scholarly journals Steam-Water Modelling and the Coal-Saving Scheduling Strategy of Combined Heat and Power Systems

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 141
Author(s):  
Junshan Guo ◽  
Wei Zheng ◽  
Zhuang Cong ◽  
Panfeng Shang ◽  
Congyu Wang ◽  
...  
Keyword(s):  
Heat Load ◽  
Large Scale ◽  
Combined Heat And Power ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Adaptive Mutation ◽  
Small Scale ◽  
Coal Consumption ◽  
Scheduling Strategy ◽  
Power Load

China aims to peak carbon emissions by 2030. As a result, small-scale coal-fired combined heat and power (CHP) units and self-provided units are gradually shut down, and large-scale coal-fired CHP units are a solution to undertake the industrial heat loads. From the perspective of the industrial heat load allocation during the non-heating season, the problems regarding the coal-saving scheduling strategy of coal-fired CHP units are addressed. The steam-water equations of CHP units are established to analyze the heat-power coupling characteristics. The energy utilization efficiency, exergy efficiency and the coal consumption are analyzed. The optimization model of saving coal consumption is established and the adaptive mutation particle swarm optimization (AMPSO) is introduced to solve the above model. The 330 MW coal-fired CHP unit is taken as an example, and the results show that for the constant main flow rate, each increase of 1 t/h industrial steam extraction will reduce the power output by about 0.321 MW. The energy utilization efficiency and the exergy are mainly influenced by industrial steam supply and the power load, respectively. For the CHP system with two parallel CHP units, the unequal allocation of industrial heat load between two units saves more coal than equal allocation. The coal consumption can be reduced when the unit with lower power load undertakes more industrial heat load. In the typical day, the total coal consumption after optimization is 3203.92 tons, a decrease of 14.66 tons compared to the optimization before. The two CHP units in the case can benefit about 5,612,700 CHY extra in one year.

Modeling and Operational Optimization Based on Energy Hubs for Complex Energy Networks With Distributed Energy Resources

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Shixi Ma ◽  
Dengji Zhou ◽  
Huisheng Zhang ◽  
Shilie Weng ◽  
Tiemin Shao
Keyword(s):  
Large Scale ◽  
Optimization Method ◽  
Integrated System ◽  
Energy Resources ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Small Scale ◽  
Distributed Energy ◽  
Operational Optimization

Energy hubs is an integrated system which is capable of transporting, transforming, and storing several types of energy. A number of hubs can be combined as a network and achieve higher efficiency by exchanging information and energy with each other. A decision-making framework for optimal integration of independent small-scale distributed energy systems and traditional large scale combined heating and power (CHP) plants is presented, and an energy supply system with renewable energy resources in Shanghai is cited as a case study. A performance simulation model of this energy network is proposed based on energy hub concept and energy flow between its elements. Furthermore, a novel optimization method named Whales optimization algorithm (WOA) is presented for 24 h operational optimization. A case study is undertaken on a seven-node energy system, including four energy hubs and three load hubs. The results of the case study show that the proposed model and optimization method can improve energy utilization efficiency and reduce system operating costs, even under a system contingency condition.

Comparison and Analysis for the Differential Heating Modes in the Large-Scale CHP System

2013 ◽  
Author(s):  
Zhen Xian Lin ◽  
Lin Fu
Keyword(s):  
Power Plants ◽  
Large Scale ◽  
Thermal Power ◽  
Heat Pumps ◽  
Back Pressure ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Heating Unit ◽  
Heating Efficiency ◽  
The Impact

With the process acceleration of China’s energy conservation and the full development of the market economy, the environmental protection is to coexist with the power plants’ benefits for thermal power plants. Relative to the traditional mode named “determining power by heat”, it is not adequate that the heating demand is only to be met, the maximizations of economy benefits and social benefits are also demanded. At present, several large-scale central heating modes are proposed by domestic and foreign scholars, such as the parallel arrangement and series arrangement of heating system for the traditional heating units and NCB heating units (NCB heating unit is a new condensing-extraction-backpressure steam turbine and used to generate the power and heat, it has the function of extraction heating turbine at constant power, back pressure turbine or extraction and back pressure heating turbine and extraction condensing heating turbine.), and running mode with heating units and absorbed heat pumps, and so on. Compare and analyze their heating efficiency, heating load, heating area, power generation, and the impact on the environment. The best heating mode can be found under the different boundary conditions, it can be used to instruct the further work. The energy utilization efficiency will be further improved.

A Novel Coal-Fired CHP System Integrated With Steam Ejectors to Realize Heat-Power Decoupling and Energy Saving

2020 ◽  
Author(s):  
Miaomiao Liu ◽  
Ming Liu ◽  
Shuran Zhao ◽  
Gege Song ◽  
Junjie Yan
Keyword(s):  
Energy Saving ◽  
Heat Load ◽  
Waste Heat ◽  
High Energy ◽  
Steam Turbines ◽  
Heat Power ◽  
Coal Consumption ◽  
Decoupling Method ◽  
Power Load ◽  
Power Decoupling

Abstract Traditional combined heat and power (CHP) units should run in the heat-controlled mode. The adjustable range of power load is restricted by the heat load, and the minimum power load increases with the heat load. Because of high penetration of intermittent renewable power, operational flexibility of CHP units is highly required. It is necessary to adopt some technical solutions to realize heat-power decoupling for CHP units. To find a heat-power decoupling method with low investment and high energy efficiency, the steam ejectors, simple in structure and low in cost, are applied to design a novel heat-power decoupling system in this study. Steam ejectors can recover the waste heat of exhaust steam of steam turbines. Therefore, the integration of steam ejector may realize heat-power decoupling and energy saving simultaneously. Three heat-power decoupling systems with steam ejectors are designed. The heat-power decoupling performance and energy consumption characteristics of these systems are investigated with a reference 330 MW coal-fired CHP unit. Results show that all three modified systems can realize heat-power decoupling. The heat-power decoupling performance of improved system III is the best, and improved system I has the least coal consumption rate for power generation.

scholarly journals Design and Energy Consumption Analysis of Small Reverse Osmosis Seawater Desalination Equipment

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2275
Author(s):  
Zhuo Wang ◽  
Yanjie Zhang ◽  
Tao Wang ◽  
Bo Zhang ◽  
Hongwen Ma
Keyword(s):  
Energy Consumption ◽  
Water Resources ◽  
Reverse Osmosis ◽  
Specific Energy Consumption ◽  
Membrane System ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Small Scale ◽  
Reverse Osmosis Membrane ◽  
Seawater Desalination

The reverse osmosis method has developed extremely rapidly in recent years and has become the most competitive seawater desalination technology in the world, and it has been widely used in all aspects. Large-scale reverse osmosis desalination plants cannot provide fresh water resources in areas with insufficient water resources and limited space. Therefore, this paper proposes a research plan for a small seawater desalination device based on reverse osmosis, which is mainly suitable for handling emergencies, disaster relief, desert areas and outdoor activities and other needs for timely freshwater resources. It mainly includes pretreatment modules, a reaction infiltration module, a post-processing module and an energy supply module. Detailed design calculations are carried out for the small-scale reverse osmosis membrane system, including the selection and quantity and arrangement of membranes. Subsequently, the one-stage two-stage small-scale reverse osmosis membrane system was modeled, and its energy consumption was analyzed theoretically from the perspectives of specific energy consumption and energy utilization efficiency; the main influencing factors were clarified, and the optimal recovery rate for system operation was determined to be 20%–30%. Finally, an experimental prototype was built to conduct relevant experiments to determine the influence trend of pressure, temperature, concentration, and flow rate on the operating performance of the reverse osmosis system.

scholarly journals The adaptive assessment method for different energy storage applications in large-scale re-electrical load access regions

2020 ◽  
Vol 165 ◽  
pp. 06030
Author(s):  
Zhicheng Xu ◽  
Jun Liu ◽  
Zhuonan Li
Keyword(s):  
Energy Storage ◽  
Large Scale ◽  
Energy System ◽  
Assessment Method ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Demand Side ◽  
Low Carbon ◽  
Electrical Load ◽  
Security Technology

In the context of energy transformation, re-electrification has become an important way to build a clean and low-carbon energy system. The large-scale re-electrical load access further increases the flexibility requirements on the user demand side. The application of the energy storage system (ESS) can not only improve the degree of electrification of the energy system but also improve the energy utilization efficiency. This paper analyzes the different development modes and key characteristics of energy storage on the power supply side, grid side and demand side in large-scale re-electrical load access areas. Five dimensions (such as storage security, technology maturity, system cost, storage scenario suitability and storage scalability) are selected to characterize the feasibility of a certain energy storage technology in a given application scenario. For different application scenarios, studying the appropriate development mode and its adaptability to the environment will help the healthy and sustainable development of energy storage.

scholarly journals ASSESSMENT OF SOLAR PV POWER POTENTIAL IN THE ASIA PACIFIC REGION WITH REMOTE SENSING CONSIDERING THE EFFECTS OF HIGH TEMPERATURE, DUST AND SNOW

2019 ◽  
Vol XLII-4/W19 ◽  
pp. 339-346
Author(s):  
J. A. Principe ◽  
W. Takeuchi
Keyword(s):  
High Temperature ◽  
Large Scale ◽  
Snow Water Equivalent ◽  
Energy Utilization ◽  
Asia Pacific ◽  
Shortwave Radiation ◽  
Small Scale ◽  
Pacific Region ◽  
Solar Pv ◽  
Asia Pacific Region

Abstract. The last half century has witnessed the increasing trend of renewable energy utilization with solar photovoltaic (PV) systems as one of the most popular option. Solar PV continues to supplement the main grid in powering both commercial establishments (mainly for reduced electricity expense) as well as residential houses in isolated areas (for basic energy requirement such as for lighting purposes). The objective of this study is to assess the available solar PV power (PPV) potential considering the effects of high temperature, dust and snow in the Asia Pacific region. The PPV potential was estimated considering the effects of the said meteorological parameters using several satellite data including shortwave radiation from Advanced Himawari Imager 8 (AHI8), MOD04 aerosol data from Moderate Resolution Imaging Spectroradiometer (MODIS), precipitation rate from Global Satellite Mapping of Precipitation (GSMaP), air temperature from NCEP/DOE AMIP-II Reanalysis-2 data, and snow water equivalent (SWE) from Microwave Scanning Radiometer for the Earth Observing System (AMSR-E). The model is validated by comparing its outputs with the measured PV power from two solar PV installations in Bangkok, Thailand and Perth, Australia. Results show that maximum PPV is estimated at 2.5 GW (cell efficiency of 17.47%) for the region with the maximum decrease in PPV estimated to be about < 2%, 22% and 100% due to high temperature (temperature coefficient of power = 0.47%/K), dust and snow, respectively. Moreover, areas in India and Northern China were observed to experience the effects of both dust and temperature during March-April-May (MAM) season. Meanwhile, countries located in the higher latitudes were severely affected by snow while Australia by high temperature during Dec-Jan-Feb (DJF) season. The model has a mean percentage prediction error (PPE) range of 5% to18% and 7% to 23% in seasonal and monthly estimations, respectively. Outputs from this study can be used by stakeholders of solar PV in planning for small-scale or large-scale solar PV projects in the solar rich region of Asia Pacific.

Modeling and Optimal Operation of a Network of Energy Hubs System With Distributed Energy Resources

2017 ◽  
Author(s):  
Shixi Ma ◽  
Dengji Zhou ◽  
Huisheng Zhang ◽  
Zhenhua Lu
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Combustion Engine ◽  
Optimal Operation ◽  
Energy Resources ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Small Scale ◽  
Distributed Energy

Energy hubs is a functional unit which is capable of transporting transforming and storing of several kinds of energy. Several hubs can be combined as a network and achieve higher efficiency by exchanging energy with each other. A framework to assist the decision-making process towards the optimal integration of independent small scale distributed energy systems and traditional large scale CHP power plants is presented using an energy supply system in Shanghai as a case study. A model of this complex network of energy hubs with renewable energy resources is presented based on energy flow between its constituent elements. Furthermore, GA optimization method is presented for short term 24-hour optimal operation. Case study are undertaken on a 7-node energy system which comprises 4 energy hubs and 3 load hubs. Results validate the high efficiency of this system. Two cases with and without internal-combustion engine failure within the network are considered. The results showed that the proposed system can enhance the energy utilization efficiency and reduce the system operation cost, even under a system contingency.

Modeling and Performance Evaluation of a Large-Scale SOFC-Based Combined Heat and Power System for Biogas Utilization at a Wastewater Treatment Facility

2012 ◽  
Author(s):  
A. A. Trendewicz ◽  
R. J. Braun
Keyword(s):  
Wastewater Treatment ◽  
Performance Evaluation ◽  
Large Scale ◽  
Exergy Analysis ◽  
Combined Heat And Power ◽  
Small Scale ◽  
Treatment Facility ◽  
Electrical Efficiency ◽  
Wastewater Treatment Facility ◽  
Chp System

Biogas has been identified as an attractive fuel for solid oxide fuel cells (SOFCs) due to its high methane content and its renewable status. Current experimental and modeling research efforts in this field have focused mainly on single-cell and small-scale systems performance evaluation. In this paper a large scale biogas source (∼15.5 MW) from a large wastewater treatment facility is considered for integration with an SOFC-based system. Data concerning biogas fuel flow rate and composition have been acquired from a wastewater reclamation facility in Denver and are used as inputs to a steady-state model of an SOFC combined heat and power (CHP) system developed with Aspen Plus. The proposed system concept for this application comprises an advanced SOFC system with anode gas recirculation (AGR) equipped with biogas clean-up and a waste heat recovery system. The system performance is evaluated at near atmospheric pressure with a 725°C nominal operating temperature of the fuel cell stack and system fuel utilization of 80%. The average biogas fuel input has a composition of 60% CH4, 39% CO2, and 1% N2 on a dry molar basis. The SOFC-CHP system employs 80% internal reforming at a steam-to-carbon ratio of 1.2. The system offers a net electrical efficiency of 51.6% LHV and a net CHP efficiency of 87.5% LHV. The influence of the operating parameters on the system efficiency is investigated and discussed. The individual contribution of system components to the total inefficiency of the system is quantified with an exergy analysis. Exergy analysis results indicate that the system could offer a tremendous energy efficiency improvement when compared to biogas-supplied combustion turbines currently installed at the facility which operate with an average net electrical efficiency of 25%-LHV.

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