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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 results of an investigation into the interdependence between the loading conditions and the number of physically possible load flows in a power system are presented. The physical interpretation of various solutions of load flow is given. The relation between practically acceptable load flows and the multiplicity of load flow solutions of 4 nonlinear load flow equations is given.

Abstract The supercritical power plant analyzed in this paper consists of the following elements: a steam turbine, a hard-coal-fired oxy-type pulverized fuel boiler, an air separation unit with a four-end-type high-temperature membrane and a carbon dioxide capture unit. The electrical power of the steam turbine is 600 MW, the live steam thermodynamic parameters are 650°C/30 MPa, and the reheated steam parameters are 670°C/6 MPa. First of all the net efficiency was calculated as functions of the oxygen recovery rate. The net efficiency was lower than the reference efficiency by 9–10.5 pp, and a series of actions were thus proposed to reduce the loss of net efficiency. A change in the boiler structure produced an increase in the boiler efficiency of 2.5–2.74 pp. The range of the optimal air compressor pressure ratio (19–23) due to the net efficiency was also determined. The integration of all installations with the steam turbine produced an increase in the gross electric power by up to 50.5 MW. This operation enabled the replacement of the steam regenerative heat exchangers with gas–water heat exchangers. As a result of these alterations, the net efficiency of the analyzed power plant was improved to 5.5 pp less than the reference efficiency.

Abstract Given the need to reduce the CO2 emissions coming from the manufacturing sector, it is important, for planning purposes, to know which countries and which manufacturing sub-sectors have the greatest potential for reducing energy use. Using data from the International Atomic Energy Agency and the United Nations Industrial Development Organization, the authors estimate trends in global decoupling of energy use and manufacturing value added, compare energy-use intensity in six country groups and estimate the potential for reducing energy use and CO2 emissions under two scenarios and compare selected sub-sector energy intensity and estimate the potential for reducing energy use CO2 emissions. The comparison of energy intensities across country groups and among countries suggests that there still remains significant potential to reduce energy use and associated CO2 emissions. The analysis of four sub-sectors in developing and transition economies also shows similar but varied potential for reducing energy use and associated CO2 emissions.

Abstract Stable aqueous TiO2 nanofluids with different particle (agglomerate) sizes and concentrations are formulated and measured for their static thermal conductivity and rheological behaviour. The nanofluids are then measured for their heat transfer and flow behaviour upon flowing upward through a vertical pipe in both the laminar and turbulent flow regimes. Addition of nanoparticles into the base liquid enhances the thermal conduction and the enhancement increases with increasing particle concentration and decreasing particle (agglomerate) size. Rheological measurements show that the shear viscosity of nanofluids decreases first with increasing shear rate (the shear thinning behaviour), and then approaches a constant at a shear rate greater than ∼100 s−1. The constant viscosity increases with increasing particle (agglomerate) size and particle concentration. Given the flow Reynolds number and particle size, the convective heat transfer coefficient increases with nanoparticle concentration in both the laminar and turbulent flow regimes and the effect of particle concentration seems to be more considerable in the turbulent flow regime. Given the particle concentration and flow Reynolds number, the convective heat transfer coefficient does not seem to be sensitive to the average particle size under the conditions of this work. The results also show that the pressure drop of the nanofluid flows is very close to that of the base liquid flows for a given Reynolds number.

SummaryThe German government has adopted a law that requires sewage plants to go beyond the recovery of phosphorus from wastewater and to promote recycling. We argue that there is no physical global short‐ or mid‐term phosphorus scarcity. However, we also argue that there are legitimate reasons for policies such as those of Germany, including: precaution as a way to ensure future generations’ long‐term supply security, promotion of technologies for closed‐loop economics in a promising stage of technology development, and decrease in the current supply risk with a new resource pool.

Abstract The direct carbon fuel cells with solid oxide electrolyte (DC-SOFC) and anodes deposited by inject printing (EM/DCIJP) were studied. The cells were fed with carbon fuel obtained by the direct RF plasma splitting of methane. Since the (EM/DCIJP)M/DCIJP technology allows easy modification of electrode material, the effect of Cu addition to the Ni–YSZ anode was investigated. The significant improvement of the cell performance with the new anode was observed.

Abstract Demand response aims to change the energy consumption patterns of normal customers in response to changes in price rate or incentive offers. This process reduces peak loads and in turn potentially lowers the energy cost for customers. In this study, we propose a new demand response scheme on the basis of an adaptive consumption level pricing scheme. On the one hand, this strategy encourages customers to manage their energy consumption and consequently lower their energy bill. On the other hand, it allows utilities to manage the aggregate consumption and predict load requirement. Unlike other pricing schemes, such as block tariff and time-of-use, the proposed pricing scheme can lower the energy bill of about 73% of customers, assuming that the total utility revenue is the same for all pricing schemes. On the basis of the currently available schemes in the literature, we find that the proposed method has significant advantages over other schemes in terms of fairness in charging customers.