in the modeled wind vary from region to region, and must be corrected for a valid evaluation of the wind power potential. For onshore wind, we quantify the potential increase of the load factor linked to the wind turbine evolution (from a current 23% to 30% under optimistic hypothesis). For offshore, our estimate of the load factor is smaller for the French coast than is currently observed for installed wind farms that are further north (around 35% versus 39%). However, the estimates vary significantly with the atmospheric model used, with a large spatial gradient with the distance from the coast. The improvement potential appears smaller than over land. The temporal variability of wind power is large, with variations of 100% of the average within 3–10 h at the regional scale and 14 h at the national scale. A better spatial distribution of the wind farms could further reduce the temporal variability by around 20% at the national scale, although it would remain high with respect to that of the demand. The impact of climate change on the wind power resource is insignificant (from +2.7% to −8.4% for national annual mean load factor) and even its direction varies among models. [ABSTRACT FROM AUTHOR]

• Environmental life cycle impacts are assessed for current and future heating. • Electric air source heat pumps are the lowest-impact option to decarbonise heating. • Boilers using H 2 from natural gas with carbon capture cannot achieve Net Zero. • Boilers using hydrogen from electrolysis have the highest impacts in 17 categories. • The proposed 2050 Net Zero heating mixes reduce GHG emissions by 84–94% per kWh. Heating and hot water within buildings account for almost a quarter of global energy consumption. Approximately 90% of this heat is derived directly from the combustion of fossil fuels, primarily natural gas, leading to the unabated emission of carbon dioxide. This paper assesses the environmental sustainability of a range of heating technologies and scenarios on a life cycle basis. The major technologies considered are natural gas boilers, air source heat pumps, hydrogen boilers and direct electric heaters. The scenarios use the UK as an example due to its status as a major economy with a legally-binding net-zero carbon target for 2050; they consider plausible future electricity and natural gas mixes, including the potential growth of domestic shale gas. The environmental impacts are estimated using ReCiPe 2016. Current gas boilers have a climate change impact of 220 g CO 2 eq./kWh of heat, which could fall to 64 g CO 2 eq./kWh for boilers fuelled by hydrogen derived from natural gas with carbon capture. Heat from electric air source heat pumps or hydrogen from electrolysis can achieve net zero with a decarbonised electricity mix, but electrolysis has the highest energy demand of all options which leads to the highest impacts across 17 of the 19 categories. Despite their high carbon emissions, gas boilers remain the lowest impact option across 12 categories as they avoid the impacts related to electricity generation, including metal depletion, toxicities and eutrophication. By 2050, the best performing scenario sees the climate change impact of the heating mix fall by 95%; this is achieved by prioritising electric air source heat pumps without hydrofluorocarbon refrigerants, alongside demand reduction. The results show that, if infrastructure and financial challenges can be overcome, there are several viable decarbonisation strategies for heating, with heat pumps offering the most environmentally sustainable option of those considered here. However, increased renewable electricity demand may worsen some environmental impacts compared to natural gas boilers. [ABSTRACT FROM AUTHOR]

• Thermal conductivity & specific heat capacity of carbon nanofluids enhanced with particle loading. • The energy cost reduced by 10.37%, using nanofluids based heat transfer in solar thermal systems. • Thermal energy storage volume reduced by 21%, using carbon nanotubes based heat transfer fluids. • The effect of pressure on heat capacity and thermal conductivity remains marginally low till 100 bar. • Water nanofluid thermal conductivity increased till 130 °C and then it starts reducing with temperature. Nanofluids are of paramount importance for the development of efficient and competitive heat transfer fluids. The research paper presents a comprehensive study of the thermal properties for developing water and Therminol oil-based nanofluids to operate at high pressure and temperature, which will ultimately support the development of a more comprehensive understanding for nanofluids based heat transport phenomena. Multiwall carbon nanotubes were suspended in water and Therminol 66 at three different weight concentrations from 0.05% to 0.5% with Acacia Gum and oleic acid as surfactants for water and Therminol 66, respectively. The experimental results show more than a 35% enhancement in the thermal conductivity for both the water-based nanofluids and Therminol-66 based nanofluids. This thermal conductivity was also found to be similar with small increment at high pressures for both the base fluid and nanofluids, up to 70 bar pressure and 300 °C. Furthermore, the simulations carried out on parabolic trough collector solar thermal system using nanofluid properties and system advisor model software, showed an enhancement in energy production along with 10.37% reduction in real power purchase agreement price as well as 21% reduction on the thermal energy storage volume. [ABSTRACT FROM AUTHOR]