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Rossi, I., Zaccaria, V. & Traverso, A. (2018). Advanced Control for Clusters of SOFC/Gas Turbine Hybrid Systems. Journal of engineering for gas turbines and power, 140(5), Article ID 051703.
Open this publication in new window or tab >>Advanced Control for Clusters of SOFC/Gas Turbine Hybrid Systems
2018 (English)In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 140, no 5, article id 051703Article in journal (Refereed) Published
Abstract [en]

The use of model predictive control (MPC) in advanced power systems can be advantageous in controlling highly coupled variables and optimizing system operations. Solid oxide fuel cell/gas turbine (SOFC/GT) hybrids are an example where advanced control techniques can be effectively applied. For example, to manage load distribution among several identical generation units characterized by different temperature distributions due to different degradation paths of the fuel cell stacks. When implementing an MPC, a critical aspect is the trade-off between model accuracy and simplicity, the latter related to a fast computational time. In this work, a hybrid physical and numerical approach was used to reduce the number of states necessary to describe such complex target system. The reduced number of states in the model and the simple framework allow real-time performance and potential extension to a wide range of power plants for industrial application, at the expense of accuracy losses, discussed in the paper. 

Place, publisher, year, edition, pages
American Society of Mechanical Engineers (ASME), 2018
Keyword
Economic and social effects; Fuel cells; Hybrid systems; Industrial plants; Model predictive control; Predictive control systems; Turbines, Advanced control; Computational time; Generation units; Load distributions; Number of state; Numerical approaches; Real time performance; System operation, Solid oxide fuel cells (SOFC)
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-38576 (URN)10.1115/1.4038321 (DOI)2-s2.0-85040680634 (Scopus ID)
Available from: 2018-02-08 Created: 2018-02-08 Last updated: 2018-02-08Bibliographically approved
Zaccaria, V., Dik, A., Bitén, N., Aslanidou, I. & Kyprianidis, K. (2017). Conceptual Design of a 3-Shaft Turbofan Engine with Reduced Fuel Consumption for 2025. In: Elsevier (Ed.), Energy Procedia: . Paper presented at 9th International Conference on Applied Energy, ICAE2017, 21-24 August 2017, Cardiff, UK. .
Open this publication in new window or tab >>Conceptual Design of a 3-Shaft Turbofan Engine with Reduced Fuel Consumption for 2025
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2017 (English)In: Energy Procedia / [ed] Elsevier, 2017Conference paper, Published paper (Refereed)
Abstract [en]

In the past decade, aircraft fuel burn has been continually decreased, mainly by improving thermal and propulsion efficiencies with consequent decrement in specific fuel consumption. In view of future emission specifications, the requirements for SFC in the forthcoming years are expected to become more stringent. In this paper, a preliminary design of a turbofan engine for entry in service in 2025 was performed. The design of a baseline 2010 EIS engine was improved according to 2025 specifications. A thermodynamic analysis was carried out to select optimal jet velocity ratio, pressure ratio, and temperatures with the goal of minimizing specific fuel consumption. A gas path layout was generated and an aerodynamic analysis was performed to optimize the engine stage by stage design. The optimization resulted in a 3-shaft turbofan jet engine with a 21% increase in fan diameter, a 2.2% increment in engine length, and a fuel burn improvement of 11% compared to the baseline engine, mainly due to an increment in propulsive efficiency. A sensitivity analysis was also conducted to highlight what the focus of technology development should be.

National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-37465 (URN)
Conference
9th International Conference on Applied Energy, ICAE2017, 21-24 August 2017, Cardiff, UK
Available from: 2017-12-15 Created: 2017-12-15 Last updated: 2018-01-26Bibliographically approved
Zaccaria, V., Branum, Z. & Tucker, D. (2017). Fuel Cell Temperature Control with a Pre-Combustor in SOFC Gas Turbine Hybrids during Load Changes. Journal of electrochemical energy conversion and storage, 14, 031006-031014.
Open this publication in new window or tab >>Fuel Cell Temperature Control with a Pre-Combustor in SOFC Gas Turbine Hybrids during Load Changes
2017 (English)In: Journal of electrochemical energy conversion and storage, ISSN 2381-6872, Vol. 14, p. 031006-031014Article in journal (Refereed) Published
Abstract [en]

The use of high temperature fuel cells, such as Solid Oxide Fuel Cells (SOFCs), for power generation is considered a very efficient and clean solution to conservation of energy resources. When the SOFC is coupled with a gas turbine, the global system efficiency can go beyond 70% on natural gas LHV. However, durability of the ceramic material and system operability can be significantly penalized by thermal stresses due to temperature fluctuations and non-even temperature distributions. Thermal management of the cell during load following is therefore essential.The purpose of this work was to develop and test a pre-combustor model for real-time applications in hardware-based simulations, and to implement a control strategy to keep constant cathode inlet temperature during different operative conditions. The real-time model of the pre-combustor was incorporated into the existing SOFC model and tested in a hybrid system facility, where a physical gas turbine and hardware components were coupled with a cyber-physical fuel cell for flexible, accurate, and cost-reduced simulations.The control of the fuel flow to the pre-combustor was proven to be effective in maintaining a constant cathode inlet temperature during a step change in fuel cell load. With a 20 A load variation, the maximum temperature deviation from the nominal value was below 0.3% (3K). Temperature gradients along the cell were maintained below 10 K/cm. An efficiency analysis was performed in order to evaluate the impact of the pre-combustor on the overall system efficiency.

Keyword
SOFC, hybrid system, control, dynamics
National Category
Energy Engineering
Research subject
Energy- and Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-37169 (URN)10.1115/1.4036809 (DOI)
Available from: 2017-11-01 Created: 2017-11-01 Last updated: 2018-01-26Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-6101-2863

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