City Research Online

Abstract

Small-scale concentrated solar power (CSP) systems coupled with micro gas turbines (MGTs) offer a promising solution for decentralised and sustainable power generation. However, CSP–MGT systems are subject to pronounced transient behaviour during start-up and operation due to fluctuating solar irradiance, making accurate transient modelling essential. This work introduces a fully coupled transient electro-thermo-mechanical model of a CSP-driven micro gas turbine, explicitly linking thermal transients and heat soakage effects to electrical performance during start-up. Unlike existing models, the proposed approach captures the interaction between turbomachinery thermal inertia, shaft dynamics, and detailed electrical machine and power converter losses under real-world transient operating conditions. The model integrates thermodynamic, mechanical, electrical, and control subsystems within a unified framework using a lumped-volume formulation suitable for real-time-capable simulations. To improve prediction accuracy at low rotational speeds, a dedicated interpolation strategy for turbomachinery performance maps is implemented. The model is validated at both component and system levels using experimental data from a 6 kWe CSP–MGT test facility. The results show good agreement with measurements, with maximum deviations of approximately 8% in receiver outlet temperature and less than 6% in air mass flow rate. The findings demonstrate that accounting for heat soakage is critical for a realistic prediction of thermal and electrical transients, as neglecting thermal inertia leads to an underestimation of the start-up electrical energy consumption by up to 140%, highlighting the dominant role of thermal mass effects in small-scale micro gas turbines compared to larger systems. The proposed model provides a robust tool for analysing start-up behaviour and supports improved control and operational strategy development for CSP–MGT systems under variable solar conditions.

Publication Type:	Article
Additional Information:	© 2026 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license.
Publisher Keywords:	micro gas turbine, concentrated solar power system, transient modelling, electro-thermo-mechanical model, start-up phase, heat soakage
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

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