Suchergebnisse

This review is focused on the study of the requirement of high thermal conductivity of thermal energy storage (TES) materials and the techniques used to enhance it as this is one of the main obstacles to achieve full deployment of TES systems. Numerical and experimental studies involving different thermal conductivity enhancement techniques at high temperature (>150 °C) are reviewed and classified. This article complements Part 1, which reviews the different requirements that TES materials and systems should consider for being used for high temperature purposes and the approaches to satisfy them. The enhancements identified for this temperature range are the addition of extended surfaces like fins or heat pipes and the combination of highly conductive materials with TES material like graphite or metal foam composites and nanomaterials. Moreover the techniques presented are classified and discussed taking into account their research evolution in terms of maturity and publications. ; The work is partially funded by the Spanish Government (ENE2011-22722 and ULLE10-4E-1305). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2014 SGR 123). The research leading to these results has received funding from the European Union׳s Seventh Framework Programme (FP7/2007-2013) under grant agreement no. PIRSES-GA-2013-610692 (INNOSTORAGE). Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861).

Industrial activities have a huge potential for waste heat recovery. In spite of its high potential, industrial waste heat (IWH) is currently underutilized. This may be due, on one hand, to the technical and economic difficulties in applying conventional heat recovery methods and, on the other, the temporary or geographical mismatch between the energy released and its heat demand. Thermal energy storage (TES) is a technology which can solve the existing mismatch by recovering the IWH and storing it for a later use. Moreover, the use of recovered IWH leads to a decrease of CO2 emissions and to economic and energy savings. Depending on the distance between the IWH source and the heat demand, TES systems can be placed on-site or the IWH can be transported by means of mobile TES systems, to an off-site heat demand. Around 50 industry case studies, in which both on-site and off-site recovery systems are considered are here reviewed and discussed taking into account the characteristics of the heat source, the heat, the TES system, and the economic, environmental and energy savings. Besides, the trends and the maturity of the cases reviewed have been considered. On-site TES systems in the basic metals manufacturing are the technology and industrial sector which has focused the most attention among the researchers, respectively. Moreover, water (or steam), erythritol and zeolite are the TES materials used in most industries and space comfort and electricity generation are the most recurrent applications. ; The work is partially funded by the Spanish government (ENE2011-22722, ENE2015-64117-C5-1-R (MINECO/FEDER)). This project has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant agreement No. 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 authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2014 SGR 123). Jaume Gasia would like to thank the Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for his research fellowship (2016FI_B 00047). Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861).

In accordance to the current worldwide trend of reducing CO2 emissions and to make the industry more competitive incrementing its efficiency, some countries are starting to quantify their quantity of Industrial Waste Heat. In fact, to be able to recover and reuse this waste heat from industrial processes as a source for other processes or activities, the availability of reliable data of the Industrial Waste Heat potential found in a region is a key point. For that, after an exhaustive literature research, this article shows Industrial Waste Heat data from 33 countries and 6 subregions of different countries. Their feasibility is assessed in the discussion part as it is expected and shown in most of the cases that the amount of Industrial Waste Heat is proportional to some parameters regarding the country and its industry like: the Energy Consumed by the Country, the Energy Consumed by the Industry and the amount of Industrial Waste Heat Intensive Industry in the country. Country scale has been chosen and it is shown that at other scales these parameters are not always available. Nevertheless, some of the studied cases found show data not fitting into this pattern (approximately 1/6 of the data found). That can be explained taking into account that in most of the studies the methodology to account the quantity of Industrial Waste Heat is not explained. Factors like the reference year of the data, the boundaries of the analysis, the type of waste heat considered, etc. affect to the report of quantity of Industrial Waste Heat. Therefore, the authors provide a set of parameters and recommend checking these in order to confirm the reliability of data referring to Industrial Waste Heat quantities. ; Special thanks to Eberhard Lävemann from ZAE Bayern (Germany) for his advice, intensive revision and support. Moreover, the authors want to thank Nurten Şahan and Prof. Dr. Halime Paksoy from Çukurova University (Turkey), Dr. Yukitaka Kato from Tokyo Institute of Technology (Japan) and Dr. Jochen Diekmann from the Deutsches Institut für Wirtschaftsforschung (Germany) for their help finding the data. The work was partially funded by the Spanish Government (project ENE2011-22722) and by BMWi the German Federal Ministry of Economics and Technology (project FKZ 0327383B Mobile Sorption Heat Storage). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2014 SGR 123). Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012–051861). Sarah Brückner would like to thank Stiftung der Deutschen Wirtschaft for her research fellowship.

High temperature thermal energy storage offers a huge energy saving potential in industrial applications such as solar energy, automotive, heating and cooling, and industrial waste heat recovery. However, certain requirements need to be faced in order to ensure an optimal performance, and to further achieve widespread deployment. In the present review, these requirements are identified for high temperature (>150 °C) thermal energy storage systems and materials (both sensible and latent), and the scientific studies carried out meeting them are reviewed. Currently, there is a lack of data in the literature analysing thermal energy storage from both the systems and materials point of view. In the part 1 of this review more than 25 requirements have been found and classified into chemical, kinetic, physical and thermal (from the material point of view), and environmental, economic and technologic (form both the material and system point of view). The enhancements focused on the thermal conductivity are addressed in the Part 2 of this review due to their research significance and extension. ; The work is partially funded by the Spanish government (ENE2015-64117-C5-1-R, ENE2011-22722 and ULLE10-4E-1305). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2014 SGR 123). This project has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant agreement No. PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 657466 (INPATH-TES). Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861). Jaume Gasia would like to thank the Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for his research fellowship (2016FI_B 00047).

Industrial waste heat (IWH) is a key strategy to improve energy efficiency and reduce CO2 emissions in the industry. But its potential for different countries remains unclear due to a non-existent or inconsistent data basis. The objective of this paper is to assess the IWH potential of the European non-metallic mineral industry, using databases which comprise CO2 emissions of more than 400 industrial sites as well as country- and sector-specific parameters. This sector is selected because of its homogenous nature, meaning that most sites carry out similar or the same processes, which facilitates site-level modelling with subsector-level assumptions. The bottom-up approach is employed to derive the IWH potential for this industry over the period 2007–2012. Average results in this period show an IWH potential per site of 0.33 PJ/a and a potential for the whole sector of 134 PJ/a. The countries with the largest IWH potentials are Germany, Italy, France and Spain with yearly average potentials of 23, 19, 17 and 16 PJ, respectively. The subsector with the most IWH potential is cement. Further work should focus on the improvement of methodologies to assess the IWH potential, in particular through a techno-economic assessment of links between IWH sources and potential sinks. ; The work is partially funded by the Spanish Government (ENE2015-64117-C5-1-R (MINECO/FEDER)). This project has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant Agreement No PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union's Horizon 2020 Research and Innovation programme under Grant Agreement No 657466 (INPATH-TES).

In the current European energy context, the use of recovered industrial waste heat provides an attractive opportunity to substitute primary energy consumption by a low-emission and low-cost energy carrier. In the case of industrial waste heat, this potential is currently not only largely untapped, but also unaccounted for. In order to achieve a widespread use of recovered industrial waste heat, assessments with a large scope and high spatial resolution are needed. Three methods published in the period 2002–2010 have been found in the literature, which are potentially transferable to other regions. These three methods are based on either the energy consumption of each manufacturing sector or the individual site CO2 emissions. The scope of this analysis is, first, to investigate in how far a transfer of the figures to different countries or regions is sensible in comparison to former studies in the literature. In the process, some uncertainties when transferring methods were identified (different definitions of industry, different standard industrial activities classifications or no standard at all, etc.). The second goal is, once the methodology is accepted, to apply it to a case study, in this case the industrial sector in Spain and two of its counties (Catalonia and the Basque Country) for the years 2001, 2009, 2010 and 2013. In this period, and based on the different approaches employed, the Spanish annual industrial waste heat potential ranges from 54.3 to 151.1 PJ, Catalonia from 8.6 to 29.7 PJ, and from 7.2 to 11.9 PJ for the Basque Country. The methods are considered highly transferable but uncertainties inevitably arise in the case that the source and destination industrial sectors are very different. ; The work is partially funded by the Spanish government (ENE2011-22722 and ULLE10-4E-1305) and by BMWi Federal Ministry for Economic Affairs and Energy in Germany (Project FKZ 0327383B Mobile Sorption Heat Storage). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2014 SGR 123). This project has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) 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). Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861).

Currently, there is an increasing interest in concentrated solar power (CSP) plants as alternative to produce renewable electricity at large scale by using mirrors to concentrate the solar energy and to convert it into high temperature heat. These facilities can be combined with thermal energy storage (TES) systems, which are, nowadays, one of the most feasible solutions in facing the challenge of the intermittent energy supply and demand. However, they are still in research process and, for that, there is a lack of environmental impact studies of these TES systems complementing solar plants. This paper accounts the environmental impact of three TES systems used nowadays in high temperature applications for CSP plants: first, a system which stores sensible heat in high temperature concrete; second, a system storing sensible heat in molten salts; and third, another system with molten salts but storing latent heat. All the systems are normalised in order to be comparable between them due to its initial storage capacity difference. The environmental impact is accounted by calculating the amount of embodied energy in the components of the different TES systems. Notice that embodied energy refers to the total energy inputs required to make a component. Between the three systems, the sensible heat system using concrete as storage material is the one with less environmental impact while the molten salts and PCM have a higher value of embodied energy, mainly due to the nitrate mixture used as storage material. Finally, advantages and disadvantages of the method proposed used are discussed ; The work was partially funded by the Spanish government (project ENE2011-22722). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2009 SGR 534). The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under Grant agreement n PIRSES-GA-2013-610692 (INNOSTORAGE). Eduard Oró would like to thank the University of Lleida for his research fellowship. Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861).

The present paper provides on one hand, a literature review of the different studies available in the scientific literature where the concept of multiple phase change materials (PCM) configuration, also named cascaded or multi-stage, has been presented and on the other hand, an experimental evaluation of the advantages of using the multiple PCM configuration instead of the single PCM configuration in thermal energy storage (TES) systems at pilot plant to fill the gap of experimental and high scales studies on this concept in the literature. Two PCM with melting temperatures in a temperature range of 150 e200 C were selected due to their high value of heat of fusion and compared: d-mannitol and hydroquinone. Three configurations were evaluated: (1) single PCM with hydroquinone, (2) single PCM with dmannitol and (3) multiple PCM with hydroquinone and d-mannitol. A discussion regarding the results on the specific energy stored and effectiveness as well as the evolution of the PCM and heat transfer fluid (HTF) through the time and at different and representative locations of the facility is presented. Results showed that the multiple PCMs configuration introduced an effectiveness enhancement of 19.36% if compared with single PCM configuration as well as a higher uniformity on the HTF temperature difference between the inlet and outlet. ; The work is partially funded by the Spanish Government (ENE2011-22722 and ULLE10-4E-1305). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2014 SGR 123). The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n PIRSES-GA-2013-610692 (INNOSTORAGE). Laia Miro would like to thank the Spanish Government for her research fellowship (BES-2012-051861).

Among all thermochemical materials for thermal energy storage salt hydrates seem to be the most promising ones. Salt hydrates present the highest energy densities, but their main drawback is their bad compatibility with some container materials, such as metals. To control the corrosion effect it is necessary to perform and evaluate experimental tests. The main goal of this paper is to show experimental results of corrosion test between the most used salt hydrates for thermochemical energy storage and the most common vessel metals. ; The research leading to these results has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under grant agreement No ENER/FP7/295983 (MERITS). Aran Solé would like to thank the Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for her research fellowship. Laia Miró would like to thank the Spanish Government for her training researcher personal fellowship (BES-2012-051861).The work is partially funded by the Spanish government (ENE2011-28269-C03-02 and ENE2011-22722). The authors would like to thank the Catalan Government for the quality accreditation given to their research groups GREA (2009 SGR 534) and research group DIOPMA (2009 SGR 645).

The selection of a proper heat transfer fluid (HTF) is a key factor to increase the efficiency of concentrated solar power plants and therefore, to reduce their internal associated CAPEX (capital expenditures of developing and constructing a plant, excluding any grid-connection charges) and OPEX (operating expenditures from the first year of a project's operation). This paper presents a comparative study of two commercial HTF which are widely used in different industries and CSP plants: thermal oil Therminol VP-1 and silicone fluid Syltherm 800. First, the authors theoretically studied the properties of both HTF based on the data given by the manufactures. Afterwards, the authors experimentally perform the comparison in a two-tank molten salt thermal energy storage pilot plant built at the University of Lleida (Spain). The study is focused on the plate heat exchanger of the facility during several charging processes with a counter flow arrangement. Results from both studies showed that, for the same working conditions, Therminol VP-1 is the best candidate for the above-mentioned purposes due to its higher heat transfer, lower thermal losses and lower power consumption associated to the HTF pump. However, it presents problems a low crystallization point, which should also be considered. ; The research leading to these results has received funding from Spanish goverment (Fondo tecnológico IDI-20090393, ConSOLida CENIT 2008-1005) and from Abengoa Solar NT. The work is partially funded by the Spanish government (ENE2008-06687-C02-01/CON, ENE2011-22722, ULLE10-4E-1305 and 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 GREA (2014 SGR 123). This project has also received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant agreement NºPIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union's Horizon 2020 research and innovation programme under grant agreement No 657466 (INPATH-TES). Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861). Jaume Gasia would like to thank the Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for his research fellowship (2017FI_B1 00092). The authors would like to thank Dr. Eduard Oró from Catalonia Institute for Energy Research (Spain) and Dr. Antoni Gil from Massachusetts Institute of Technology (USA) for their help during the initial stages of the experimentation.

Despite the fact that there are some commercial concentrated solar power plants worldwide, there is currently a lack of experimental reports about the operational characteristics of this type of plants. Therefore, a two-tank molten salts thermal energy storage (TES) pilot plant at the University of Lleida (Spain) was used to analyze charging and discharging processes under real conditions. In this facility, 1000 kg of molten salts are used as TES material and Therminol VP-1 is used as heat transfer fluid (HTF). This facility is equipped with measurement equipment which allows an exhaustive analysis of the processes. In this study, the fact of varying the flow arrangement in the heat exchanger (parallel and counter flow arrangements) and the temperature difference between the molten salts and the HTF have been studied and discussed in terms of temperature profiles, energy and power stored/released from/to both HTF and molten salts, efficiencies and effectiveness. The best working conditions found were counter flow arrangement with a temperature grading of about 65 °C. ; The research leading to these results has received funding from Spanish government (Fondo tecnológico IDI-20090393, ConSOLida CENIT 2008-1005) and from Abengoa Solar NT. The work is partially funded by the Spanish government (ENE2008-06687-C02-01/CON, ENE2011-28269-C03-02, ENE2011-22722 and ULLE10-4E-1305). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2014 SGR 123). This project has also received funding from the European Commission Seventh Framework Programme (FP/2007-2013) 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). Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861). Jaume Gasia would like to thank the Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for his research fellowship (2016FI_B 00047).

From the literature review it was observed that there is no established methodology, neither a common pattern, when selecting a phase change material for a thermal energy storage application. Melting temperature and enthalpy have traditionally been the considered thermal properties for the material selection. Therefore, the authors of this paper propose a new method of investigation on the suitability of a PCM that takes into account not only thermal properties but also health hazard and both cycling and thermal stability. Health hazard is related with the handling of the material, and both cycling and thermal stabilities with durability. This methodology is applied to five different PCM in the 150–200 °C range: salicylic acid, benzanilide, d-mannitol, hydroquinone, and potassium thiocyanate. Results show that for an application in the 150–200 °C range the suitable PCM are benzanilide and d-mannitol. Moreover, hydroquinone is also suitable but only in closed systems. ; The research leading to these results has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) 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 (ENE2011-22722). The authors would also like to thank the Catalan Government for the quality accreditation given to their research group GREA (2014 SGR 123). Aran Solé would like to thank the Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for her research fellowship. Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861).

The thermal behavior of a commercial paraffin with a melting temperature of 58 ºC is analyzed as a phase change material (PCM) candidate for industrial waste heat recovery and domestic hot water applications. A full and complete characterization of this PCM is performed based on two different approaches: a laboratory characterization (mass range of milligrams) and an analysis in a pilot plant (mass range of kilograms). In the laboratory characterization, its thermal and cycling stability, its health hazard as well as its phase change thermal range, enthalpy and specific heat are analyzed using a differential scanning calorimeter, thermogravimetric analysis, thermocycling and infrared spectroscopy. Laboratory analyses showed its suitability up to 80 ºC and for 1200 cycles. In the pilot plant analysis, its thermal behavior was analyzed in a shell-and-tube heat exchanger under different heat transfer fluid mass flow rates in terms of temperature, power and energy rates. Results from the pilot plant analysis allowed understanding the different methods of heat transfer in real charging and discharging processes as well as the influence of the geometry of the tank on the energy transferred and required time for charging and discharging processes. ; The work is partially funded by the Spanish government (ULLE10-4E-1305, ENE2015- 64117-C5-1-R and ENE2015-64117-C5-3-R). This project has received funding from the European Commission Seventh Framework Programme (FP/2007–2013) under Grant agreement N PIRSES-GA-2013-610692 (INNOSTORAGE) and No ENER/FP7/295983 (MERITS), and from the European Union's Horizon 2020 Research and Innovation Programme under Grant agreement No 657466 (INPATH-TES). The authors would like to thank the Catalan Government for the quality accreditation given to their research groups GREA (2014 SGR 123) and DIOPMA (2014 SGR 1543). Jaume Gasia would like to thank the Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for his research fellowship (2016FI_B 00047). Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861). Alvaro de Gracia and Camila Barreneche would like to thank the Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940 and FJCI-2014-22886, respectively.

Renewable energies are main players to ensure the long-term energy supply. Solar power plants with thermal energy storage (TES) are one of the available renewable technologies which have more potential. Nowadays, there are still several aspects in the design and operation of these power plants which need to be improved, such as the correct operation of some specific instrumentation, the compatibility between TES materials and storage tanks materials, and operational process strategies. This paper presents the acquired experience during the design, start-up, and operation of a kWh scale pilot experimental facility built at the University of Lleida (Spain) together with Abengoa Research (Spain) in 2008. The versatility of this facility has allowed simulating real working conditions and therefore testing different TES systems, TES materials, solar power plant components, and operational strategies focused on TES for temperatures up to 400 °C. In the present paper, the authors show the lessons learnt at pilot and present the main problems and limitations encountered, and give advices of this experimental set-up to extrapolate the data to real plant, to provide solutions to technical problems and reduce the cost of commercial plants. ; The authors want to thank specially to Dr. Eduard Oró (today at Institut de Recerca d'Energies de Catalunya, Spain) and Dr. Antoni Gil (today at Massachusetts Institute of Technology, USA) for their help in the design, start-up and operation of the pilot plant facility. The research leading to these results has received funding from Spanish government through CDTI granted projects (Fondo tecnológico IDI-20090393, ConSOLida CENIT 2008-1005) and from Abengoa Solar NT. The work is partially funded by the Spanish government (ENE2008-06687-C02-01/CON, ENE2011-22722, ULLE10-4E-1305, and 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 GREA (2014 SGR 123). GREA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. This project has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant agreement NºPIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union's Horizon 2020 research and innovation programme under grant agreement No 657466 (INPATH-TES). Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861). Jaume Gasia would like to thank the Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for his research fellowship (2017FI_B1 00092).

Phase change materials (PCM) can provide high thermal energy storage capacities in narrow temperature ranges around their phase change temperature. The expectable maximum storage capacity of a PCM in a defined temperature range is equal to the enthalpy change in that range and can be determined via calorimetric measurements such as differential scanning calorimetry (DSC) or T-History calorimetry. T-History samples (aprox. 15 ml) are about 1000 times larger than DSC samples (aprox. 15 ml). Experiments in a pilot plant are performed to study the charging and discharging behaviour of even larger amounts of the PCM (aprox. 150 l). The common practise is to investigate PCM at one scale, rarely at two scales. In this work, the characterisation was carried out at three scales (DSC, T-History, and pilot plant) for four PCM (RT58, bischofite, D-mannitol, and hydroquinone). Thereby, the question arises how the enthalpy changes measured at different scales and under different conditions can be compared. In literature, the melting enthalpy is usually assigned to a single temperature without indicating the temperature range considered for evaluation. In very few instances, the enthalpy change within a defined temperature range is stated. In both cases, results measured under different conditions are difficult to compare. In this work, it is demonstrated that enthalpy-temperature plots facilitate the comparison and interpretation of measurements obtained under different experimental methods at different sample scales. ; The work of ZAE Bayern was part of the project EnFoVerM and was supported by the German Federal Ministry for Economic Affairs and Energy under the project code 0327851D. The work at the University of Lleida is partially funded by the Spanish government (ENE2011-22722, ENE2015-64117-C5-1-R (MINECO/FEDER) and ULLE10-4E-1305). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2014 SGR 123). GREA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) 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 authors want also to thank the collaboration of Antoni Gil from Massachusetts Institute of Technology (USA), Eduard Oró from Catalonia Institute for Energy Research (Spain), and Jaume Gasia and Gerard Peiró from University of Lleida (Spain). Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861). The work of the University of Antofagasta was supported by FONDAP SERC-Chile (grant N° 15110019), and the Education Ministry of Chile Grant PMI ANT 1201. Authors thank the SALMAG Company for providing of bischofite. Andrea Gutierrez would like to acknowledge to the Ministry of Education of Chile her doctorate scholarship ANT 1106 and CONICYT/PAI N° 7813110010.