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Article
Publication date: 20 October 2020

Ibrahim Yildiz and Hakan Caliskan

The purpose of this study is to evaluate the energy and exergy prices and carbon emission equivalents of the jet kerosene (Jet A-1) fuel considering 12 months data for an…

Abstract

Purpose

The purpose of this study is to evaluate the energy and exergy prices and carbon emission equivalents of the jet kerosene (Jet A-1) fuel considering 12 months data for an air craft used in the air transport sector in Turkey.

Design/methodology/approach

In the selection of the energy resources, one of the most important factors besides the need is the price of the energy resources. To use and save the energy resources efficiently, the prices should be evaluated in terms of exergy too. In this context, the exergy prices and carbon emission equivalents of the jet kerosene fuel have been examined.

Findings

According to analysis results, after January 2020, a steady decline in energy prices has been obtained until April 2020. In this regard, directly proportional changes have been obtained in exergy prices. The minimum exergy price of the fuel is calculated as 74.36 US cents/kWh for April 2020, while the maximum exergy price of the fuel is calculated as 150.02 US cents/kWh for September 2019. The minimum exergy price based carbon emission equivalents for the jet kerosene fuel is determined as 1,099.98 US cents/kg for April 2020, while the maximum exergy price based carbon emission equivalents for the jet kerosene fuel is found to be 2,219.29 US cents/kg for September 2019.

Originality/value

The new contribution has been made to the open literature by examining the energy and exergy prices of the jet kerosene fuel. In addition, the carbon emission equivalents of the jet kerosene fuel have been determined not only energy but also exergy methods.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 3
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 4 September 2017

Ahmet Topal and Onder Turan

The purpose of this study is to perform an exergy analysis of a turbojet engine combustor at different cycle parameters.

Abstract

Purpose

The purpose of this study is to perform an exergy analysis of a turbojet engine combustor at different cycle parameters.

Design/methodology/approach

Base cycle parameters have been defined for the engine, and then differentiation of the combustor exergy efficiencies and destruction rates have been evaluated by changing overall pressure ratio, combustor exit temperature and combustor pressure ratio.

Findings

For the basic engine cycle, combustor unit is found to have lowest exergy efficiency as 62.3 for the sea level static condition. Compressor turbine exhaust and whole engine exergy efficiencies have been calculated as 88.7, 96.5, 68.2 and 69.4, respectively.

Practical implications

Because of the biggest exergy, destruction is seen mainly in combustion system; effect of the combustor inlet pressure (related to the compressor design technology), pressure drop and exit temperature on the exergy efficiencies have been analyzed and combustor second law efficiency have been evaluated.

Social implications

The investigation’s purposes are highly connected with social wellness and targeted at sustainable development of the society. Practical implementation of the obtained scientific results is directed on the improving of combustor for a turbojet engines and decreasing negative influence on the environment.

Originality/value

As a result of this paper, the following are the contribution of this paper in the field of gas turbine exergy subjects: Combustor has been found as the most critical component in respect of the exergy efficiency. Therefore, the effect of the combustor main cycle parameters such as inlet pressure, combustor pressure ratio and exit temperature have been analyzed.

Details

Aircraft Engineering and Aerospace Technology, vol. 89 no. 5
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 6 August 2020

Ali Dinc, Yasin Şöhret and Selcuk Ekici

This study aims to introduce exergy analysis of a three-spool turboprop engine during the complete flight.

Abstract

Purpose

This study aims to introduce exergy analysis of a three-spool turboprop engine during the complete flight.

Design/methodology/approach

In this study, a flight scenario of the aircraft is assumed. Operating parameters of the aircraft and its engine are modelled based on the assumed flight scenario with the aid of a genuine code. And then performance analysis of the engine is performed for each flight path point with the aid of exergy.

Findings

At the end of the study, major exergy parameters of the engine are calculated during the complete flight of a cargo aircraft three-spool turboprop engine.

Practical implications

Findings of the study may be beneficial for industry and practitioners to improve performance of the evaluated engine.

Originality/value

To the best of authors’ knowledge, this paper presented the exergy analysis of a three-spool turboprop engine during the complete flight for the first time. It was shown how the exergy destruction rate depends on the altitude and manoeuvre.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 10
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 1 October 2019

Soroush Sadripour, Mohammad Estajloo, Seyed Abdolmehdi Hashemi, Ali J. Chamkha and Mahmoud Abbaszadeh

The purpose of this study is to reduce energy consumption in bakeries. Due to fulfill this demand, quite a few parameters such as energy and exergy efficiency, energy…

Abstract

Purpose

The purpose of this study is to reduce energy consumption in bakeries. Due to fulfill this demand, quite a few parameters such as energy and exergy efficiency, energy waste and fuel consumption by different traditional flatbreads bakeries (Sangak, Barbari, Taftun and Lavash should be monitored and their roles should not be neglected.

Design/methodology/approach

In the present study, experimental measurements and mathematical modeling are used to scrutinize and investigate the effects of the aforementioned parameters on energy consumption by bakeries.

Findings

The results show that by doing reported methods in this paper, the wasted energy of the walls can be decreased by about 65 per cent; and also, by controlling the combustion reaction to perform with 5 per cent excess air, the wasted energy of excess air declines by about 90 per cent. And finally, the energy and exergy efficiency of bakeries is increased, and as a result, the annual energy consumption of Sangak, Barbari, Taftun and Lavash bakeries diminish about 71, 59, 57 and 40 per cent, respectively.

Originality/value

As evidenced by the literature review, it can be observed that neither numerical studies nor experimental investigations have been conducted about energy and exergy analyses of Iranian machinery traditional flatbread bakeries. It is clear that due to a high preference of Iranians to use the traditional bread and also the popularity of baking this kind of bread in Iran, if it is possible to enhance the traditional oven conditions to decrease the loss of natural gas instead of industrializing the bread baking, the energy consumption in the country can be optimized.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 6
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 5 March 2018

Yasin Şöhret and T. Hikmet Karakoc

It is essential to develop more environment-friendly energy systems to prevent climate change and minimize environmental impact. Within this scope, many studies are…

Abstract

Purpose

It is essential to develop more environment-friendly energy systems to prevent climate change and minimize environmental impact. Within this scope, many studies are performed on performance and environmental assessments of many types of energy systems. This paper, different from previous studies, aims to prove exergy performance of a low-emission combustor of an aero-engine.

Design/methodology/approach

It is a well-known fact that, with respect to previous exergy analysis, highest exergy destruction occurs in the combustor component of the engine. For this reason, it is required to evaluate a low-emission aero-engine combustor thermodynamically to understand the state of the art according to the authors’ best of knowledge. In this framework, combustor has been operated at numerous conditions (variable engine load) and evaluated.

Findings

As a conclusion of the study, the impact of emission reduction on performance improvement of the aero-engine combustors exergetically is presented. It is stated that exergy efficiency of the low-emission aero-engine combustor is found to be 64.69, 61.95 and 71.97 per cent under various operating conditions.

Practical implications

Results obtained in this paper may be beneficial for researchers who are interested in combustion and propulsion technology and thermal sciences.

Originality/value

Different from former studies, the impact of operating conditions on performance of a combustor is examined from the viewpoint of thermodynamics.

Details

Aircraft Engineering and Aerospace Technology, vol. 90 no. 2
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 26 August 2014

Hari Bhaskaran Anangapal

The purpose of this study is to carry out energy and exergy analysis of fuels. Production of power and heat in industrialized countries is almost entirely based on…

Abstract

Purpose

The purpose of this study is to carry out energy and exergy analysis of fuels. Production of power and heat in industrialized countries is almost entirely based on combustion of fuels. Usually, combustion takes place in boilers or furnace; well-designed boilers have high thermal efficiencies of > 90 per cent. Even very high efficiencies, close to 100 per cent can be achieved depending on the applied fuel and boiler type. These high thermal efficiencies do suggest that combustion processes are highly optimized and do not need further improvements with regard to their thermodynamic performance. Second law (entropy or exergy) evaluations, however, shows that thermodynamic losses of boiler and furnaces are much larger than the thermal efficiencies do suggest. During combustion, air is predominantly used. When using air, the adiabatic combustion temperature depends only on the properties of fuel and air. The determining parameters for optimal fuel utilization are the fuel type, their composition and moisture content, the air temperature and air factor at combustion inlet.

Design/methodology/approach

Following assumptions are made for the analysis: calculation on the basis of 100 kg of dry and ash free fuel entering the control volume; fuel entering the control volume at T0, P0 and reacting completely with air entering separately at T0, P0 to form CO2, SO2, N2 and H2O, which exit separately at T0, P0 (T0 = 298 K; P0 = 1 atm); all heat transfer occurs at temperature T0; and the chemical exergy of the ash has been ignored The availability change and the irreversibility for chemical reactions of hydrocarbon fuels were studied because fuel and dry air composed of O2 and N2 react to form products of combustion in the restricted dead state, and fuel and dry air composed of O2 and N2 react to form products of combustion which end up in the environmental (unrestricted) dead state. The difference between the above two statement, is the chemical availability of the product gases as they proceed from the restricted to the unrestricted dead state. These evaluations were made in terms of enthalpy and entropy values of the reacting species. T0 extend these concepts to the most general situation, it is considered a steady-state control volume where the fuels enters at the restricted dead state, the air (oxidant) is drawn from the environment, and the products are returned to the unrestricted dead state.

Findings

It is evident from the analysis that an air factor of 1.10-1.20 is sufficient for liquid fuels, whereas solid fuels will require air factors of 1.15–1.3. When the temperatures of the products of combustion (Tp) are cooled down to that of T0, the maximum reversible work occurs. From the analysis, it is clear that the rather low combustion temperature and the need for cooling down the flue gases to extract the required heat are the main causes of the large exergy losses. The maximum second law efficiency also occurs when Tp is set equal to T0. The maximum second law efficiency per kilo mole of fuel is found to be 73 per cent, i.e. 73 per cent of the energy released by the cooling process could theoretically be converted into useful work. It is evident that reducing exergy losses of combustion is only useful if the heat transferred from the flue gas is used at high temperatures. Otherwise, a reduction of exergy loss of combustion will only increase the exergy loss of heat transfer to the power cycle or heat-absorbing process. The exergy loss of combustion can be reduced considerable by preheating combustion air. Higher preheat temperatures can be obtained by using the flue gas flow only for preheating air. The remainder of the flue gas flow can be used for heat transfer to a power cycle or heat-absorbing process. Even with very high air preheat temperatures, exergy losses of combustion are still > 20 per cent. The application of electrochemical conversion of fuel, as is realized in fuel cells, allows for much lower exergy loses for the reaction between fuel and air than thermal conversion. For industrial applications, electrochemical conversion is not yet available, but will be an interesting option for the future.

Originality/value

The outcome of the study would certainly be an eye-opener for all the stakeholders in thermal power plants for considering the second law efficiency and to mitigate the irreversibilities.

Details

International Journal of Energy Sector Management, vol. 8 no. 3
Type: Research Article
ISSN: 1750-6220

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Article
Publication date: 3 December 2018

Hongbin Zhao, Yu Cao, Chang Liu and Xiang Qi

The purpose of this paper is to investigate the performance of coke oven gas (COG)-combined cooling, heating and power (CCHP) system and to mainly focus on studying the…

Abstract

Purpose

The purpose of this paper is to investigate the performance of coke oven gas (COG)-combined cooling, heating and power (CCHP) system and to mainly focus on studying the influence of the environmental conditions, operating conditions and gas conditions on the performance of the system and on quantifying the distribution of useful energy loss and the saving potential of the integrated system changing with different parameters.

Design/methodology/approach

The working process of COG-CCHP was simulated through the establishment of system flow and thermal analysis mathematical model. Using exergy analysis method, the COG-CCHP system’s energy consumption status and the performance changing rules were analyzed.

Findings

The results showed that the combustion chamber has the largest exergy loss among the thermal equipments. Reducing the environmental temperature and pressure can improve the entire system’s reasonable degree of energy. Higher temperature and pressure improved the system’s perfection degree of energy use. Relatively high level of hydrogen and low content of water in COG and an optimal range of CH4 volume fraction between 35 per cent and 46 per cent are required to ensure high exergy efficiency of this integration system.

Originality/value

This paper proposed a CCHP system with the utilization of coke oven gas (COG) and quantified the distribution of useful energy loss and the saving potential of the integrated system under different environmental, operating and gas conditions. The weak links of energy consumption within the system were analyzed, and the characteristics of COG in this way of using were illustrated. This study can provide certain guiding basis for further research and development of the CCHP system performance.

Details

World Journal of Engineering, vol. 15 no. 6
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 8 April 2016

Sunday Olayinka Oyedepo, Richard Olayiwola Fagbenle, Samuel Sunday Adefila and Md Mahbub Alam

This study aims to use an environomics method to assess the environmental impacts of selected gas turbine power plants in Nigeria.

Abstract

Purpose

This study aims to use an environomics method to assess the environmental impacts of selected gas turbine power plants in Nigeria.

Design/methodology/approach

In this study, exergoenvironomic analysis has been carried out to investigate the environmental impact of selected gas turbine power plants in Nigeria from an exergetic point of view.

Findings

The exergy analysis reveals that the combustion chamber is the most exergy destructive component compared to other cycle components. The exergy destruction of this component can be reduced by increasing gas turbine inlet temperature (GTIT). The results of the study show that thermodynamic inefficiency is responsible for the environmental impact associated with gas turbine components. The study further shows that CO2 emissions and cost of environmental impact decrease with increasing GTIT.

Originality/value

The exergo-environomic parameters computed in this study are CO2 emission in kg per MWh of electricity generated, depletion number, sustainability index, cost flow rate of environmental impacts (Ċenv) in $/h and total cost rates of products (ĊTot) in $/hr. For the period considered, the CO2 emissions for the selected plants vary from 100.18 to 408.78 kgCO2/MWhm, while cost flow rate of environmental impacts varies from $40.18 /h to $276.97 /h and the total cost rates of products vary from $2935.69/h to $12,232.84/h. The depletion number and sustainability index vary from 0.69 to 0.84 and 1.20 to 1.44, respectively.

Details

World Journal of Engineering, vol. 13 no. 2
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 1 November 2019

P. Gunasekar, S. Manigandan, Venkatesh S., R. Gokulnath, Rakesh Vimal and P. Boomadevi

The depletion of fossil fuel and emissions of harmful gases forced the pioneers in search of alternate energy source. The purpose of this study is to present an effective…

Abstract

Purpose

The depletion of fossil fuel and emissions of harmful gases forced the pioneers in search of alternate energy source. The purpose of this study is to present an effective use of hydrogen fuel for turbojet engines based on its exergetic performance.

Design/methodology/approach

This study was performed to measure the assessment of exergetic data of turbojet engines. Initially, the test was carried out on the Jet A-1 fuel. Then, a series of similar tests were carried out on turbojet engines with hydrogen fuel to measure their performance results. Finally, the exergetic values of both were compared with each other.

Findings

The introduction of hydrogen fuel reduced the exergy efficiency, and a 10 per cent reduction was observed in exergy efficiency. Simultaneously, the waste exergy rate increased by 9 per cent. However, because of the high specific fuel exergy, hydrogen fuel was better than Jet A-1 fuel. Note that parameters such as environmental effect factor and ecological effect witnessed an increase in their index owing to the addition of hydrogen.

Practical implications

Introduction of alternative blends is necessary for achieving lower emission of gases such as CO, NOx and CO2 from gas turbine engines without compromising on performance. The Jet A fuels were replaced by blends to obtain better emission characteristics.

Originality/value

The use of hydrogen in turbojet engines showed an adverse effect on exergetic performance. However, it was very impressive to see a 200 per cent reduction in emissions. From the comparison of exergy efficiency results of inlet, combustion and nozzle, it is evident that the combustion chamber has the largest values of exergy ratio, waste exergy ratio, cost flow, ecological factor, environmental factor and fuel ratio owing to irreversibility in the combustion process.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 2
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 23 August 2015

S.O. Oyedepo, R.O. Fagbenle, S.S. Adefila and Md. Mahbub Alam

In this study, exergoeconomic analysis and performance evaluation of selected gas turbine power plants in Nigeria were carried out. The study was conducted using operating…

Abstract

In this study, exergoeconomic analysis and performance evaluation of selected gas turbine power plants in Nigeria were carried out. The study was conducted using operating data obtained from the power plants to determine the exergy efficiency, exergy destruction, unit cost of electricity and cost of exergy destruction of the major components of a gas turbine engine in the selected power plants. The results of exergy analysis confirmed that the combustion chamber is the most exergy destructive component compared to other cycle components as expected. The total efficiency defects and overall exergetic efficiency of the selected power plants vary from 38.64 to 69.33% and 15.66 to 30.72% respectively. The exergy analysis further shows that the exergy improvement potential of the selected plants varies from 54.04 MW to 159.88 MW. The component with the highest exergy improvement potential is the combustion chamber and its value varies from 30.21 MW to 88.86 MW. The results of exergoeconomic analysis show that the combustion chamber has the greatest cost of exergy destruction compared to other components. Increasing the gas turbine inlet temperature (GTIT), both the exergy destruction and the cost of exergy destruction of this component were found to decrease. The results of this study revealed that an increase in the GTIT of about 200 K can lead to a reduction of about 29% in the cost of exergy destruction. From exergy costing analysis, the unit cost of electricity produced in the selected power plants varies from cents 1.99 /kWh (N3.16 /kWh) to cents 5.65 /kWh (N8.98 /kWh).

Details

World Journal of Engineering, vol. 12 no. 3
Type: Research Article
ISSN: 1708-5284

Keywords

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