Computer Simulation of Performance and Economic Assessment of a Single Shaft Gas Turbine Combined Heat Cooling and Power Plant
International Journal of Turbo and Jet Engines, 2010
This study provides an intergraded practical tool, which simulates the future operation (technica... more This study provides an intergraded practical tool, which simulates the future operation (technical and economic) of a Combined Heat Cooling and Power Plant, capable of helping the potential investor decide if it is profitable to proceed with the investment. The study is based on an overall technical-economic analysis of the tri-generation system, including the following steps: Firstly, the data research concerning the energy demands of an actual case. The second part deals with the gas turbine modelling and simulation, including the Design Point and Off-Design performance analysis of the gas turbine. The third part includes the simulation of the absorption cooling system alone and/or in co-operation with the prime mover. Finally, an evaluation methodology of tri-generation plants is introduced taking into account both technical facts and realistic economic data helping the potential users to decide whether it is profitable to use such technology or not. The economic evaluation includes the basic factors such as initial cost, handling and operational cost (fuel prices, maintenance etc), using a methodology based on the Net Present Value. The results are evaluated using suitable sensitivity analysis. A major conclusion reveals that the tri-generation plant is more profitable than the conventional way of energy production. K e y w o r d s : c o m b i n e d hea t c o o l i n g and p o w e r , c o g e n e r a t i o n , ga s t u rb ine , ch i l le r , t r i g e n e r a t i o n p lan t , e l ec t r i c
Contentwise, the post-print version is identical to the final published version, but there may be... more Contentwise, the post-print version is identical to the final published version, but there may be differences in typography and layout.
Single and Two Shaft Gas Turbine Configurations Performance Analysis, Using Different Types of Fuels
Coal gas and biofuels as alternative fuels have recently become more attractive, because of their... more Coal gas and biofuels as alternative fuels have recently become more attractive, because of their benefits, especially in electrical power industry. The major obstruction to their use is the relatively low calorific values. This paper presents a comprehensive simulation method for calculating the adiabatic temperature of various fuels when they are used in combustion chambers under constant pressure. The adiabatic temperature is presented as a function of combustion fuel air ratios and the fuels low calorific values. In addition, the utilization of various gaseous fuels in single shaft and two shaft gas turbine engines is analyzed. This analysis includes the design point (DP) and off-design (OD) performance of the two engines. The calorific values of the four gases investigated correspond to natural gas (NG) and to fuels with significantly lower calorific values than that of NG (coal synthetic gases, biofuels). Two main conclusions are drawn from this analysis. Firstly, for both single shaft and two shaft engines and for a given turbine entry temperature (TET), both power and thermal efficiency are increasing when fuels with decreasing calorific value are burnt. Secondly, for both single shaft and two shaft engines and for a given power, the thermal efficiency is slightly reduced.
Imece 2011-63359 Long-Term Operation Strategies Case Studies for Combined Heat and Power
In the next years Distributed Poly-generation Systems are expected to play an increasingly import... more In the next years Distributed Poly-generation Systems are expected to play an increasingly important role in the electricity infrastructure and market. The successful spread of small-scale generation either connected to the distribution network or on the customer side of the meter depends on diverse issues, such as the possibilities of technical implementation, resource availability, environmental aspects, and regulation and market conditions. The aim of this study is to develop an economical and parametric analysis of a Distributed Generation System based on gas turbines able to satisfy the energy demand of a typical Hotel complex. Here we show the economic performance of six cases combining different designs and regimes of operation. The software Turbomatch, the gas turbine performance code of Cranfield University, was used to simulate the off-design performance of the engines in different ambient and load conditions. A clear distinction between cases running at full load and foll...
The geothermal energy that is stored in the earth is so vast that could supply all the energy nee... more The geothermal energy that is stored in the earth is so vast that could supply all the energy needed by humanity. The difficulty in tapping this energy lies in its diffusivity. The geothermal energy in regions close to volcanoes is close to the surface and easy to use economically. The main objective of this work is to utilize the existing geothermal potential of the Greek island of Nisyros located in the south-eastern part of the Aegean Sea for desalination of seawater. The exploitation of the geothermal brine will be done in a way that the cooling load of the island, in the summer months, will be completely covered from the geothermal energy. The technologies for the exploitation of geothermal energy are the Multi Flash Desalination (MFD) and the Single effect absorption chiller. The exploitation of the geothermal hot water sources located in the island combined with an effective desalination technology can eliminate energy use from hydrocarbons, minimize the environmental impact ...
Renewable and Sustainable Energy Reviews 14 (2010) , 2010
Energy requirements in Greece have been continuously increasing in the past three decades. The sh... more Energy requirements in Greece have been continuously increasing in the past three decades. The share of renewable energy sources use has not kept up with the increase in energy demand. As a resultmore and more conventional energy sources are used and in this case lignite which is an indigenous source of energy and natural gas, imported from Russia. This energy picture leads towards a greater environmental impact due to the increase of pollutants to the atmosphere. It has been the objective of the European Union to satisfy 22.1% of its electric energy needs by the year 2010 with renewable energy sources. In the year of 1997 only 13.9% were satisfied with renewable energy. For Greece the corresponding figure was 8.6%. Renewable energy sources could cover a major part, if not all, of Thessaloniki’s ‘‘Makedonia’’ airport needs, following the promising results of the recent renewable energy sources exploration in the region. The airport ‘‘Makedonia’’ is located a few kilometres south of the city of Thessaloniki on the coastline of Thessaloniki’s bay. In this work an optimization model has been developed to determine the optimum share of renewable energy sources in various end-uses such as heating, cooling, and lighting. In this model the reliability and environmental parameters were taken into consideration. The renewable energy sources include solar energy, geothermal energy and biomass.
The efficient use of renewable energy sources (RES) is one of the major issues in the modern ener... more The efficient use of renewable energy sources (RES) is one of the major issues in the modern energy sector. The objective of this work was to examine the potential of wind energy, solar energy (e.g., photovoltaics), and biomass energy sources to meet the current energy use in the island of Lemnos in Greece. An optimization methodology was applied to the energy system of the island, where various RES are abundant and could be exploited to satisfy part of the island's energy needs. An optimization model has been developed having as an objective the satisfaction of Lemnos Island energy needs from RES taking into consideration a multiplicity of criteria such as environmental impacts, energy demand, energy cost, and resources availability. A series of solutions have resulted, based on determinis-tic model runs, providing decision makers the flexibility to choose the appropriate solution based on the given situation.
Volume 5: Industrial and Cogeneration; Microturbines and Small Turbomachinery; Oil and Gas Applications; Wind Turbine Technology, 2010
ABSTRACT Geopolitical issues give rise to problems in the smooth and continuous flow of oil and n... more ABSTRACT Geopolitical issues give rise to problems in the smooth and continuous flow of oil and natural gas from the production countries to the consumers' development countries. In addition, severe environmental issues such as greenhouse gas emissions, eventually guide the consumers to fuels more suitable to the present situation. Alternative fuels such as biogas and coal gas have recently become more attractive because of their benefits, especially for electricity generation. On the other hand, the use of relatively low heating value fuels has a significant effect to the performance parameters of gas turbines. In this paper, the impact of using four fuels with different heating value in the gas turbine performance is simulated. Based on the high efficiency and commercialization criteria, two types of engines are chosen to be simulated: two-shaft simple and single-shaft recuperated cycle gas turbines. The heating values of the four gases investigated, correspond to natural gas and to a series of three gases with gradually lower heating values than that of natural gas. The main conclusions drawn from this design point (DP) and off-design (OD) analysis is that, for a given TET, efficiency increases for both engines when gases with low heating value are used. On the contrary, when power output is kept constant, the use of gases with low heating value will result in a decrease of thermal efficiency. A number of parametric studies are carried out and the effect of operating parameters on performance is assessed. The analysis is performed with customized software, which has been developed for this purpose.
Volume 4: Cycle Innovations; Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Marine, 2009
ABSTRACT Coal gas and biofuels as alternative fuels have recently become more attractive, because... more ABSTRACT Coal gas and biofuels as alternative fuels have recently become more attractive, because of their benefits, especially in electrical power industry. The major obstruction to their use is the relatively low calorific values. This paper presents a comprehensive simulation method for calculating the adiabatic temperature of various fuels when they are used in combustion chambers under constant pressure. The adiabatic temperature is presented as a function of combustion fuel air ratios and the fuels low calorific values. In addition, the utilization of various gaseous fuels in single shaft and two shaft gas turbine engines is analyzed. This analysis includes the design point (DP) and off-design (OD) performance of the two engines. The calorific values of the four gases investigated correspond to natural gas (NG) and to fuels with significantly lower calorific values than that of NG (coal synthetic gases, biofuels). Two main conclusions are drawn from this analysis. Firstly, for both single shaft and two shaft engines and for a given turbine entry temperature (TET), both power and thermal efficiency are increasing when fuels with decreasing calorific value are burnt. Secondly, for both single shaft and two shaft engines and for a given power, the thermal efficiency is slightly reduced.
Energy consumption in buildings vary significantly, depending on factors as the use of the buildi... more Energy consumption in buildings vary significantly, depending on factors as the use of the building, the construction type, maintenance, existing heating, cooling and lighting systems and other types of services. Hotel buildings have high energy consumption rate, as a result of their unique operational characteristics. Energy consumption in hotels is among the highest in the non-residential building sector in absolute values. Available specific information on the energy characteristics, thermal performance, energy losses, electric loads, and comfort conditions play significant role for the sustainable
development of hotel’s systems. These data can also be used to identify whether there is space for improvement in new or existing hotels by comparing them against predicted or actual building energy performance. The aim of the present paper is to analyze the energy and exergy utilization in four hotels in Rethimno, Crete (Southern Greece) and in Kassandra, Halkidiki (Northern Greece)
Long-Term Operation Strategies Case Studies for Combined Heat and Power
Volume 4: Energy Systems Analysis, Thermodynamics and Sustainability; Combustion Science and Engineering; Nanoengineering for Energy, Parts A and B, 2011
Short-Term Generation Schedule Optimisation for Combined Heat and Power
Volume 4: Energy Systems Analysis, Thermodynamics and Sustainability; Combustion Science and Engineering; Nanoengineering for Energy, Parts A and B, 2011
Techno-Economic Evaluation of a Tri-Generation Energy Supply System for a Non-Interconnected Island Using Single-Shaft Gas-Turbine
Volume 5: Industrial and Cogeneration; Microturbines and Small Turbomachinery; Oil and Gas Applications; Wind Turbine Technology, 2010
... country is Greece. The average inflation of Greece for the years 2005 to 2008 was 3.0% [16]. ... more ... country is Greece. The average inflation of Greece for the years 2005 to 2008 was 3.0% [16]. The economics of tri-generation are made up of the investment costs, the unforeseen cost and the ongoing costs. Capital costs typically ...
Comparison Between Two-Shaft Simple and Single-Shaft Recuperated Brayton Cycles Using Different Types of Gaseous Fuels
Volume 5: Industrial and Cogeneration; Microturbines and Small Turbomachinery; Oil and Gas Applications; Wind Turbine Technology, 2010
ABSTRACT Geopolitical issues give rise to problems in the smooth and continuous flow of oil and n... more ABSTRACT Geopolitical issues give rise to problems in the smooth and continuous flow of oil and natural gas from the production countries to the consumers' development countries. In addition, severe environmental issues such as greenhouse gas emissions, eventually guide the consumers to fuels more suitable to the present situation. Alternative fuels such as biogas and coal gas have recently become more attractive because of their benefits, especially for electricity generation. On the other hand, the use of relatively low heating value fuels has a significant effect to the performance parameters of gas turbines. In this paper, the impact of using four fuels with different heating value in the gas turbine performance is simulated. Based on the high efficiency and commercialization criteria, two types of engines are chosen to be simulated: two-shaft simple and single-shaft recuperated cycle gas turbines. The heating values of the four gases investigated, correspond to natural gas and to a series of three gases with gradually lower heating values than that of natural gas. The main conclusions drawn from this design point (DP) and off-design (OD) analysis is that, for a given TET, efficiency increases for both engines when gases with low heating value are used. On the contrary, when power output is kept constant, the use of gases with low heating value will result in a decrease of thermal efficiency. A number of parametric studies are carried out and the effect of operating parameters on performance is assessed. The analysis is performed with customized software, which has been developed for this purpose.
Performance Simulation and Economic Evaluation of Tri-Generation Plant, Based on a Single Shaft Gas Turbine
Volume 4: Cycle Innovations; Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Marine, 2009
ABSTRACT This paper provides an intergraded realistic tool, which simulates the future operation ... more ABSTRACT This paper provides an intergraded realistic tool, which simulates the future operation (technical and economic) of a tri-generation plant, capable of helping the potential investor decide if it is profitable to proceed with the investment. The paper is based on an overall technical-economic analysis of the tri-generation system, including the following steps: Firstly, the data research concerning the energy demands of an actual case. The second part deals with the prime mover (namely the GT) modelling and simulation, including the Design Point (DP) and Off-Design (OD) performance analysis of the GT. The third part includes the simulation of the absorption cooling system alone and/or in co-operation with the prime mover. Finally, an evaluation methodology of tri-generation plants is introduced taking into account both technical facts and realistic economic data helping the potential users to decide whether it is profitable to use such technology or not. The economic scene will include the basic economic facts such as initial cost, handling and operational cost (fuel prices, maintenance etc), using methodology based on NPV. The results are valuated using suitable sensitivity analysis. The results of the analysis generally shown, that the tri-generation plant is more profitable than the conventional way of energy production.
Single and Two Shaft Gas Turbine Configurations Performance Analysis, Using Different Types of Fuels
Volume 4: Cycle Innovations; Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Marine, 2009
ABSTRACT Coal gas and biofuels as alternative fuels have recently become more attractive, because... more ABSTRACT Coal gas and biofuels as alternative fuels have recently become more attractive, because of their benefits, especially in electrical power industry. The major obstruction to their use is the relatively low calorific values. This paper presents a comprehensive simulation method for calculating the adiabatic temperature of various fuels when they are used in combustion chambers under constant pressure. The adiabatic temperature is presented as a function of combustion fuel air ratios and the fuels low calorific values. In addition, the utilization of various gaseous fuels in single shaft and two shaft gas turbine engines is analyzed. This analysis includes the design point (DP) and off-design (OD) performance of the two engines. The calorific values of the four gases investigated correspond to natural gas (NG) and to fuels with significantly lower calorific values than that of NG (coal synthetic gases, biofuels). Two main conclusions are drawn from this analysis. Firstly, for both single shaft and two shaft engines and for a given turbine entry temperature (TET), both power and thermal efficiency are increasing when fuels with decreasing calorific value are burnt. Secondly, for both single shaft and two shaft engines and for a given power, the thermal efficiency is slightly reduced.
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Papers by A. Polyzakis
more conventional energy sources are used and in this case lignite which is an indigenous source of energy and natural gas, imported from Russia. This energy picture leads towards a greater environmental
impact due to the increase of pollutants to the atmosphere. It has been the objective of the European Union to satisfy 22.1% of its electric energy needs by the year 2010 with renewable energy sources. In the
year of 1997 only 13.9% were satisfied with renewable energy. For Greece the corresponding figure was 8.6%. Renewable energy sources could cover a major part, if not all, of Thessaloniki’s ‘‘Makedonia’’ airport
needs, following the promising results of the recent renewable energy sources exploration in the region.
The airport ‘‘Makedonia’’ is located a few kilometres south of the city of Thessaloniki on the coastline of Thessaloniki’s bay. In this work an optimization model has been developed to determine the optimum
share of renewable energy sources in various end-uses such as heating, cooling, and lighting. In this model the reliability and environmental parameters were taken into consideration. The renewable
energy sources include solar energy, geothermal energy and biomass.
development of hotel’s systems. These data can also be used to identify whether there is space for improvement in new or existing hotels by comparing them against predicted or actual building energy performance. The aim of the present paper is to analyze the energy and exergy utilization in four hotels in Rethimno, Crete (Southern Greece) and in Kassandra, Halkidiki (Northern Greece)