Thermoeconomic optimization of organic Rankine bottoming cycles for micro gas turbines

Campos, Gustavo Bonolo de; Bringhenti, Cleverson; Traverso, Alberto; Tomita, Jesuíno Takachi

doi:10.1016/j.applthermaleng.2019.114477

Cited by 33 publications

(8 citation statements)

References 46 publications

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“…The nominal power rating of the MGT is 30 kWe with top efficiency of 26% at full power with a maximum exhaust temperature at 548 K. Relatively low nominal efficiency of Micro Gas Turbines is mainly due to low overall pressure ratio and low turbine inlet temperature. 45,46 The turbine is designed to operate with either gas fuels or liquid fuels, with natural gas, biogas, associated gas, sour gas, and propane as common gas fuels and kerosene, jet fuels, and ultra-low sulfur diesel as standard liquid fuels. The inherent fuel flexibility of an MGT also makes engine retrofitting possible to allow the engine to operate on alternative fuels for off-grid communities.…”

Section: Hybrid System Component Modeling and Optimization Strategymentioning

confidence: 99%

Optimization of Micro Gas Turbine Based Hybrid Systems for Remote Off-grid Communities

Basmadjian

Yun

Hong

2022

Energy & Environment

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Inherent fuel flexibility of micro gas turbine (MGT) makes the engine a promising energy solution to remote Canadian communities that are not connected to the North American electricity grid, where bio-oils derived from locally available bio-mass may be utilized to meet local power and heat demands to reduce fossil fuel consumption. The switch to bio-oils enabled by MGTs reduces not only carbon footprints but also operating expenses due to high transportation costs of fossil fuels. However, MGT efficiencies are greatly reduced at partial loads. This work investigates the feasibility of addressing MGT efficiency drops at partial loads by incorporating MGT with a Battery Energy Storage System (BESS) to form a hybrid system so that the MGT can be operated at near full power at all times for better efficiencies. In this study, a daily power demand profile of a typical Canadian household is adopted for optimizing battery size and MGT operating strategies. By optimizing MGT daily start time and the engine's threshold partial load factor, the specific fuel consumption and battery size can be minimized for a specific number of households on a micro-grid supported by the MGT-based hybrid power system.

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Section: Hybrid System Component Modeling and Optimization Strategymentioning

confidence: 99%

Optimization of Micro Gas Turbine Based Hybrid Systems for Remote Off-grid Communities

Basmadjian

Yun

Hong

2022

Energy & Environment

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“…To carry out the performance analysis presented in this paper, a previously developed model from de Campos et al was used and modified [8]. The main change to this code is the extraction of heat during the expansion and the use of this heat later in the same cycle.…”

Section: Model Descriptionmentioning

confidence: 99%

Carnot cycle in practice: compensating inefficiencies of ORC expanders through thermal regeneration

et al. 2021

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The Organic Rankine Cycle (ORC) is a thermodynamic cycle that can operate with a hot source over a wide range of temperatures, especially with low-grade heat (below 200°C). One of the main limitations for the success of small-scale ORC cycles (few to 100 kWe) is the relatively low isentropic efficiency of the typically used turbomachinery. Low turbine efficiency leads to low ORC cycle performance. To increase the performance of the cycle, the turbine efficiency must be increase, however, this significantly increases the cost of the machinery, making the cycle less profitable. In this work, the performance evaluation of low-temperature ORC cycles (100-150°C) with heat extraction along the expansion process is investigated, in an attempt to overcome this limitation. The studied cycle works in the same way as a conventional ORC, except that during the expansion process, heat is extracted. This heat is re-used later in the cycle, just before the hot source, allowing to reduce its load. The different cycles presented in this paper, using pentane as working fluid, are compared based on their exergetic and energetic efficiencies. The influence of three parameters on the cycle performance is studied: the regeneration ratio, the maximum temperature of the cycle and the turbine isentropic efficiency. In the case of a cycle using pentane with a maximum temperature of 150 °C and an turbine isentropic efficiency of 65%, the energy efficiency increases from 6.2% to 16.3% when going from no regeneration to full regeneration, and the exergy efficiency increases from 21.1 to 45.8%.. Secondly, the influence of the maximum temperature of the cycle is studied. Using pentane as the working fluid, the higher the maximum temperature is, the larger the benefits of heat extraction. However, this temperature cannot exceed the critical temperature of the organic fluid to stay in the case of a subcritical cycle. Finally, considering the turbine isentropic efficiency, it is possible to demonstrate that using a less efficient turbine, for example in small ORC systems, the performance of a cycle with an ideal turbine isentropic efficiency (100%) can be achieved compensating at cycle level the turbine losses with the heat extraction along the expansion process.

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“…The MT efficiency with one 801 pass recuperator with biogas fuel is around 16% and for other renewable fuel could be around 802 15.6%. De Campos et al [82] have revealed that an optimized closed cycle 100 kWe micro turbine 803 efficiency is around %30 and that appropriate choice of working fluid could increase the efficiency to a upper limit %35.…”

Section: Fig 17 T-s Diagram Of the 12 Kwe Output Microturbine Cycle With Renewable Fuelsmentioning

confidence: 99%

Design, manufacture and test of a micro-turbine renewable energy combustor

Bazooyar

Darabkhani

2020

Energy Conversion and Management

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The ever-increasing demand on highly efficient decentralized power generation with low CO2 emission has made microturbines for power generation in micro-combined heat and power (mCHP) generation systems popular when running on biofuels as a renewable source of energy. This document presents a state-of-the-art design, and optimization (in terms of design, performance and emission control) of a micro-turbine renewable energy combustor that fits into the existing Bladon 12kWe recuperated microturbine plenum while running on a range of biofuels as it can successfully provide the required power of the mCHP. Governing equations for in-depth analysis of the combustor consist of manufacturer empirical data to simulate system-level operation with respect to replacement of the fossil with biofuels. The Model developed and validated at company's ISO conditions confirms the output power of the new combustor fits the conventional system with slight eco-energy improvements. The modeling of the combustor in a complete microturbine assembly system is performed, then was utilized to further analysis of the microturbine with the designed combustor. The experimental results gave on average 46.7% electrical efficiency, 83.2% system efficiency, 12 kWe electrical power, and 90% recuperator effectiveness at nominal operating conditions of microturbine (MT). Sensitivity analyses evaluate changes in performance with respect to fuel phase (e.g., liquid or gaseous) and design variables (e.g., orientation, shape, and dimensions of combustor), leading to energy optimization of the unit.Experimental findings demonstrate that the combustor in microturbine can meet the target performance specifications of a company conventional diesel microturbine with significant savings. An objective function including both combustor and recuperator technical energy data is defined for finding the best ratio of fuel and air and their flow rates to find the most effective operating points for the operation of MT. Annual time series simulations completed for Coventry, West Midlands, United Kingdom indicate a new combustor can reduce operational costs of diesel 3 fuel combustor by 8%, 2%, 36%, and 25% when supplying bioethanol, DME, biogas, and NG, respectively. Annual operating time of the renewable microturbine combustor at rated capacity included an 11% reduction in exergy loss with biogas fuel relative to diesel fuel.

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Thermoeconomic optimization of organic Rankine bottoming cycles for micro gas turbines

Cited by 33 publications

References 46 publications

Optimization of Micro Gas Turbine Based Hybrid Systems for Remote Off-grid Communities

Optimization of Micro Gas Turbine Based Hybrid Systems for Remote Off-grid Communities

Carnot cycle in practice: compensating inefficiencies of ORC expanders through thermal regeneration

Design, manufacture and test of a micro-turbine renewable energy combustor

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