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Platform Idexlab - One of the best experts on this subject based on the ideXlab platform.

Takanori Shibata - One of the best experts on this subject based on the ideXlab platform.

  • Starting Characteristic Analysis of a Radial Inflow Turbine for the Regenerative Brayton Cycle
    Journal of Engineering for Gas Turbines and Power, 2015
    Co-Authors: Susumu Nakano, Tadaharu Kishibe, Manabu Yagi, Kuniyoshi Tsubouchi, Takanori Shibata
    Abstract:

    Microturbines have been developed as compact gas turbines to be applied in the regenerative Brayton cycle. A typical Microturbine is composed of a centrifugal compressor and a radial inflow turbine. As such, the Microturbine has a starting characteristic peculiar to radial inflow turbines. An idling state known as the windage point for mass flow rate can be formed because of improper inlet flow conditions for turbine expansion flow. The present study looked at the relationships between the radius ratio of the radial inflow turbine to the centrifugal compressor and the starting characteristic and at the effects of turbine inlet flow conditions on the starting characteristic. Fundamental equations for the relationships between the radius ratio and the starting characteristic were obtained. Effectiveness of the equations was compared with experiment results obtained with a 150 kW class prototype Microturbine.

T M I Mahlia - One of the best experts on this subject based on the ideXlab platform.

  • design of an optimized photovoltaic and Microturbine hybrid power system for a remote small community case study of palestine
    Energy Conversion and Management, 2013
    Co-Authors: Mahmoud S Ismail, M Moghavvemi, T M I Mahlia
    Abstract:

    Hybrid systems are defined as systems that utilize more than one energy source to supply a certain load. The implementation of a hybrid system that is based upon Photovoltaic (PV) to supply power to remote and isolated locations is considered a viable option. This is especially true for areas that receive sufficient amounts of annual solar radiation. While analysis of hybrid systems that depend on diesel generators as backup sources can be found in many previous research works, detailed techno economic analysis of hybrid systems that depend on Microturbines as backup sources are less addressed. A techno-economic analysis and the design of a complete hybrid system that comprises of Photovoltaic (PV) panels, a battery system, and a Microturbine as a backup power source for a remote community is presented in this paper. The investigation of the feasibility of using the Microturbines as backup sources in the hybrid systems is one of the purposes of this study. A scenario depending on PV standalone system and other scenario depending on Microturbine only were also studied in this paper. The comparison between different scenarios with regards to the cost of energy and pollutant emissions was also conducted. A simulation program was developed to optimize both the sizes of the PV system and the battery bank, and consequently determine the detailed specifications of the different components that make up the hybrid system. The optimization of the PV tilt angle that maximizes the annual energy production was also carried out. The effect of the variation of some parameters on the cost of energy was duly evaluated. Powering a rural community using Microturbine alone indicates lower values of cost of energy (COE) production compared to the hybrid system in which a combination of PV panels, battery bank and Microturbine has been used. The difference is very small and taking into account the environmental effect of the Microturbine surely will make the hybrid system with limited running hours of the Microturbine more attractive. Furthermore, as it is obvious from the sensitivity analysis, any reduction in the price of the PV panels or any increase in the natural gas price will make the hybrid system economically and environmentally more attractive.

Colin F. Mcdonald - One of the best experts on this subject based on the ideXlab platform.

  • small recuperated ceramic Microturbine demonstrator concept
    Applied Thermal Engineering, 2008
    Co-Authors: Colin F. Mcdonald, Colin Rodgers
    Abstract:

    Abstract It has been about a decade since Microturbines first entered service in the distributed generation market, and the efficiencies of these turbogenerators rated in the 30–100 kW power range have remained essentially on the order of 30%. In this time frame the cost of fuel (natural gas and oil) has increased substantially, and efforts are now underway to increase the efficiency of Microturbines to 40% or higher. Various near-term means of achieving this are underway by utilizing established gas turbine technology, but now based on more complex thermodynamic cycles. A longer-term approach of improving efficiency is proposed in this paper based on the retention of the basic recuperated Brayton cycle, but now operating at significantly higher levels of turbine inlet temperature. However, in small low pressure ratio recuperated Microturbines embodying radial flow turbomachinery this necessitates the use of ceramic components, including the turbine, recuperator and combustor. A development approach is proposed to design, fabricate and test a 7.5 kW ceramic Microturbine demonstrator concept, which for the first time would involve the coupling of a ceramic radial flow turbine, a ceramic combustor, and a compact ceramic fixed-boundary high effectiveness recuperator. In a period of some three years, the major objectives of the proposed small ceramic Microturbine R&D effort would be to establish a technology base involving thermal and stress analysis, design methodology, ceramic component fabrication techniques, and component development, these culminating in the assembly and testing to demonstrate engine structural integrity, and to verify performance. This would provide a benchmark for more confidently advancing to increased size ceramic-based turbogenerators with the potential for efficiencies of over 40%. In addition, the power size of the tested prototype could possibly emerge as a viable product, namely as a natural gas-fired turbogenerator with the capability of meeting the total energy needs of an average house.

  • Recuperator considerations for future higher efficiency Microturbines
    Applied Thermal Engineering, 2003
    Co-Authors: Colin F. Mcdonald
    Abstract:

    First-generation Microturbines are based on the use of existing materials and proven technology, and with low levels of compressor pressure ratio and modest turbine inlet temperatures, have thermal efficiencies approaching 30% for turbogenerators rated up to 100 kW. For such small machines the goal of advancing beyond this level of performance is unlikely to include more complex thermodynamic cycles, but rather will be realised with higher turbine inlet temperatures. Advancing engine performance in this manner has a significant impact on recuperator technology and cost. In the compact heat exchanger field very efficient heat transfer surface geometries have been developed over the last few decades but further improvements perhaps using CFD methods will likely be only incremental. Automated fabrication processes for the manufacture of Microturbine recuperators are in place, and on-going developments to facilitate efficient higher temperature operation are primarily focused in the materials area. Based on the assumptions made in this paper it is postulated that in the 100 kW size the maximum thermal efficiency attainable for an all-metallic engine is 35%. To achieve this the recuperator cannot be designed in an isolated manner, and must be addressed in an integrated approach as part of the overall power conversion system. In this regard, temperature limitations as they impact the recuperator and turbine are put into perspective. In this paper there is strong focus on recuperator material selection and cost, including a proposed bi-metallic approach to establish a cost-effective counterflow primary surface recuperator for higher temperature service. If indeed there is a long-term goal to achieve an efficiency of 40% for small Microturbines, it can only be projected based on the utilisation of ceramic hot end components. Alas, the high temperature component that has had the minimum development in recent years to realise this goal is the ceramic recuperator, and efforts to remedy this situation need to be undertaken in the near future.

  • Microturbine / Fuel-Cell Coupling for High-Efficiency Electrical-Power Generation
    Volume 2: Coal Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations, 2000
    Co-Authors: Aristide F. Massardo, Colin F. Mcdonald, Theodosios Korakianitis
    Abstract:

    Microturbines and fuel cells are currently attracting a lot of attention to meet future users needs in the distributed generation market. This paper addresses a preliminary analysis of a representative state-of-the-art 50 kW Microturbine coupled with a high-temperature solid-oxide fuel cell (SOFC). The technologies of the two elements of such a hybrid-power plant are in a different state of readiness. The Microturbine is in an early stage of pre-production and the SOFC is still in the development phase. It is premature to propose an optimum solution. Based on today’s technology the hybrid plant, using natural gas fuel, would have a power output of about 389 kW, and an efficiency of 60 percent. If the waste heat is used the overall fuel utilization efficiency would about 80 percent. Major features, parameters and performance of the Microturbine and the SOFC are discussed. The compatibility of the two systems is addressed, and the areas of technical concern, and mismatching issues are identified and discussed. Fully understanding these, and identifying solutions, is the key to the future establishing of an optimum overall system. This approach is viewed as being in concert with evolving technological changes. In the case of the Microturbine changes will be fairly minor as they enter production on a large scale within the next year or so, but are likely to be significant for the SOFC in the next few years, as extensive efforts are expended to reduce unit cost. It is reasonable to project that a high performance and cost-effective hybrid plant, with high reliability, will be ready for commercial service in the middle of the first decade of the 21st century.While several Microturbines can be packaged to give an increased level of power, this can perhaps be more effectively accomplished by coupling just a single gas turbine module with a SOFC. The resultant larger power output unit opens up new market possibilities in both the industrial nations and developing countries.Copyright © 2000 by ASME

  • Microturbine fuel cell coupling for high efficiency electrical power generation
    Volume 2: Coal Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations, 2000
    Co-Authors: Aristide F. Massardo, Colin F. Mcdonald, Theodosios Korakianitis
    Abstract:

    Microturbines and fuel cells are currently attracting a lot of attention to meet future users needs in the distributed generation market. This paper addresses a preliminary analysis of a representative state-of-the-art 50 kW Microturbine coupled with a high-temperature solid-oxide fuel cell (SOFC). The technologies of the two elements of such a hybrid-power plant are in a different state of readiness. The Microturbine is in an early stage of pre-production and the SOFC is still in the development phase. It is premature to propose an optimum solution. Based on today’s technology the hybrid plant, using natural gas fuel, would have a power output of about 389 kW, and an efficiency of 60 percent. If the waste heat is used the overall fuel utilization efficiency would about 80 percent. Major features, parameters and performance of the Microturbine and the SOFC are discussed. The compatibility of the two systems is addressed, and the areas of technical concern, and mismatching issues are identified and discussed. Fully understanding these, and identifying solutions, is the key to the future establishing of an optimum overall system. This approach is viewed as being in concert with evolving technological changes. In the case of the Microturbine changes will be fairly minor as they enter production on a large scale within the next year or so, but are likely to be significant for the SOFC in the next few years, as extensive efforts are expended to reduce unit cost. It is reasonable to project that a high performance and cost-effective hybrid plant, with high reliability, will be ready for commercial service in the middle of the first decade of the 21st century.While several Microturbines can be packaged to give an increased level of power, this can perhaps be more effectively accomplished by coupling just a single gas turbine module with a SOFC. The resultant larger power output unit opens up new market possibilities in both the industrial nations and developing countries.Copyright © 2000 by ASME

  • Microturbine/Fuel-Cell Coupling for High-Efficiency Electrical-Power Generation
    Journal of Engineering for Gas Turbines and Power, 2000
    Co-Authors: Aristide F. Massardo, Colin F. Mcdonald, Theodosios Korakianitis
    Abstract:

    Microturbines and fuel cells are currently attracting a lot of attention to meet future users needs in the distributed generation market. This paper addresses a preliminary analysis of a representative state-of-the-art 50-kW Microturbine coupled with a high-temperature solid-oxide fuel cell (SOFC). The technologies of the two elements of such a hybrid-power plant are in a different state of readiness. The Microturbine is in an early stage of pre-production and the SOFC is still in the development phase. It is premature to propose an optimum solution. Based on today's technology the hybrid plant, using natural gas fuel, would have a power output of about 389 kW, and an efficiency of 60 percent. If the waste heat is used the overall fuel utilization efficiency would be about 80 percent. Major features, parameters, and performance of the Microturbine and the SOFC are discussed. The compatibility of the two systems is addressed, and the areas of technical concern, and mismatching issues are identified and discussed. Fully understanding these, and identifying solutions, is the key to the future establishing of an optimum overall system. This approach is viewed as being in concert with evolving technological changes. In the case of the Microturbine changes will be fairly minor as they enter production on a large scale within the next year or so, but are likely to be significant for the SOFC in the next few years, as extensive efforts are expended to reduce unit cost. It is reasonable to project that a high performance and cost-effective hybrid plant, with high reliability, will be ready for commercial service in the middle of the first decade of the 21st century. While several Microturbines can be packaged to give an increased level of power, this can perhaps be more effectively accomplished by coupling just a single gas turbine module with a SOFC. The resultant larger power output unit opens up new market possibilities in both the industrial nations and developing countries.

Jacques De Ruyck - One of the best experts on this subject based on the ideXlab platform.

  • combustion of syngas in a pressurized Microturbine like combustor experimental results
    Applied Energy, 2010
    Co-Authors: Frank Delattin, Svend Bram, Giovanni Di Lorenzo, Sergio Rizzo, Jacques De Ruyck
    Abstract:

    The different routes for power production from biomass often lead to an intermediary product such as a synthesis gas or syngas, which is typically rich in hydrogen and carbon monoxide. The simple design, fuel flexibility and size, which often matches the amount of waste energy available in industrial sites, makes Microturbines an attractive solution for on-site, decentralized power generation using a limited range of alternative fuels such as synthetic gas. The properties of the synthetic fuel differ from properties of natural gas and a detailed experimental study with a separated Microturbine-like pressurized combustor is therefore necessary. The present article reviews the experimental results obtained by gradually switching the fuel feed from natural gas to wet syngas in a pressurized, slightly modified lean premix Microturbine combustor. Temperature profiles, pressure, emissions and flame imaging were closely monitored to detect possible problems in operability of the combustor caused by the strong difference in fuel characteristics. No problems regarding auto-ignition, dynamic or static instability were observed throughout the test-run. Temperature profiles stayed well within allowable limits and did not reveal any significant shift in flame anchoring position. The combustion of syngas during full or part load of the combustor produced remarkably low NOx and CO emissions. The Microturbine combustor achieved stable full load combustion of syngas at the end of the test-run.

  • Effects of steam injection on Microturbine efficiency and performance
    Energy, 2008
    Co-Authors: Frank Delattin, Svend Bram, Sofie Knoops, Jacques De Ruyck
    Abstract:

    Abstract Microturbines offer new perspectives in small-scale heat and power production. Non-continuous heat demand however often leads to a reduced number of yearly running hours. This paper proposes an alternative by introducing water or steam injection without significantly increasing the overall cost. Steam injection (STIG®) has been successful to boost performance and efficiency in industrial gas turbine cycles and similar effects are expected in the case of Microturbines. Owing to the different way of controlling Microturbines at non-constant shaftspeed, the response to steam or water injection differs from current STIG® cycles. The purpose of this study was to examine the effects of steam injection on Microturbine behavior by simulating its off-design characteristics in Aspen. The dry behavior of a microgasturbine has first been simulated and validated against a limited number of available measurements. After increasing steam injection up to the surge limit, we concluded a large amount of steam can potentially be injected. Next, the heat required to generate steam was rerouted from the water heater. When CHP mode is disabled and all residual heat after the recuperator is used in a STIG® route, 3.3% water can be injected and electric efficiency rises by 5.1%.