scholarly journals Comparison of Exergy and Various Energy Analysis Methods for a Main Marine Steam Turbine at Different Loads

2020 ◽  
Vol 59 (1) ◽  
pp. 9-34
Author(s):  
Nikola Anđelić ◽  
Vedran Mrzljak ◽  
Ivan Lorencin ◽  
Sandi Baressi Šegota
Keyword(s):  
Energy Efficiency ◽  
Steam Turbine ◽  
Exergy Analysis ◽  
Energy Analysis ◽  
Energy Losses ◽  
Analysis Method ◽  
Expansion Process ◽  
Analysis Methods ◽  
Energy And Exergy ◽  
Pressure Cylinder

This paper present energy and exergy analysis of the main marine steam turbine, which is used for the commercial LNG (Liquefied Natural Gas) carrier propulsion, at four different loads. Energy analysis is performed by using four different methods. The presented analysis allows distinguishing advantages and disadvantages of all observed energy analysis methods and its comparison to exergy analysis of the same steam turbine. Each analysis is based on the measurement results obtained in main turbine exploitation conditions. Main turbine is composed of two cylinders – High Pressure Cylinder (HPC) and Low Pressure Cylinder (LPC). At low turbine loads, the dominant power producer is HPC, while at middle and high loads the dominant power producer is LPC. Energy analysis Method 1 which is based on the same principles as exergy analysis, should be avoided if the majority of turbine losses are not known. Other observed energy analysis methods can be applied in the analysis of any steam turbine, with a note that increase in ideal (isentropic) steam expansion process divisions will result with an increase in energy losses and with a decrease in energy efficiency. Energy analysis Method 2 which consist of only one ideal (isentropic) steam expansion process, for the whole turbine and at all observed loads, results with the lowest energy losses (in the range between 639.98 kW and 6434.17 kW) as well as with the highest energy efficiency (in a range between 53.70% and 79.40%) in comparison to other applicable energy analysis methods. For the observed loads, whole main turbine exergy destruction is in range from 608.64 kW to 5922.86 kW, while the exergy efficiency range of the whole turbine is between 54.94% and 80.73%. Exergy analysis and all three applicable energy analysis methods show that increase in the main turbine load results with simultaneous increase in turbine losses and efficiencies (both energy and exergy).

scholarly journals ANALISA ENERGI DAN EKSERGI PADA PENGERINGAN TEPUNG TAPIOKA MENGGUNAKAN PENGERING KONTINYU UNGGUN FLUIDISASI GETAR

REAKTOR ◽  
2016 ◽  
Vol 16 (1) ◽  
pp. 24 ◽  
Author(s):  
Suherman Suherman ◽  
Rona Trisnaningtyas
Keyword(s):  
Energy Efficiency ◽  
Fluidized Bed ◽  
Exergy Analysis ◽  
Cassava Starch ◽  
Energy Utilization ◽  
Exergetic Efficiency ◽  
Energy And Exergy ◽  
Vibrated Fluidized Bed ◽  
Energy And Exergy Analysis ◽  
Utilization Ratio

Energy and exergy analysis of cassava starch drying in continuous vibrated fluidized bed dryer were carried out to assess the performance of the system in terms of energy utilization ratio, energy efficiency, exergy inflow and outflow, exergy loss, and exergetic efficiency. The results showed cassava starch has starch content 87%, degree of whiteness 95%, negative fiber content, sperichal granula with average diameter12.32 μm, orthorhombic crystal structure and crystal size 47.467 nm . Energy utilization and energy utilization ratio increased from 0.08 to 0.20 J/s and 0.35 to 0.4 as the drying temperature  increased from 50 to 70 oC. Energy efficiency increased from 13.80 % to 23.31 %, while exergy inflow, outflow, and losses increased from 4.701 to 14.678, 2.277 to 6.344, and 2.424 to 8.334 J/s respectively in the above temperature range. Exergetic efficiency decreased with increase in drying air temperature, while exergetic improvement potential increased with increased drying air temperature. Keywords: Cassava starch, continuous drying, energy and exergy analysis, vibrated fluidized bed Abstrak Analisis energi dan eksergi pengeringan pati tapioka menggunakan pengering kontinu unggun fluidisasi getar, telah dilakukan untuk menilai kinerja sistem dalam bentuk utilisasi energi, efisiensi energi, eksergi masuk dan keluar, eksergi hilang dan efisiensi eksergi. Hasil analisis pati memiliki kandungan starch 87%, tingkat keputihan 95%, kandungan serat negatif, bentuk partikel granular spherical dengan diameter 12,32 μm, struktur kristal orthorhombic dan ukuran kristal sebesar 47,467 nm. Peningkatan suhu pengering dari 50 menjadi 70 0C akan meningkatkan utilisasi energi dan rasio utilisasi energi dari 0,08 menjadi 0,20 J/s dan 0,35 menjadi 0,4. Efisiensi energi meningkat dari 13,80% hingga 23,31%, sedangkan eksergi masuk dan keluar, eksergi hilang meningkat dari 4,701 menjadi 14,678, 2,277 menjadi 6,344, dan 2,424 menjadi 8,334 J/s. Efisiensi eksergi menurun dengan naiknya suhu sedangkan potensi pengembangan eksergi meningkat dengan naiknya suhu. Kata kunci:. Analisis energi dan eksergi, pati tapioka, pengeringan kontinu, unggun fluidisasi getar

Energy and Exergy Analysis of Solar Parabolic Dish Thermoelectric Generator

2014 ◽  
Vol 592-594 ◽  
pp. 2437-2441 ◽  
Author(s):  
Gunalan Muthu ◽  
Subramaniam Shanmugam ◽  
Arunachalam R. Veerappan
Keyword(s):  
Energy Efficiency ◽  
Concentration Ratio ◽  
Thermoelectric Generator ◽  
Exergy Analysis ◽  
Exergy Loss ◽  
Thermal System ◽  
Increase With Increase ◽  
Energy And Exergy ◽  
Parabolic Dish ◽  
Energy And Exergy Analysis

The Performance of a thermal system is generally analysed by carrying out energy and exergy analysis of its different subsystems. In the present study the performance of subsystem namely PDC, receiver plate and PDC in a system of solar parabolic dish thermoelectric generator is studied. It is found that the energy and exergy loss are minimum in the receiver plate as compared to PDC and thermoelectric generator (TEG) at a particular direct normal irradiation (DNI). The exergy and energy efficiency in the PDC and TEG increase with increase in concentration ratio.

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.

scholarly journals Energy and Exergy Analysis of the Condensate Pump During Internal Leakage from the Marine Steam Propulsion System

Pomorstvo ◽  
2018 ◽  
Vol 32 (2) ◽  
pp. 268-280
Author(s):  
Igor Poljak ◽  
Josip Orović ◽  
Vedran Mrzljak
Keyword(s):  
Exergy Analysis ◽  
Pump Energy ◽  
Propulsion System ◽  
Normal Operation ◽  
Energy Losses ◽  
Load Range ◽  
Condensate Pump ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Exergy Losses

An energy and exergy analysis of the condensate pump from the marine steam propulsion system during the condensate leakage between pump stages is presented in this paper. Measurements from the steam propulsion system during exploitation were necessary for collecting all the data for the condensate pump analysis. Due to condensate leakage inside the pump casing, the producer specified condensate pressures at the pump outlet could not be obtained during the exploitation. Low condensate pressure at the pump inlet and condensate temperature slightly above the atmospheric significantly influences the pump exergy analysis. Increase in pump load resulted in an increase of pump energy and exergy losses and efficiencies. In the observed load range during the leakage, pump energy losses are between 19.88 kW and 24.78 kW, while pump energy efficiencies are between 11.12 % and 41.54 %. Pump exergy losses are slightly higher, while exergy efficiencies are slightly lower when compared to energy losses and efficiencies. During normal operation, without leakage, the pump energy efficiencies are from 5 % to 20 % higher in comparison with pump operation when the leakage occurs.

scholarly journals Performance, Emission, Energy, and Exergy Analysis of a C.I. Engine Using Mahua Biodiesel Blends with Diesel

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Nabnit Panigrahi ◽  
Mahendra Kumar Mohanty ◽  
Sruti Ranjan Mishra ◽  
Ramesh Chandra Mohanty
Keyword(s):  
Energy Input ◽  
Exergy Analysis ◽  
Energy Analysis ◽  
Emission Energy ◽  
Exhaust Gases ◽  
Mahua Oil ◽  
Brake Power ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Mahua Biodiesel

This paper presents an experimental investigation on a four-stroke single cylinder diesel engine fuelled with the blends of Mahua oil methyl ester (MOME) and diesel. The performance emission, energy, and exergy analysis has been carried out in B20 (mixture of 80% diesel by volume with 20% MOME). From energy analysis, it was observed that the fuel energy input as well as energy carried away by exhaust gases was 6.25% and 11.86% more in case of diesel than that of B20. The unaccounted losses were 10.21% more in case of diesel than B20. The energy efficiency was 28%, while the total losses were 72% for diesel. In case of B20, the efficiency was 65.74 % higher than that of diesel. The exergy analysis shows that the input availability of diesel fuel is 1.46% more than that of B20. For availability in brake power as well as exhaust gases of diesel were 5.66 and 32% more than that of B20. Destructed availability of B20 was 0.97% more than diesel. Thus, as per as performance, emission, energy, and exergy part were concerned; B20 is found to be very close with that of diesel.

Discussion of Energy Consumption Analysis Method on Energy System

2011 ◽  
Vol 130-134 ◽  
pp. 1578-1581
Author(s):  
Cai Juan Zhang ◽  
Li Gang Wang ◽  
Ling Nan Wu ◽  
Tong Liu ◽  
Qiang Lu ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Economic Analysis ◽  
Energy Saving ◽  
Exergy Analysis ◽  
Energy Analysis ◽  
Rapid Development ◽  
Second Law Of Thermodynamics ◽  
Energy Utilization ◽  
Second Law ◽  
Analysis Method

With the social rapid development, the earth's limited primary energy such as coal, oil, natural gas etc will be exhausted; energy problem has caused worldwide widespread attention. Therefore, under the development of renewable energy, without exception, each country is actively trying to explore the new theory and using energy-saving and technology to improve energy utilization ratio and reduce the energy consumption and the harm on environment. Scientific analysis of energy saving is an important link of digging energy saving potential, effective energy analysis method plays a pivotal role in implementing saving energy. This paper summarized several energy analysis methods on the basis of the first and second law of thermodynamics, introduced the most widely used enthalpy analysis method, entropy analysis, exergy analysis and exergy economic analysis which are based on the second law of thermodynamics, introduced emphatically the specific consumption analysis theory development with exergy analysis and exergy economic analysis.

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