This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018-093849-B-C31). The author would like to thank the Catalan Government for the quality accreditation given to her research group GREiA (2017 SGR 1537). GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme.
The building sector, as a major energy consumer with high direct and indirect CO2 emissions, plays a vital role in the fight against climate change. In order to make buildings more comfortable, functional, efficient and safe, building services are used. Therefore, building services are the key to decrease their contribution to climate change. Due to the lack of organized literature on this topic, this paper presents the first comprehensive assessment of trends in the literature on building services related to climate change, which was completed by conducting a bibliometric analysis of the existing literature on the topic. The ultimate goal is to provide a source where researchers and other interested parties can find this information in an organized manner. Results show that the most abundant and recent studies related to building services are based on improving energy efficiency by optimizing systems such as ventilation or lighting, the latter with the installation of LED lights. In addition, recent studies have focused on social factors such as housing and urban growth. ; Funding: This research was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018-093849-B-C31—MCIU/AEI/FEDER, UE) and by the Ministerio de Ciencia, Innovación y Universidades—Agencia Estatal de Investigación (AEI) (RED2018-102431-T). Data Availability Statement: Data are available upon request to the corresponding author. Acknowledgments: The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREiA (2017 SGR 1537). GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme.
Thermal energy storage (TES) increases concentrating solar power (CSP) plant capacity factors, but more important, improves dispatchability; therefore, reducing the capital cost of TES systems is very important to reduce cost of energy and serve as an enabler for commercial solar power plants. After presenting the concept of a novel cascade PCM configuration of CSP and demonstrating it energy efficiency, it is needed to develop a thoughtful economic evaluation of the concept. The goal of this paper was to investigate this system through annual modelling, engineering procurement company price quotes, and levelized cost metric comparison with a baseline case, the commercial two-tank molten salt storage system. Simulation results show that this new PCM concept decrease levelized costs of storage. The baseline of using shell and tube heat exchangers for PCM storage offers a reduction in capital and levelized cost, but this paper also shows that there are further cost reduction possibilities, as shown in the scenarios presented here, such as thermal conductivity enhancement, encapsulation of the PCM, or modification of the material to improve its thermal properties. Therefore, although the basic shell and tube PCM system has been shown to offer a cost savings, the 1.8% reduction in LCOE may not be worth the risk of further development. The shell and tube system should be a jumping off point to more appropriate technologies. The variants studied are likely to yield cost reductions in cost performance quotient (CPQ) as high at 80% and in LCOE as high as 10%, representing an unprecedented and valuable avenue of CSP plant cost reduction. ; The research leading to these results has received funding from CDTI in the project Innterconecta Thesto (ITC-20111050). We would like to thank Abengoa Thermal Storage Team for their comments and suggestions. This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018-093849-B-C31 - MCIU/AEI/FEDER, UE) and by the Ministerio de Ciencia, Innovación y Universidades - Agencia Estatal de Investigación (AEI) (RED2018-102431-T). Dr. Cabeza would like to thank the Catalan Government for the quality accreditation given to her research group GREiA (2017 SGR 1537). GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme.
A systematic review of the technological options and strategies to achieve zero energy buildings was carried out to establish today state-of-the-art knowledge base and to present key design and performance factors that define those technologies with the final aim of contributing to climate change mitigation options of buildings. All relevant literature published from January 2013 to August 2019 was critically as- sessed. A total of 14,895 papers were identified and 220 reviews were evaluated as first literature source; this literature showed that the published information is diverse and not organized, therefore climates and building typologies is not possible solely through published information. Collected evidence shows that with appropriate design, buildings can contribute to climate change mitigation decreasing the embodied energy in the materials used in their construction and decreasing the energy demand and use during their operation phase. ; This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018-093849-B-C31 - MCIU/AEI/FEDER, UE). This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades - Agencia Estatal de Investigación (AEI) (RED2018-102431-T). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme.
Concentrated solar power (CSP) is today recognized as a unique renewable energy for electricity generation due to its capability to provide dispatchable electricity incorporating thermal energy storage (TES). Molten salts TES is the most widespread technology in commercial CSP but the industry is looking for cheaper and more efficient TES systems and phase change materials (PCM) have been highlighted as potential low cost and high energy TES systems. This paper presents a completely new concept of PCM energy storage systems to be used in solar thermal electricity plants with its technical assessment. A cascade type PCM storage system is evaluated, using four buckets with the PCM organized based on melting temperature and the latent energy of the materials. Daily, monthly, and annual transient simulations of the plant performance are carried out. The main conclusion is the similarity between this new concept and the commercial two-tank indirect molten salt system. The cumulative power production over the year is similar and the net production of both systems is well matched. ; The work was partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER)). Dr. Cabeza would like to thank the Catalan Government for the quality accreditation given to her research group (2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia.
Following the EC SET-Plan Education and Training Roadmap, the goal of INPATH-TES is to create a network of academia, research institutes and small and medium-sized enterprises (SMEs) to implement a joint PhD programme on Thermal Energy Storage (TES) technologies. The project consortium consists of 22 partners from academia, industry and SMEs from 14 different countries. The final result of such a network is to educate professionals on these technologies for the European research and industry institutions. Some of the main challenges identified so far consist of the development of the programme, the implementation of the programme in each country/institution, and to ensure the continuity of the programme after EU funding ends. ; The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This study has received funding from European Union's Horizon 2020 research and innovation programme under grant agreement Nº 657466 (INPATH-TES). The work is partially funded by the Spanish government ENE2015-64117-C5-1-R (MINECO/FEDER).
Energy storage is a key challenge to a sustainable energy supply. To design new storage systems accurateand representative thermal property measurements are essential. The T-history method is quick anduncomplicated, however numerous adaptations have been proposed over the years. In this study thesemethods have been classified and critically assessed based on their mathematical formulation and exper-imental configuration. They can be broadly categorized according to one of three assumptions regardingthe heat transfer coefficient for natural convection: it is constant either as a function of time or tem-perature, or it is negligible. This work proves in addition that the heat transfer coefficient for naturalconvection, varies both as a function of time and temperature. This is demonstrated both experimentallyand through rigorous simulation of the proposed configurations. Thus T-history methods which show themost promise for precise and unambiguous measurements eliminate convection by making conductionthe dominant thermal resistance in the system. These techniques can be tailored to different materialsand do not require a simultaneous reference due to the use of a rigorous fundamental model comparedto the lumped parameter approximation. The addition of heat flux sensors to quantify actual heat lossesis recommended for absolute measurement certainty. ; The research leading to these results has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) and under Grant agreement N°PIRSES-GA-2013-610692 (INNOSTORAGE), and from the European Union's Horizon 2020 research and innovation programme under grant agreement No 657466 (INPATH-TES). The work is partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER)). Dr. Luisa F. Cabeza would like to thank the Catalan Government for the quality accreditation given to the research group GREA (2014 SGR 123).
The enhancement and the understanding of the societal dynamics in the energy systems within transition entails the inclusion of innovative policy and research strategies. This inclusion raises several questions that change profoundly the nature of the research and innovation endeavour, questions that have not been sufficiently explored in the literature. These questions are, among others, the complexities an scope of socio-technical integration or the emergence of new roles and patterns such as user-inspired innovations or community innovations. Based on the assumptions of the responsible-based approaches advocating to energy system actors to collaborate sharing responsibility and the benefits that perspectives integration brings in the development of proactive and archivable energy and climate policies, this study analyses a group of researchers within the field of thermal energy storage (TES) for renewable energy applications, for the purpose of evaluating their perception regarding to the inclusion of alternative policy proposals and collaborative research strategies. The proposed methodology was based on the use of the common theoretical backgrounds of socio-technical transition for the construction of an responsibility-based approach and the proposal of a survey tool for gathering the empirical evidence from researchers opinions. The survey data was collected from a representative group of researchers (33 countries, 215 targeted researches completing the surveys at 31% with a final N = 72). Findings shows willingness to include citizens as beneficiaries but not as participants of research decisions, the prevalence of the use of social sciences to increase the acceptance of technology and remarkable unawareness regarding collaborative research strategies. This paper brings an important contribution for the selected researchers that can be extrapolate to other energy communities since illuminates the possibility of adapting and asses TES to include new patterns and new governance strategies based in RRI. ; This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018-093849-B-C31). The authors of this paper would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme.
The operating temperature of a steam turbine is limited to 565 °C by the molten nitrate heat-transfer fluid; therefore, molten-salt CSP technologies require alternative salt chemistries such as chloride. The prevention of high-temperature corrosion on containment materials plays a critical role, and a corrosion mitigation plan is needed to achieve the target plant lifetime of 30 years. This paper performed a materials screening test, using a eutectic ternary chloride molten salt, composed by 20.4 wt. % KCl + 55.1 wt. % MgCl2 + 24.5 wt. % NaCl, in stainless steel (AISI 304) and two Ni base materials (Inconel 702 and Haynes 224). The corrosion mechanism and corrosion rates were obtained through electrochemical impedance spectroscopy (EIS). Ni base alloys showed a protective scale layer during 8 hours of immersion with a corrosion rate of 6.34 mm/year (In702) and 3.12 mm/year (HR224). Monitoring corrosion results were confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), obtaining alumina and chromia protective layers. ; Angel G. Fernández wants to acknowledge the financial support from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant No 712949 (TECNIOspring PLUS) and from the Agency for Business Competitiveness of the Government of Catalonia. This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España(RTI2018-093849-B-C31- MCIU/AEI/FEDER, UE). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREiA (2017 SGR 1537). GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme.
The new generation of concentrated solar power (CSP) plants to be developed presents a great challenge related to the increase in maximum operating temperature since molten salt CSP technologies require alternative salt chemistries such as chloride. The cathodic protection strategy involves the addition of a sacrificial metal to prevent corrosion of the alloy tested as container material in a CSP plant. In this paper, aluminum (Al) metal was analyzed as a corrosion inhibitor in OCT and HR224 alloys, obtaining corrosion rates of 4.37 and 0.27 mm/y, respectively. It has been confirmed that the use of Al metal can reduce the anodic current which is directly related to the corrosion rate. The formation of protective alumina scales (Al2O3) was assessed by scanning electron microscopy (SEM) and X‐ray diffraction (XRD), confirming the corrosion model results from electrochemical impedance spectroscopy monitoring tests. ; Funding: This project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska‐Curie grant No 712949 (TECNIOspring PLUS) and from the Agency for Business Competitiveness of the Government of Catalonia. This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018‐093849‐B‐C31 ‐ MCIU/AEI/FEDER, UE). This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades ‐ AgencHia Estatal de Investigación (AEI, RED2018‐102431‐T). This work is partially supported by ICREA under the ICREA Academia program. Acknowledgments: The authors would like to thank the Catalan Government for the quality accreditation given to their research group (GREiA 2017 SGR 1537).
Molten salt technology using nitrate salts as thermal energy storage material is the current state-of-the-art of concentrated solar power technology and power tower central receivers are currently limited by the maximum operating temperature of their working fluid. The limit of solar salt (60wt.%NaNO3 + 40wt.%KNO3) thermal stability is around 565°C with ambient air as the cover gas. In order to obtain higher efficiency goals using molten salt technologies working at higher temperatures (e.g., 650°C to 750°C), a different salt chemistry is required for new generation of CSP plants and chlorides molten salts could be a feasible option. Corrosion mitigation could solve the current issues related with the use of chloride salt at high temperature. In this work, the proposal of different corrosion mitigation strategies has been evaluated, as well as the identification of the most corrosive impurities present in the ternary chloride salt composed by MgCl2/KCl/NaCl (60/20/20 mol%). For this purpose, electrochemical impedance spectroscopy tests were carried out at 700°C on austenitic stainless steel (AISI 304) and a Ni base alloy (Inconel 702) during 100 hours. In this case, MgOHCl was identified as the main important corrosive impurity, present in the chloride salt, to control in the storage system. Regarding the materials tested, Ni base alloy (Inconel 702) showed the most promising results for their use as container material. ; The research leading to these results has received funding from Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER)). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREiA (2017 SGR 1537). GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. Angel G. Fernández wants to acknowledge the financial support from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant No 712949 (TECNIOspring PLUS) and from the Agency for Business Competitiveness of the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme.
In order to redefine the influence of the energy and technological transitions upon the challenge of climate change this paper shows that buildings are key agents. This paper discusses the importance of addressing building energy efficiency in a holistic and transformational way, to avoid that incremental measures increase the lock-in effect. Moreover, policies should consider a demand-side energy transition, contrary to today's discourse, where the supply side and energy production are prominent. Finally, the most important issues in this energy transition are intergenerational divide and justice. ; Dr. Cabeza would like to thank the Catalan Government for the quality accreditation given to her research group GREiA (2017 SGR 1537). GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme.
The generation of a natural protective coating in alumina-forming alloys was analyzed using a ternary chloride molten salt as a thermal energy storage material for concentrated solar power (CSP) technology. The formation of the protective layer was monitored using electrochemical impedance spectroscopy (EIS). A protective layer model for the OCT alloy and a localized corrosion model for the OCI and OC4 alloys were obtained after 5 h of immersion. The corrosion rates calculated using the linear polarization technique (LPR), were 8.03, 21.55, and 7.61 mm/year for OC4, OCI, and OCT alloys, respectively. These results were confirmed by scanning electron microscopy and X-ray diffraction. Our analysis showed that MgAl2O4 was the main protective coating generated by the alumina-forming alloys. ; Angel G. Fernández would like to acknowledge the financial support from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant No 712949 (TECNIOspring PLUS) and from the Agency for Business Competitiveness of the Government of Catalonia. This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018- 093849-B-C31 - MCIU/AEI/FEDER, UE) and the Agencia Estatal de Investigación (AEI) of the Ministerio de Ciencia, Innovación y Universidades (RED2018-102431-T). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREiA (2017 SGR 1537). GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme.
The prevention of high-temperature corrosion on containment materials plays a critical role, and a corrosion mitigation plan is needed to achieve the target plant lifetime of 30 years. This paper analyzed two mitigation corrosion strategies (anodic and cathodic protection) in a eutectic ternary chloride molten salt, composed by 20.4wt.% KCl + 55.1wt.% MgCl2 + 24.5wt.% NaCl. The corrosion mechanism and corrosion rates were obtained through electrochemical impedance spectroscopy (EIS). Ni base alloys generate a protective scale layer (anodic protection) during 8 hours of immersion with a corrosion rate of 6.34 mm/year (In702) and 3.12 mm/year (HR224). Monitoring corrosion results were confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), obtaining alumina and chromia protective layers. ; Angel G. Fernández wants to acknowledge the financial support from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant No 712949 (TECNIOspring PLUS) and from the Agency for Business Competitiveness of the Government of Catalonia. This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018-093849-B-C31). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREiA (2017 SGR 1537). GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme.
Corrosion mechanisms for current heat transfer fluid and storage media used in CSP plants working at temperatures from 300°C to 600°C are reviewed in this paper. The studies found in the literature show that these mechanisms are influenced by the impurities present in the salt and the relation between Mg(NO3)2, moisture, CO2, perchlorates, and sulphates with the corrosion process. Corrosion mechanisms were identified along with a discussion of the corrosion products and their influence on the corrosion layers formed. ; The research leading to these results has received funding from Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER)). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREiA (2017 SGR 1537). GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia.
