A Thermoeconomics-Based Approach to the Integrated Optimization of Design and Operation for Decentralised Energy Systems and Variable Load Conditions

2006 ◽  
Author(s):  
Antonio Piacentino ◽  
Fabio Cardona
Keyword(s):  
Control System ◽  
Power Systems ◽  
Energy Demand ◽  
Net Present Value ◽  
Energy Systems ◽  
Economic Indicator ◽  
Primary Energy ◽  
Variable Load ◽  
Industrial Energy ◽  
High Level

The many comprehensive approaches formulated for the optimization of large industrial energy systems have been rarely applied to small and medium scale units, because of the difficulties in handling a continuously variable energy demand and of the lower margins for energy and emissions saving. Today, the growing interest for decentralised energy systems in the civil sector stimulates major efforts for the optimization of such plants, with a particular focus on the control system and on a management strategy able to exploit the opportunities existing in the free energy market. In this paper a methodology is proposed for the optimization of design and operation of variable demand systems supplying different non-storable products. In such systems, efficiency penalty due to off-design operation is usually assumed as a key issue; the proposed method, however, introduces an original and meaningful interpretation of the capital depreciation cost and keeps into account the possibility for grid connected power systems to produce surplus electricity to be sold. The proposed optimization process, based on the Lagrange multipliers method, assumes either an economic indicator (the Net Present Value, NPV or the Net Cash Flow, NCF) or a function depending only on fuel consumption (as usually proposed in literature) as objective function. Main advantages of the proposed method are the high level of integration between the optimization of design and operation and the possibility to automate the algorithm in order to drive a real-time optimized control system aiming to achieve the maximum profitability or the maximum primary energy saving.

scholarly journals Energy Flexibility as Additional Energy Source in Multi-Energy Systems with District Cooling

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 519
Author(s):  
Alice Mugnini ◽  
Gianluca Coccia ◽  
Fabio Polonara ◽  
Alessia Arteconi
Keyword(s):  
Energy Source ◽  
Energy Demand ◽  
Energy Systems ◽  
Energy System ◽  
Energy Performance ◽  
Primary Energy ◽  
Energy Sources ◽  
Variable Load ◽  
Additional Energy ◽  
The Impact

The integration of multi-energy systems to meet the energy demand of buildings represents one of the most promising solutions for improving the energy performance of the sector. The energy flexibility provided by the building is paramount to allowing optimal management of the different available resources. The objective of this work is to highlight the effectiveness of exploiting building energy flexibility provided by thermostatically controlled loads (TCLs) in order to manage multi-energy systems (MES) through model predictive control (MPC), such that energy flexibility can be regarded as an additional energy source in MESs. Considering the growing demand for space cooling, a case study in which the MPC is used to satisfy the cooling demand of a reference building is tested. The multi-energy sources include electricity from the power grid and photovoltaic modules (both of which are used to feed a variable-load heat pump), and a district cooling network. To evaluate the varying contributions of energy flexibility in resource management, different objective functions—namely, the minimization of the withdrawal of energy from the grid, of the total energy cost and of the total primary energy consumption—are tested in the MPC. The results highlight that using energy flexibility as an additional energy source makes it possible to achieve improvements in the energy performance of an MES building based on the objective function implemented, i.e., a reduction of 53% for the use of electricity taken from the grid, a 43% cost reduction, and a 17% primary energy reduction. This paper also reflects on the impact that the individual optimization of a building with a multi-energy system could have on other users sharing the same energy sources.

Investigations on a Test Bench for Integrated ORC-FC Micro-CHP Energy Systems

2014 ◽  
Author(s):  
M. Bianchi ◽  
A. De Pascale ◽  
F. Melino ◽  
A. Peretto ◽  
L. Branchini
Keyword(s):  
Energy Demand ◽  
Test Bench ◽  
Energy Systems ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Test Facility ◽  
Small Scale ◽  
Variable Load ◽  
Low Grade ◽  
Calculation Code

Micro-CHP (Combined Heat and Power) energy systems are potentially suitable for residential and tertiary utilities, typically characterized by low-grade heat demand and limited electric-to-thermal energy demand ratio values. Different innovative and under development CHP technologies are currently investigated in small scale units, but a standard has not been identified till now. Moreover, depending on the load request, the produced electricity can be used, stored in electric accumulator or in the external net, or integrated with other external sources. Contextually, the available heat can be used, accumulated inside the system or dissipated. The actual convenience of small size CHP systems depends on the demand profiles and the operation management logic. A test facility is being developed, at the University of Bologna, for the experimental characterization of the cogenerative performance of small scale hybrid power systems, composed of micro-CHP systems of different technologies: a Micro Rankine Cycles (MRC), a Proton Exchange Membrane (PEM) Fuel Cells (FC), a battery and a heat recovery subsystem. The test set-up is also integrated with an external load simulator, in order to generate variable load profiles. This report describes the main characteristics of the implemented test bench, the selection procedure of the adopted micro-CHP unit and expected performance. Further the development of a calculation code able to simulate the performance of the considered systems will be described. This calculation code has been applied to design the components of the test bench. More in details, in this paper the sizing of the electrical energy storage system, and of the thermal and H2 storage tanks will be presented and discussed.

1. Energy systems

2019 ◽  
pp. 5-18
Author(s):  
Nick Jenkins
Keyword(s):  
Energy Demand ◽  
Fossil Fuels ◽  
Energy Use ◽  
Energy Systems ◽  
Modern Society ◽  
Electrical Energy ◽  
Distribution Networks ◽  
Primary Energy ◽  
Environmental Consequences ◽  
The Difference

‘Energy systems’ explains the difference between energy and power and between energy and electrical energy. It then outlines the sources of primary energy, describing the environmental consequences of burning fossil fuels, and attempts at limiting energy use. It also considers the difficulties of storing electricity in large quantities and cost-effectively. It is impossible to conceive of a modern society without reliable and effective systems to provide energy when and where it is needed. Modern energy systems continue to evolve in response to energy demand and to changing sources of supply. Increasingly environmental considerations and costs determine which energy sources are used and how the energy transmission and distribution networks are constructed and operated.

Design and Simulation of Smart Control System for Internet Traffic Distribution on Servers by Using Fuzzy Logic System

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Raid Daoud ◽  
Yaareb Al-Khashab
Keyword(s):  
Fuzzy Logic ◽  
Control System ◽  
Input Parameter ◽  
Traffic Density ◽  
The Internet ◽  
Linguistic Variables ◽  
Internet Service ◽  
Traffic Distribution ◽  
Smart Control ◽  
High Level

The internet service is provided by a given number of servers located in the main node of internet service provider (ISP). In some cases; the overload problem was occurred because a demand on a given website goes to very high level. In this paper, a fuzzy logic control (FLC) has proposed to distribute the load into the internet servers by a smart and flexible manner. Three effected parameters are tacked into account as input for FLC: link capacity which has three linguistic variables with Gaussian membership function (MF): (small, medium and big), traffic density with linguistic variables (low, normal and high) and channel latency with linguistic variables (empty, half and full); with one output which is the share server status (single, simple and share). The proposed work has been simulated by using MATLAB 2016a, by building a structure in the Fuzzy toolbox. The results were fixed by two manners: the graphical curves and the numerical tables, the surface response was smoothly changed and translates the well-fixed control system. The numerical results of the control system satisfy the idea of the smart rout for the incoming traffics from the users to internet servers. So, the response of the proposed system for the share of server ratio is 0.122, when the input parameter in the smallest levels; and the ratio is 0.879 when the input parameters are in highest level. The smart work and flexible use for the FLC is the main success solution for most of today systems control.

scholarly journals Eco-Emission Analysis of Multi-Carrier Microgrid Integrated with Compressed Air and Power-to-Gas Energy Storage Technologies

2021 ◽  
Vol 13 (9) ◽  
pp. 4681
Author(s):  
Khashayar Hamedi ◽  
Shahrbanoo Sadeghi ◽  
Saeed Esfandi ◽  
Mahdi Azimian ◽  
Hessam Golmohamadi
Keyword(s):  
Energy Storage ◽  
Power Systems ◽  
High Efficiency ◽  
Objective Assessment ◽  
Energy Systems ◽  
Vital Role ◽  
Compressed Air ◽  
Emission Analysis ◽  
Multi Objective ◽  
Power To Gas

Growing concerns about global greenhouse gas emissions have led power systems to utilize clean and highly efficient resources. In the meantime, renewable energy plays a vital role in energy prospects worldwide. However, the random nature of these resources has increased the demand for energy storage systems. On the other hand, due to the higher efficiency of multi-energy systems compared to single-energy systems, the development of such systems, which are based on different types of energy carriers, will be more attractive for the utilities. Thus, this paper represents a multi-objective assessment for the operation of a multi-carrier microgrid (MCMG) in the presence of high-efficiency technologies comprising compressed air energy storage (CAES) and power-to-gas (P2G) systems. The objective of the model is to minimize the operation cost and environmental pollution. CAES has a simple-cycle mode operation besides the charging and discharging modes to provide more flexibility in the system. Furthermore, the demand response program is employed in the model to mitigate the peaks. The proposed system participates in both electricity and gas markets to supply the energy requirements. The weighted sum approach and fuzzy-based decision-making are employed to compromise the optimum solutions for conflicting objective functions. The multi-objective model is examined on a sample system, and the results for different cases are discussed. The results show that coupling CAES and P2G systems mitigate the wind power curtailment and minimize the cost and pollution up to 14.2% and 9.6%, respectively.

scholarly journals Dynamic Modelling of LNG Powered Combined Energy Systems in Port Areas

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3640
Author(s):  
Davide Borelli ◽  
Francesco Devia ◽  
Corrado Schenone ◽  
Federico Silenzi ◽  
Luca A. Tagliafico
Keyword(s):  
Energy Savings ◽  
Ghg Emissions ◽  
Dynamic Modelling ◽  
Energy Systems ◽  
Energy System ◽  
Primary Energy ◽  
Time Behavior ◽  
Vapor Compression Refrigeration Cycle ◽  
Integrated Energy System ◽  
Energy Share

Liquefied Natural Gas (LNG) is a crucial resource to reduce the environmental impact of fossil-fueled vehicles, especially with regards to maritime transport, where LNG is increasingly used for ship bunkering. The present paper gives insights on how the installation of LNG tanks inside harbors can be capitalized to increase the energy efficiency of port cities and reduce GHG emissions. To this purpose, a novel integrated energy system is introduced. The Boil Off Gas (BOG) from LNG tanks is exploited in a combined plant, where heat and power are produced by a regenerated gas turbine cycle; at the same time, cold exergy from LNG regasification contributes to an increase in the efficiency of a vapor compression refrigeration cycle. In the paper, the integrated energy system is simulated by means of dynamic modeling under daily variable working conditions. Results confirm that the model is stable and able to determine the time behavior of the integrated plant. Energy saving is evaluated, and daily trends of key thermophysical parameters are reported and discussed. The analysis of thermal recovering from the flue gases shows that it is possible to recover a large energy share from the turbine exhausts. Hence, the system can generate electricity for port cold ironing and, through a secondary brine loop, cold exergy for a refrigeration plant. Overall, the proposed solution allows primary energy savings up to 22% when compared with equivalent standard technologies with the same final user needs. The exploitation of an LNG regasification process through smart integration of energy systems and implementation of efficient energy grids can contribute to greener energy management in harbors.

A PSO–GA optimal model to estimate primary energy demand of China

Energy Policy ◽  
2012 ◽  
Vol 42 ◽  
pp. 329-340 ◽  
Author(s):  
Shiwei Yu ◽  
Yi-Ming Wei ◽  
Ke Wang
Keyword(s):  
Energy Demand ◽  
Primary Energy ◽  
Optimal Model ◽  
Primary Energy Demand

scholarly journals Energy Demand Analysis and Design of a Hybrid Power System in Bawean Islands, Indonesia

2018 ◽  
Vol 164 ◽  
pp. 01038
Author(s):  
Ridho Hantoro ◽  
Cahyun Budiono ◽  
Ronald Kipkoech Ketter ◽  
Nyoman Ade Satwika
Keyword(s):  
Power Systems ◽  
Energy Demand ◽  
Peak Load ◽  
Electricity Consumption ◽  
Simulation Software ◽  
Diesel Generator ◽  
Time Step ◽  
Analysis And Design ◽  
Optimum System ◽  
Hybrid Power

Over 70 000 000 people in Indonesia have no access to electricity. This study was carried out in Bawean Islands which are located in the Java Sea about 150 km North of Surabaya, the headquarters of East Java. The study to determine the energy services available in the Bawean Island was done through interviewing a random sample of 72 households in two villages namely Komalasa and Lebak. Based on the average monthly electricity consumption of the sampled households connected to the grid, a hybrid renewable energy based electrical supply system was designed for Gili Timur Island, one of the satellite islands around Bawean Island. The system was designed with the aid of a time step simulation software used to design and analyze hybrid power systems. A sensitivity analysis was also carried out on the optimum system to study the effects of variation in some of the system variables. HOMER suggests that for the expected peak load of 131 kW, an optimum system will consist of 150 kW from PV array, two wind turbines each rated 10 kW, a 75 kW diesel generator and batteries for storage.

Sign in / Sign up

Export Citation Format

Share Document