Search

Highlights • Micro Gas Turbine as a valid alternative to Stirling Engine in Solar Dish Applications. • Simulation Tool for concentrated solar power plant optimal operations. • Solar to Power Efficiency up to 10% for 5 kWe net generated power. • Concentred Solar Power and Brayton Cycle Gas Turbine for distributed generation. • Genetic Algorithms and Quadratic Programming for robust and fast computations. Abstract In the scenario of the small scale 3–35 kWe concentrated solar power plant based on point receiver technologies, the dish-Stirling configuration is one of the most commonly adopted one. New and clean efficiency of these Stirling engines is typically of 30–40%. Yearly average efficiency, during the system operations, is significantly reduced to 10–15% due to the Stirling engines high maintenance costs and poor reliability issues. These drawbacks limit the small scale dish-Stirling engines market attractiveness. The adoption of cheap, reliable and widely available engines, such as micro gas turbines is a promising solution for substituting Stirling engines since it ensures constant performance over time. Since micro gas turbines for concentrated solar power plants equipped with dish concentrator have not been widely deployed, the development of a plant simulator is helpful for predicting the overall concentrated solar power plant performance and for optimizing the plant operations under different boundary conditions. The plant simulator is aimed to demonstrate the economic viability and the technical feasibility of dish-micro gas turbine systems. The paper includes the methods for developing a simulation tool for solar dish – micro gas turbine applications. The solar concentrator, receiver/absorber, micro gas turbine, high speed generator and power electronic systems have been modelled and the plant simulator has been set-up by means of a quadratic programming technique. The simulator has been used to perform steady state simulations for predicting the performance and for ensuring a safe and reliable power plant operation when the direct normal irradiation changes. The results for a net generated power of about 6 kWe have shown a nominal peak efficiency of about 10%, making this micro gas turbine solar plant layout market attractive. [ABSTRACT FROM AUTHOR]

• Hourly load profiles and PV production for 4 years, before, during and after pandemic. • Technologies CAPEX and OPEX in 2020 and their projections for 2030 and 2040. • Simulating the operation of 500, 1000, 1500 and 2000 kWh of different storages. • Impact of lockdown restrictions and temporary and structural changes in load profiles. • The optimal dispatching of the Renewable Energy Community is not impacted by tariff. Solar hydrogen technology, i.e. producing green hydrogen by electrolysis fed by solar panels, is gaining attention as studies show it can compete with traditional electric batteries. Contemporary, the interest in the realization of Renewable Energy Community driven by the recent adoption in almost all the EU Countries of the RED II Directive is increasing. To match innovative technologies and new business models making the energy demand and the production closer in terms of time and space, the feasibility of Renewable Hydrogen Energy Community is explored. To determine the profitability of these solutions and size and operate the energy system, energy and economic analyses are needed as well as the optimization of its performance. A building complex with 180 kWp of PhotoVoltaics was studied using hourly real data on energy loads and production. Storage capacities ranging from 500 to 2000 kWh were simulated for hydrogen and electric battery options. The cost of investment and operation was also analyzed for the years 2020, 2030, and 2040 to evaluate changes in technology readiness level as well as accounting for the strong changes in electricity tariff due to the geopolitical issues effects on the market. The analysis was conducted using the DECAPLAN™ digital platform, which employs a mixed integer linear programming solver. Finally, the dispatch on hourly base has been compared for the same two months in 2019, 2020 and 2021 corresponding to pre, during and after pandemic restrictions. [ABSTRACT FROM AUTHOR]

Thermoelectric generator is a solid-state energy converter which can convert waste heat directly into electricity. During the past decades, thermoelectric materials have been widely investigated whereas the integrated design of thermoelectric generators have been less studied. This paper proposes and implements a framework for the design of thermoelectric generators, consisting of thermoelectric modules and heat exchangers, based on the Taguchi method. As compared with previous researches which optimize the thermoelectric module alone and assume fixed temperature or fixed heat fluxes for the thermoelectric modules, this work proposes a methodology to optimize the thermoelectric module and the heat exchanger together. Five design parameters (namely the height, the fill-ratio, the ratio of cross-sectional area of n-type material over p-type material of thermoelectric module, the length and the material of the heat exchanger) were analyzed for two different applications, waste heat recovery from marine and automotive engines. In order to perform the analysis, a L 27 (3 5 ) orthogonal array was employed to assess all of the design parameters returning the maximum output power. By analysis of variance, it is found that the thermoelectric module height is the most important design parameter contributing for the 69.6% and 30.25% in automotive and marine application, respectively. And the optimal design parameter set are also determined in both applications. [ABSTRACT FROM AUTHOR]

• This paper proposes a distributed thermoelectric model based on discretization. • The thermoelectric model is compared with experiments at different module geometry. • Parametric studies were conducted to study the effect of thermoelectric module geometry. • Optimal geometry parameters are identified. The majority of existing commercial thermoelectric modules have fixed geometry, with customers purchasing those modules without adjusting its geometry for a specific application. However, previous investigations show that thermoelectric module geometry can have a significant influence on its output power – careful design considerations are therefore required. In this study, both simulation and experimental investigations are conducted to optimize the geometry of thermoelectric modules, in order to achieve higher power while maintaining the cost low. The experimental setup is built, and three thermoelectric modules with different geometries but same material are tested. The documented experimental results agree well with the simulation results. Based on parametric studies, optimal thermoelectric module height to achieve maximum output power is found to be 1.1 mm at the given thermal condition, slightly lower compared with the value used for most commercial products, which are around 1.5 mm. The effect of geometry design parameters on efficiency and power per material cost are also discussed, and the optimal design parameters are identified. Further improvements are proposed based on the simulation and experimental results. [ABSTRACT FROM AUTHOR]