Sharif Digital Repository

In the last decade, technological innovations have resulted in considering distributed generation with heat recovery capability in addition to centralised generation. This work aims to develop a comprehensive model analysing techno-economic parameters of energy supply in an office building. The energy model is developed on the basis of the reference energy system with the linear programming technique. The objective function is the annual value of total costs of the energy supply system. The results of the model for the building of Sharif Energy Research Institute indicate that the most appropriate generation technology is an internal combustion engine of 461 kW and a water boiler of 152 kW.... 

A generic framework is developed to study the application of energy hubs and its related network model to demonstrate the optimal design and operation of distributed energy systems (DESs) in urban areas. A novel multi-objective approach based on augmented epsilon constraint technique is employed to carry out this work. As an illustrative example, the proposed model is applied to an urban area in Ontario, Canada. Different scenarios are defined to investigate the effect of energy storage systems and energy exchange within a network on the optimal configuration and operation of the system. Moreover, multi-objective optimization is carried out based on two conflicting objectives, namely, total... 

With regard to increased sustainability, managers not only need to know WHAT is needed for their company to improve, but also HOW to do so in detail is equally important. Energy management (EnM) is a pillar to the transformation of industrial energy systems towards enhanced energy efficiency and increased sustainability. One way to develop more and improve EnM both practically and theoretically is to shed light on how the combination of techniques and operation can contribute to successful EnM. This paper, therefore, through investigation of 10 Swedish foundries aims to present the structure of the energy strategy and associated practices at first; second, to assess industry’s EnM program... 

This paper presents a day-ahead scheduling approach for a multi-carrier residential energy system (MRES) including distributed energy resources (DERs). The main objective of the proposed scheduling approach is the minimization of the total costs of an MRES consisting of both electricity and gas energy carriers. The proposed model considers both electrical and natural gas distribution networks, DER technologies including renewable energy resources, energy storage systems (ESSs), and combined heat and power. The uncertainties pertinent to the demand and generated power of renewable resources are modeled using the chance-constrained approach. The proposed model is applied on the IEEE 33-bus... 

In this study, the optimal sizing and performance analysis of a standalone integrated solar power system equipped with different storage scenarios to supply the power demand of a household is presented. One of the main purposes when applying solar energy resource is to face the increasing environmental pollutions resulting from fossil fuel based electricity sector. To this end, and to compare and examine two energy storage technologies (battery and hydrogen storage technology), three storage scenarios including battery only, hydrogen storage technology only and hybrid storage options are evaluated. An optimization framework based on Energy Hub concept is used to determine the optimum sizes... 

This paper provides an overview of the power sector development in Iran for the period 1984–2014. A retrospective optimization approach is applied to assess economic and environmental benefits that would have been achieved through appropriate long-term planning. MESSAGE, a systems engineering optimization model, is used for this analysis. Two alternative scenarios are defined to explore the impact of supply- and demand-side strategies on the power generation mix, fuel consumption and CO2 emissions. The focus on the past choice of energy scenarios provides some insights for future scenario design. The results of the cost-optimal scenarios with international fuel prices are compared with the... 

The use of hybrid renewable energy has increased in recent years due to the growing environmental concerns caused by the consumption of fossil fuels. The purpose of this study was the economic-environmental feasibility of using hybrid energy systems in one of the most polluted and populated provinces in Iran, Isfahan province. Various components of the hybrid energy system such as wind turbine (WT), photovoltaic panel (PV), diesel generator (DG), converter (CV) along with two scenarios of energy storage including battery (BT) and hydrogen storage have been considered in modeling the energy system. Six scenarios were considered based on the combination of different components for supplying... 

The paper presents further experiments with an extended version of a comprehensive model for assessment of energy technologies and research and development (R&D) planning to evaluate the impact of innovation programs on development of Iranian electricity-supply system. This analytical instrument is a model of energy R&D resource allocation with an explicit perspective of developing countries which has been linked to a bottom-up energy-systems model. Three emerging electricity generation technologies of solar PV, wind turbine and gas fuel cell are considered in the model and the impact of innovation programs on cost-reducing innovation for them is examined. The main results provided by the... 

A microgrid is a controllable component of the smart grid defined as a part of distribution network capable of supplying its own local load even in the case of disconnection from the upstream network. Microgrids incorporate large amount of renewable and non-renewable distributed generation (DG) that are connected to the system either directly or by power electronics (PE) interface. The diversity of technologies used in DGs and loads, high penetration of DGs, economic operation of DGs, dynamics of low-inertia conventional DGs and PE interfaced inertialess DGs and smart operation by means of enhanced communication infrastructure have raised challenges in widespread utilization of microgrids as... 

Energy hubs that incorporate a variety of energy generation and energy transformation technologies can be used to provide the energy storage needed to enable the efficient operation of a ‘smart energy network’. When these hubs are combined as a network and allowed to exchange energy, they create efficiency advantages in both financial and environmental performance. Further, the interconnectedness of the energy network design provides an added layer of reliability. In this paper, a complex network of energy hubs is modeled and optimized under different scenarios to examine both the financial viability and potential reduction of greenhouse gas emissions. Two case studies consisting of two and... 

In this study, hybrid renewable energy system based on wind/electrolyzer/PEM fuel cell are conceptually modeled, and also, exergy and energy analysis are performed. The energy and exergy flows are investigated by the proposed model for Khaf region-Iran with high average wind speed and monsoon. Exergy and energy analysis framework is made based on thermodynamic, electro-chemical and mechanical model of the different component of hybrid system. Also, the effects of various operating parameters in exergy efficiency are calculated. The results show an optimum wind speed where the exergy efficiency and power coefficient is at maximum level, and also, when the ambient temperature start to be... 

New days, the concepts of 'Smart Grid' and 'Energy Hub' have been introduced to improve the operation of the energy systems. This paper introduces a new conception entitling Smart Energy Hub (S. E. Hub), as a multi-carrier energy system in a smart grid environment. To show the application of this novel idea, we present a residential S. E. Hub which employs Reinforcement Learning (RL) method for finding a near optimal solution. The simulation results show that by applying the S. E. Hub model and then using the proposed method for a residential customer, running cost is reduced substantially. While, comparing with the classical ones, the RL method does not require any data about the... 

The purpose of this paper is to investigate the effects of annealing phenomena on the energy absorption of Al-steel bilayer sheets, bonded by cold rolling, through wedge tearing. Tearing by wedge is a dissipating energy system that includes three components: cutting, friction and plastic deformation due to bending. In order to find the bonding and annealing effects on energy absorption, the non-bonded bilayer sheets are prepared in the same condition of bonded ones. The results show that energy absorption of bonded sheets is larger than that of non-bonded ones. This is due to different plastic bending moment of bonded and non-bonded bilayer sheets. Whenever the bond is improved by heat... 

As a cost-effective and reliable alternative to supply remote areas, standalone hybrid energy systems (HESs) are recently under investigation to address various concerns associated with technical, financial, and environmental issues. This paper presents a comprehensive algorithm that can simultaneously optimize the component size, operation strategy, and slope of the photovoltaic panels of a standalone HES using an improved variant of particle swarm optimization (PSO), designated as the passive congregation PSO. A new operation strategy is proposed based on the set points of the control system. The optimization algorithm determines the optimal values of the set points to efficiently optimize... 

Energy storage is one of the most important components of renewable energy systems. Among different methods, thermal energy storage (TES) in forms of sensible or latent has been the subject of many studies in the past decades. The main difficulty in optimal design of storage tanks is associated with low thermal conductivity of the storing (solid or phase change) material. In fact, the distribution of thermal energy from a source to the body of storing material poses a volume to point problem which is the subject of constructal theory. Therefore, the objective of the present paper is to investigate the transient behavior of a rectangular thermal energy storage tank equipped with fin... 

The paper presents a comprehensive electric arc furnace (EAF) model, developed for simulation and model-based control of the EAF processes. The model consists of three sub models, i.e., (i) arc model; (ii) chemical and slag model; and (iii) heat-transfer model. Arc model predicts the amount of energy dissipated from the arcs using arc currents and arc lengths; chemical and slag model calculates chemical energy and changes of elements/compounds, slag height and slag quality; while the heat-transfer model uses calculations of the other two models in order to establish a reference energy system (RES) for each zone in the EAF due to the variations in arc length, slag height, and bath height. The... 

Sustainable economic growth and improvement of the social welfare depend upon the sufficient supply of energy resources, while the utilization of energy resources is one of the main factors of environmental degradation. This research is involved with development of a sustainable energy system model and a new method for sustainability assessment. This model represents the flow of energy from primary resources through processing, conversion, and end-use technologies in an optimization framework where the useful energy demand in various social and economic sectors is met. The impact of energy supply and consumption chain on the environment at each level of energy system is also embedded in the... 

This paper proposes a new methodology to find the most economic system configuration and energy management strategy for Li-ion battery based off-grid renewable energy systems. A system level macroscopic model and a microscopic battery lifetime prediction model are incorporated into the optimization framework to simulate hourly performance of the system. Due to the computational efficiency of the model, optimization is carried out using enumerative method (evaluating all the possible combinations of components and control strategies) to ensure finding the global optimum solution of the problem. To investigate the effectiveness of the proposed methodology, the optimization results are compared...