• Energy Research
• Closed Access close
• Restricted close
• 7. Clean energy close
• 2. Zero hunger close
• PL close

Vehicles with hybrid drive systems, are increasingly more often being equipped with solutions that increase the drive systems efficiency. One of such solutions is to use an increased supply voltage for electric motors of such vehicles. The battery voltage is increased several times in the inverter system in order to increase the electrical power supplied to the electric motor. This article presents possible uses of such voltage amplification (called boost) in urban traffic conditions. The tests used the latest models of vehicles with hybrid drive systems equipped with the same drive units: Lexus NX 300h and Toyota RAV4 Hybrid. The study analyses the conditions of starting such a system and the characteristics of its operation. It has been shown that the amplification of the voltage powering the electrical machinery in both vehicles occurs at high torque values. The maximum voltage amplification–almost threefold (up to 650 V) allows a two-fold increase in the torque of the drive system.

Abstract The paper presents a review of publications devoted to the use of thermal-electric analogy in the analyses of solar collectors’ performance, with special focus on the shortcomings of the proposed models of the equivalent thermal network (ETN). Additionally, the study describes the principles of construction of the ETN, especially for large-scale solar thermal circuits. The process of heating the working medium flowing through the collector battery was also shown. The ETN model was presented both analytically (nodal potential method) and with the use of the Simulink package (MATLAB), which made it possible to investigate the effect of operating conditions on the parameters of the solar collector.

This paper is focused on the energy performance of buildings containing massive exterior building envelope components. The effect of mass and insulation location on heating and cooling loads is analyzed for six characteristic wall configurations. Correlations between structural and dynamic thermal characteristics of walls are discussed. A simple one-room model of a building exposed to periodic temperature changes is analyzed to illustrate the effect of material configuration on the ability of a wall to dampen interior temperature swings. Whole-building dynamic modeling using DOE-2.1E is employed for the energy analysis of a one-story residential building with various exterior wall configurations for six different US climates. The best thermal performance is obtained when massive material layers are located at the inner side and directly exposed to the interior space.

Abstract The paper was aimed at evaluating the efficiency of impregnation of composite catalysts consisting of K, Na and/or Ca on a coal surface and the impact of composition of two-component catalysts and amount of three-component catalysts on the steam gasification reactions of coal. To this end, detailed analysis of the prepared samples was performed, and isothermal gasification measurements at various temperatures were carried out. The measurements enabled the examination of carbon conversion reaction and formation reactions of CO and H2 using reactivity indicators and kinetic parameters. The most efficient composites were 3 wt% of K/Na/Ca and 2 wt% of K/Na, although impregnation of Na was the least efficient, wherein the catalytic effect was observed only at low temperatures. In turn, higher amounts of three-component catalysts were catalytically inactive. Therefore, catalyst composition was more crucial than its amount or impregnation efficiency.

Abstract Currently, the first generation of silicon solar cells is dominating the photovoltaic market. Silicon cells are produced by various methods, which employ either crystalline or multi-crystalline substrates. However, both these manufacturing processes are expensive and potentially harmful to the environment and health. One example of this is that the surface is given its texture in a highly corrosive water solution of nitric and hydrofluoric acid. Additionally, both the diffusion and manufacturing of p-n junction and of metal contacts are associated with very high temperatures. This prompted us in our search for cheaper and more environmental friendly technologies. In this work, we discuss the possibility of producing components of photovoltaic cells by employing atomic layer deposition and hydrothermal technologies. This does not require the use of hazardous chemicals and high temperatures. The maximum efficiency of zinc oxide/silicon solar cells is 14% and 10% for textured and planar structures, respectively. A environmentally-friendly and simple procedure is thus being proposed, which, together with its relative efficiency, makes it an attractive alternative to the present procedure.

Adsorption technology enables construction of chillers that can be driven with a low temperature cogeneration, solar or waste heat source. As compared with absorption chillers, the adsorption devices have the unique advantages like the utilization of heat source characterized by lower temperature. The paper presents the thermodynamic model of a three-bed adsorption chiller of a cooling capacity equal to 90 kW. The chiller has been commissioned at Wroclaw Technology Park and is instrumented in a way allowing a full identification of important thermodynamic and operational parameters like COP (coefficient of performance), switching time, temperatures and pressures of adsorption and desorption processes as well as water condensation. The chiller provides cooling power at two temperature levels of about 13 and 8 °C. Experimental results of a long-term chiller investigation are presented. The dependence of the chiller COP on the adsorption bed regeneration temperature in the range from 45 °C to 70 °C has been identified. It has been demonstrated that the chiller can be driven with a hot water of 65 °C, what is a typical cogeneration heating temperature in distributed systems. It allows the utilization of cogeneration heat in trigeneration mode, what is especially important for distributed heating systems in summer time.

Abstract A conceptual model of BIM-based design and refurbishment, based on pre-built indicators and allowing the assessment of the building energy demand and eco-building parameters, is presented. The new approach presented in this model creates a knowledge-based decision-making environment for refurbishment strategies and quality control, in this way creating the preconditions to bridge the gap between expected and actual energy performance. The model with integration of new BIM-based optimization subsystems enables energy management and optimization processes. For a comprehensive evaluation of refurbishment measures, it is suggested to include energy efficiency, eco-efficiency, and economic parameters.

Abstract The article analyses to what extent ‘negative net CO2 emissions’ from decarbonised biogas-to-electricity can contribute to solving Poland’s carbon capture and sequestration dilemmas. From the criteria-based evaluation of low-carbon power technologies it is found, that biogas-to-electricity is among technologies having increasing production potential in Poland. Therefore, in future biogas will be able to contribute to solving Poland’s CCS dilemmas, because it offers carbon-neutral electricity. Moreover, by applying CCS into biogas-to-electricity the ‘negative net CO2 emissions’ can be achieved. The article examines three biogas-to-electricity technologies involving CO2 capture, i.e. biogas-to-biomethane, biogas-to-CHP and biogas-to-electricity via the ORFC cycle. It is emphasised that the ORFC cycle offers low-cost CO2 separation from a CO2–H2 mixture, low O2-intensity, and the opportunities for advanced mass and energy integration of involved processes. Besides, energy conversion calculations show that the ORFC cycle can offer comparable cycle efficiency with air- and oxy-combustion combined cycles. In regard to the design of biogas-based energy systems it is recommended to include (i) distributed production of biogas in order to avoid costs of long-distance transportation of high-moisture content biomass and (ii) centralised large-scale decarbonised biogas-to-electricity power plants since costs of pipeline transportation of gases are low but large-scale plants could benefit from increased energy and CCS efficiencies.

Head objective of the paper is to create and stimulate a Novel Dual Stator Sandwiched Rotor Hybrid Magnetic Pole Six-Phase PMSG (NDSSRHMPSP-PMSG) for harnessing wind power. Wind energy is the most optimized plan for innovation since it erases the need of water and is eco-accommodating and can be a superior option for expanded energy usage. A multiphase PMSG is a superior alternative for wind energy utilization. The two-fold rotor-stator setup upgrades the machine’s voltage regulation as well as its dependability and execution. The designed NDSSRHMPSPPMSG possesses novelty in terms of its magnet structure. A Hybrid Magnetic Pole (HMP) is inserted into the rotatory portions. The concept of HMP introduces the combination of V-Shaped Magnets (VSM) and Multi-Layer Embedded Magnets (MLEM). This remarkable combination of two different magnetic formation provides a higher flux density and contributes towards an efficient operation of the proposed system. To construct the generator optimally and for evaluation, magnetostatic and transient setups are used. Because of proper examination, it may be very well presumed that the proposed novel framework is legitimate and effective.