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Ultrarich filtration combustion of ethane is studied in a porous medium composed of alumina spheres with the aim to achieve optimized conversion to hydrogen and syngas. Temperature, velocities, and...

Cogeneration of heat and electricity is an important pillar of energy and climate policy. To plan the production and distribution system of combined heat and power (CHP) systems for residential heating, suitable methods for decision support are needed. For a comprehensive feasibility analysis, the integration of the location and capacity planning of the power plants, the choice of customers, and the network planning of the heating network into one optimization model are necessary. Thus, we develop an optimization model for electricity generation and heat supply. This mixed integer linear program (MILP) is based on graph theory for network flow problems. We apply the network location model for the optimization of district heating systems in the City of Osorno in Chile, which exhibits the “checkerboard layout” typically found in many South American cities. The network location model can support the strategic planning of investments in renewable energy projects because it permits the analysis of changing energy prices, calculation of break-even prices for heat and electricity, and estimation of greenhouse gas emission savings.

Abstract A new method for providing ventilation in large enclosures, which utilizes the principle of ‘selective withdrawal’ of contaminants while ensuring energy-efficiency and allowing a better use of space, is presented in this study. The concept is based on dividing the enclosed space ventilation-wise into separate zones using a combination of horizontal partitions by stratification and vertical partitions by temporary walls. This gives a high degree of flexibility in the use of available space. The relative influence of all the parameters on the flow patterns inside an enclosure is discussed in order to identify the design parameters that should be controlled to apply the technique successfully. An experimental study in a scale model was conducted, which provided a better understanding of the physical processes that occur in such enclosures. The influence of exhaust location on the flow field was studied in particular. It was found that by controlling the position of exhaust the stratification effects are enhanced and maintained at a desired level in order to achieve a successful utilization of the selective ventilation system.

The growing demand for electric power and the need for an energy transition that contributes to the reduction of global greenhouse gas emissions have driven the development of various energy generation, storage, and offset technologies. These technologies are known as distributed energy resources. Their integration into distribution power systems not only contributes to improving operating aspects, but also allows supplying electricity to areas that do not have access to large-scale power systems. Therefore, the integration and management of these resources has become a topic of interest, and several studies seek to optimize their impact on technical, economic, and environmental aspects. However, this optimization poses specific challenges related to the type and number of variables related to the operation of a distribution power system. This review article aims to describe the main challenges posed by three-phase AC three-phase distribution power systems under scenarios involving the integration of distributed energy resources. In addition, it presents some approaches proposed by different authors to improve the technical, economic, and environmental aspects of power grids. It can be stated that the strategies presented in the literature fail to consider scenarios that simultaneously integrate different types of technologies and optimize them while following a multi-objective approach and considering three-phase systems in a context of variable generation and demand. Therefore, future work in this field should address these aspects in a holistic manner, taking into account the computation efforts and processing times required by intelligent algorithms.

Building-integrated greenery (BIG) systems, which include green roofs and green facades, are well-established nature-based solutions (NBS) with proven scientific benefits. However, initial costs and economic apprehensions stemming from potential negative outcomes act as adoption barriers. Furthermore, the lack of standardized indicators and assessment methodologies for evaluating the city-level impacts of BIG systems presents challenges for investors and policy makers. This paper addresses these issues by presenting a comprehensive set of indicators derived from widely accepted frameworks, such as the Common International Classification of Ecosystem Services (CICES) and the NBS impact evaluation handbook. These indicators contribute to the creation of a ‘sustainability factor’, which facilitates cost–benefit analyses for BIG projects using locally sourced data. The practical application of this factor to a 3500 m2 green roof in Lleida, Catalonia (Spain) demonstrates that allocating space for urban horticultural production (i.e., food production), CO2 capture, and creating new recreational areas produces benefits that outweigh the costs by a factor value of nine during the operational phase of the green roof. This cost–benefit analysis provides critical insights for investment decisions and public policies, especially considering the significant benefits at the city level associated with the implementation of BIG systems.

Abstract Biofuels are considered as an alternative to partially replace fossil fuels and mitigate climate change effects. A life cycle assessment of second generation ethanol, derived from banana agricultural wastes, was developed to assess its environmental sustainability and demonstrate its capacity of reducing greenhouse gas emissions. The methodological approach was conducted in a Well-to-Wheel perspective, using as functional unit 1 MJ of energy released in the combustion of bioethanol in a passenger car from different bioethanol blends. Primary and secondary information sources were used for the assessment; mass balance and ethanol yield data came from laboratory experimentation. The environmental assessment was carried out using SimaPro 8.0.4.30 with the ReCiPe midpoint (H) impact assessment methodology. The quantified impact categories were climate change (CC), terrestrial acidification (TA), freshwater eutrophication (FE), photochemical oxidant formation (PO), particulate matter formation (PM), and fossil depletion (FD). In addition, net energy value and energy ratio (ER) were analyzed to ensure a positive energy balance. Compared to using pure gasoline, blended gasoline reduced CC, PO, PM, and FD impacts, but increased FE and TA impacts. The obtained energy balance was positive, with an ER of 2.68 MJ/MJ. Wastewater treatment is the process that presented the greatest energy consumption. Since Ecuador is the world's largest exporter of bananas, and a great amount of agricultural waste is available, a case study in this country was analyzed. This case study indicated that Ecuador could use banana residue for ethanol production, considering its positive and negative impacts. In conclusion, second generation ethanol derived from banana agricultural waste has potential to reduce greenhouse gas emissions and fossil depletion and has a positive energy balance.

Abstract A brief history of solar stills in Chile is presented. Theoretical studies of solar stills in that country are described. These deal with efficiency, thermal balance, thermal intertia, thermal capacity, thermal conductance, thermal lag and distillation lag with regard to solar irradiation maximum, and time constant. Chilean solar still designs with evaporating trays of wood, metal, cement, and plastic, and evaporating cloths of various designs have been tested by the authors. Tests were made with glass and plastic covers in the Solar Energy Laboratory of the Universidad Santa Maria (Valparaiso) and in the Atacama Desert (Quillagua). Their purpose was to make theoretical predictions of still characteristics under different environmental conditions.

Abstract This research aims to explore public views and social attitudes toward the use of geothermal energy as a heating and electricity source in an area where the geothermal energy production technology has yet to be widely introduced. This case study focuses on the community that surrounds the Villarrica Volcano in the Araucania region of Chile. This area is considered to be one of the six high enthalpy geothermal zones in the Chilean Andes with the highest potential for geothermal energy production but actual production is nearly non-existent. Taking a risk communication approach, this research includes in-depth semi-structured interviews with local stakeholders. It suggests that there is a low level of understanding of the technology involved in geothermal energy production, and it highlights social barriers such as lack of trust, spiritual relationship to volcanoes, and uncertainty about environmental impact as factors that affect risk and public perception.

Islas Huichas, located in Chile’s remote Aysén region, has long faced water scarcity due to a lack of natural sources. The community relies on rainwater collection pools managed by the Rural Drinking Water Committee (RDWC), which face increased pressure during the summer tourist season, leading to frequent shortages. In 2014, a Reverse Osmosis (RO) plant with a 240 m3 daily capacity was installed to address the issue. While the RO plant helps alleviate summer shortages, it has high energy costs and maintenance challenges, exceeding the financial capacity of the RDWC. This study evaluates various scenarios to reduce the plant’s operational costs and emissions reduction.