scholarly journals Performance Analyses of a Renewable Energy Powered System for Trigeneration

2019 ◽  
Vol 11 (21) ◽  
pp. 6006 ◽  
Author(s):  
Olusola Bamisile ◽  
Qi Huang ◽  
Paul O. K. Anane ◽  
Mustafa Dagbasi
Keyword(s):  
Renewable Energy ◽  
Exergy Analysis ◽  
Hot Water ◽  
Chicken Manure ◽  
Exergy Destruction ◽  
Maize Silage ◽  
Water Chamber ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Absorption Cycle

In this research, a novel trigeneration powered by a renewable energy (RE) source is developed and analyzed. The trigeneration system is designed to produce electricity, hot water, and cooling using two steam cycles, a gas cycle, hot water chamber, and an absorption cycle. The RE source considered in the scope of this study is biogas generated from chicken manure and maize silage. The energy and exergy analysis of the trigeneration system is performed with the aim to achieve higher efficiencies. The efficiencies are presented based on power generation, cogeneration (electricity and cooling) and trigeneration. The overall trigeneration energy and exergy efficiency for the system developed is 64% and 34.51%. The exergy destruction within the system is greatest in the combustion chamber.

scholarly journals Energy and Exergy Analysis of Sensible Thermal Energy Storage—Hot Water Tank for a Large CHP Plant in Poland

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4842 ◽  
Author(s):  
Ryszard Zwierzchowski ◽  
Marcin Wołowicz
Keyword(s):  
Energy Storage ◽  
Ambient Temperature ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Exergy Analysis ◽  
Hot Water ◽  
Water Tank ◽  
Exergy Destruction ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis

The paper contains a simplified energy and exergy analysis of pumps and pipelines system integrated with Thermal Energy Storage (TES). The analysis was performed for a combined heat and power plant (CHP) supplying heat to the District Heating System (DHS). The energy and exergy efficiency for the Block Part of the Siekierki CHP Plant in Warsaw was estimated. CHP Plant Siekierki is the largest CHP plant in Poland and the second largest in Europe. The energy and exergy analysis was executed for the three different values of ambient temperature. It is according to operation of the plant in different seasons: winter season (the lowest ambient temperature Tex = −20 °C, i.e., design point conditions), the intermediate season (average ambient temperature Tex = 1 °C), and summer (average ambient temperature Tex = 15 °C). The presented results of the analysis make it possible to identify the places of the greatest exergy destruction in the pumps and pipelines system with TES, and thus give the opportunity to take necessary improvement actions. Detailed results of the energy-exergy analysis show that both the energy consumption and the rate of exergy destruction in relation to the operation of the pumps and pipelines system of the CHP plant with TES for the tank charging and discharging processes are low.

The Energy and Exergy Efficiencies of Renewable Energy Utilization in a Building Stock

2013 ◽  
Vol 361-363 ◽  
pp. 335-338
Author(s):  
Xiao Chen
Keyword(s):  
Renewable Energy ◽  
Exergy Analysis ◽  
Hot Water ◽  
Energy Utilization ◽  
Efficiency Improvement ◽  
Building Stock ◽  
Domestic Hot Water ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Heating Mode

An surface water heat pump (SWHP) system and some solar domestic hot water (SDHW) systems were constructed in a building stock located in Xiangtan for the purpose of energy saving and environmental improvement. This study aims to evaluate the energy and exergy efficiencies of renewable energy utilization based on energy and exergy analysis. We found the energy and exergy efficiencies of the SWHP system in heating mode to be 395% and 17.78%, respectively. The energy and exergy efficiencies for the SDHW systems were found to be 34.96% and 17.5%, respectively. Some measures for the exergy efficiency improvement are discussed in this paper.

Experimental Evaluation of the Thermal Behavior of a Vertical Solar Tank Using Energy and Exergy Analysis

2005 ◽  
Author(s):  
Ali A. Dehghan ◽  
Mohammad H. Hosni ◽  
S. Hoda Shiryazdi
Keyword(s):  
Temperature Distribution ◽  
Flow Rate ◽  
Storage Tank ◽  
Thermal Stratification ◽  
Exergy Analysis ◽  
Hot Water ◽  
Second Law ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Hot Water Supply

The thermal performance of a Thermosyphon Domestic Solar Water Heater (DSWH) with a vertical storage tank is investigated experimentally. The system is installed on a roof - top of a four person family house and its thermal characteristics is evaluated by means of carefully measuring the temperature distribution of water inside the storage tank, solar collector flow rate and its inlet and outlet temperatures as well as load/consumption outlet and inlet temperatures and the corresponding water flow rate under a realistic operating conditions. The measurements are conducted every hour starting from morning until late night on a daily basis and continued for about 120 days during August until November 2004. It is seen that thermal stratification is well established inside the tank from 11 AM until 10 PM especially during August to September enabling the tank to provide the necessary amount of hot water at an acceptable temperature. However, thermal stratification is observed to start degrading from mid-night until morning when there is no hot water supply from the collector and due to the diffusion of heat from the top hot water layers to the bottom cold region and conduction through tank’s wall. The thermal behavior of the storage tank is also assessed based on both energy and exergy analysis and its first and second law efficiencies are calculated. It is observed that the storage tank under study has an average first law efficiency of 47.8% and is able to supply the required amount of hot water at a proper temperature. The average second law efficiency of the storage tank is observed to be 28.7% and, although is less than its first low efficiency, but is high enough to ensure that the quality of the hot water supply is well preserved. The proper level of second law efficiency is due to the preservation of the thermal stratification inside the storage tank, leading to supply of hot water at highest possible temperature and hence highest possible energy potential. Experiments are also done for no-load conditions when the storage tank only interacts with the collector, without hot water withdrawal from the tank. It is seen that for no-load condition, thermal stratification continuously develops from morning until around 16 PM after which no noticeable changes in the temperature distribution inside the tank is observed.

Energy and Exergy Analysis of the Teduction Zone in a Downdraft (Biomass) Gasifier

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Avdhesh Kr. Sharma ◽  
Raj Kumar Singh
Keyword(s):  
Kinetic Models ◽  
Exergy Analysis ◽  
Internal Heat ◽  
Calorific Value ◽  
Exergy Destruction ◽  
Reduction Zone ◽  
Reactor Performance ◽  
General Validity ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis

This article describes the energy and exergy analysis of the reduction zone in a downdraft biomass gasifier. A simplistic formulation for describing the pyrolysis and oxidation of these products has been presented for initialization. Equilibrium and kinetic models are used to predict the reduction products leaving the reduction zone and thus the 1st law efficiency. In the reduction zone, exergy destruction due to chemical, physical, compositional, internal heat transfer and heat loss to the surrounding has been quantified to describe 2nd law efficiency. The comparison of equilibrium and kinetic models is carried out with experimental data for general validity. Parametric analysis of char bed length and inflow temperature on gas composition, un-converted char, exergy destruction, 1st law and the 2nd law efficiency has also been carried out. Simulation results identified a critical char bed length (where all char gets consumed) for a given feedstock, which depends on residence time and reaction temperature in the reduction zone. Near critical char bed length, predictions show high calorific value of gas with relatively less exergy destruction and thus optimum reactor performance. The accuracy of the prediction depends on the validity of initial input conditions.

scholarly journals Energy and Exergy Analysis of Combined Organic Rankine Cycle-Single and Dual Evaporator Vapor Compression Refrigeration Cycle

2019 ◽  
Vol 9 (23) ◽  
pp. 5028 ◽  
Author(s):  
Pektezel ◽  
Acar
Keyword(s):  
Exergy Analysis ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Exergy Destruction ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Vapor Compression Refrigeration

This paper presents energy and exergy analysis of two vapor compression refrigeration cycles powered by organic Rankine cycle. Refrigeration cycle of combined system was designed with single and dual evaporators. R134a, R1234ze(E), R227ea, and R600a fluids were used as working fluids in combined systems. Influences of different parameters such as evaporator, condenser, boiler temperatures, and turbine and compressor isentropic efficiencies on COPsys and ƞex,sys were analyzed. Second law efficiency, degree of thermodynamic perfection, exergy destruction rate, and exergy destruction ratio were detected for each component in systems. R600a was determined as the most efficient working fluid for proposed systems. Both COPsys and ƞex,sys of combined ORC-single evaporator VCR cycle was detected to be higher than the system with dual evaporator.

scholarly journals Application of energy and exergy analysis to increase efficiency of a hot water gas fired boiler

2014 ◽  
Vol 20 (4) ◽  
pp. 511-521 ◽  
Author(s):  
Milena Todorovic ◽  
Dragoljub Zivkovic ◽  
Marko Mancic ◽  
Gradimir Ilic
Keyword(s):  
Exergy Analysis ◽  
Energy Analysis ◽  
Hot Water ◽  
Engineering Practice ◽  
Economic Optimization ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Reliable Solution ◽  
Control Volumes ◽  
Functional Components

In engineering practice exergy can be used for technical and economic optimization of energy conversion processes. The problem of increasing energy consumption suggests that heating plants, i.e. hot water boilers, as energy suppliers for household heating should be subjected to exergy and energy analysis. Heating plants are typically designed to meet energy demands, without the distinguished difference between quality and quantity of the produced heat. In this paper, the energy and exergy analysis of a gas fired hot water boiler is conducted. Energy analysis gives only quantitative results, while exergy analysis provides an insight into the actually available useful energy with respect to the system environment. In this paper, a hot water boiler was decomposed into control volumes with respect to its functional components. Energy and exergy of the created physical model of the hot water boiler is performed and destruction of exergy and energy loss in each of the components is calculated. The paper describes the current state of energy and exergy efficiency of the hot water boiler. The obtained results are analyzed and used to investigate possibilities for improvement of availability and reliability of the boiler. A comparison between the actual and the proposed more reliable solution is made.

Comparative Energy and Exergy Analysis of Proposed Gas Turbine Cycle With Simple Gas Turbine Cycle at Same Operational Cost

2019 ◽  
Author(s):  
M. N. Khan ◽  
Ibrahim M. Alarifi ◽  
I. Tlili
Keyword(s):  
Gas Turbine ◽  
Fuel Consumption ◽  
Exergy Analysis ◽  
Pressure Ratio ◽  
Specific Fuel Consumption ◽  
Exergy Destruction ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Gas Turbine Cycle ◽  
The Impact

Abstract Environmentally friendly and effective power systems have been receiving increased investigation due to the aim of addressing global warming, energy expansion, and economic growth. Gas turbine cycles are perceived as a useful technology that has advanced power capacity. In this research, a gas turbine cycle has been proposed and developed from a simple and regenerative gas turbine cycle to enhance performance and reduce Specific fuel consumption. The impact of specific factors regarding the proposed gas turbine cycle on thermal efficiency, net output, specific fuel consumption, and exergy destruction, have been inspected. The assessments of the pertinent parameters were performed based on conventional thermodynamic energy and exergy analysis. The results obtained indicate that the peak temperature of the Proposed Gas Turbine Cycle increased considerably without affecting fuel consumption. The results show that at Pressure Ratio (rp = 6) the performance of the Proposed Gas Turbine Cycle is much better than Single Gas Turbine Cycle but the total exergy destruction of Proposed Gas Turbine Cycle higher than the SGTC.

scholarly journals Exergy Analysis of Adiabatic Liquid Air Energy Storage (A-LAES) System Based on Linde–Hampson Cycle

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 945
Author(s):  
Lukasz Szablowski ◽  
Piotr Krawczyk ◽  
Marcin Wolowicz
Keyword(s):  
Energy Storage ◽  
Research And Development ◽  
Large Scale ◽  
Exergy Analysis ◽  
The Other ◽  
Compressed Air ◽  
Exergy Destruction ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Discharge Pressure

Efficiently storing energy on a large scale poses a major challenge and one that is growing in importance with the increasing share of renewables in the energy mix. The only options at present are either pumped hydro or compressed air storage. One novel alternative is to store energy using liquid air, but this technology is not yet fully mature and requires substantial research and development, including in-depth energy and exergy analysis. This paper presents an exergy analysis of the Adiabatic Liquid Air Energy Storage (A-LAES) system based on the Linde–Hampson cycle. The exergy analysis was carried out for four cases with different parameters, in particular the discharge pressure of the air at the inlet of the turbine (20, 40, 100, 150 bar). The results of the analysis show that the greatest exergy destruction can be observed in the air evaporator and in the Joule–Thompson valve. In the case of air evaporator, the destruction of exergy is greatest for the lowest discharge pressure, i.e., 20 bar, and reaches over 118 MWh/cycle. It decreases with increasing discharge pressure, down to approximately 24 MWh/cycle for 150 bar, which is caused by a decrease in the heat of vaporization of air. In the case of Joule–Thompson valve, the changes are reversed. The highest destruction of exergy is observed for the highest considered discharge pressure (150 bar) and amounts to over 183 MWh/cycle. It decreases as pressure is lowered to 57.5 MWh/cycle for 20 bar. The other components of the system do not show exergy destruction greater than approximately 50 MWh/cycle for all considered pressures. Specific liquefaction work of the system ranged from 0.189 kWh/kgLA to 0.295 kWh/kgLA and the efficiency from 44.61% to 55.18%.

scholarly journals Energy and Exergy Analysis of a Steam Power Plant in Suda

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Osman Shamet ◽  
Rana Ahmed ◽  
Kamal Nasreldin Abdalla
Keyword(s):  
Power Plant ◽  
Energy Loss ◽  
Heat Loss ◽  
Exergy Analysis ◽  
Primary Objective ◽  
Exergy Destruction ◽  
Steam Power ◽  
Steam Power Plant ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis

In this study, the energy and exergy analysis of Garri 4 power plant in Sudan is presented. The primary objective of this paper is to identify the major source of irreversibilities in the cycle. The equipment of the power plant has been analyzed individually. Values regarding heat loss and exergy destruction have been presented for each equipment. The results confirmed that the condenser was the main source for energy loss (about 67%), while ex­ergy analysis revealed that the boiler contributed to the largest percentage of exergy destruction (about 84.36%) which can be reduced by preheating the inlet water to a sufficient temperature and controlling air to fuel ratio.

scholarly journals ENERGY AND EXERGY ANALYSIS OF A CYLINDRICAL HOT WATER STORAGE TANK: EXPERIMENTAL AND CFD ANALYSIS

2020 ◽  
Author(s):  
Tomas Kropas ◽  
Giedrė Streckienė
Keyword(s):  
Numerical Model ◽  
Storage Tank ◽  
Exergy Analysis ◽  
Water Storage ◽  
Exergy Efficiency ◽  
Hot Water ◽  
Water Storage Tank ◽  
Environment Temperature ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis

Active solar water heating systems typically include hot water storage tanks. The selection of the storage system strongly affects the performance of the entire system. This article presents a detailed analysis of a hot water storage tank during charging and dynamic charging-discharging mode. A numerical model using computational fluid dynamics for the storage tank was developed to investigate the temperature distribution inside of it. Transient thermal analysis was carried using ANSYS Fluent. The numerical model was validated with the experimental results. The energy and exergy analysis as an important tool for the evaluation of the thermal systems quantitatively and qualitatively was performed. The calculation procedures were described. The energy and exergy efficiencies, heat losses were calculated for steady and dynamic processes. Effect of mass flow rate was analysed. The results from parametric analysis showed that charging dynamics reduced the thermocline and efficiency of the hot water storage tank. The dependency of the exergy efficiency of the heat storage tank on the reference environment temperature during the dynamic operation was analysed. Exergy efficiencies for two cities with different climates were compared. This indicated that the higher envi-ronmental temperature gave lower exergy efficiency of the storage tank.

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