SCARABEUS participates to the European Corner at the 6th International Seminar on Organic Rankine Cycle Power Systems

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The 6th edition of the International Seminar on ORC Power Systems was held in October, organized by the Technical University of Munich and the Knowledge Centre on Organic Rankine Cycle technology (KCORC). It was a very exciting event, with lots of interesting presentations and panels on different aspects of the energy industry and technologies, including some excellent works on the utilization of Carbon Dioxide mixtures in supercritical power cycles.

The conference was held virtually but, akin to the previous edition of the conference, a European Corner to raise awareness of the large research projects on the topic funded by the European Commission was organized. SCARABEUS was one of such projects. The Exploitation Manager, Noelia Martínez Sanz (Abengoa), prepared some materials to offer an interactive environment to get to know about the potential and challenges of the technology. These are shared on the SCARABEUS website now so you can enjoy the same experience!

 

 

D7.9 Final Data Management Plan

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D7.3 Dissemination and Communication

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New SCARABEUS paper discusses the benefits brought about by the utilization of Carbon Dioxide mixtures in supercritical power cycles applied to Concentrated Solar Power plants

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The SCARABEUS consortium (University of Seville, University of Brescia, Politecnico di Milano and LEAP) has just published in Energy journal their recent research in the area of cycle performance. This research paper provides a through analysis of the underpinning reasons why the utilization of mixtures enables higher maximum (thermal) efficiency and it also reveals the best combinations of cycle layout and working fluid composition.

The paper, whose abstract is pasted below, is now available in Open Access on the publisher’s website (link). Check it out now!

The present paper explores the utilisation of dopants to increase the critical temperature of Carbon Dioxide (sCO2) as a solution towards maintaining the high thermal efficiencies of sCO2 cycles even when ambient temperatures compromise their feasibility. To this end, the impact of adopting CO2-based mixtures on the performance of power blocks representative of Concentrated Solar Power plants is explored, considering two possible dopants: hexafluorobenzene (C6F6) and titanium tetrachloride (TiCl4). The analysis is applied to a well-known cycle -Recuperated Rankine- and a less common layout -Precompression-. The latter is found capable of fully exploiting the interesting features of these non-conventional working fluids, enabling thermal efficiencies up to 2.3% higher than the simple recuperative configuration. Different scenarios for maximum cycle pressure (250–300 bar), turbine inlet temperature (550–700ºC) and working fluid composition (10–25% molar fraction of dopant) are considered. The results in this work show that CO2-blends with 15–25%(v) of the cited dopants enable efficiencies well in excess of 50% for minimum cycle temperatures as high as 50ºC. To verify this potential gain, the most representative pure sCO2 cycles have been optimised at two minimum cycle temperatures (32ºC and 50ºC), proving the superiority of the proposed blended technology in high ambient temperature applications.

 

SCO2-Flex Final Event: The Role of sCO2 cycles in Europe’s future energy system

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SCO2-Flex Final Event: The Role of sCO2 cycles in Europe’s future energy system

On the 16th June 2021 the Sco2-Flex project will host its final event to present the results of the project and also introduce 5 other Horizon 2020 projects working with sco2 technology. 

In the context of the EU’s energy transition, the last few years have seen the potential of supercritical CO2 (carbon dioxide) cycles emerge as an efficient replacement of steam in the cycles converting heat into power, leading to a more flexible and lower-emission electricity production.

 

Indeed, since they can be adapted to any type of production (from conventional production to heat recovery, including nuclear and renewable energy), sCO2 cycles offer very interesting prospects in terms of increased efficiency, flexibility, cost control and reduced environmental impact.

 

All over the world, numerous research projects and demonstrators are being set up, and Europe is positioning itself as one of the players in this area. The number of research projects on sCO2, financed by the European Commission, has been increasing for more than 6 years and demonstrates the dynamics of European academic and industrial actors.

 

Given this fact, the event proposed within the framework of the sCO2-flex project aims to show the versatility of sCO2 cycles in energy production as well as the objectives and results obtained by the actors of these European projects.

In addition to a presentation by the European Commission, 6 projects will present their vision of the potential of sCO2 cycles. They are:

 

Check out the full Agenda and to register please click HERE

 

The event will take place online from 2pm to 5pm CET.

 

Registrations will close on the 15th June or until hosting capacity is reached. After registering, you will be sent a link to join the online session the day before the event.

Carbon Dioxide mixtures at the 4th European sCO2 Conference for Energy Systems, Prague

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The 4th edition of the European sCO2 Conference for Energy Systems, held virtually on March 23-24, gathered some forty excellent works presented by international authors. The number of attendees and quality of works presented confirmed that the sCO2 community is vibrant and the future of the technology looks bright.

A number of very interesting papers dedicated to CO2 blends triggered the interest of the SCARABEUS consortium:

  • 1 Valencia Chapi, R., Fierros-Peraza, O., Coco-Enríquez, L., Muñoz-Antón, J., Modeling and study of a printed circuit heat exchanger for Brayton power cycles using supercritical CO2 mixtures as working fluid (Universidad Politécnica de Madrid)
  • 2 Ayub, A., Di Marcoberardino, G., Invernizzi, C.M., Iora, P., Advanced thermodynamic power cycles utilizing carbon dioxide based mixtures as working fluids for high temperature waste heat recovery (University of Brescia)
  • 3 Rath, S., Mickoleit, E., Gampe, U., Breitkopf, C., Jäger, A., Study of the influence of additives to CO2 on the performance parameters of a sCO2-cycle (TU Dresden)

These added to two works by University of Seville and City, University of London, presented on behalf of the consortium:

  • Aqel, O., White, M., Sayma, A., Binary interaction uncertainty in the optimization of a transcritical cycle: consequences on cycle and turbine design (City, University of London)
  • Crespi, F., Rodríguez-de Arriba, P., Sánchez, D., Ayub, A., Di Marcoberardino, G., Invernizzi, C.M., Martínez, G.S., Iora, P., Di Bona, D., Binotti, M., Manzolini, G.,  Thermal efficiency gains enabled by using supercritical CO2 mixtures in Concentrated Solar Power applications (University of Seville, Politecnico di Milano, University of Brescia, LEAP)

Different CO2 mixtures were proposed for Concentrated Solar Power and Waste Heat Recovery applications. Rath et al. performed a vast screening of 135 candidates out which five were selected: Krypton, Xenon, Carbonyl sulfide (COS), Propane and Sulfur hexafluoride for WHR systems. For the same application, Ayub et al. studied CO2-Novec mixtures in three different layouts, concluding that a 3 percentage point gain with respect to pure CO2 seems possible. Regarding CSP, Crespi et al. investigated the use of CO2-C6F6 and CO2-TiCl4 mixtures, coming to the conclusion that it is possible for the power block to achieve and even exceed 50% thermal efficiency even under semi-arid boundary conditions, provided that the suitable cycle layout is selected for each working fluid-was achievable. Also for CSP plants, Valencia-Chapi et al. modelled a printed circuit heat exchanger and studied its performance for different CO2 mixtures, noting that heat transfer coefficients of the mixtures were higher than those of pure CO2; this favours lower heat exchang areas. Finally, the turbine of large power blocks running on CO2-C6F6, CO2-H2S and CO2-NOD (non-organic dopant) were studied by Aqel, White & Sayma.

Common to all work was the emphasis on the suitable fluid modelling of CO2 mixtures. In the work of Ayub et al., binary interaction parameters of different CO2 mixtures (Novec 5110, Novec 649, R134a, HFO1234yf and HFO1234ze(E)) were estimated using experimental VLE data from literature and then applying Peng-Robinson with Van der Walls mixing rule to estimate thermodynamic properties. The same fluid model was used by Crespi et al. for CO2-C6F6 and CO2-TiCl4 mixtures. Valencia-Chapi et al. modelled CO2 mixtures using the Aungier-Redlich-Kwong real gas model. Aqel, White & Sayma studied the influence of four different Equations of State and of the uncertainty in the estimates of binary interaction parameters on cycle performance and turbine geometry. Rath et al. use a predictive model to calculate mixture properties based on the best available EoS for the pure components.

In addition to the works by Aqel et al. and Crespi et al., which describe the latest results obtained by the SCARABEUS consortium, a series of works developed by other projects funded by the European Commission (sCO2 Hero and sCO2 Flex) were presented at the conference. Moreover, several interesting topics regarding sCO2 cycle performance, turbomachinery and heat exchanger design and novel sCO2 cycle configurations have been thoroughly discussed. The entire set of presentations and papers are available online in the conference repository (https://sco2.eu/conference-repository/4th-conference-online/) so, if you wish to take a closer look at some of the works, just follow this link and enjoy!