Increasing Energy Costs Research Articles

ORGANIC MATERIAL POTENTIAL AND ENERGY ANALYSIS FOR BIOGAS APPLICATION OF BATMAN

With the decrease of fossil fuels in the world, increasing energy costs caused the countries to turn to different kinds of energy sources. One of these sources is biogas energy whic is a renewable energy source. Biogasorganic is a kind of energy resulting from the fermentation of domestic and industrial wastes in indoor environment. In this study, biogas amounts and energy analysis which can be obtained by determining the potentials of organic (animal and herbal) wastes belonging to Batman province have been made. As a result of the researches, 52% of the total wastes in the province of Batman are composed of organic wastes. According to the data obtained in the calculations; It has been found that the biogas production potential in Batman province is 115,745 m3 / day biogas and 544,000 KWh / day electrical energy from the wastes and 1.563 m3 / day biogas and 7.346 KWh / day electrical energy from the vegetable wastes. The obtained data are given in table and graph.

청주시 취약계층 독거노인 가구의 에너지비용 부담 경험과 인식

Energy cost increase affects energy cost burden of households, and households with limited resources are influenced even worse. Especially, the elderly are far more vulnerable to negative indoor conditions such as cold, heat, extreme temperature changes, humidity. This study was aimed to explore perception and experiences of energy costs burdens of the elderly living alone in Cheongju-si, Chungbuk, in order to make suggestions to improve their energy welfare condotion. During February and March 2018, a questionnaire survey was conducted to the elderly single-person households in Cheongju and 219 useable responses were analyzed statistically. Major findings were as follows. (1) Average income to energy cost ratio in winter time was 54.5%. (2) 89.0% were found to be ‘winter-time energy poor’ to spend 10% or more of their income for energy costs. (3) Older elderly, the elderly living in rural area or singlefamily detached homes, and those who were not beneficiaries of any support program of basic pension were found to have a greater chance to be winter-time energy poor than other respondents. (4) More than 83% were found to have perceived energy cost burdens in recent three years, and 69.6% had experiences to reduce essential spendings and 26.2% had to borrow money to afford energy bills.

Investigating ride quality of the machine-tractor unit with a variable mass during transport work

The disclosure of issues related to solving problems of transport work has always been relevant. Today, in the study of types of transport works used in agriculture, there is a problem in the study of the movement of machine-tractor unit with trailed or semi-trailer tanks, which are filled with liquid. Since the transportation of liquid cargo causes significant internal oscillations, the impact on the operation of the wheeled tractor and tank is significant. This process causes longitudinal and transverse instability, which contributes to the increase of both energy costs and emergency situations (there is an effect on vibrations of motion, controllability and stability of the vehicle, increasing the dynamic loading of the running system, etc.). The goal of the work is to study the smoothness of the machine-transport unit with variable weight (semitrailer-tank and tank-trailer) by simulating the vibrational system of the vehicle. Namely, to study the effect of forced oscillations on the movement of a semi-trailer tank and a trailer tank, as well as when varying the rigidity of the tires of the wheeled tractor. In solving the set goal, a methodology was used which included the analysis of the results of mathematical modeling of the vibration of the wheeled tractor and the tank with a liquid containing a free surface in the dynamic solution of the problem. The model used takes into account the redistribution of liquid in the tank, which is caused by fluctuations of the shell, using the characteristics of the Rayleigh surface waves. As a result, the data of theoretical research, which take into account the variable weight of the semi-trailer and trailer unit during the performance of the machine-tractor unit of transport work with varying rigidity of tires, is obtained. The originality is in determining the dependence of the rigidity index of the wheels of the wheeled tractor on the smoothness of the machine-tractor unit with a semi-trailer and trailer tanker. The practical value of the work is in the recommendations on the use of one or another pressure in the tires of the wheeled tractor during operation.Key words: wheeled tractor; transport work; tank, vibrations; mass redistribution.

Metabolic and Hemodynamic Efficiency of Identical Workloads Performed with Stable Supine vs Upright Cycle Ergometry

Although differences among postural positions during cycle ergometry generally display a metabolic response favoring the upright posture, the use of identical workloads regardless of pedal frequency are scarce. Using an electromagnetically braked ergometer with a constant load that accommodates a range of pedal frequency of 155 rpm, provided an identical workload despite positional changes and/or variation in pedal frequency. In addition, a lack of subject stability during supine exercise may contribute to an increased energy cost. PURPOSE: To determine the metabolic efficiency between supine (S) versus upright (U) cycling at identical workloads with stable supine subject positioning. METHODS: 15 healthy college students (age 20.9 ± 1.3 yr, ht. 172.3 ± 8.5 cm, body mass 76.9 ± 12.6 kg, 8♂) volunteered to participate in two randomly assigned GXT trials preceded by 5 minutes of rest, followed by a progressive increase of 25 watts per 3 min stage, starting at 50 w. Open circuit spirometry measured metabolism and hemodynamics were assessed by cardiac impedance. The seat was located 12° posterior of vertical above the center crank (CC) for the U trial and the subject was supine with the CC elevated 33 cm above the platform for the S trial. RESULTS: VO2 (L/min) were 1.12 ± 0.17 vs 1.06 ± 0.14, 1.35 ± 0.18 vs 1.28 ± 0.13, 1.55 ± 0.17 vs 1.52 ± 0.12, and 1.76 ± 0.17 vs 1.78 ± 0.15, and cardiac output [Q](L/min) were 13.6 ± 2.8 vs 12.0 ± 3.5, 15.1 ± 3.1 vs 14.1 ± 3.5, 16.4 ± 3.1 vs 16.6 ± 2.0, and 18.3 ± 3.0 vs 19.1 ± 2.4, for 50, 75, 100, and 125 watt workloads, for U vs S trials, respectively. NSD was found between VO2 or Q at all workloads, except VO2 at 75 w. CONCLUSION: Often extraneous subject supine mobility may impact cycling energy cost, however the subjects used a supine cycling platform, thus shoulder support prevented posterior body migration. At low to moderate intensity cycle exercise, with subjects in a stable position, the hemodynamic and metabolic response to supine vs upright cycling is virtually indistinguishable.

An innovative approach for harmonising availability and energy efficiency in data centres: A case study

A Data Centre (DC) as critical, energy-hungry infrastructure is dominated by two main driving forces: i) Availability and ii) Energy requirements. As a result of increasing energy costs, algorithms for optimising energy efficiency have been devised. However, these algorithms do not take availability into consideration. This paper aims to present a combination of Failure Mode, Effects and Criticality Analysis (FMECA)/Reliability, Availability, Maintainability (RAM)/Energy Analysis as an innovative approach for harmonising availability and energy efficiency in DC. Based on various measures defined by FMECA/RAM, corresponding availability and reliability are modelled and calculated. In parallel, potential energy saving measures are included in RAM simulation to quantify their influence on the availability and reliability of DC infrastructure. As a result, a set of the most promising optimisation measures is selected. Results show that some energy saving measures are highly correlated with availability. However, required data centre availability can be achieved with improved energy efficiency if the right set of optimisation measures is implemented. This approach guides DC managers to identify improvement potentials in terms of availability and energy efficiency, providing a reliable decision basis for future investments.

Minimum-Energy Distributed Consensus Control of Multiagent Systems: A Network Approximation Approach

This paper investigates the problem of minimizing the global energy cost for multiagent systems to achieve consensus over undirected network topologies. Conventional optimization problems so defined require all-to-all network topologies for interagent communications, which precludes the use of distributed control or otherwise demands that the network be complete. To circumvent this difficulty, we introduce a network approximation (NA) scheme in the optimization criterion, which tends to render the optimization problem to one seemingly over a complete graph network, thus removing the all-to-all communication requirement. With the NA cost, we show that a distributed optimal consensus algorithm always exists for any given connected network topology, which can be determined by solving a single-agent-level parametric algebraic Ricatti equation (PARE). We also investigate the performance of the optimal consensus algorithm, focusing on the minimal energy cost required to achieve consensus optimally, and the speed at which consensus is achieved. Furthermore, for certain more special yet worthy cases, such as single-integrator, double-integrator, and first-order unstable agents, we derive explicit expressions for the energy cost and the consensus speed. It can be seen from these results that the energy cost can be made arbitrarily small for single-integrator and double-integrator systems under the optimal distributed control. On the other hand, for the first-order unstable agents, the energy cost increases and consensus speed decreases monotonically with the value of the agent's real unstable pole.

Optimization of energy consumption and surface roughness in slot milling of AISI 6061 T6 using the response surface method

Industrial sectors are looking for reducing their energy consumption due to the concerns on fossil fuel depletion and climate change, along with the increasing energy costs. In recent years, research on optimizing the energy consumption of machining processes has received significant attention as a way to diminish their environmental impact.

Stochastic optimal energy management system for RTG cranes network using genetic algorithm and ensemble forecasts

Abstract In low voltage networks, Energy Storage Systems (ESSs) play a significant role in increasing energy cost savings, peak reduction and energy efficiency whilst reinforcing the electrical network infrastructure. This paper presents a stochastic optimal management system based on a Genetic Algorithm (GA) for the control of an ESS equipped with a network of electrified Rubber Tyre Gantry (RTG) cranes. The stochastic management system aims to improve the reliability and economic performance, for given ESS parameters, of a network of cranes by taking into account the uncertainty in the RTGs electrical demand. A specific case study is presented using real operational data of the RTGs netwrok in the Port of Felixstowe, UK, and the results of the stochastic control system is compared to a standard set-point controller. In this paper, two forecast data sets with different levels of accuracy are used to investigate the impact of the crane demand forecast error in the proposed ESS control system. The results of the proposed control strategies indicate that the stochastic management system successfully increases the electric energy cost savings, the peak demand reductions and successfully outperforms a comparable set-point controller.

Вплив низькочастотного електромагнітного поля на динаміку виходу біогазу

Вплив низькочастотного електромагнітного поля на динаміку виходу біогазу

Differential privacy for renewable energy resources based smart metering

The increasing energy costs and increase in losses in traditional power grid system triggered the integration of Renewable Energy Resources (RERs) in smart homes. The global desire of consumers to rely on RERs such as solar energy, and wind energy has increased dramatically. Similarly, the IT technologies are also playing their part in smart grid development, such as real time data monitoring. On the other hand, with the advancement of these IT technologies in smart meters, the privacy of customers is also at risk Smart grid utility knows the exact generation of any specific renewable resource in a specific interval of time. Utility need to monitor this real time data for load forecasting and implementation of demand response scenarios. However, the utility may misuse the data and may increase the prices for specific time slots when RERs are not present. Similarly, real time monitoring of data can lead to estimation of life routines of users such as sleeping habits, time of usage of heavy appliances, and lifestyle. In this paper, a Differential Privacy based real time Load Monitoring approach (DPLM) is proposed that preserve the privacy of users by masking the values of load in such a way that utility will not be able to judge the usage of specific RER and the daily routine of any smart meter user. We compare our scheme with Gaussian Noise Differential Privacy (GNDP) strategy. Experimental results validate that our DPLM approach provides a desirable solution to protect smart grid user’s privacy by efficient noise addition and peak value protection along with having an error rate of only 1.5%.

Cooperative and hybrid energy efficient schemE for wireless sensor networks

ABSTRACT Widespread multiple mobile agents (MAs) algorithms for wireless sensor networks use MAs itineraries starting and returning back to the sink node. Furthermore, each MA must carry the processing code to collect the sensory data and go back to the sink with the accumulated data. However, these assumptions increase the number of MA’s migration hops, which consequently consumes more energy and time. To overcome this problem, this paper proposes a Cooperative and Hybrid Energy Efficient SchemE for wireless sensor networks (CHEESE) that aims to soften the substantial increase in energy and time cost, used in the data transporting process. To do this, the sink node of the proposed approach ‘CHEESE’ sends only one main MA to the target area in the network. Then this main MA, will be hosted by a virtual sink in the target area, which will generate multiple MAs to collect and aggregate data. By the end of all MAs processes, the virtual sink gathers all the MAs data, aggregates and fuses them to send only the pertinent information to the sink. Moreover, CHEESE uses light MAs itineraries by browsing only a part of source nodes. CHEESE simulation results have effectively confirmed its efficiency in many scenarios.

The The Methodology of Thermal Energy Management for Nearly Zero Energy Buildings

Distributed generation causes an unbalanced power grid, which leads to a problem with unpredicted energy surplus balancing. In this vast problem, active cooperation with individual consumers on the energy market is crucial to ensure stability of the power system. Therefore, basing on analysis of power demand for the power system, the control algorithm of Thermal Energy Management System for the net Zero Energy Buildings was developed. One of the possibility of shifting peak power demand is using a building structure as a thermal energy storage. The potential of energy management was confirmed by numerical analysis of two nearly zero energy building models (a heavy and a light construction). A heavy construction building consumes less energy than a light construction but possibilities of obtaining measurable cost savings for user are higher in a case of light construction building. The objective of this study is to show that it is possible to save about 17–28% of the yearly cost of electricity by using the proposed control algorithm. On the contrary, lack of active and conscious usage will result in yearly increase of energy costs at the level of 5–8%. At the same time functioning of the HVAC system according to the proposed algorithm does not significantly effects on thermal comfort.

Climate change in Africa: costs of mitigating heat stress

We applied two metrics, apparent temperature and humidex, to calculate heat stress in both present and future climates. We use an ensemble of CORDEX-Africa simulations to estimate heat stress during a baseline period and at two specific warming levels, 2 and 4 ∘C above pre-industrial. The increase in temperatures and changes to the precipitation distribution under climate change are projected to increase the intensity of heat stress events in Sahelian Africa and introduce new heat stress events in Northern and Central Africa. As the intensity of heat stress increases, it is expected that the use of energy-intensive cooling will increase. The energy system, therefore, will need to be able to supply more energy to power fans or air conditioning units. The cooling demand to turn a heat stress event into a non-heat stress event is computed. This value is then weighted by the population to find the total cooling required to prevent heat stress across the continent. Country-level results indicate that the greatest increases in cooling demand will occur in countries with densely populated regions, most notably Nigeria. Supplying this additional cooling demand will present the greatest challenge to less developed countries like Somalia. We find the least-cost future energy system that meets the projected increase in demand and derive the increase in energy system costs with the TIAM-UCL model. The total increase in energy costs to prevent heat stress is found to be $51bn by 2035 and $487bn by 2076.

“Is Renewable Energy Affordable?” By Derek George Birkett; Cambridge Scholars Publishing, Newcastle upon Tyne, UK. (2019). Price £58.99 ISBN (10): 1-5275-2046-3; ISBN (13): 978-1-5275-2046-2

This book is written by a retired grid engineer and deals with renewable sources of energy and the instability of the electrical distribution grid. Derek Birkett carefully goes through the arguments about the electrical supply and the effect of intermittent and variable renewable sources of energy on grid stability. As a result of investment in renewable energy and the increasing costs of carbon taxes levied on fossil fuel fired generation, the government has created a situation which is very expensive for consumers and industry, and is unsustainable. The government has intervened in the energy market and provided subsidies and policy support for renewable energy without considering the consequences for the stability of the electrical grid system. The government has no strategic vision of the future for energy generation and no expertise to draw upon. Consumers experience increasing energy costs, power outages and blackouts which will be costly and hard to recover from. Derek states quite clearly that “… the state should no longer use environmental regulation for political purposes unless there is a clear imperative for national well-being and security.”

Modified Dynamic Programming Algorithm for Optimization of Total Energy Consumption in Flexible Manufacturing Systems

Based on the Petri net (PN) models of the flexible manufacturing systems (FMSs), this paper focuses on solving the scheduling problem of minimizing the total energy consumption of FMSs. In the view of different energy consumption rates of resources under different working statuses, two energy consumption functions are considered. The dynamic programming (DP) models of the scheduling problems based on PNs are established, where a reachable marking of a PN model, start processing time vector, route vector, and the transition sequence leading to the reachable marking from the initial one, is regarded as a state, and the Bellman equation is based on transition firing. For small-size scheduling problems, their optimal solutions can be obtained by the presented DP algorithm. However, it is difficult to solve larger-scale ones since the number of explored states increases exponentially with the problem size, which makes DP computationally infeasible. To obtain an optimal or suboptimal schedule in an acceptable time, modified DP (MDP) algorithm is proposed, in which fewer states are explored. In MDP, two ways are introduced through which only the most promising states are explored. One is keeping only one transition sequence for each marking through an evaluation function. Another is selecting the most promising states in each stage for further exploration through a heuristic function. To guarantee that the generated states are safe, a deadlock controller is applied in the recursion procedure of MDP. Experimental results on manufacturing systems and comparisons with existing works are provided to show the effectiveness of MDP. Note to Practitioners —This paper is motivated by the need of optimizing the energy consumption of manufacturing systems, considering the increasing energy cost and environmental concerns. Existing studies on energy optimization rarely focus on flexible manufacturing systems (FMSs) which exhibit a high degree of resource sharing and route flexibility and can be highly adaptable to various production plans and goals. Scheduling becomes more challenging when facing deadlock-prone FMSs. This paper provides a method to solve this complex scheduling problem efficiently. In this paper, dynamic programming (DP) is formulated for it, and the optimal energy consumption schedules are found. Considering the computational burden of implementing DP in the scheduling of large-size FMSs, a novel scheduling method named modified DP (MDP) is proposed. Experimental tests on an FMS and a stamping system suggest that MDP can successfully find feasible solutions. Besides, it can be applied to other FMS scheduling problems and industrial cases, once their processing time of operations and energy consumption of resources per unit time are known.

Algorithm of Distillation Plant Parameters Selection Based on “Mass Flow Rate-Enthalpy” Diagram

The problem of fresh water lack can be solved my desalination of the seawater. Desalination of the seawater can be accomplished by several methods. Distillation of the seawater is one of the most promising among them. This article deals with algorithm of distillation plant parameters selection based on “mass flow rate-enthalpy” diagram. This diagram allows to estimate operation of the plant by several criteria such as energy efficiency, real distillation plant output, steam compressor and evaporator efficiency. Criterion of optimal coordination of Steam Compressor (SC) and Evaporator-Condenser (EC) characteristics is minimal distance between point which is characteristics of SC and line - characteristics of EC. Diagram shows an example of coordination of two SC with different productivity with characteristics of one EC. Location of these SC characteristics as a points 2a and 2b on the line which is characteristics of EC means perfect example of coordination when potentials of SC and EC productivities are fully utilized. Diagram confirms linear increase of the total energy cost and quadratic increase of the required power of SC if productivity is necessary to increase at constant EC heat exchange area. Besides, considering bended characteristics of EC, it is possible to note higher energy efficiency of distillation plant at higher temperatures Analysis shows that distillation plant with consecutive evaporation of initial water provides optimal value of specific work spent for compression and consecutive connection of stages by steam have the worst value of work spent for compression.

Successful strategies for increasing energy self-sufficiency at Grüneck wastewater treatment plant in Germany by food waste co-digestion and improved aeration

Population growth, tightening effluent discharge requirements and increasing energy costs are driving the wastewater treatment sector to improve energy efficiency and strive towards energy self-sufficiency. Despite many strategies being proposed for improving energy self-sufficiency at wastewater treatment plants (WWTPs), limited case studies have been conducted. This full-scale case study at Grüneck WWTP evaluates the effectiveness of two different strategies and quantifies their plant-wide impact. Grüneck WWTP increased energy self-sufficiency by 24% (from 64 to 88%) through reducing energy consumption with aeration upgrades (8% increase) and increasing energy production with food waste co-digestion (16% increase). The plant-wide analysis indicated that the aeration upgrades did not affect effluent quality; however co-digesting food waste at 20% additional organic load caused some minor downstream impacts including reduced dewaterability, fluctuating biogas quality and solids accumulation. A solar dryer was installed to manage the increased biosolids production resulting from co-digestion. The dryer reduced biosolids transportation costs by 30% with minimal increase in total plant energy (below 2%). Payback periods for the co-digestion facility and blower upgrade were 10 and 17 months, respectively. The solar dryer, however, has a payback period of 30 years. Findings from this case study provide practical knowledge of the trade-offs for different strategies commonly employed to improve energy self-sufficiency at WWTPs. The results provide evidence that there is significant incentive for similar plants to improve energy self-sufficiency through co-digestion and aeration upgrades.

Assessment of grinding additives for promoting chromite liberation

Liberation of the valuable minerals of an ore from its gangue is a prerequisite for the economic recovery of the valuable minerals to concentrates. Mineral liberation is achieved by reducing the size of ore particles in various crushing and grinding devices. The fineness to which the ore must be ground, so as to yield sufficient degrees of liberation, increases if the valuable minerals with small grain sizes are disseminated throughout the gangue. Intensive fine grinding, however, increases energy costs and can lead to the loss of very fine untreatable particles into the tailings. Therefore, research should be oriented toward developing methods to foster breakage through the mineral grain boundaries to accomplish liberation at relatively coarser grinds. The purpose of this study is to determine if the pretreatment of the samples of a chromite ore with aqueous solutions of some salt and surfactant additives could improve the liberation by promoting preferential fracturing at the grain boundaries between the chromite and silicate minerals in the ore. For this purpose, untreated and pretreated samples of −9.53 + 6.35 mm size fraction of the ore were broken in a drop-weight tester, and the liberation spectra and the mass distribution of the resultant progenies were measured and compared. Optical and scanning electron microscope images and spectroscopic tools were used to find evidence for grain-boundary fracturing in the breakage progeny fragments. Results support the promoting effect of hydrolysis on grain-boundary fracturing. Aqueous salt and surfactant species enhance grain-boundary fracturing by forming surface complexes and dislocating aluminum atoms at the grain boundaries. Grain-boundary fracturing yields exposed chromite surfaces and enriched chromite content in the coarse progeny particles. The grain-boundary weakening is associated with slight hardness variation along the boundary.

Energy-saving walking mechanisms in obese adults.

Energy-saving mechanisms are used in human walking. In obese adults the energy cost of walking (Cw) is higher compared with normal-body mass adults. However, the biomechanical factors involved in this extra cost should result in a higher Cw. The aim of this study was to compare energy-saving walking mechanisms [i.e., mechanical energy saved via pendulum (Recovery) and maximum possible elastic energy usage (MPEEu)] and their influence on Cw in obese vs. lean individuals. The net Cw (NetCw), external work (Wext), Recovery, MPEEu, and gait weight transfer duration (gWT) were computed for 13 lean [L; body mass index (BMI) 21.9 ± 1.5 kg/m2] and 13 obese (O; BMI 33.8 ± 2.5 kg/m2) individuals during treadmill walking at five speeds (0.56, 0.83, 1.11, 1.39, 1.67 m/s). No significant difference was found between groups in relative (per kg of body mass) NetCw (P = 0.13). Relative positive Wext was significantly lower at the three fastest speeds (P ≤ 0.003) whereas Recovery was higher at the two fastest speeds (P ≤ 0.01) in O than in L individuals. MPEEu tended to be lower in O than in L (P = 0.06), with significantly lower values in O compared with L at 1.39 and 1.67 m/s (P ≤ 0.017). gWT was significantly shorter in O than in L individuals at 1.67 m/s (P = 0.001). The present results reveal that obese adults rely more on the pendular mechanism than on the storage and release of elastic energy for decreasing the amount of positive Wext and thus limiting the increase in the relative NetCw. NEW & NOTEWORTHY We observed that obese individuals had a lower maximum possible elastic energy usage per kilogram of body mass than their lean counterparts and they may rely more on the pendular mechanism of walking than on the storage and release of elastic energy for decreasing the external mechanical work and thus limiting the increase in the relative net energy cost of walking.

Benchmarking of a Free Vortex Wake Model for Prediction of Wake Interactions

Turbine-wake interactions pose significant challenges in the development of wind farms. These interactions can lead to an increase in wind energy cost through reduction in wind farm power efficiency as well as a reduction of functional turbine lifetime. The overall objective of this work is to assess the free vortex wake (FVW) approach for capturing wind farm interactions in the context of improved wind farm optimization. Specific focus areas include (1) analyzing the effects of turbine-wake interaction and (2) benchmarking of the model against experimental wind farm measurements. The effects of turbine-wake interactions are analyzed in terms of wake structure, rotor power, and structural response. The FVW model predicts increased unsteadiness in wake-influenced turbine rotor power and out-of-plane blade root bending moment. This could have implications for prediction of turbine life and suggests that the transient as well as average response of turbines should be considered to fully capture the effects of wake interaction. Comparisons between the FVW predictions and experimental measurements of relative rotor power are made over varying yaw angle and freestream velocity. Overall trends are predicted by the FVW approach, with less than 13% error on average when compared to wind farm measurements. These results indicate the FVW method is a useful tool for carrying out improved optimization of wind farms.