Exergy Distribution Characters Analysis of a 130t/h Biomass-Fired Boiler

2015 ◽  
Vol 713-715 ◽  
pp. 1356-1359
Author(s):  
Fang Yang ◽  
Chang Qing Dong ◽  
Zhi Zhong Kang ◽  
Zong Ming Zheng ◽  
Xiao Ying Hu
Keyword(s):  
Heat Balance ◽  
Exergy Analysis ◽  
Second Law Of Thermodynamics ◽  
Energy Utilization ◽  
Analysis Model ◽  
The Real ◽  
First Law Of Thermodynamics ◽  
The Heat Balance ◽  
Exergy Losses

Currently, most of the boilers in power plant are designed by the heat balance based on first law of thermodynamics only, and it analyses the condition of using energy from the perspective of quantity of energy. However, The real energy utilization should be justified not only from the quantity but also from the quality, because the quality of energy based on second law of thermodynamics can reflect the irreversibility in processes and components. In order to revealing the real energy losses, we must establish exergy analysis model of 130t/h Biomass-Fired Boiler. This article calculates the exergy losses of all kinds of boiler surface and the overall exergy efficiency of boiler, together with exergy distribution characters analysis result of 130t/h Biomass-Fired Boiler. The results obtained open out the greatest exergy loss and the place to generate these losses of boiler, and provide scientific gist for improving utilization of boiler energy.

Heat Coupling of Gasoline Upgrading and Fluid Catalytic Cracking Processes

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Xingying Lan ◽  
Chunming Xu ◽  
Gang Wang ◽  
Jian Chang ◽  
Chunxi Lu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Balance ◽  
Cfd Simulation ◽  
Flow Behavior ◽  
Operating Conditions ◽  
Energy Utilization ◽  
Regeneration System ◽  
Fcc Gasoline ◽  
Fcc Catalysts ◽  
The Heat Balance

Heat supplement is necessary for FCC gasoline upgrading processes to keep the heat balance of reaction-regeneration system, while excess heat would be removed in FCC process due to the processing of heavy feedstock. Combining gasoline upgrading processes with FCC process can realize the heat coupling so as to achieve the maximum energy utilization. In this paper, the heat balance calculations of a commercial FCC unit and a FCC gasoline aromatization process were carried out, and the feasibility as well as the way to accomplish the heat coupling for the two processes was investigated. The results showed that the coked aromatization catalysts could be heated to the desired temperature by the direct contact with the hot regenerated FCC catalysts. The pilot experiment and CFD simulation was carried out to investigate the flow behavior and heat transfer of the direct coupling system of FCC process and FCC gasoline aromatization process. The results indicated that the well-mixing and efficient heat transfer between FCC catalysts and aromatization catalysts, as well as the sufficient regeneration of aromatization catalysts, could be achieved at appropriate operating conditions.

Thermodynamic analysis of the apple drying process

2005 ◽  
Vol 219 (1) ◽  
pp. 1-14 ◽  
Author(s):  
E. K. Akpinar ◽  
A Midilli ◽  
Y Bicer
Keyword(s):  
Thermodynamic Analysis ◽  
Single Layer ◽  
Second Law Of Thermodynamics ◽  
Energy Utilization ◽  
Drying Process ◽  
Cent Relative Humidity ◽  
Apple Slices ◽  
Drying Conditions ◽  
Drying Chamber ◽  
Exergy Losses

This paper is concerned with thermodynamic analysis of the process of single-layer drying of apple slices by means of a cyclone-type dryer. Using the first law of thermodynamics, energy analysis was performed to estimate the ratios of energy utilization throughout the drying process. Exergy analysis was carried out to determine exergy losses during the drying process by applying the second law of thermodynamics. It was concluded that the exergy losses increased with increasing energy utilization in both trays and the drying chamber. Values of the energy utilization ratio (EUR) of the drying chamber varied in the range 0−41.64 per cent depending on the drying conditions. The most exergy losses took place on the first tray (EUR = 0−21.06 per cent) during the drying of apple slices. It is emphasized that apple slices are sufficiently dried in the range 60−80°C with 20−10 per cent relative humidity and a drying air velocity of 1.5 m/s over a 3.33−5.33 h period in spite of exergy losses of 0−1.243 kj/s (EUR = 0−34.72 per cent).

scholarly journals Heat Balance Calculation and Energy Efficiency Analysis for Building Clusters Based on Psychrometric Chart

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7606
Author(s):  
Shihai Yang ◽  
Huiling Su ◽  
Xun Dou ◽  
Mingming Chen ◽  
Yixuan Huang
Keyword(s):  
Energy Efficiency ◽  
Energy Management ◽  
Heat Balance ◽  
Efficiency Analysis ◽  
Energy Utilization ◽  
Pipe Network ◽  
Accurate Calculation ◽  
Balance Calculation ◽  
The Heat Balance ◽  
Energy Efficiency Analysis

How to perform accurate calculation of heat balance and quantitative analysis of energy efficiency for building clusters is an urgent problem to be solved to reduce building energy consumption and improve energy utilization efficiency. This article proposes a method for the heat balance calculation and energy efficiency analysis of building clusters based on enthalpy and humidity diagrams and applies it to the energy management of building clusters containing primary return air systems and heating pipe networks. Firstly, the basic structure and energy management principle of building clusters with a primary return air system and a heating pipe network were given, and the heat balance calculation and energy efficiency analysis method based on i-d diagram was proposed to realize the accurate calculation of heat load and the quantification of energy utilization. Secondly, the energy management model of the building cluster with a primary return air system and a heating pipe network was established to efficiently manage the indoor temperature and the heating schedule of ASHP, HN and HI. Finally, the proposed method was validated by calculation examples, and the results showed that the proposed method is beneficial for improving the energy economy and energy efficiency of building clusters.

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.

scholarly journals Heat, work and subtle fluids: a commentary on Joule (1850) ‘On the mechanical equivalent of heat’

2015 ◽  
Vol 373 (2039) ◽  
pp. 20140348 ◽  
Author(s):  
John Young
Keyword(s):  
Second Law Of Thermodynamics ◽  
Scientific Work ◽  
Conservation Of Energy ◽  
First Law Of Thermodynamics ◽  
Mechanical Equivalent ◽  
Scientific Establishment ◽  
Series Of Experiments ◽  
Scientists And Engineers ◽  
350Th Anniversary

James Joule played the major role in establishing the conservation of energy, or the first law of thermodynamics, as a universal, all-pervasive principle of physics. He was an experimentalist par excellence and his place in the development of thermodynamics is unarguable. This article discusses Joule's life and scientific work culminating in the 1850 paper, where he presented his detailed measurements of the mechanical equivalent of heat using his famous paddle-wheel apparatus. Joule's long series of experiments in the 1840s leading to his realisation that the conservation of energy was probably of universal validity is discussed in context with the work of other pioneers, notably Sadi Carnot, who effectively formulated the principle of the second law of thermodynamics a quarter of a century before the first law was accepted. The story of Joule's work is a story of an uphill struggle against a critical scientific establishment unwilling to accept the mounting evidence until it was impossible to ignore. His difficulties in attracting funding and publishing in reputable journals despite the quality of his work will resonate with many young scientists and engineers of the present day. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society .

scholarly journals ANALISIS EKSERGI PENGERINGAN IRISAN TEMULAWAK

2016 ◽  
Vol 36 (01) ◽  
pp. 96
Author(s):  
Lamhot Parulian Manalu ◽  
Armansyah Halomoan Tambunan
Keyword(s):  
Exergy Analysis ◽  
Second Law Of Thermodynamics ◽  
Exergy Efficiency ◽  
Energy Utilization ◽  
Second Law ◽  
Process Conditions ◽  
Drying Process ◽  
Conservation Of Energy ◽  
Thin Layer Drying ◽  
Curcuma Xanthorrhiza

Java turmeric (Curcuma xanthorrhiza Roxb.) is a medicinal plant used as raw material for making herbal medicine, its rhizome cut into slices and dried so called simplicia. Curcuma has a harvest moisture content is high enough to need a great energy for drying. Generally, the theory used to analyze the energy efficiency is the first law of thermodynamics that describes the principle of conservation of energy. However, this theory has limitations in measuring the loss of energy quality. To determine whether the energy used in the drying process has been used optimally in terms of quality, the second law of thermodynamics -known as exergy analysis- is used. The purpose of this study is to determine the efficiency of the thin layer drying of curcuma slices with exergy analysis. The results show that the process conditions affect the energy utilization ratio and exergy efficiency of drying. Exergy analysis method based on the second law of thermodynamics has been used to determine the amount of exergy destroyed so that the efficiency of the drying process can be determined more accurately. Exergy efficiency varies between 96.5%-100% for temperatures of 50 °C to 70 °C at 40% RH and 82.3% - 100% for 20% to 40% RH at 50 °C.Keywords: Drying, energy, exergy efficiency, curcuma slices ABSTRAKTemulawak (Curcuma xanthorrhiza Roxb.) merupakan tanaman obat yang simplisianya digunakan sebagai bahan baku pembuatan jamu atau obat tradisional. Pengeringan merupakan proses utama dalam memproduksi simplisia. Untuk menganalisis efisiensi energi suatu proses pengeringan umumnya digunakan hukum termodinamika pertama yang menjelaskan tentang prinsip kekekalan energi. Akan tetapi teori ini mempunyai keterbatasan dalam mengukur penurunan kualitas energi. Untuk mengetahui apakah energi yang digunakan pada proses pengeringan sudah digunakan secara optimal dari sisi kualitas, digunakan hukum termodinamika kedua atau yang dikenal dengan analisis eksergi. Tujuan penelitian ini adalah menentukan efisiensi proses pengeringan lapisan tipis irisan temulawak dengan metode analisis energi dan eksergi. Dalam studi ini, metode analisis energi dan eksergi berdasarkan hukum termodinamika pertama dan kedua telah digunakan untuk menghitung rasio penggunaan energi dan besaran eksergi yang musnah (exergy loss). sehingga efisiensi proses pengeringan irisan temulawak dapat ditentukan secara akurat. Hasil penelitian menunjukkan bahwa kondisi proses pengeringan mempengaruhi rasio penggunaan energi dan efisiensi eksergi pengeringan. Semakin tinggi suhu dan RH pengeringan maka rasio penggunaan energi semakin rendah dan efisiensi eksergi semakin tinggi. Efisiensi eksergi pengeringan temulawak bervariasi antara 96,5%-100% untuk selang suhu 50 oC hingga 70 oC pada RH 40% serta 82,3% - 100% untuk selang RH 20% hingga 40% pada suhu 50 oC. Kata kunci: Pengeringan, energi, efisiensi eksergi, temulawak

scholarly journals Analysis of Exergy and Energy of Gasifier Systems for Coal-to-Fuel

2012 ◽  
pp. 246-252
Author(s):  
Nishant Sharma ◽  
Bhupendra Gupta ◽  
Ranjeet Pratap Singh Chauhan
Keyword(s):  
Exergy Analysis ◽  
Second Law Of Thermodynamics ◽  
Conservation Of Energy ◽  
Synthetic Natural Gas ◽  
Entrained Flow ◽  
Technology Improvement ◽  
Water Quench ◽  
Entrained Flow Gasifier ◽  
Quench Cooling

The purpose of this study is to investigate the performance features of coal-to-fuel systems based on different gasification technologies. The target products are the Fischer–Tropsch synthetic crude and synthetic natural gas. Two types of entrained-flow gasifierbased coal-to-fuel systems are simulated and their performance features are discussed. One is a single-stage water quench cooling entrained-flow gasifier, and another one is a two-stage syngas cooling entrained-flow gasifier. The conservation of energy (first law of thermodynamics) and the quality of energy (second law of thermodynamics) for the systems are both investigated. The results of exergy analysis provide insights about the potential targets for technology improvement. The features of different gasifier-based coal-to-fuel systems are discussed. The results provide information about the research and development priorities in future.

scholarly journals Exergy Analysis of Energy Systems in Buildings

Buildings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 180 ◽  
Author(s):  
Gianpiero Evola ◽  
Vincenzo Costanzo ◽  
Luigi Marletta
Keyword(s):  
Energy Conversion ◽  
Fossil Fuels ◽  
Exergy Analysis ◽  
Second Law Of Thermodynamics ◽  
Energy Conversion Efficiency ◽  
Lessons Learned ◽  
Energy Sources ◽  
Heating And Cooling ◽  
Energy Conversion Systems

The performance of space heating and cooling systems in buildings is usually measured by applying the first law of thermodynamics, which makes it possible to quantify the energy losses of the single components and to measure their energy conversion efficiency. However, this common approach does not properly consider that different forms of energy have different potentials to produce useful work, the latter being a function of the temperature at which energy is made available. As a result, it is not possible to properly address how the “quality” of energy is exploited or conserved in the different processes. On the contrary, the second law of thermodynamics is able to do that by introducing the concept of exergy: This is the maximum amount of work that can be produced through an ideal reversible process evolving until a full condition of equilibrium with the environment is attained. Exergy is; thus, a possible way to measure the “quality” of an energy flow or an energy source. This perspective is particularly relevant when dealing with buildings and their energy conversion systems, which usually deliver thermal energy at a temperature level that is close to the environmental temperature. This means that the users require “low-quality” energy; notwithstanding, this energy comes from the depletion of “high-quality” energy sources, such as fossil fuels and electricity. The exergy analysis helps with identifying such irrational use of the energy sources, which cannot come to light from the energy analysis. In this paper, a literature review identifies methods and metrics commonly used to carry out the exergy analysis of buildings and their energy technologies, while also underlining discrepancies and open methodological issues. Then, the review discusses the main lessons learned from selected works, providing significant advice about the rational use of energy in buildings as well as the most effective technological solutions.

Reducing the Risk of Fire Fighting in Harsh Climatic Conditions

2021 ◽  
pp. 69-74
Author(s):  
T.A. Kulagina ◽  
◽  
T.A. Yenutina ◽  
V.I. Tereshkov ◽  
◽  
...  
Keyword(s):  
Heat Transfer ◽  
Balance Equation ◽  
Heat Balance ◽  
Climatic Conditions ◽  
Maximum Length ◽  
Heat Balance Equation ◽  
Ambient Temperatures ◽  
First Law Of Thermodynamics ◽  
Flow And Heat Transfer ◽  
The Heat Balance

The sustainability of the development of the northern territories of Russia from the Urals to the Pacific Ocean, where the bulk of the country natural resources is concentrated in the twenty-first century, is determined by the integrated approach to planning and managing the risks of using machines, structures and equipment, critical and hazardous industrial facilities and technological support and support at the stages of their operation. Climatic factors have a noticeable effect on increasing the risks of abnormal situations occurrence in emergency situations, for example, on the efficiency of fire departments activity in the winter period of the year and at extinguishing fires in harsh climatic conditions, when water may freeze inside the hoses and in the working chamber of the feed pump. Due to a malfunction in the fire equipment, the scale of the territory covered by the flames can significantly increase, and the extinguishing process will become more complicated. Operability of the hose lines in low temperature conditions is calculated using Methodological Recommendations for ensuring the operability of pump and hose systems of fire trucks when extinguishing fires in the conditions of extremely low temperatures, determining the maximum length of the hose line before icing begins. It is shown in the paper that the maximum length of the hose line, that is, the distance from the pump to the beginning of icing, should be calculated using the heat balance equation, which is based on two equations of the first law of thermodynamics — for flow and heat transfer. At the same time, it is required to combine thermal and hydraulic calculations. The methods are presented in the article for predicting the operability of pumps and hose lines in the conditions of extremely low ambient temperatures, used in fire truck systems for extinguishing fires, including at the energy facilities. It is shown that there are errors and shortcomings in the Methodological Recommendations for ensuring the operability of pump and hose systems of the fire trucks when extinguishing fires in the conditions of extremely low ambient temperatures, including at the energy facilities. It is also shown that the maximum length of the hole line, that is, the distance from the pump to the beginning of icing, should be calculated using the heat balance equation, which is based on two equations of the first law of thermodynamics — for flow and heat transfer.

Exergetic Assessment of Biogas Engine-Driven Heat Pump Systems for Using Sewage Resource

2012 ◽  
Vol 455-456 ◽  
pp. 1251-1256
Author(s):  
Xiao Ming Li ◽  
Wen Xia Wang ◽  
Ai Jie Wang ◽  
Zhi Yao Wang ◽  
Yue Shi
Keyword(s):  
Wastewater Treatment ◽  
Heat Pump ◽  
Wastewater Treatment Plant ◽  
Exergy Analysis ◽  
Weak Link ◽  
Treatment Plant ◽  
Exergy Efficiency ◽  
Energy Utilization ◽  
Utilization Rate ◽  
Exergy Losses

In order to improve energy utilization rate of biogas engine-driven heat pump (BEHP) systems for wastewater treatment plant, the exergy analysis is applied in this paper. The paper concludes the exergy losses and exergy efficiency of each equipment, and reveals the weak link of energy transformation of the whole system. According to the calculation of one example, the location of maximum exergy loss is the biogas engine-driven, while the location of minimum exergy efficiency is the compressor, which provides powerful theoretic references to improve and optimize BEHP systems for wastewater treatment plant.

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