The paper describes a novel approach in battery storage system modelling. Different types of lithium-ion batteries exhibit differences in performance due to the battery anode and cathode materials being the determining factors in the storage system performance. Because of this, the influence of model parameters on the model accuracy can be different for different battery types. These models are used in battery management system development for increasing the accuracy of SoC and SoH estimation. The model proposed in this work is based on Tremblay model of the lithium-ion battery. The novelty of the model lies in the approach used for parameter estimation as a function of battery physical properties. To make the model perform more accurately, the diffusion resistance dependency on the battery current and the Peukert effect were also included in the model. The proposed battery model was validated using laboratory measurements with a LG JP 1.5 lithium-ion battery. Additionally, the propose... [more]

The article presents the results of research on the efficiency of photovoltaic (PV) modules cooled with water. The aim of the experiment was to improve the working conditions of solar modules. A temperature decrease was obtained for the PV module by pouring cool tap water onto the upper surface of the modules, either in imitation of rain or as a water film. The power of the cooled and non-cooled devices were then compared. The temperature of the cooled modules dropped to almost 25 °C, whilst the temperature of the non-cooled module was 45 °C. The best results were achieved by cooling modules with a water film, since there were no water splashes, and the continuous cooling of the surface leads to a 20% increase in power. During the test, the non-cooled module attained a maximum power of 105.3 W/m2, compared to 125.5 W/m2 for its cooled counterpart. Cooling the module, therefore, resulted in a power increase of 20.2 W/m2. The results of the work may be of particular interest for small in... [more]

To manage greenhouse gas emissions, directives on renewable energy usage have been developed by the European Commission with the objective to reduce overall emissions by 40% by 2030 which presents a significant potential for renewable energy sources. At the same time, it is a challenge for these energy technologies which can only be solved by integrated solutions. Carbon capture and storage combined with geothermal energy could serve as a novel approach to reduce CO2 emissions and at the same time facilitate some of the negative impacts associated with fossil fuel-based power plants. This study focuses on the technical and economic feasibility of combining these technologies based on a published model, data and market research. In the European Union, Germany is the most energy intensive country, and it also has an untapped potential for geothermal energy in the northern as well as the western regions. The CO2 plume geothermal system using supercritical carbon dioxide as the working flu... [more]

CO2 methanation is typically carried out using Ni-supported catalysts containing promoters such as alkali or alkali-earth metals to improve their properties. In this work, bimetallic Ni-based USY zeolite catalysts containing alkali (Li, K and Cs) and alkali-earth (Mg, Ca) metal compounds were prepared using the same conditions (15 wt% of metals; co-impregnation), characterized by N2 sorption, XRD, TGA, CO2 adsorption−desorption, DRS UV-Vis and H2-TPR, and finally applied in CO2 methanation reaction (86,100 mL h−1 g−1, PCO2 = 0.16 bar, H2:CO2 = 4:1). For each group, the effects of the second metal nature on the properties and performances were assessed. Alkali metals incorporation induced considerably low catalytic performances (CH4 yields < 26%), attributed to their negative impact on zeolite structure preservation. On the contrary, alkali-earth metal-containing catalysts exhibited lower structural damage. However, the formation of Ni-Mg mixed oxides in Ni-Mg/USY catalyst and CaCO3... [more]

Perovskites are well-known oxides for thermochemical energy storage applications (TCES) since they show a great potential for spontaneous O2 release due to their non-stoichiometry. Transition-metal-based perovskites are particularly promising candidates for TCES owing to their different oxidation states. It is important to test the thermal behavior of the perovskites for TCES applications; however, the amount of sample that can be used in thermal analyses is limited. The use of redox cycles in fluidized bed tests can offer a more realistic approach, since a larger amount of sample can be used to test the cyclic behavior of the perovskites. In this study, the oxygen release/consumption behavior of Mn- or Cu-substituted SrFeO3 (SrFe0.5M0.5O3; M: Mn or Cu) under redox cycling was investigated via thermal analysis and fluidized bed tests. The reaction enthalpies of the perovskites were also calculated via differential scanning calorimetry (DSC). Cu substitution in SrFeO3 increased the perf... [more]

Carbon emissions are a prominent issue for sustainable energy production and management. Energy policies under the growing competitive environment could change the priorities of emission reduction and investment decisions. This paper aims to forecast carbon emissions from China and to rank the importance of carbon emissions with interval type 2 (IT2) fuzzy sets (FS) for sustainable energy investments. For this purpose, the quadratic model is applied to measuring emission trends and the Qualitative Flexible Multiple Criteria Method (QUALIFLEX) is used for measuring sustainable energy investment alternatives by the several emission levels. Forecasted values of 29 provinces in China are converted into the linguistic and fuzzy numbers based on IT2 FS respectively to measure the priorities of emission reduction for sustainable economies. The novelty of this paper is to propose a hybrid decision-making approach based on quadratic modeling and the QUALIFLEX method and to discuss the overall e... [more]

This study explores the relationship between the morphology and solar potential of high-density areas in the subtropics high density city known as Shanghai. 1260 parametric scenarios were modeled and their solar irradiation potentials were simulated via a customized workflow. In addition to the five well-known morphological parameters, this study proposed two innovative morphological parameters SSU600 and SSU400, which captured the solar receiving properties of the building envelopes and could be easily calculated based on the meteorological data. For analytical purposes, the previously morphological parameters were considered as independent variables, whereas the new solar performance indicators SRU600 and SRU400 were both examined as dependent variables. The correlation analysis results suggested that the new morphological parameters displayed a strong linear correlation with the corresponding solar performance indicators, surpassing all the other morphological parameters. Two predic... [more]

In the present work, the electrical and thermal performances of a newly designed PV/T (photovoltaic/thermal) air collector, which was proposed and fabricated by the author, have been investigated experimentally in the natural weather conditions. The PV/T air collector has a single-pass double-flow air channel. Also, a non-uniform cross-section transverse rib was attached at the back surface of the PV (photovoltaic) module to improve the heat transfer performance between the PV module and flowing air. The experiment was carried out in an outdoor field on a clear day with various air mass flow rates ranges from 0.0198 kg/s to 0.07698 kg/s. In the results, it was found that the average thermal efficiency of the PV/T collector increased from 35.2% to 56.72% as the air mass flow rate increased. The average electrical efficiency also increased from 14.23% to 14.81% with an increase in an air mass flow rate, but the effect of air mass flow rate on the increase in electrical efficiency was inc... [more]

Increasing concentrations of greenhouse gases in the atmosphere are leading to increased production and use of biofuels. The industrial development of biodiesel production and the use of biodiesel in the EU transport sector have been ongoing for almost two decades. Compared to mineral diesel production, the process of producing biodiesel is quite complex and expensive, and the search for new raw materials and advanced technologies is needed to maintain production value and expand the industrial production of biodiesel. The purpose of this article is to review the application possibilities of one of the new technologies—simultaneous extraction of oil from oily feedstock and transesterification (in situ)—and to evaluate the effectiveness of the abovementioned process under various conditions.

This paper presents a battery-aware stochastic control framework for residential energy management systems (EMS) equipped with energy harvesting, that is, photovoltaic panels, and storage capabilities. The model and control rationale takes into account the dynamics of load, the weather, the weather forecast, the utility, and consumer preferences into a unified Markov decision process. The embedded optimization problem is formulated to determine the proportion of energy drawn from the battery and the grid to minimize a cost function capturing a user-defined tradeoff between battery degradation and financial expense by user preferences. Numerical results are based on real-world weather data for Golden, Colorado, and load traces. The results illustrate the ability of the system to limit battery degradation assessed using the Rain flow counting method for lithium ion batteries.

Copper coordination complexes have emerged as a group of transition metal complexes that play important roles in solar energy conversion, utilization and storage, and have the potential to replace the quintessential commonly used transition metals, like Co, Pt, Ir and Ru as light sensitizers, redox mediators, electron donors and catalytic centers. The applications of copper coordination compounds in chemistry and energy related technologies are many and demonstrate their rightful place as sustainable, low toxicity and Earth-abundant alternative materials. In this perspective we show the most recent impact made by copper coordination complexes in dye-sensitized solar cells and other energy relevant applications.

This study proposes a method to evaluate the impact of transmission congestion on the flexibility of a power system, based on the ramping capability shortage expectation (RSE). Here, flexibility refers to the ability to retain a power balance in response to changes in the net load. The flexibility issue arises due to the extensive integration of renewable energy resources; specifically, the higher the degree of integration, and the greater the variability and uncertainty in the power system. Flexibility is further limited by the net transfer capacity (NTC) of transmission lines. Here, we propose a method capable of capturing the extent to which transmission congestion affects the power system, to identify transmission reinforcement options for improved flexibility. In Korea, transmission congestion occurs frequently in regions to the north and southeast. A case study for a Korean power system in 2030 was conducted. Simulation results showed that the impact of transmission reinforcement... [more]

The use of passive solutions for building envelopes represents an important step toward the achievement of more efficient and zero-energy building targets. Trombe walls are an interesting and viable option for the reduction of building energy requirements for heating, especially in cold climates. This study presents the experimental analysis of an innovative Trombe wall configuration, named a thermo-diode Trombe wall, which was specifically designed to improve the energy efficiency by providing a proper level of insulation for the building envelope. Such a design is essential in cold climates to limit the thermal losses whilst increasing solar heat gains to the heated spaces. An experimental campaign was conducted from December to March that involved monitoring the external climatic conditions and the main thermal parameters to assess the thermal performance of the proposed solution. The results demonstrated that in the presence of solar radiation, the thermo-diode Trombe wall was able... [more]

Coconut husks with the shells attached are potential bioenergy resources for fuel-constrained communities in Ghana. In spite of their energy potential, coconut husks and shells are thrown away or burned raw resulting in poor sanitation and environmental pollution. This study focuses on quantifying the waste proportions, calorific values and pollutant emissions from the burning of raw uncharred and charred coconut wastes in Ghana. Fifty fresh coconuts were randomly sampled, fresh coconut waste samples were sun-dried up to 18 days, and a top-lit updraft biochar unit was used to produce biochar for the study. The heat contents of the coconut waste samples and emissions were determined. From the results, 62−65% of the whole coconut fruit can be generated as wastes. The calorific value of charred coconut wastes was 42% higher than the uncharred coconut wastes. PM2.5 and CO emissions were higher than the WHO 24 h air quality guidelines (AQG) value at 25 °C, 1 atmosphere, but the CO concentra... [more]

Liquefied natural gas (LNG) is one of the hydrocarbon fuels with the least carbon footprint having a rapidly rising global share in the prime energy market. LNG processing for transportation at longer distances works under cryogenic conditions, especially when used for liquefaction and gasification applications. The supply chain of the eco-environmental friendly hydrocarbon is heavily dependent on the processing plant used for liquefaction and subsequent re-gasification of the natural gas. Plate-fin heat exchangers are extensively used in the LNG industry for both re-gasification as well as liquefaction processes. The exchange of heat during the process of natural gas phase change involves plate-fin heat exchangers working under cryogenic low-temperature conditions. The heat exchangers are designed to have brazed joints that are most vulnerable to failure under these temperature conditions. One failure of such a joint can not only hinder the supply chain but also may result in fire and... [more]

This study developed a microwave-mediated noncatalytic esterification of oleic acid for producing ethyl biodiesel. The microwave irradiation process outperformed conventional heating methods for the reaction. A highest reaction conversion, 97.62%, was achieved by performing esterification with microwave irradiation at a microwave power of 150 W, 2:1 ethanol:oleic acid molar ratio, reaction time of 6 h, and temperature of 473 K. A second-order reaction model (R2 of up to 0.997) was established to describe esterification. The reaction rate constants were promoted with increasing microwave power and temperature. A strong linear relation of microwave power to pre-exponential factors was also established, and microwave power greatly influenced the reaction due to nonthermal effects. This study suggested that microwave-assisted noncatalytic esterification is an efficient approach for biodiesel synthesis.

This article aims to present the results from studies on the energy performance upgrade of buildings and facilities located in Crete, Greece, in a typical Mediterranean climate. In Mediterranean islands, the most buildings remain uninsulated, classified in C or even lower energy performance rank. In this article four reference buildings and one sports facility are investigated: a residential building, a municipality building, a school building, a museum and the Pancretan Stadium. Detailed calculations based on the computational simulation of each examined facility were executed, giving accurate results on the heating and cooling loads, both for the existing conditions and after the integration of the proposed passive measures. Thorough dimensioning and energy calculations have been executed for specific active energy systems too, particularly proposed for each examined case. With this parametric approach, the article indicates the effect and the economic efficiency of the proposed acti... [more]

Towards the middle of the current century, the DEMOnstration power plant, DEMO, will start operating as the first nuclear fusion reactor capable of supplying its own loads and of providing electrical power to the European electrical grid. The presence of such a unique and peculiar facility in the European transmission system involves many issues that have to be faced in the project phase. This work represents the first study linking the operation of the nuclear fusion power plant DEMO to the actual requirements for its correct functioning as a facility connected to the power systems. In order to build this link, the present work reports the analysis of the requirements that this unconventional power-generating facility should fulfill for the proper connection and operation in the European electrical grid. Through this analysis, the study reaches its main objectives, which are the definition of the limitations of the current design choices in terms of power-generating capability and the... [more]

The acquisition of inductive power transfer (IPT) technology in commercial electric vehicles (EVs) alleviates the inherent burdens of high cost, limited driving range, and long charging time. In EV wireless charging systems using IPT, power electronic converters play a vital role to reduce the size and cost, as well as to maximize the efficiency of the overall system. Over the past years, significant research studies have been conducted by researchers to improve the performance of power conversion systems including the power converter topologies and control schemes. This paper aims to provide an overview of the existing state-of-the-art of power converter topologies for IPT systems in EV charging applications. In this paper, the widely adopted power conversion topologies for IPT systems are selected and their performance is compared in terms of input power factor, input current distortion, current stress, voltage stress, power losses on the converter, and cost. The single-stage matrix... [more]

A power flow study aims to analyze a power system by obtaining the voltage and phase angle of buses inside the power system. Power flow computation basically uses a numerical method to solve a nonlinear system, which takes a certain amount of time because it may take many iterations to find the final solution. In addition, as the size and complexity of power systems increase, further computational power is required for power system study. Therefore, there have been many attempts to conduct power flow computation with large amounts of data using parallel computing to reduce the computation time. Furthermore, with recent system developments, attempts have been made to increase the speed of parallel computing using graphics processing units (GPU). In this review paper, we summarize issues related to parallel processing in power flow studies and analyze research into the performance of fast power flow computations using parallel computing methods with GPU.

In order to enhance heat transfer in the abrasive-milling processes to reduce thermal damage, the concept of employing oscillating heat pipes (OHPs) in an abrasive-milling tool is proposed. A single-loop OHP (SLOHP) is positioned on the plane parallel to the rotational axis of the tool. In this case, centrifugal accelerations do not segregate the fluid between the evaporator and condenser. The experimental investigation is conducted to study the effects of centrifugal acceleration (0−738 m/s2), heat flux (9100−31,850 W/m2) and working fluids (methanol, acetone and water) on the thermal performance. Results show that the centrifugal acceleration has a positive influence on the thermal performance of the axial-rotating SLOHP when filled with acetone or methanol. As for water, with the increase of centrifugal acceleration, the heat transfer performance first increases and then decreases. The thermal performance enhances for higher heat flux rises for all the fluids. The flow inside the ax... [more]

Bioenergy plays a major role as a renewable energy source in the European Union. Solid biomass is derived mainly as wood from forests and wood processing plants. Willow plantations set up on marginal lands can be a supplementary source of wood for energy generation. This study aimed to determine the energy value of yield and the thermophysical properties and elemental composition of the biomass of 7-year rotation willow harvested on marginal soil. Three varieties and three clones were cultivated in the Eko-Salix system on three marginal soils in northern Poland: riparian, alluvial soil, classified as heavy complete humic alluvial soil (Obory); organic, peat−muck soil formed from peat (Kocibórz); very heavy mineral clay soil (Leginy). Favourable conditions for obtaining high energy value biomass were at Kocibórz and Obory with a high groundwater level. The energy value of biomass at Leginy was lower than at Kocibórz and Obory (by 33% and 26%, respectively). The Ekotur variety had the si... [more]

This paper provides models for managing and investigating the power flow of a grid-connected solar photovoltaic (PV) system with an energy storage system (ESS) supplying the residential load. This paper presents a combination of models in forecasting solar PV power, forecasting load power, and determining battery capacity of the ESS, to improve the overall quality of the power flow management of a grid-connected solar PV system. Big data tools were used to formulate the solar PV power forecasting model and load power forecasting model, in which real historical solar electricity data of actual solar homes in Australia were used to improve the quality of the forecasting models. In addition, the time-of-use electricity pricing was also considered in managing the power flow, to provide the minimum cost of electricity from the grid to the residential load. The output of this model presents the power flow profiles, including the solar PV power, battery power, grid power, and load power of we... [more]

This article considers the problem of the evaluation of the sustainability of heterogeneous process systems, which can have different areas of focus: from single process operations to complete supply chains. The proposed method defines exergy-based concepts to evaluate the assets, liabilities, and the exergy footprint of the analysed process systems, ensuring that they are suitable for Life Cycle Assessment. The proposed concepts, evaluation framework and cumulative Exergy Composite Curves allow the quantitative assessment of process systems, including alternative solutions. The provided case studies clearly illustrate the applicability of the method and the close quantitative relationship between the exergy profit and the potential sustainability contribution of the proposed solutions. The first case study demonstrates how the method is applied to the separation and reuse of an acetic-acid-containing waste stream. It is shown that the current process is not sustainable and needs subst... [more]

This study aims to build a potential map for the installation of a central receiver concentrated solar power plant in Chile under the terms of the average net present cost of electricity generation during its lifetime. This is also called the levelized cost of electricity, which is a function of electricity production, capital costs, operational costs and financial parameters. The electricity production, capital and operational costs were defined as a function of the location through the Chilean territory. Solar resources and atmospheric conditions for each site were determined. A 130 MWe concentrated solar power plant was modeled to estimate annual electricity production for each site. The capital and operational costs were identified as a function of location. The electricity supplied by the power plant was tested, quantifying the potential of the solar resources, as well as technical and economic variables. The results reveal areas with great potential for the development of large-s... [more]