Equivalent Power Consumption Research Articles

Online Power Management Method for Fuel Cell/Supercapacitor Hybrid Power Tram Based on Equivalent Power Consumption

Online Power Management Method for Fuel Cell/Supercapacitor Hybrid Power Tram Based on Equivalent Power Consumption

Off-design performance analysis of supercritical CO2 mixture Brayton cycle with floating critical points

The thermodynamic performance of supercritical CO2 (sCO2) Brayton cycle deteriorates significantly due to the mismatch between the cold source temperature and the working fluid’s critical point. Here, we present the first study on the off-design performance of a novel supercritical CO2 mixture Brayton cycle with floating critical points. A distillation based regulation subsystem is integrated into the power cycle to dynamically adjust the circulating composition of the binary CO2 mixture, thereby making its critical point float with the ambient temperature and achieving good temperature matching. The off-design behavior of the system operating with the representative mixture is investigated based on an in-house code. The influence of trigger conditions of critical point regulation on energy consumption of the regulation process is investigated. When the maximum temperature difference of the design points for consecutive days is set to 3 °C, the equivalent power consumption can be limited to 2.34 × 106 MJ per year, which affects the annual efficiency by less than 1 %. The results confirms that using the floating critical point method can improve the annual efficiency by 7 %-10.9 % and improve the specific output power by 6.1 %-9.4 % compared to the sCO2 cycle, depending on the power plant locations.

Modifications in impeller blades for high efficiency mixing of pseudoplastic fluid in a stirred tank

Abstract Self-similarity impeller (SS impeller) was applied to enlarge the cavern region for the mixing of pseudoplastic fluid. The mixing characteristics of pseudoplastic fluid in an SS impeller stirred tank were explored by employing experimental and numerical simulation. The results indicated that the utilization of SS impeller resulted in significant improvement in the largest Lyapunov exponent of mixing system, as well as reduced mixing time and decreased mixing efficiency number compared with pitched-blade impeller (PB impeller) operating at an equivalent power consumption per unit volume. A reduction in power consumption was obtained through the application of self-similar configuration for the impeller blades. Meanwhile, SS impeller could enhance the fluidity of pseudoplastic fluid, minimize the stagnation regions, and enlarge the cavern region. This phenomenon was even more pronounced as the increase in self-similar iteration number of SS impeller. It was found that the design of self-similar structure for impeller blades could expand the cavern region and enhance the mixing efficiency for the mixing of pseudoplastic fluid, particularly as the self-similar iteration number increased.

Modeling and analysis of the voyage cycle for ferryboat electrification

Voyage cycle modeling provides an estimation of the battery energy requirements in preparation for the electrification of passenger ships. In this study, the objectives are to model the voyage cycle of a public transportation ferry and to determine the appropriate battery storage capacity in preparation for ferry electrification. Pasig River Ferry Service (PRFS), located in Metro Manila, Philippines, was used to model a voyage cycle for ferryboat electrification. Speed and route characteristic data were gathered during the operations of the ferry through a surveyor equipped with a GPS logger. The voyage characteristics gathered, ferry specifications, and diesel engine look-up table were used as inputs to develop a Simulink model that provides the estimated fuel consumption and the equivalent power consumption of the ferry in the case of electrification. The fuel consumption estimate was validated by comparing it to the fuel consumed during actual operation. Based on initial results, the fuel consumption estimates have percentage errors that vary from 2.25 to 12.94 % compared to the actual recorded fuel consumption during operations. The instantaneous power consumption from the voyage cycle Simulink model was used as an input to battery discharge simulations to evaluate the target battery design of the equivalent electric ferry system. Using the methodology of this study, the battery configuration and capacity were determined and evaluated for a single roundtrip voyage of the passenger boat. Highlights Voyage Cycle modeling can provide an overview of the performance of a ferry Fuel and energy consumption can be estimated from the voyage cycle Battery discharge simulation is a method used to verify the battery system design Voyage Cycle Modeling is an initial step for existing boat operators in determining the energy requirements prior to electrification

Design and Test of the Clearing and Covering of a Minimum-Tillage Planter for Corn Stubble

Conservation tillage technology can reduce wind erosion and soil erosion, improve soil fertility, avoid straw burning and relieve ecological pressure. It is an important measure to achieve sustainable agricultural development. In northeast China, there is a large amount of straw covering the ground after the corn machine harvest, which can easily lead to the blockage of the soil-touching parts during no-tillage seeding, affecting sowing quality and crop yield. In order to solve the above problems, the clearing and covering of a minimum-tillage planter for corn stubble was developed. The machine can complete multiple processes, such as seedbed preparation, seeding, fertilization, covering and suppression, straw covering, etc., in a single entity. This paper focuses on the design of the straw cleaning device and uses discrete element method software (EDEM 2018, Altair Engineering, Troy, MI, USA) to establish the straw cleaning device–straw–soil discrete element simulation model. The quadratic-regression orthogonal center-of-rotation combination test method is used to optimize the parameter combination of the machine, using the operating speed, the speed of the knife roller and the penetration depth of the knife as the test factors and using the rate of cleaning straw and the equivalent power consumption as the evaluation index. The results show that each factor has a significant influence on the performance evaluation indices, and the order of influence of each factor on the rate of cleaning straw is operation speed > penetration depth of knife > speed of knife roller, and the order of influence of each factor on the equivalent power consumption is penetration depth of knife > speed of knife roller > operation speed. The optimal combination of parameters is a 5.5–6.2 km/h operation speed, a 500 rpm speed of the knife roller, a 40 mm penetration depth of the knife, a straw-cleaning rate of more than 90% and an equivalent power consumption of less than 8 kW. This study provides technical and equipment support for the promotion of conservation tillage technology in Northeast China.

Investigation on a novel pumpless module driven by thermal energy and gravity and its application in an ORC system

The “virtual” pump without power supply is a potential replacement for the electrically-driven pump in the conventional Organic Rankine Cycle (ORC) system. In this paper, a pumpless module and a 10 kW ORC system are designed and constructed, and the optimization for the system control method is studied with the performance evaluation of the pumpless module. The experimental results show that the generated power fluctuates periodically with applying the pumpless module. There exists an optimal liquid level range of (280–340) mm in a pumping cycle to stabilize the output power near the peak. By optimizing the input vapor flowrate, pressure balance time, and upper and lower limits of the liquid level of the pumpless module, the liquid flowrate and the average power generation can reach 1.25 kg/s and 11.76 kW respectively. In addition, the heat consumption and the equivalent power consumption of the pumpless module are analyzed. The heat consumption as a percentage of the total input heat increases from 4.2% to 14.7% as the heat source temperature increases from 90 °C to 130 °C, and its equivalent power consumption can save 36.1% at 90 °C compared to the electrically-driven pump while consumed 7.8% more than the electrically-driven pump at 130 °C.

The FastEddy® Resident‐GPU Accelerated Large‐Eddy Simulation Framework: Model Formulation, Dynamical‐Core Validation and Performance Benchmarks

AbstractThis paper introduces a new large‐eddy simulation model, FastEddy®, purpose built for leveraging the accelerated and more power‐efficient computing capacity of graphics processing units (GPUs) toward adopting microscale turbulence‐resolving atmospheric boundary layer simulations into future numerical weather prediction activities. Here a basis for future endeavors with the FastEddy® model is provided by describing the model dry dynamics formulation and investigating several validation scenarios that establish a baseline of model predictive skill for canonical neutral, convective, and stable boundary layer regimes, along with boundary layer flow over heterogeneous terrain. The current FastEddy® GPU performance and efficiency gains versus similarly formulated, state‐of‐the‐art CPU‐based models is determined through scaling tests as 1 GPU to 256 CPU cores. At this ratio of GPUs to CPU cores, FastEddy® achieves 6 times faster prediction rate than commensurate CPU models under equivalent power consumption. Alternatively, FastEddy® uses 8 times less power at this ratio under equivalent CPU/GPU prediction rate. The accelerated performance and efficiency gains of the FastEddy® model permit more broad application of large‐eddy simulation to emerging atmospheric boundary layer research topics through substantial reduction of computational resource requirements and increase in model prediction rate.

Introduce a novel configurationof microchannel andhigh-conductivity insertsfor cooling of disc-shaped electronic components

Purpose Electronic components’ efficiency is the cornerstone of technology progress. The cooling process used for electronic components plays a main role in their performance. Embedded high-conductivity material and provided microchannel heat sink are two common cooling methods. The former is expensive to implement while the latter needs micro-pump, which consumes energy to circulate the flow. The aim of this study is providing a new configuration and method for improving the performance of electronic components. Design/methodology/approach To manage these challenges and improve the cooling efficiency, a novel method named Hybrid is presented here. Each method's performance has been investigated, and the results are widely compared with others. Considering the micro-pump power, the supply of the microchannel flow and the thermal conductivity ratio (thermal conductivity ratio is defined as the ratio of thermal conductivity of high thermal conductivity material to the thermal conductivity of base solid), the maximum disk temperature of each method was evaluated and compared to others. Findings The results indicated that the Hybrid method can reduce the maximum disk temperature up to 90 per cent compared to the embedded high thermal conductivity at the same thermal conductivity ratio. Moreover, the Hybrid method further reduces the maximum disk temperature up to 75 per cent compared to the microchannel, at equivalent power consumption. Originality/value The information in this research is presented in such a way that designers can choose the desired composition, the limited amount of consumed energy and the high temperature of the component. According to the study of radial-hybrid configuration, the different ratio of microchannel and materials with a high thermal conductivity coefficient in the constant cooling volume was investigated. The goal of the investigation was to decrease the maximum temperature of a plate on constant energy consumption. This aim has been obtained in the radial-hybrid configuration.

Simulation research on a variable-lift absorption cycle and its application in waste heat recovery of combined heat and power system

To solve the dilemma between temperature lift capability and coefficient of performance (COP) when absorption heat pump is applied in low grade heat utilization, a variable-lift absorption cycle and an improved one based on it are introduced here. The variable-lift absorption cycles have relatively simple systems and contains enough number of absorbers and condensers to develop plenty of gradually increasing temperature levels to match heating process. For a given heating demand and waste heat temperature level, the results of application of variable-lift absorption cycles in waste heat recovery of combined heat and power(CHP) system show that, the variable-lift cycles can always work efficiently when return water temperature of primary heating network (PHN) varies from 30 °C to 50 °C. The needed heat source temperatures of variable-lift cycles are always over 12 °C lower than single effect cycle. The higher return water temperature of PHN yields more obvious advantage of the improved cycle. When the return water temperature of PHN is 50 °C, variable lift-2C cycle and variable lift-3C cycle can reduce the equivalent power consumption for space heating by 8.5% and 15% respectively when comparing to single effect cycle. The essence of the variable-lift cycles is further clarified from the heat transfer analysis in T-Q diagram.

Power-based energy grade study of China's on-grid distributed combined heating and power systems

China has been vigorously developing natural-gas-based urban district heating (UDH) to reduce the severe impact of emissions from coal-based UDH. China has strict regulations concerning the energy utilization efficiency and heat-to-power ratio of combined heating and power (CHP) according to national conditions. These regulations determine the particularities of China's CHP. This study proposes a distributed energy system (DES) with heat pump heating (DES + HPH) and power-based energy grade methodology. The equivalent power consumption of steam and hot water consumed for heating is calculated according to the resulting reduction in the power output of the DES by providing steam and hot water. The comparable coefficient of performance (CCOP, i.e., the ratio of the heat output to the sum of heating equivalent power consumption and electricity consumption of HPH) can be applied to directly evaluate various heating systems because the denominator of CCOP has the same energy grade as power consumption. When the maximum heat load of HPH accounts for 40% of the maximum heat load of UDH, the average CCOP of the DES + HPH for conditions in Beijing reaches a maximum value of approximately 4.4, and its natural gas consumption corresponding to heating is approximately 64% lower than that of gas-fired heating boilers.

Comparable analysis methodology of CCHP based on distributed energy system

Energy and environmental issues have become increasingly prominent in the world. Distributed energy systems (DESs) and the combined cooling, heating, and power (CCHP) have been applied in the world. However, the evaluation of DESs and CCHP performance based on primary energy consumption is in dispute. Moreover, pursuing high performance of separate cooling/heating system is not beneficial for popularizing low-exergy cooling/heating technology in the field of DES in China. This study uses the pure-power-generation working condition of the DES as a baseline condition to conduct comparable analysis on DES-based CCHP according to energy grade. It is found that equivalent power consumption of steam and hot water consumed for CCHP is the power-generation capacity reduction of the DES compared with the baseline condition of the DES. DES-based steam and hot-water heating systems can save comparable energy cost (a sum of the equivalent and the direct power consumptions) by approximately 72% and 98%, respectively, compared with natural-gas-fired boilers. Hot-water-driven and steam-driven absorption cooling system based on the DES reach comparable coefficient of performances (a ratio of cooling capacity to comparable energy cost) of approximately 11.4 and 5.7. Thus, the proposed analysis methodology uses the power-generation capacity as benchmark to conduct energy grade analysis, and can more comparably and reasonably identify energy-saving capability of DES-based CCHP.

A CMOS Low Noise, Chopper Stabilized Low-Dropout Regulator With Current-Mode Feedback Error Amplifier

Low 1/f noise, low-dropout (LDO) regulators are becoming critical for the supply regulation of deep-submicron analog baseband and RF system-on-chip designs. A low-noise, high accuracy LDO regulator (LN-LDO) utilizing a chopper stabilized error amplifier is presented. In order to achieve fast response during load transients, a current-mode feedback amplifier (CFA) is designed as a second stage driving the regulation FET. In order to reduce clock feed-through and 1/f noise accumulation at the chopping frequency, a first-order digital SigmaDelta noise-shaper is used for chopping clock spectral spreading. With up to 1 MHz noise-shaped modulation clock, the LN-LDO achieves a noise spectral density of 32 nV/radic(Hz) and a PSR of 38 dB at 100 kHz. The proposed LDO is shown to reduce the phase noise of an integrated 32 MHz temperature compensated crystal oscillator (TCXO) at 10 kHz offset by 15 dB. Due to reduced 1/f noise requirements, the error amplifier silicon area is reduced by 75%, and the overall regulator area is reduced by 50% with respect to an equivalent noise static regulator. The current-mode feedback second stage buffer reduces regulator settling time by 60% in comparison to an equivalent power consumption voltage mode buffer, achieving 0.6 mus settling time for a 25-mA load step. The LN-LDO is designed and fabricated on a 0.25 mum CMOS process with five layers of metal, occupying 0.88 mm2.

A CMOS Low-Dropout Regulator With Current-Mode Feedback Buffer Amplifier

Current feedback amplifiers (CFAs) provide fast response and high slew rate with Class-AB operation. Fast response, low-dropout regulators (LDRs) are critical for supply regulation of deep-submicron analog baseband and RF system-on-chip designs. An LDR with an CFA-based second stage driving the regulation field-effect transistor is presented. The low dropout (LDO) achieves an output noise spectral density of 67.7 nV radicHz, and PSR of 38 dB, both at 100 kHz. In comparison to an equivalent power consumption voltage feedback buffer LDO, the proposed CFA-based LDO settles 60% faster, achieving 0.6- settling time for a 25-mA load step. The LDO with CFA buffer is designed and fabricated on a 0.25- CMOS process with five layers of metal, occupying 0.23- silicon area.

Destruction of formic acid using high frequency cup horn reactor

Degradation of formic acid has been studied in a high frequency cup horn type reactor with an aim of understanding the effect of operating parameters on the destruction efficiency. The methodology used in the work serves as a useful guideline for the optimization exercise for the sonochemical reactors to establish a set of operating parameters at large scale operation for achieving maximum efficiency. Firstly energy efficiency of the reactor has been established as a function of the operating volume with an aim of optimization of the capacity of the reactor for maximum extent of degradation. It has been observed that maximum transfer of supplied power is obtained at 300 ml capacity and hence the actual degradation studies have been performed with this operational capacity. The effect of time of irradiation, initial concentration of the pollutant, stirrer speed, presence of sodium sulfite (to scavenge the initial dissolved oxygen) on the extent of degradation has been investigated. Maximum extent of degradation has been observed under the conditions of 500 mg/l initial concentration, 200 rpm stirrer speed and presence of initial dissolved oxygen (no sodium sulfite in the system). Process intensification studies have been carried out using sodium chloride over a range of initial concentration and it has been observed that maximum extent of degradation of formic acid is obtained at 4% NaCl concentration. Comparison has been also made with different sonochemical configurations operating at lower frequency of irradiation (typically in the range of 20–50 kHz) with an aim of comparing the efficacies of the reactor at equivalent power consumption.