• Energy Research
• mechanical engineering close
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The Competition involved actions on two contiguous blocks of housing, one of them with serious structural problems that requiered its demolition and replacement with a new bioclimatic building, The other building was renovated by environmental and accessibility alterations. After the initial study of the study of the climate and environment, the design decisions matched these conditiosn in order to achieve a better environemental sustainability together with other technical, formal and social values. In both blocks, yhe bad orientation of the existing blocks (with façades to the east and west) han been corrected, folding the skin of the building to capture sunligth to the interior in winter and provide protection in the summer, creating a series of “climatisation galleries” with capture windows facing south-east in the living rooms of the houses. These galleries are protected by shading elements on the glass which prevent the greenhouse effect in summer and are protected by exterior blinds that also create shade and chambers that prevent cooling by cold air convection outside in the winter. The exterio woodwork consist of profiles that break the thermal brigde and double glazing with low emissions treatment. In the new block, to improve the summer conditions inside the houses and taking into account that active cooling is needed on a few days of the year when temperatures are high, natual cooling chimneys have been provided. Ther are two types of façade walls, one consisting iof walls with great heat inertia and exterior rendered insulation and the other also within insulation on the exterior layer but with a ventilated chamber finished with prefabricated panels. Together, the buildings achieve a level of insulation an suitability that is about 200% of the requiered by standards. Total accessibility has been provided for all the new and existing houses and low consumtion lifts installed. El Concurso planteaba la actuación sobre dos bloques de viviendas contiguos, uno de ellos con graves problemas estructurales, que obligaron a su demolición, ha sido sustituido por un nuevo edificio bioclimático. El otro edificio ha sido objeto de una rehabilitación para su adecuación medioambiental y de accesibilidad. Tras el estudio previo del clima y del entorno, las decisiones sobre el diseño correspondían a estas condiciones de manera que se logra la mejor adecuación ambiental junto con otros valores técnicos, formales y sociales. En ambos bloques la mala orientación de los bloques existentes (con fachadas al Este y Oeste), ha sido corregida, plegando la piel del edificio para conseguir la captación de radiación solar hacia el interior en invierno y su protección en verano, creando una serie de “galerías de climatización”, con ventanas captoras orientadas a sureste en zonas de estancia de las viviendas. Estas galerías están protegidas por elementos de sombra sobre los vidrios que eliminan el efecto invernadero en verano y quedan protegidas por persianas exteriores que también dan sombra y crean cámaras que evitan el enfriamiento por convención del aire frío exterior en invierno. Las carpinterías exteriores están realizadas con perfiles que consiguen la rotura del puente térmico y acristaladas con vidrio doble de baja emisividad. En el edificio de nueva planta, para mejorar las condiciones de verano en el interior de las viviendas y teniendo en cuenta que haría falta una refrigeración activa unos pocos días al año en los que las temperaturas máximas se elevan, se han previsto unas chimeneas de refrigeración natural. Se han realizado dos tipos de cerramiento de fachada: una, compuesta por muros de gran inercia térmica con aislamiento exterior revocado, y otra, también con el aislamiento en la capa exterior, pero con cámara ventilada acabada con paneles prefabricados. El conjunto de los edificios consigue un nivel de aislamiento y adecuación superior en un 200% al exigible por normativa. Para todas las viviendas nuevas y ya existentes, se ha conseguido accesibilidad total a las mismas, y la dotación de ascensores de bajo consumo.

Most of the existed works on the radio resource allocation (RRA) problem commonly assume the channel-state information (CSI) can be perfectly obtained by the transmission source. However, such assumption is not practical in the realistic wireless systems. In this work, we consider the practical implementation issues of resource allocation in orthogonal frequency division multiple access (OFDMA) two-way relay networks: the inaccuracy of channel-state information (CSI) available to the source. Instead, only the estimated channel status is known by the source. In this context, a joint optimization of subcarrier pairing and allocation, relay selection, and transmit power allocation is formulated in OFDMA two-way amplify-and-forward relay networks. Moreover, the objective of this work is to minimize the energy consumption of the overall system. Further, to ensure the quality of service (QoS) or data rate requirement, the energy consumption must be minimized without compromising the QoS. Therefore, by applying convex optimization techniques, energy-efficient algorithms are developed with the objective to minimize the total transmit power with guaranteeing the required data rates. Through simulation studies, energy consumption performance of the systems under the proposed schemes is investigated. It can be observed that our proposed scheme can improve the energy consumption performance of the considered system.

Deployment of photovoltaic (PV) systems has recently been encouraged for large-scale and small-scale businesses in order to meet the global green energy targets. However, one of the most significant hurdles that limits the spread of PV applications is the dust accumulated on the PV panels’ surfaces, especially in desert regions. Numerous studies sought the use of cameras, sensors, power datasets, and other detection elements to detect the dust on PV panels; however, these methods pose more maintenance, accuracy, and economic challenges. Therefore, this paper proposes an intelligent system to detect the dust level on the PV panels to optimally operate the attached dust cleaning units (DCUs). Unlike previous strategies, this study utilizes the expanded knowledge and collected data for solar irradiation and PV-generated power, along with the forecasted ambient temperature. An expert artificial intelligence (AI) computational system, adopted with the MATLAB platform, is utilized for a high level of data prediction and processing. The AI was used in this study in order to estimate the unprovided information, emulate the provided measurements, and accommodate more input/output data. The feasibility of the proposed system is investigated using actual field data during all possible weather conditions.

The use of natural gas as an energy source is increasing significantly due to its low greenhouse gas emissions. However, the common methods of natural gas storage and transportation, such as liquefied or compressed natural gas, are limited in their applications because they require extreme conditions. Gas hydrate technology can be a promising alternative to conventional approaches, as artificially synthesized hydrates provide an economical, environmentally friendly, and safe medium to store energy. Nevertheless, the low rate of hydrate formation is a critical problem that hinders the industrial application of this technology. Therefore, chemical promoters are being developed to accelerate the kinetics of gas hydrate formation. In this paper, the effect of new sodium sulfosuccinate compounds, synthesized based on glycerol and pentaerythritol, on methane hydrate formation was studied. Experiments under dynamic conditions using high-pressure autoclaves demonstrated that the conversion of water-to-hydrate forms increased from 62 ± 5% in pure water to 86 ± 4% for the best promoter at concentration 500 ppm. In addition, the rate of hydrate formation increases 2–4 times for different concentrations. Moreover, none of the synthesized reagents formed foam, compared to sodium dodecyl sulfate, in which the foam rate was 3.7 ± 0.2. The obtained reagents showed good promotional properties and did not form foam, which makes them promising promoters for gas hydrate technology.

Purpose. In modern conditions of energy consumption growth and a rapid increase in energy prices the actual problem is the development and implementation of energy efficiency programs and resource-saving conversion in to a source to provide the needs of industry and municipal power. The paper aims to solve the urgent problem of energy saving and efficient use of fuel-energy ones and heat supply system optimization on the basis of Uman National University of Horticulture (UNUH). Methodology. The work investigated the process of heating and hot water supply in the course of 2007-2015 years. Implementation of current problems of energy saving is grounded on the scientific-practical and efficient assurance of fuel and energy usage. At the same time energy-saving technologies are viewed as a priority direction of the energy sector development, reduction of man-induced impact on the environment and as a way of improving the competitiveness of the national economy. Findings. Statistical data acquisition and analyzing of gas flow and outside air temperature for nine years was carried out. On the basis of this analysis, the problem was identified and specific targets for its solutions were set. Originality. Scientific novelty lies in solving the problem of energy saving and efficient use of fuel resources in Ukraine through the use of a systematic approach, the methodology development of efficient use of different fuels and optimization of local heating operation, applying contemporary automation and control systems. Firstly it was in detail analyzed and conducted the comprehensive assessment of various factors influence on energy conservation. It takes into account the human factor, professionalism and responsibility of the operators of boilers and their superiors, as well as the relevant control services. Practical value. For UNUH campus hybrid use of solid fuel and gas boilers was carried out. Decentralization of the university heating system has been conducted through the restoration of 350 individual heating systems in residential buildings, remote departments and campus dormitories. The conclusions propose the list of activities upon the real economy of fuel and energy resources, and measures to overcome the economic and political crisis in the country.

The global climate protection policy aimed at achieving a zero greenhouse gas emissions target has led to the fast incorporation of large-scale photovoltaics into the power network. The conventional AC grid was not modeled to be incorporated with large-scale non-synchronous inverter-based energy resources (IBR). Incorporating inertia-free IBR into the grid leads to technical issues such as the degradation of system strength and inertia, therefore affecting the safety and reliability of the electrical power system. This research introduced a new solution to incorporate a flywheel in the rotor of a synchronous machine to improve the dynamic inertia control during a system disruption and to maintain the constancy of the system. The objective of this work is to enhance large-scale photovoltaic systems in such a way that they can avoid failures during a fault. A model of transient constancy with two synchronous generators and a LSPV is established in PowerWorld modeling software. A line-to-ground and three-phase fault are simulated in a system with up to 50% IBR penetration. The outcomes showed that the power network was able to ride through faults (RTFs) and that the stability of frequency and voltage are enhanced because of a flywheel that improved grid inertia and strength.

Approximately 40% of the overall energy consumption of society is consumed by buildings. Most building energy usage is due to poor envelope performance. In regions with cold winters, the corners of structures typically have the lowest interior surface temperature. In corners, condensation, frost, and mold are common. This has a substantial effect on building energy usage and residents’ comfort. In this study, the heat loss of corner envelopes is evaluated, and a suitable insulation construction of wall corners is constructed to increase the surface temperature of the envelope interior. Computational Fluid Dynamics simulation has been used to examine the heat transmission in a corner of an ultra-low energy building in this study. By comparing the indoor surface temperature to the soil temperature beneath the building, the insulation construction of wall corners has been tuned. The study results indicate that the planned insulation construction of wall corners can enhance the internal surface temperature in the corner and the soil temperature under the structure by approximately 8.5 °C, thereby decreasing the indoor–outdoor temperature differential and the heat transfer at ground level. In extremely cold places, the insulation horizontal extension belt installation can help prevent the earth beneath the building from freezing throughout the winter.