Energy use and appliance ownership in Ireland

This paper examines household energy use and appliance ownership in Ireland. Logit regression analyses on a large micro-dataset reveal how household characteristics can help explain the ownership of energy using appliances. Using OLS regression models, we explore the factors affecting residential energy demand conditional on appliance ownership. Results suggest that the methods of space and water heating employed by a household are even more important than electrical appliances in explaining domestic energy usage. However, the stock of appliances must be included in such models so that results will not be biased. The methods employed in this paper can be easily adopted for studies of household energy use in other countries where household expenditure survey data are available.     

State identification of home appliance with transient features in residential buildings

Nonintrusive load monitoring (NILM) is crucial for extracting patterns of electricity consumption of household appliance that can guide users’ behavior in using electricity while their privacy is respected. This study proposes an online method based on the transient behavior of individual appliances as well as system steady-state characteristics to estimate the operating states of the appliances. It determines the number of states for each appliance using the density-based spatial clustering of applications with noise (DBSCAN) method and models the transition relationship among different states. The states of the working appliances are identified from aggregated power signals using the Kalman filtering method in the factorial hidden Markov model (FHMM). Thereafter, the identified states are confirmed by the verification of system states, which are the combination of the working states of individual appliances. The verification step involves comparing the total measured power consumption with the total estimated power consumption. The use of transient features can achieve fast state inference and it is suitable for online load disaggregation. The proposed method was tested on a high-resolution data set such as Labeled hIgh-Frequency daTaset for Electricity Disaggregation (LIFTED) and it outperformed other related methods in the literature.     

Evaluating the benefits of an electrical energy storage system in a future smart grid

Interest in electrical energy storage systems is increasing as the opportunities for their application become more compelling in an industry with a back-drop of ageing assets, increasing distributed generation and a desire to transform networks into Smart Grids. A field trial of an energy storage system designed and built by ABB is taking place on a section of 11 kV distribution network operated by EDF Energy Networks in Great Britain. This paper reports on the findings from simulation software developed at Durham University that evaluates the benefits brought by operating an energy storage system in response to multiple events on multiple networks. The tool manages the allocation of a finite energy resource to achieve the most beneficial shared operation across two adjacent areas of distribution network. Simulations account for the key energy storage system parameters of capacity and power rating. Results for events requiring voltage control and power flow management show how the choice of operating strategy influences the benefits achieved. The wider implications of these results are discussed to provide an assessment of the role of electrical energy storage systems in future Smart Grids.     

With time comes increased loads—An analysis of solar home system use in Lundazi, Zambia

Solar energy can bring a number of electric services to the user but also puts up a number of limitations in terms of usage. The design of the system will affect the output from the system as well as the technical life. This article is based on a case-study of a photovoltaic-Energy Service Company (PV–ESCO) project company in Lundazi, Zambia. The solar technology has enabled clients to improve light quality in their houses or shops, which is the most valued benefit according to clients. Clients to the ESCO have acquired a number of electric appliances since they received the service. Radio cassette players are commonly found in households both with and without solar services, while TV sets has been acquired first after they have received this service. To the clients the solar services have resulted in an improvement of the living standards. Energy use and charge was logged during a six-month period. Average usage range from 10 to 14 Ah/day. The load is concentrated to mornings and evenings, but the possibility to access energy services, such as light during the night, is appreciated by the clients. The average energy output from the solar module is 14.5 Ah/day. Increased panel effect, change of the cutting points of the regulator and improve the users knowledge on proper operation of the system are options to tackle the situation of increased loads put on the system.     

Behavioral aspects of regulation: A discussion on switching and demand response in Turkish electricity market

Electricity sector has been transformed from state-owned monopolistic utilities to competitive markets with an aim to promote incentives for improving efficiency, reducing costs and increasing service quality to customers. One of the cardinal assumptions of the liberalized and competitive electricity markets is the rational actor, and decision-makers are assumed to make the best decisions that maximize their utility. However, a vast literature on behavioral economics has shown the weakness of economic theory in explaining and predicting individuals’ decision-making behavior. This issue is quite important for competition in electricity markets in which consumers’ preferences have a significant role. Despite its importance, this issue has almost been neglected in Turkey, which has taken major steps in electricity sector restructuring. Therefore, this paper aims to examine switching and demand response behavior in Turkish electricity market by using multiple correspondence and panel data analysis, and findings are discussed in light of the neoclassical and behavioral economics literature. Analyses’ results show that consumers’ switching and demand response behavior is consistent with the neoclassical literature to some extent; however, behavioral factors are also affecting consumers’ decisions. Furthermore, there are systemic problems that hinder effective functioning of the electricity market and restrict competition.     

Dynamic modeling and experimental validation for the electrical coupling in a 5-cell solid oxide fuel cell stack in the perspective of thermal coupling

The electrical coupling in a 5-cell solid oxide fuel cell (SOFC) stack is investigated in this research. The electrical characteristics tests of a single cell and the stack were performed in an electrical furnace. It was found that the single cell with the highest temperature does not give the highest output voltage in the stack test, which is different from the result that the output voltage increases with temperature in the single cell test. A physical interpretation for this phenomenon is given specifically from the standpoint of electrical coupling on the basis of thermal coupling between cells in the stack. Furthermore, a system level electrical coupling dynamic model is developed to characterize the electrical characteristics of the stack by considering the contact resistance between cells. In addition, the electrical coupling dynamic model is calibrated and validated based on the experimental data. The results demonstrate that the electrical coupling dynamic model can depict and predict accurately the electrical characteristics of SOFC stacks. The accurate electrical coupling dynamic model is important for the system level study of SOFCs, such as the optimization of stack structures and the design of peripheral control systems.     

Analysis of biomass residues potential for electrical energy generation in Albania

This paper presents the status of research of biomass potential for producing electrical energy in Albania. Biomass potential can be generated by different sources. Three types of biomass energy sources are included: dedicated bioenergy crops, agricultural and forestry residues and waste. The technical electrical energy considered in this study was calculated with two converting techniques: (1) combustion of the feedstock directly in an incinerator and then driving a steam generator for producing electrical energy and (2) production of biogas from an anaerobic digester and running a turbine for electrical energy generation. Analysis of the potential biomass resource quantity was computed according to statistical reports, literature review and personal investigations. From the biomass residue potential was calculated in terms of the theoretical energy content (total heating value) of every type of feedstock and the technical energy content for every Albanian prefecture according to different burning processes and different operation efficiencies. Results show that Albania was producing around of 4.8 million tons of dry biomass in year 2005. The theoretical energy content of biomass in Albania was 11.6 million MWh/a, and the technical electrical energy production was 3 million MWh/a. The electrical energy produced is equivalent to 45.8% of total Albania Country annual electrical consumption. In Albania Country, residues from agriculture, forest and urban waste represent a large biomass potential. By actual conversion techniques it is possible to generate one third of the theoretical heat energy into technical electrical energy. The use of heat from cogeneration plants depends on local heat provision conditions. It is another big energy potential but excluded in this study, so the rest of energy is considered as heat losses.     

Effect of nonuniformity of the contact pressure distribution on the electrical contact resistance in proton exchange membrane fuel cells

Electrical contact resistance (ECR) is one of the most important factors affecting the ohmic loss in proton exchange membrane (PEM) fuel cells. Dominated by the contact pressure at the interface of two neighboring components, the ECR can be reduced by increasing the clamping force applied on fuel cell stack. However, too large a clamping force will result in excessive resistance to the transport of reactants in the gas diffusion layer (GDL) and even damage to the fuel cell components. Therefore, for a given clamping force, the minimum ECR is expected by making the pressure distribution as uniform as possible. This paper investigates two questions: (a) how to evaluate the distribution of non-uniform pressure based on the ECR, and (b) in what situation will a uniform pressure distribution reduce the ECR obviously, i.e., the sensitivity of the contact resistance to the pressure distribution.     

Role of porosity on the equilibration kinetics in electrical conductivity relaxation experiments

The role of porosity on the equilibration kinetics in electrical conductivity relaxation (ECR) experiments is highlighted. Both porous and dense conductivity bars are used to determine the chemical oxygen surface exchange coefficient (k_chem) of neodymium nickelate Nd₂NiO_4+δ (NNO) from 600 to 800 °C. Using porous bars allows for quicker ECR experiments during which the conductivity transient is rate limited only by oxygen surface exchange which enables the use of a simple transient model. Additionally, porous bars have similar microstructures to porous electrodes which means they are critical for determining the oxygen exchange kinetics of realistic electrodes. ECR results on dense bars with porous coatings are also presented. The conductivity transients of dense and porous bars both show similar trends with oxygen partial pressure. Additionally, both porous and dense bars show a difference between oxidation and reduction transients with oxidation transients being faster than reduction transients.     

The demand for electrical energy in Korean industry

There is no question that energy is an important ingredient in the development of any country. Unfortunately, the ability of less developed countries to respond to the particular nuances of the energy market is not well understood. This paper endeavors to look at one aspect of this potential responsiveness in one country (Korea). After establishing an empirical relationship between the consumption of electrical energy in various industries and the price of electrical energy, the price of petroleum, and the price of coal, estimates of the magnitudes of the relationships are obtained. Finally, the stability of the estimated relationship is examined with the resultant suggestion that industries' demand for electrical energy was fairly stable over the decade of the seventies.     

Measurement of ice movement in water using electrical capacitance tomography

The permafrost with the highest altitude and largest area in the mid and low latitude is located in the Qinghai-Tibet Plateau. As most frozen soils contain ice particles which are very sensitive to temperature and other external parameters, thus influencing the stability of the embankment in permafrost regions, it is very important to develop techniques to prevent damages to railway embankments due to thaw settlement. In this paper, the electrical capacitance sensors are designed to study the freezing front movement in a vessel and ice movement in water, which is the first step to apply the ECT system to the study of frozen soil. Two sensor arrangements are put into use. First, the traditional closed electrode sensors are put into use. In this arrangement, the electrodes are attached to the outside of the pipe or vessel, and the cross-sectional distribution of ice and water could be reconstructed from the capacitances measured. Also, the ice moving track at the cross section could be reflected thoroughly. Since the traditional closed electrode sensors can not meet the needs of measuring the ice freezing front movement, a new electrode sensors structure, that is, the unclosed electrode sensors are designed to satisfy the specific test of frozen soil. In this arrangement, several pairs of electrodes are arranged along the height of the vessel. A sudden decrease in the measured capacitance is observed when the freezing front advances past the electrodes. Therefore, according to the capacitance variation, the ice movement can be reflected. In summary, electrical capacitance tomography has the advantages of being non-intrusive. With different electrode sensor arrangement, ice movement and ice freezing front can be obtained. The electrical capacitance sensor system can be applied to investigate the complicated phenomena in frozen soil.     

Optical and electrical characterization of carbon nanoparticles produced in laminar premixed flames

Optical and electrical properties of carbonaceous particles produced in laboratory scale, premixed ethylene/air flames are obtained. Light absorption and Raman spectroscopy show that the change in particle nanostructure follows a graphitization trajectory as the flame richness increases. The optical band gap decreases and the size of the aromatic network in the particle increases, while the interlayer spacing between parallel layers decreases. The electrical conductivity of the materials increases by increasing flame richness in agreement to the graphitization trajectory. A non-ohmic behavior has been found and explained in terms of electron tunneling in a percolative network. Our results show that the electrical properties of flame formed carbon nanoparticles are strongly dependent on their nanostructure, and hence they have to be used carefully for the determination of particle concentration with conductometric sensors. Moreover, the dependence of the electrical properties of combustion formed particles might be useful for the development of cheap sensors for the selective detection of different classes of combustion aerosols.     

Dynamics of three-dimensional temperature field in electrical system of floor heating

In the paper dynamics of a three-dimensional temperature field in the system of direct floor heater was investigated. A step response (heating on curve) and local and global time constants of the device were determined. Then, a spatial-temporal distribution of the field in the system controlled by the on-off regulator was found. The mathematical model of heat propagation was a non-homogeneous and homogeneous equation of a three-dimensional diffusion with an adequate set of boundary conditions. Four methods were applied for the solution of the above: superposition of states (coupled with separation of variables), finite elements, criterion of an averaged time constant and superposition of step characteristics. It was found that time profiles of the temperature depend very strongly on the position of an observing point. All relations were processed numerically. The obtained results are presented in a graphic form. A physical interpretation of the achieved solutions is included.     

Energy use in industry—V: Energy use in a heavy engineering workshop

The paper describes energy use in a particular heavy engineering workshop and investigates the consequences of possible improvements to lighting, to the thermal performance of the building and to the means of distribution of power. Comparisons are made with previous work done on other factories engaged in engineering. A method of describing the economic potential of energy conservation as an element of energy strategy is proposed.     

Industrial energy use-1: Power losses in electrically driven machinery

Much work has been done on the energy losses in electro-mechanical power transmission chains. This paper suggests a useful presentation and interpretation of the data.     

Exergy analysis of the energy use in Greece

In this work, an analysis is being done on the concept of energy and exergy utilization and an application to the residential and industrial sector of Greece. The energy and exergy flows over the period from 1990 to 2004 were taken into consideration. This period was chosen based on the data reliability. The energy and exergy efficiencies are calculated for the residential and industrial sectors and compared to the findings of a previous study concerning the exergy efficiency of the Greek transport sector. The residential energy and exergy efficiencies for the year 2003 were 22.36% and 20.92%, respectively, whereas the industrial energy and exergy efficiencies for the same year were 53.72% and 51.34%, respectively. The analysis of energy and exergy utilization determines the efficiency of the economy as a whole. The results can play an important role in the establishment of efficiency standards of the energy use in various economy sectors. These standards could be utilized by energy policy makers.     

An electrical resistance tomography technique for the monitoring of a radioactive waste separation process

An electrical resistance tomography (ERT) technique is suggested to monitor a radioactive waste separation process. This paper presents analytical results for a simple model problem to estimate the boundary between two distinct waste streams in a rotating separator as well as the conductivity value of each stream. To solve this highly non-linear identification problem, the particle swarm optimization (PSO) algorithm is successfully introduced. The results show the feasibility of the ERT for monitoring the separation process.     

Effect of polyaniline on the electrical conductivity and activation energy of electrospun nylon films

Nano films of nylon 6 and polyaniline (0, 1, 2, 3, 4, 5, and 6 wt. %) were prepared by the electrospinning technique. The addition of polyaniline increased the electrical conductivity of nylon 6. Pure nylon had an electrical conductivity of 3.8 × 10^?3 S/cm, while the conductivity of nylon 6 with 1% polyaniline was 10.2 × 10^?3 S/cm. In addition, the electrospinning process increased the electrical conductivity of bulk nylon 6 from 10^?14 S/c to 10.2 × 10^?3 S/cm. The viscosity and surface tension of nylon 6 decreased with increasing polyaniline content. The morphology of the prepared films was observed with SEM, and the average diameter of the fibre diameters, which was measured statically from the SEM images, was found to be 74 nm for a nylon film with 4 wt.% polyaniline, and 180 nm for pure nylon. The nanofibre films showed an enhanced electrical conductivity with increasing polyaniline concentration, from 2.627 × 10^?10 S/cm for a pure nylon film to 3.44 × 10^?7 S/cm for a nylon film with 6 wt.% polyaniline. The activation energy decreased with increasing polyaniline concentration. The activation energy was 0.135, 0.0899, 0.0864, 0.0811, 0.078, 0.075 and 0.07299 eV for pure nylon, and nylon with 1, 2, 3, 4, 5, and 6 wt.% polyaniline, respectively. The activation energy of the prepared nylon films decreased in comparison with the activation energy of a pure nylon 6 film, while the electrical conductivity increased as the amount of polyaniline was increased.     

Communications on energy Industrial coal use in the Netherlands

The results of a study to analyse the potential penetration of coal in the Dutch industrial sector are presented. It is concluded that coal will play a modest role both as a fuel and as a chemical feedstock. Coal input could be substantially higher if the coal is gasified first, after which the gas can be used as fuel and gas and synthesis gas. The environmental impacts of the use of coal and the proposed emission standards are described.     

Impact of coal quality on the cost of electrical power generation: A technoeconomic model

The paper describes a computer based technoeconomic model that can accurately predict the impact of coal quality and other key variables on the busbar cost of electricity generated by new power plants. The model, IMPACT, focuses on the four major cost sectors of the coal-to-electricity chain: transportation, power plant, post combustion particulate and SO₂ emission controls, and waste disposal. Technically and economically established technologies in each sector are included in the model to facilitate a comprehensive evaluation of possible strategies. The user can select any combination of these technologies and evaluate the consequent impact on the busbar cost of electricity. Different strategies can be examined by selecting different options or through sensitivity analyses by changing coal or system parameters. IMPACT is structured to reflect regional and national cost differences by the use of appropriate cost indexes and site-specific cost parameters; it is, therefore, independent of location. IMPACT is a flexible and powerful decision making tool that can be used for a variety of purposes such as exploring the various avenues open to a utility in the selection of a coal supply, or evaluating various emission control and waste disposal strategies, energy supply alternatives and utility expansion options. The model can also be used to determine the realistic value of a coal and optimal beneficiation levels; it can therefore be used by coal producers in the preparation of competitive bids.