scholarly journals Energy analysis of municipal waste in Dubrovnik

2018 ◽  
pp. 40-48
Author(s):  
Paweł Król ◽  
Goran Krajačić
Keyword(s):  
Waste Management ◽  
Biogas Production ◽  
Rankine Cycle ◽  
Waste Utilization ◽  
Combined Cycle ◽  
Brayton Cycle ◽  
Waste Production ◽  
Technical Issues ◽  
Potential Impact ◽  
The Impact

In each touristic city waste management system has to overcome the impact of visitors. Dubrovnik, famous as popular touristic destination, particularly notices tourists visiting city. Therefore potential impact of waste management in touristic cities, such as Dubrovnik, is presented. The paper includes estimation of yearly waste production by inhabitants and tourists visiting those city. Waste digestion is a method for biogas production. On the basis of the preceding estimation combined-cycle installation generating heat and electricity is proposed. The model combines Brayton cycle with low temperature Kalina model based on Rankine cycle. Literature analysis presents state of the art in this field. The simulation is prepared in Cycle-Tempo. Numerical analyses lead to technical issues, which have to be taken into consideration during waste utilization with such installation. Thus benefits and threats are discussed. The presented analysis assesses the maximal electric gain, which subsequently should consider waste preparation and purification

Errors Resulting From Excluding the Effects of Humidity on the Performance of Combustion Turbine Plants Equipped With Evaporative Coolers

2010 ◽  
Author(s):  
John Sasso
Keyword(s):  
The United States ◽  
Combined Cycle ◽  
Brayton Cycle ◽  
Cooling Systems ◽  
Combustion Gas ◽  
Ambient Temperatures ◽  
The Past ◽  
Potential Impact ◽  
And Performance ◽  
The Impact

Combustion turbine combined cycle (CTCC) plants have generally been the “power plant of choice” over the past two decades for a number of reasons, including first cost, efficiency, and low emissions. Combustion (Gas) turbine (CT) based plants now account for over 30% of the electric power capacity in the United States. Despite the significant reliance on this technology, the electric Independent System Operators (ISOs) have yet to recognize and acknowledge in their production templates, test forms and performance predicting software the Brayton Cycle limitations, most notably how humidity affects output for CT plants equipped with evaporative cooling systems. Such plants account for an estimated 48% of the CT power installed in the last 10 years. Ignoring the impact of humidity on these plants can lead to errors in production predictions beyond the normal tolerance band of 3% to as high as 9% during peak ambient temperatures for certain units. As such the electric ISO’s prediction of available generation and the associated capacity reserve margins have the potential to be overestimated. The article explores the situation in more depth, presents examples within the NYISO, quantifies the potential impact and recommends easy solutions to close the gap.

scholarly journals Waste production and waste management in the EU

2021 ◽  
Vol 900 (1) ◽  
pp. 012024
Author(s):  
S Matušková ◽  
M Taušová ◽  
L Domaracká ◽  
P Tauš
Keyword(s):  
Waste Management ◽  
Living Standards ◽  
Raw Material ◽  
Material Resources ◽  
Waste Production ◽  
The World ◽  
Long Time ◽  
The Impact ◽  
Constant Growth ◽  
The Eu

Abstract The constant growth of the population increases the demands on raw material resources, which is reflected in increasing pressure on the environment. The impact of mankind on the environment is nowadays an increasingly acute problem, which is being addressed by the governments of individual countries, not only the EU, through legislative interventions. The most addressed areas are the issue of production and subsequent waste management. Waste production in the world has been growing for a long time, which causes considerable problems for individual countries. Each country is currently looking for the optimal way of waste management to reuse it as secondary raw material. In this paper, we analysed twenty-eight EU countries in terms of production and waste management and found significant differences between countries. We looked for factors that lead to different results between countries in the production and management of waste, based on the population, the size of the country to the indicators of living standards, and legislation applicable to those countries.

Development of a Novel Combined Absorption Cycle for Power Generation and Refrigeration

2006 ◽  
Vol 129 (3) ◽  
pp. 254-265 ◽  
Author(s):  
Na Zhang ◽  
Noam Lior
Keyword(s):  
Water System ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Cycle Performance ◽  
Base Case ◽  
Ammonia Water ◽  
Energy And Exergy ◽  
The Impact

Cogeneration can improve energy utilization efficiency significantly. In this paper, a new ammonia-water system is proposed for the cogeneration of refrigeration and power. The plant operates in a parallel combined cycle mode with an ammonia-water Rankine cycle and an ammonia refrigeration cycle, interconnected by absorption, separation, and heat transfer processes. The performance was evaluated by both energy and exergy efficiencies, with the latter providing good guidance for system improvement. The influences of the key parameters, which include the basic working solution concentration, the cooling water temperature, and the Rankine cycle turbine inlet parameters on the cycle performance, have been investigated. It is found that the cycle has a good thermal performance, with energy and exergy efficiencies of 27.7% and 55.7%, respectively, for the base-case studied (having a maximum cycle temperature of 450°C). Comparison with the conventional separate generation of power and refrigeration having the same outputs shows that the energy consumption of the cogeneration cycle is markedly lower. A brief review of desirable properties of fluid pairs for such cogeneration cycles was made, and detailed studies for finding new fluid pairs and the impact of their properties on cogeneration system performance are absent and are very recommended.

scholarly journals A Useful Equation for Gas Turbine Design

2018 ◽  
Vol 140 (03) ◽  
pp. S52-S53
Author(s):  
Lee S. Langston
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Gas Turbine ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Brayton Cycle ◽  
Nonlinear Superposition ◽  
Transient Conditions ◽  
One Dimensional ◽  
Turbine Design

This article presents three different gas turbine phenomena and design cases. The sketch in the article shows a schematic of a combined cycle powerplant consisting of a Brayton cycle (gas turbine) whose exhaust provides energy to a Rankine cycle (steam turbine). Frequently, one can use simple but exact one-dimensional (1D) heat conduction solutions to estimate the heat loss or gain of gas turbine components under transient conditions. These easy-to-use solutions are found in most undergraduate heat transfer texts. The article suggests that those three widely different gas turbine phenomena and design cases all have the simple, nonlinear superposition form.

scholarly journals INFORMAL SECTOR STRATEGY IN URBAN INORGANIC WASTE MANAGEMENT TOWARD 3 M MANAGEMENT (MERUBAH: CHANGING, MENGURANGI: REDUCING, MANFAAT: BENEFIT) IN SEMARANG CITY

2017 ◽  
Vol 41 (4) ◽  
pp. 278-287
Author(s):  
Djoko INDROSAPTONO ◽  
Joesron Alie SYAHBANA
Keyword(s):  
Qualitative Research ◽  
Waste Management ◽  
Informal Sector ◽  
Economic Value ◽  
Community Empowerment ◽  
Urban Waste ◽  
Waste Production ◽  
Inorganic Waste ◽  
Urban Waste Management ◽  
The Impact

Moreover urban waste can be seen as a cultural problem because it affects various aspects of life, and the impact on urban waste management system nowadays are not effective and efficient yet. The reason for conducting this research is the emergence of the informal sector phenomena of urban waste management that can contribute to reduce the volume of urban waste production. The purpose of this research is to find out the informal sector strategy in urban waste management, especially inorganic waste. The researchers used qualitative research to explain the phenomenon as the focus of research. The result of research is 3M phenomenon, that is derived from Indonesian words (Mengubah = Changing, Mengurangi = Reducing, Manfaat = Benefit), in the management of urban inorganic waste. The explanation are; Mengubah: turning waste into economic value; Mengurangi: If the economic value of the urban waste volumes increases, the volume of urban waste will eventually be reduced; and Manfaat: the benefits obtained are management cultivating empowerment, reducing the burden of the landfill volume, being closer to inorganic zero waste condition. Suggestions are as follows: [a] development of management towards go-green, [b] urban waste management based on predictable community empowerment will be more effective and efficient in the future.

Reduction of Radioactive Waste Production: Where Is the Optimum?

2001 ◽  
Author(s):  
P. Havard
Keyword(s):  
Waste Management ◽  
New Technologies ◽  
Waste Treatment ◽  
Negative Impact ◽  
Production Costs ◽  
Waste Production ◽  
Medium Level ◽  
History Of ◽  
Intermediate Storage ◽  
The Impact

Abstract Low and medium level waste management means reducing the amount of waste generated during maintenance and operation of the plant, in accordance with the ALARA concept, while keeping not only the quality of the product but also the associated costs under control. All this waste is managed by ONDRAF/NIRAS, the Belgian Federal Agency responsible for waste management, including conditioning, intermediate storage and final disposal. Unfortunately, the actions taken by ONDRAF/NIRAS and the producers in order to reduce waste production have had a negative impact on waste treatment tariffs. It has become necessary to re-examine the relationship between ONDRAF/NIRAS and the producers, in order to control the costs of waste management. This problem concerns not only the treatment costs but also the disposal costs. The volume of waste has fallen from 30M3/Thwh in 1985 to 4.m3/Twh in 2000, not by chance but as the result of a new site organisation geared towards achieving this aim. This paper presents firstly the history of Belgian waste management, taking into account the impact on the associated costs, and secondly the measures that have to be taken in order to be able to decide which new technologies are necessary to go further with the objective of waste volume reduction in a new environment, namely deregulation and consequently high pressure on production costs. Finally, it presents a few conclusions.

scholarly journals Why We Need Nuclear Power Plants

2018 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Power Plant ◽  
Natural Gas ◽  
Gas Turbine ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Brayton Cycle ◽  
Gen Iv

The major growth in the electricity production industry in the last 30 years has centered on the expansion of natural gas power plants based on gas turbine cycles. The most popular extension of the simple Brayton gas turbine has been the combined cycle power plant with the Air-Brayton cycle serving as the topping cycle and the Steam-Rankine cycle serving as the bottoming cycle for new generation of nuclear power plants that are known as GEN-IV. The Air-Brayton cycle is an open-air cycle and the Steam-Rankine cycle is a closed cycle. The air-Brayton cycle for a natural gas driven power plant must be an open cycle, where the air is drawn in from the environment and exhausted with the products of combustion to the environment. This technique is suggested as an innovative approach to GEN-IV nuclear power plants in form and type of Small Modular Reactors (SMRs). The hot exhaust from the AirBrayton cycle passes through a Heat Recovery Steam Generator (HSRG) prior to exhausting to the environment in a combined cycle. The HRSG serves the same purpose as a boiler for the conventional Steam-Rankine cycle [1].

Electrical Power Generation: Fossil Fuels

2017 ◽  
Author(s):  
Peter Rez
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Power Plants ◽  
Fossil Fuels ◽  
Turbine Blades ◽  
Electrical Power ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Brayton Cycle ◽  
Steam Temperature

Nearly all electrical power is generated by rotating a coil in a magnetic field. In most cases, the coil is turned by a steam turbine operating according to the Rankine cycle. Water is boiled and heated to make high-pressure steam, which drives the turbine. The thermal efficiency is about 30–35%, and is limited by the highest steam temperature tolerated by the turbine blades. Alternatively, a gas turbine operating according to the Brayton cycle can be used. Much higher turbine inlet temperatures are possible, and the thermal efficiency is higher, typically 40%. Combined cycle generation, in which the hot exhaust from a gas turbine drives a Rankine cycle, can achieve thermal efficiencies of almost 60%. Substitution of coal-fired by combined cycle natural gas power plants can result in significant reductions in CO2 emissions.

High-Efficiency Solar Dynamic Space Power Generation System

1991 ◽  
Vol 113 (3) ◽  
pp. 131-137 ◽  
Author(s):  
Aristide Massardo
Keyword(s):  
Power Generation ◽  
Power Systems ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Working Fluid ◽  
Brayton Cycle ◽  
Generation System ◽  
Dynamic Power ◽  
Power Generation System

Space power technologies have undergone significant advances over the past few years, and great emphasis is being placed on the development of dynamic power systems at this time. A design study has been conducted to evaluate the applicability of a combined cycle concept—closed Brayton cycle and organic Rankine cycle coupling—for solar dynamic space power generation systems. In the concept presented here (solar dynamic combined cycle), the waste heat rejected by the closed Brayton cycle working fluid is utilized to heat the organic working fluid of an organic Rankine cycle system. This allows the solar dynamic combined cycle efficiency to be increased compared to the efficiencies of two subsystems (closed Brayton cycle and organic fluid cycle). Also, for small-size space power systems (up to 50 kW), the efficiency of the solar dynamic combined cycle can be comparable with Stirling engine performance. The closed Brayton cycle and organic Rankine cycle designs are based on a great deal of maturity assessed in much previous work on terrestrial and solar dynamic power systems. This is not yet true for the Stirling cycles. The purpose of this paper is to analyze the performance of the new space power generation system (solar dynamic combined cycle). The significant benefits of the solar dynamic combined cycle concept such as efficiency increase, mass reduction, specific area—collector and radiator—reduction, are presented and discussed for a low earth orbit space station application.

Thermodynamic Analysis and Multi-Objective Optimizations of a Combined Recompression sCO2 Brayton Cycle: tCO2 Rankine Cycles for Waste Heat Recovery

2018 ◽  
Author(s):  
Ali S. Alsagri ◽  
Andrew Chiasson ◽  
Ahmad Aljabr
Keyword(s):  
Carbon Dioxide ◽  
Thermodynamic Analysis ◽  
Thermal Efficiency ◽  
High Efficiency ◽  
Waste Heat ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Brayton Cycle ◽  
Power Cycle ◽  
Exhaust Temperature

A thermodynamic analysis and optimization of a newly-conceived combined power cycle were conducted in this paper for the purpose of improving overall thermal efficiency of power cycles by attempting to minimize thermodynamic irreversibilities and waste heat as a consequence of the Second Law. The power cycle concept comprises a topping advanced recompression supercritical carbon dioxide (sCO2) Brayton cycle and a bottoming transcritical carbon dioxide (tCO2) Rankine cycle. The bottoming cycle configurations included a simple tCO2 Rankine cycle and a split tCO2 Rankine cycle. The topping sCO2 recompression Brayton cycle used a combustion chamber as a heat source, and waste heat from a topping cycle was recovered by the tCO2 Rankine cycle due to an added high efficiency recuperator for generating electricity. The combined cycle configurations were thermodynamically modeled and optimized using an Engineering Equation Solver (EES) software. Simple bottoming tCO2 Rankine cycle cannot fully recover the waste heat due to the high exhaust temperature from the top cycle, and therefore an advance split tCO2 Rankine cycle was employed in order to recover most of the waste heat. Results show that the highest thermal efficiency was obtained with recompression sCO2 Brayton cycle – split flow tCO2 Rankine cycle. Also, the results show that the combined CO2 cycles is a promising technology compared to conventional cycles.

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