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In the last years, even more attention was paid to the alternative fuels that allow both reducing the fossil fuel consumption and the pollutant emissions. Gaseous fuels like methane and hydrogen are the most interesting in terms of engine application. This paper reports a comparison between methane and different methane/hydrogen mixtures in a single-cylinder Port Fuel/Direct Injection spark ignition (PFI/DI SI) engine operating under steady state conditions. It is representative of the gasoline engine for automotive application. Engine performance and exhaust emissions were evaluated. Moreover, 2D-digital cycle resolved imaging was performed with high spatial and temporal resolution in the combustion chamber. In particular, it allows characterizing the combustion by means of the flame propagation in terms of mean radius and velocity. Moreover, the interaction of turbulence with the local flame was evaluated. For both the engine configurations, it was observed that the addition of hydrogen results in a more efficient combustion, even though the engine configuration plays an important role. In PFI mode, the lower density of hydrogen causes a lower energy input. In DI mode, instead, the larger hydrogen diffusivity counteracts the charge stratification especially for larger hydrogen content. © 2016 Elsevier Ltd. All

Thermal performance of SS-PCM composites, simulating building envelope conditions, is difficult to asset with traditional laboratory equipment. However, in this work, the evaluation of three SS-PCM based on eutectic fatty acid mixtures of capric-myristic (CA/MA), lauric-myristic (LA/MA) and palmitic-stearic (PA/SA) was accomplished by a testing setup that allows to test samples in steady-state and dynamic conditions. Moreover, a SS-PCM-based acrylic plaster was evaluated as a fiber cement siding finish. The obtained values were used to calculate the thermal transmittance (U-value), heat storage capacity, and thermal inertia parameters under a simulated diurnal cycle. Results showed that the use of phase change materials in powder form increase thermal lag between 148% and 180% and present a decrement factor <0.2. Furthermore, building envelopes as fiber cement siding with a SS-PCM-based acrylic plaster coating decreased 20.8% the indoor temperature, increase 67.26% the thermal lag and decrease 9% of the decrement factor. The authors are pleased to acknowledge the financial assistance of the “Ministerio de Ciencia, Tecnología e Innovación-MINCIENCIAS” through the PhD grant 758-2016-Contract 036–2016, Universidad de Antioquia and Sumicol S.A.S. The work is partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018-093849-B-C31—MCIU/AEI/FEDER, UE) and by the Ministerio de Ciencia, Innovación y Universidades—Agencia Estatal de Investigación (AEI) (RED2018-102431-T). This work is partially supported by ICREA under the ICREA Academia programme. Dr. Cabeza would like to thank the Catalan Government for the quality accreditation given to her research group GREiA (2017 SGR 1537). GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia.

Abstract This paper defines two electric grids for the area of Jutland in Denmark, namely the existing grid versus a “nature protection grid”, in which all 400 kV AC overhead lines are replaced by 150 kV lines. According to official Danish policies for laying underground cables, such a replacement makes it economically feasible on a long-term basis to replace all overhead lines with underground cables. The two grids are then tested against different energy demand and supply systems in a load-flow analysis. It is found that the “nature protection grid” is well suited for the implementation of sustainable energy systems exploiting both CHP and renewable energy sources such as wind power if certain strategies for the technical regulation of decentralised CHP units are used.

The large use of portable devices imposes a new interest in the development of power backup systems with constraints in terms of compactness and safety. Such systems have to match the use as battery backups as well as a self-standing operating. Thermoelectric generators (TEGs) allow access to new ways of power supply thanks to their long lifetimes, their competitive efficiencies at low powers and their capability of providing multiple outputs. In this work, a TEG based on catalytic combustor has been proposed aiming to approach electrical output and dimension of the commonly used AA batteries. Catalytic combustion provides the possibility to profit from the high power densities of hydrocarbon in limited space and low burning temperatures meeting the needs of the TEGs as a heat engine. The system has been characterized for different fuel flow rates. The measured TEG efficiency is 3.4% with the electrical power output of 5.3 W. The system thermal behavior has been experimentally investigated according to literature models, by evaluating the effectiveness of the design and of the chosen practical solutions. The system produced reached the electrical output target, matching the characteristics proper of most of the common commercial AA batteries in a similar device volume.

Artículos en revistas A previously developed procedure to evaluate a biomass plant feasibility has been improved, now considering availability and cost of the biomass resources around the plant's location. The plant is an organic Rankine cycle cogeneration facility located in mainland Spain. All the villages over 15.000 inhabitants have been considered as potential locations. Partial load operation is considered as well as cogeneration (CHP) and trigeneration (CCHP) schemes. Biomass calculations were performed using BIORAISE (a free GIS tool) showing that, in all the locations, the available biomass within a 30-km radius is larger than the demand, with an average cost of 10 /MWh. No subsidies have been considered. In CHP operation, all the locations lead to «high efficiency cogeneration» plants, with the best profitability in medium-severe to severe-winter climate zones. In CCHP mode, only locations in medium-to severe-winter climate zones reach «high efficiency». This mode is worthwhile in climate zones with mild winters and medium to hot summers. The optimum plant size is found to be smaller in CCHP compared to CHP in all the locations and the biggest plants are situated in climate zones with severe winters. Avoided CO2 emissions reach higher values in CHP mode compared to CCHP. info:eu-repo/semantics/publishedVersion

Abstract This Special Section provides introduction to the 15th Conference Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (PRES 2012). In this editorial introduction, the editors are highlighting the individual articles included in this issue and discussing the main points. The main areas of this issue can be summarised as: Process Integration for Energy Saving, Integrating Renewable Energy Sources and Energy Optimisation issues.

We present trends in energy intensities for 56 Dutch economic sectors over the 20-year period 1969–1988. The intensities were calculated by using input–output analysis. The effects of energy-price changes were examined. More than half of the economic sectors show significant declines in energy intensities as a result of increasing energy prices. As a result, the energy intensity for final demand shows a significant decline, although a shift to more energy-intensive sectors was found.

Abstract Ireland is currently striving to source 10% of the energy required for its transport fleet from renewable energy sources by 2020. As part of the measures being implemented in order to help realise this ambitious target a number of Government schemes have been introduced to financially subsidise the purchase of alternative energy vehicles in an effort to achieve 10% EV (electric vehicle) penetration in the country's road fleet by 2020. The replacement of ICE (internal combustion engine) vehicles with EV equivalents poses challenges for grid operators while simultaneously offering opportunities in terms of distributed energy storage and flexible load. This paper examines how optimising the charging cycles of an electric car using DSM (Demand Side Management) based on a number of criteria could be used to achieve financial savings, increased demand on renewable energy, reduce demand on thermal generation plant, and reduce peak load demand. The results demonstrate that significant gains can be achieved using currently available market data which highlights the point that DSM can be implemented without any further technological advents.