• Energy Research
• DE close
• NL close
• FI close

Access to reliable and affordable energy is vital for sustainable development. In the off-grid areas of developing countries, decentralized energy solutions have received increasing attention due to their contributions to reducing poverty. However, most of the rural population in many developing countries still has little or no access to modern energy technologies. This paper assesses the factors that determine the successes and failures of decentralized energy solutions based on local harmonized case studies from heterogeneous contexts from Asia, sub-Saharan Africa, and South America. The case studies were analyzed through the coupled lenses of energy transition and the Water–Energy–Food Security (WEF) Nexus. The findings indicate that access to modern decentralized energy solutions has not resulted in complete energy transitions due to various tradeoffs with the other domains of the WEF Nexus. On the other hand, the case studies point at the potential for improvements in food security, incomes, health, the empowerment of women, and resource conservation when synergies between decentralized energy solutions and other components of the WEF Nexus are present.

The REN21 Renewables Global Status Report (GSR) provides an annual look at the tremendous advances in renewable energy markets, policy frameworks and industries globally. Each report uses formal and informal data to provide the most up-to-date information available. Reliable, timely and regularly updated data on renewable energy are essential as they are used for establishing baselines for decision makers; for demonstrating the increasing role that renewables play in the energy sector; and illustrating that the renewable energy transition is a reality.

In the present work, an experimental study on a lab-scale adsorption refrigerator, based on activated carbon/ethanol working pair is reported. An extensive testing campaign has been carried out at the CNR ITAE laboratory, with multiple aims. First, the performance has been evaluated in terms of both COP and Specific Cooling Power (SCP), under different boundary conditions, including both air conditioning and refrigeration applications. Attractive SCPs, up to 180 W/kg and 70 W/kg for air conditioning and refrigeration, respectively, were measured. Under the same conditions, COP between 0.17 and 0.08 were obtained. In addition, different management strategies, namely, heat recovery between adsorbers and re-allocation of phase durations, were evaluated to identify their influence on the system. Both strategies confirmed the possibility of increasing COP and SCP up to 40% and 25%, respectively. Moreover, a design analysis based on the experimental results has been carried out, to suggest possible improvements of the system. The obtained results demonstrated the possibility of employing a non-toxic refrigerant like ethanol reaching performance comparable with other harmful refrigerants like ammonia and methanol.

Abstract Fruit and vegetables are stored for up to several months in large bin stacks in refrigerated rooms. Gaps between the bins and bin wall openings should allow the circulation of cooling air to remove field and respiration heat from produce. In an industrial apple store, the effects of the stacking array, fan position and number on airflow distribution in vertical gaps and inside plastic bins were investigated using stepwise reduction of fan revolution. At 100% fan power, the average air velocity in vertical gaps between bin rows in the main flow direction increased with reducing total cross section of the gaps. In contrast, the number of vertical gaps between bin rows had little effect on the average air speed between fruit inside the bins, probably due to additional flow paths in the horizontal gaps. The lowest air speed was measured when bins were stacked in one block without vertical gaps and a distance to the side walls of only 10 cm. A stacking arrangement with only one central vertical gap between four bin rows or with a large distance (> 1 m) between the wall opposite to the fans and the bins enhanced flow uniformity. Three fans situated above the vertical gaps was more effective for the ventilation of bins than four fans above the bin rows.

Abstract In the production process of pharmaceutical pellets with a narrow size distribution and a high sphericity, a combined extrusion-spheronization technique is frequently used. The rounding of the wet cylindrical extrudates in the spheronizer after the extrusion step is influenced by various interfering mechanisms, in particular plastic deformation, breakage, attrition and coalescence. Due to the complexity of these mechanisms which depend on the particle dynamics, there is no sufficient description of the particle rounding process in the spheronizer. In this study, the Discrete Element Method (DEM) which runs on the micro scale is coupled with a Particle Shape Evolution (PSE) model on the macro scale to describe how the particle shape changes due to collisions. For the DEM simulation a new contact model was used which was developed to capture the cyclic, dominant visco plastic deformation behaviour. Based on the DEM collision data, the changing particle shape was described in the PSE model by applying the proposed submodels for the different formation mechanisms. The resulting particle shapes obtained with this simulation framework are in a good agreement with experimental data.

This paper constitutes a first analysis on stock returns and stock return volatility of energy corporations from the Eurozone. According to our results, the gas market does not play a role for the pricing of Eurozone energy stocks. However, changes in the Euro to U.S. Dollar exchange rate as well as developments at the money and especially at the oil market strongly affect returns of the energy stock portfolios analyzed. While oil price hikes negatively impact on stock returns of European utilities, they lead to an appreciation of oil and gas stocks. Most importantly, we show that oil market volatility negatively affects European oil and gas stocks. In contrast, energy stock volatility is not driven by volatility of the resource market, but only by its own dynamics.

During the Engineering Validation and Engineering Design Activities (EVEDA) phase (2007-2014) of the International Fusion Materials Irradiation Facility (IFMIF), an advanced engineering design of the High Flux Test Module (HFTM) has been developed with the objective to facilitate the controlled irradiation of steel samples in the high flux area directly behind the IFMIF neutron source. The development process addressed included manufacturing techniques, CAD, neutronic, thermal-hydraulic and mechanical anal- yses complemented by a series of validation activities. Validation included manufacturing of 1:1 parts and mockups, test of prototypes in the FLEX and HELOKA-LP helium loops of KIT for verification of the thermal and mechanical properties, and irradiation of specimen filled capsule prototypes in the BR2 test reactor. The prototyping activities were backed by several R&D studies addressing focused issues like han- dling of liquid NaK (as filling medium) and insertion of Small Specimen Test Technique (SSTT) specimens into the irradiation capsules. This paper provides an up-todate design description of the HFTM irradiation device, and reports on the achieved performance criteria related to the requirements. Results of the vali- dation activities are accounted for and the most important issues for further development are identified.

This study proposes a coordinated and distributed smart grid based method for optimal set points of distributed generators (DGs) as well as on‐load tap changer (OLTC) transformer in the unbalanced power distribution grid. In this approach, energy efficiency is improved and voltage profile is kept in an acceptable range under different operating conditions of renewable energy resources and loads. In the first level of proposed hierarchical method, DGs are independently trying to keep voltage profile in an acceptable range in an optimal way. If the first level is not succeeding, at the second level, OLTC cooperates with the first level to eliminate the voltage violation in the system. The rules for updating control setting are derived based on distributed gradient algorithm. The proposed distributed solution presents analogous steady state results in comparison with centralised optimisation solution. Since the processing data is reduced, short‐timed response to change operating conditions could be achieved. Simulation results on three distribution test systems with different sizes demonstrate the effectiveness of proposed control solution.