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Domestic electricity load profile is essential for energy planning and renewable energy system design. This paper presents analysis of domestic electric load characteristics and a method to model domestic and regional load profile. Multiple Gaussian functions are used to express the load characteristics in the proposed model. This is done by associating the Gaussian function parameters with the peak load changes, e.g. changing height parameters to reflect the peak magnitude. The result of the load curve represented with multiple Gaussian functions allows the model to generate a regional load profile using the number of homes, the number of bedrooms (Nr) and the number of occupants (Np). The proposed model simulates domestic load profile by its load demand change characteristics instead of its appliance ownership and use pattern, etc. Data requirement for the proposed method is significantly lower than the previous top-down and bottom-up approaches. Seasonal change is not included in the present paper, but the method is capable of including seasonal changes if each season’s load demand changes in relation to Np and Nr is available. A demonstration of modelling England and Wales’s national hourly load profile in 2001 and 2011 is presented in this paper. Comparison is made of the proposed method with two other published domestic load profile models. Results show that the proposed method improves the mean percentage errors by at least 5.7% on average hourly load profile. [ABSTRACT FROM AUTHOR]

In a previous paper, we have introduced a simulation and optimization framework for the integration of renewable generators into an electrical distribution network. The framework searches for the optimal size and location of the distributed renewable generation units (DG). Uncertainties in renewable resources availability, components failure and repair events, loads and grid power supply are incorporated. A Monte Carlo simulation–optimal power flow (MCS–OPF) computational model is used to generate scenarios of the uncertain variables and evaluate the network electric performance with respect to the expected value of the global cost ( ECG ). The framework is quite general and complete, but at the expenses of large computational times for the analysis of real systems. In this respect, the work of the present paper addresses the issue and introduces a purposely tailored, original technique for reducing the computational efforts of the analysis. The originality of the proposed approach lies in the development of a new search engine for performing the minimization of the ECG , which embeds hierarchical clustering analysis (HCA) within a differential evolution (DE) search scheme to identify groups of similar individuals in the DE population and, then, ECG is calculated for selected representative individuals of the groups only, thus reducing the number of objective function evaluations. For exemplification, the framework is applied to a distribution network derived from the IEEE 13 nodes test feeder. The results show that the newly proposed hierarchical clustering differential evolution (HCDE) MCS–OPF framework is effective in finding optimal DG-integrated network configurations with reduced computational efforts. [ABSTRACT FROM AUTHOR]

Highlights • A novel daylight quality evaluation metric named " N-Daylit area" was developed. • The daylighting simulation model in Daysim was experimentally validated. • The daylight and energy performance of STPV facades was investigated. • An optimal design of STPV facades was offered in view of daylight and energy saving. Abstract Building-integrated semi-transparent photovoltaics (STPV) technology has attracted more and more attentions for its obvious advantage in renewable energy utilization. However, the STPV facades have potential conflicts of interest between daylighting and energy efficient. Thus, this paper reported an investigation of the daylighting and overall energy performance of STPV facades in cold climatic regions of China, with the aim of resolving the conflicts. Firstly, the reliability of daylighting model in Daysim was experimentally verified. In addition, a novel dynamic daylighting evaluation metric named " N-Daylit area" was developed, considering the glare phenomenon and setting reasonable indoor illumination thresholds. On basis of this, the effect of several key design parameters, including transmittance、orientation and window-wall ratio (WWR), on the performance of STPV facades installed in a generic reference office was studied, by using a comprehensive simulation method. According to the simulation result, the transmittance and WWR of the STPV façade were recommended to be in the ranges of 50–60% and 40–50%, respectively, for the purpose to improve the energy efficiency of STPV facades with the premise of ensuring a satisfied daylight quality of the tested room. Furthermore, the results also revealed that south facing was the preferred orientation of STPV facades, to obtain the best daylighting quality and the lowest annual net electricity use of the space. [ABSTRACT FROM AUTHOR]

Abstract Promoting renewable energy utilization is treated as a must in current energy market worldwide. This paper studies the layout optimization process for wind farms with more realistic mathematical models. It uses a recent evolutionary algorithm known as BBO (biogeographical based optimization), which produces better results for various benchmarks, especially in continuous problems. Single and multiple wake models are adopted from latest work, which gives the best approximation according to real-world experiments and exact computer-aided simulations. Cost function models have been designed to best simulate a detailed practical farm during its lifetime. Weibull distribution for wind speed over a year period with arbitrary factors is considered for the site under study; this model is applied to the farm with the uniformly distributed wind to be able to compare turbine micro sitting results. Utilization of the realistic and detailed models provides different results compared to those of generic models. The practicality of the obtained results forms the distinction between the present work and previous studies. Various tests are performed using the aforementioned wake model on the former results for wind farm layout optimization problem (WFLOP). In addition to the suggested layouts for different land types and wind models, the sensitivity analysis of financial parameters is also conducted in this work. [ABSTRACT FROM AUTHOR]

Smart Grids consist of multiple actors and physical phenomena, which are often difficult to capture in one single simulation framework. Therefore, researchers increasingly couple distinct simulators to form novel “co-simulations”. In this paper we present a literature survey of 26 smart grid co-simulation frameworks. First of all, we present our understanding of a co-simulation. We then classify the 26 frameworks on multiple characteristics, such as simulation tools, synchronization methods and research topics. Finally, we present correlations between different key characteristics, analyze possible research gaps and discuss possible trends and future development areas in the field of smart grid co-simulations. [ABSTRACT FROM AUTHOR]

In this paper, two sets of design schemes of air source heat pump heating and gas boiler heating are given, and the economical performance of the two heating modes is compared. Through the simulation and calculation of the two kinds of heating system economy, it can be concluded that the operating cost of the gas-fired boiler is about 21.39 RMB•m -2 in the normal operation of the whole year. The operating cost of the air-source heat pump system in the regular operation is about 17.81 RMB•m -2 , and it is about 10.82 RMB•m -2 in the valley operation. [ABSTRACT FROM AUTHOR]

Building renovation is too often carried out with only one objective: necessary maintenance, updating design and functions, or reducing energy consumption. But, if a necessary maintenance is exploited as an opportunity for renovation, energy improvements can be implemented, house functions can be updated, and indoor climate improved with minimal nuisance and expense. This paper illustrates this approach by documenting the renovation of a single-family house in Denmark, and monitoring its energy consumption and indoor climate before and after the renovation. Building elements were replaced where necessary, and the total energy consumption was reduced by 23%, giving the house owners a saving of about DKK 8400 per year. The energy consumption for heating was reduced by 53%, close to the 58% found using dynamic simulations. The temperatures reached a more comfortable level, and the house owners were satisfied with the result. The increased value of the house was estimated to cover about 77% of the investment. [ABSTRACT FROM AUTHOR]

The sustainable materials back the trio of economy, environment, and energy because as a renewable source it has numerous positive affects on employment and it fuels the economic activities in the world. The building materials can be produced from sustainable sources recycled, re-used or harmlessly disposed on end use. In this paper, the thermal and mechanical characteristics of the insulation materials obtained from different waste (fly ash-FA) and natural (modified corn oil-MCO, perlite-P and clay-C) raw materials, as sustainable building wall's components are analyzed within the framework of a simulation model developed for the purpose of this research. A novel bio-composite material is obtained from these materials as its components. These materials' suitability as insulation materials for sustainable buildings is investigated through a software programme. For the period of January in Ankara province, the temperature distributions of the diverse wall types insulated together with only the Modified Corn Oil (MCO)-based block wall are evaluated with heat flow formulations by the ANSYS software programme. For this simulation, the construction-insulation material produced with the lowest thermal conductivity coefficient is applied to the diverse wall surfaces. This sustainable material's practicability is evaluated. It can be concluded that using fly ash-modified corn oil-perlite-clay in the specimen, allows obtaining a biocomposite with good mechanical and thermal characteristics, which can be used in structural components as a novel renewable material for energy performance in construction industry. [ABSTRACT FROM AUTHOR]

A measurement based model of hydrogen generating cell for simulation of complex energy system is described in this paper. The model parameter estimation has been performed based on measurement data obtained during the detailed examination of a demonstration cell. A series of experiments has been carried out on a HHO (Oxyhydrogen) gas producing dry cell in order to find its optimal electrochemical, (e.g. electrolyte concentration, current value, etc.) and geometric (distance between the plates) parameters. The novel element is the current and concentration dependent Matlab Simulink model of the hydrogen generation cell. Hydrogen generation enables the long range storage of spare electric energy collected but not consumed or injected into the low voltage grid. The generated hydrogen can be consumed by vehicles for transportation purposes or it can be applied in fuel cells generating direct electrical energy for energy-deficient low voltage network situations. The potentially occurring energetic situations were simulated in a complex energetic system model. The simulations showed that the presented hydrogen generating cell model met the engineering expectations. [ABSTRACT FROM AUTHOR]

This work describes and evaluates a new simulation model for direct steam generation in parabolic-trough solar collectors. In direct steam generation, water is heated and evaporated through a solar field to feed a steam Rankine cycle or an industrial process. However, the behaviour of the involved multiphase fluid poses some challenges to simulation models. The model explained in this work is based on a steady-state approach but deals with transient conditions such as start-up, shutdown and clouds in a reasonable computing time. A new simulation tool is implemented in the TRNSYS software environment by means of new components that are suitable to be integrated into a whole solar plant model in order to carry out long-term energy production analyses with low computational resources. The main advantages of the new quasi-dynamic approach include fast computation with satisfactory accuracy; consideration of thermal inertia when addressing transient conditions; and flexibility to use different types of collector or solar field configurations. The performance of the model is validated with real experimental data obtained from the DISS solar test loop in Plataforma Solar de Almería, Spain. This paper describes the modelling approach and summarizes the comparison of simulation results with measurements taken at the DISS facility. [ABSTRACT FROM AUTHOR]

Biogas from anaerobic digestion of organic matter is a promising renewable energy source and fuel cells appear as a breakthrough technology to improve the performance of the biogas-to-energy valorisation chain. The vast majority of studies addressing biogas energy recovery through Solid Oxide Fuel Cells published in recent years correspond to simulations and lab-scale performance with synthetic biogas. This paper assesses the pilot performance of a 2.8 kW e SOFC unit powered with cleaned sewage biogas for around 700 h in a Wastewater Treatment Plant. The biogas thorough treatment consisting of a biological desulphurisation with a biotrickling filter followed by a deep cleaning step based on adsorption is successful for removing sulphur compounds, siloxanes and hydrocarbons. The influence of the heat-to-power ratio on fuel cell performance is investigated operating the system at O/C ratio of 2, reforming temperature of 550 °C, stack temperature of 800 °C and at a constant voltage of 43 V. At optimized conditions for electrical production satisfying heat demand in the WWTP, system electrical and thermal efficiencies account for 34% and 28%. Cogeneration efficiency remains constant at around 59–62% for all the heat-to-power ratios tested. Furthermore, the impact of the oxygen content in the biogas is also studied. [ABSTRACT FROM AUTHOR]

This paper tests and analyzes the working capability of a resistive superconducting fault current limiter (SFCL) in a microgrid. The microgrid is a test-bed, consisting of a conventional power plant, two renewable energy sources in the form of wind-farm and solar-farm as two distributed generation (DG) units and five loads (i.e., industrial and domestic). Utilization of DG in mainstream is increasing and hence, various consequences that arise from DG penetration are to be considered accordingly. It is observed that DG penetration in existing distribution alters the fault current during a grid disturbance and hence imbalances the system. Based on this, the research work focuses on contribution of fault current from renewable energy sources in a microgrid, and how resistive SFCL offers positive result in minimizing the fault levels. The test-bed is modeled in MATLAB/Simulink, and simulation results are presented to show the effectiveness of resistive SFCL during various fault conditions. [ABSTRACT FROM AUTHOR]

This paper describes a holistic approach to operation and maintenance (O&M) processes in the domain of offshore wind farm power generation. The acquisition and process visualization is followed by a risk analysis of all relevant processes. Hereafter, a tool was designed, which is able to model the defined processes in a BPMN 2.0 notation, as well as connect and simulate them. Furthermore, the notation was enriched with new elements, representing other relevant factors that were, to date, only displayable with much higher effort. In that regard a variety of more complex situations were integrated, such as for example new process interactions depending on different weather influences, in which case a stochastic weather generator was combined with the business simulation or other wind farm aspects important to the smooth running of the offshore wind farms. In addition, the choices for different methodologies, such as the simulation framework or the business process notation will be presented and elaborated depending on the impact they had on the development of the approach and the software solution. [ABSTRACT FROM AUTHOR]

Efforts to meet climate change mitigation and energy security targets spur investments in variable renewable energy sources. Their implications for the operation of power plants are frequently investigated drawing on unit commitment and dispatch models. However, the temporal granularity and operational detail these models consider is commonly omitted in the broader family of long-term energy system models. To compensate this short-coming, these two types of tools have sometimes been ‘soft-linked’ and harmonised for limited simulation years. This paper assesses an alternative approach. We examine an extended version of an open source energy system model (OSeMOSYS), which is able to capture operating reserve and related investment requirements within a single tool. The implications of these model extensions are quantified through comparison with an Irish case study. That case study examined the effects of linking a long-term energy system model (TIMES) with a unit commitment and dispatch model (PLEXOS). It analysed the year 2020 in detail, applying a yearly temporal resolution that is over 700 times higher than in OSeMOSYS. Without increasing temporal resolution (and computational burden) we show that results of the enhanced OSeMOSYS model converge to results of TIMES and PLEXOS: Investment mismatches decrease from 21.4% to 5.0%. The OSeMOSYS analysis was then extended to 2050 to assess the implications of short-term variability on future capacity investment decisions. When variability was ignored, power system investments in 2050 were found to be 14.3% lower. This might imply that energy policies derived from such long-term models – of which there are many – may underestimate the costs of introducing variable renewables and thus meeting climate change or energy security targets. [ABSTRACT FROM AUTHOR]