Suchergebnisse

Thermal energy storage systems work in conjunction with solar technologies with the aim of increasing their dispatchability and competitiveness in the energy market. Among others, latent heat thermal energy storage systems have become an appealing research subject and many efforts have therefore been invested in selecting the best phase change material (PCM) to fit the final application. In this study, an extended corrosion characterization was performed for two PCM candidates, solar salt (40 wt.% KNO3/60 wt.% NaNO3) and myo-inositol (C6H12O6), to be applied in Fresnel solar plants. Corrosion rates were determined in aluminium, stainless steel (AISI 304), carbon steel (AISI 1090), and copper by gravimetric tests, gauging the weight loss after 2000 h of immersion at 250 ºC. The corrosion products were characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD). The corrosion tests carried out with myo-inositol did not show accurate enough results to draw conclusions regarding corrosion on the metals. However, it was observed that this sugar alcohol strongly sticks to the metal specimens, making myo-inositol extremely difficult to manage as an energy storage material. Therefore, the present paper discourages the use of myo-inositol as a PCM beyond its corrosion rate. ; Funding: The research received funding from Spanish government (MINECO/FEDER), grant number ENE2015-64117-C5-1-R. This work was partially funded by the European Union´s Horizon 2020 Research & Innovation Programme under Grant Agreement 723596 with reference name Innova MicroSolar. José Miguel Maldonado received funding from the Spanish Government for his research fellowship, grant number BES-2016-076554. Ángel G. Fernández has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement 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. 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 systematic review presents and discusses the previous research about hybrid devices which combine latent thermal energy storage (TES) technology and heat pipes. A bibliometric analysis of this issue shows how hybrid systems have globally grown popularity during time, providing details about the main researchers and research centres on this particular field. Then, the identified papers are assessed and categorized in two main sections, the experimental research carried out, and the numerical modelling of hybrid systems. Experimental research is later classified regarding the operating temperature range, and their final application. Numerical studies are also further categorized, accordingly to how heat pipes were modelled in this case. This review points out the lack of experimental studies at high temperatures, especially when many simulations extended their models (validated at low temperatures) to higher temperature designs. The paper provides details about the research performed, so the gap for future investigations can be spotted. ; This work was partially funded by the European Union's Horizon 2020 Research & Innovation Programme under Grant Agreement 723596 with reference name Innova MicroSolar. 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 Agencia Estatal de Investigación (AEI), of the Ministerio de Ciencia, Innovación y Universidades (RED2018-102431-T). José Miguel Maldonado would like to thank the Spanish Government for his research fellowship (BES-2016-076554). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). GREiA is a certified TECNIO agent in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme.

This paper experimentally evaluates the implementation of heat pipes in latent heat thermal energy storage systems. The well-known performance of heat pipes as a heat transfer technology makes them great candidates to be used as heat exchangers. However, previous studies compared their efficacy against solid metal rods, where heat pipes clearly succeeded. Therefore, the objective of this study is to experimentally evaluate the advantages of using heat pipes instead of a common shell and tubes system, during charging processes. In particular, five latent heat thermal energy storage systems were tested. One based on the shell and tubes, and the remaining four based on heat pipes. The experiments were conducted at constant heat transfer fluid temperature and flow rate, and the results were analysed from the temperature, heat transfer, and visual point of view. The results show that in heat pipes systems the phase change material melts homogeneously through all the storage container. However, the shell and tubes tank performed the charging process in 25 min while the fastest heat pipe one took 40 min for it. On the other hand, in the shell and tubes configuration melt from the heat transfer fluid inlet towards the outlet. Moreover, systems with more heat pipe surface inside the heat transfer fluid collector rovided higher power rates. Comparing the best and the worst heat pipe storage tanks during the first 30 min, the heat transfer rate increased over 40%. But the storing material low conductivity cushioned those high heat transfer rates. ; 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 Agencia Estatal de Investigación (AEI), of the Ministerio de Ciencia, Innovación y Universidades (RED2018-102431-T). José Miguel Maldonado would like to thank the Spanish Government for his research fellowship (BES-2016-076554). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). GREiA is a certified TECNIO agent in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme.

This paper experimentally studies and compares the addition of fins and the addition of metal wool in a latent heat thermal energy storage (TES) system as heat transfer enhancement techniques. Despite the well-known suitability of fins as enhancement technique, their implementation cost in the TES system is one of its main drawbacks. Therefore, the objective of this study is to evaluate the potential of adding a cheap and commercially available metallic wool in order to overcome the abovementioned drawback. In particular, four different latent heat TES systems based on the shell-and-tube heat exchanger concept were designed using n-octadecane as phase change material (PCM). One of them was used as a reference, while in the remaining configurations the heat transfer surface was increased by means of seventeen rectangular fins and by means of metallic wool arbitrarily distributed within the PCM and compacted in a finned shape. Charging and discharging processes with constant heat transfer fluid temperature and flow rate were evaluated from the temperature and heat transfer points of view. Results were focused on the metal wool because is a cheap and handmade solution which can be implemented in an already made heat exchanger. The addition of metal wool showed an enhancement, during the charge, higher than 10% when it was arbitrarily distributed, while compacting the metal wool in a finned shape showed practically no improvement. During the discharge, both metal wool configurations allowed minimal improvements. ; The work was partially funded by the 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 (2017 SGR 1537). GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. 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 (2018 FI_B2 00100). José Miguel Maldonado would like to thank the Spanish Government for his research fellowship (BES-2016-076554). Francesco Galati would like to thank the Erasmus+ Programme: Traineeship Bet for Jobs for his research fellowship.

In Europe the building sector represents 41% of the final energy consumption and the 40% of the total GHG emissions of end-use sectors (Directive 2010/31/EU) [1]. Solar energy is one of the forms of renewable energy that has great potential to enable EU the ambition of 12% of heating coming from renewable sources by 2020 [2]. Within this context, the overall objective of the project Innovative Micro Solar Heat and Power System (Innova MicroSolar) is to develop a high performance and cost effective solar heat and power system, which consist in a novel flat Fresnel mirror solar concentrating collector and micro organic Rankine cycle plant combined with advanced phase change materials as thermal storage, all system managed by smart control units. This technology will be initially implemented in individual dwellings and small business residential buildings for on-site electricity and heat generation using solar thermal energy. ; This study has received funding from European Union's Horizon 2020 research and innovation programme under grant agreement Nº723596 (Innova MicroSolar) and Nº 657466 (INPATHTES), from the European Commission Seventh Framework Programme (FP/2007-2013) under grant agreement Nº PIRSES-GA-2013-610692 (INNOSTORAGE). The work is partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER) and ENE2015- 64117-C5-3-R (MINECO/FEDER)). GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940.

Rapid expansion of solar thermal energy for increasing energy efficiency of buildings has been adopted in short/medium and long-term energy strategies of EU countries. This enhancement of energy efficiency in buildings is in line with regional actions with the European climate energy objectives as defined in the European Union's "20-20-20" targets and in the European Commission's Energy Roadmap 2050. Within this context, the overall objective of this work is to develop an innovative high performance and cost effective hybrid solar heat and power system, which consist in a novel flat Fresnel mirror solar concentrating collector and micro organic Rankine cycle plant combined with advanced phase change materials as thermal storage, all system managed by smart control units. The initial application is to be implemented in individual dwellings and small business residential buildings for on-site electricity and heat generation using solar thermal energy. It is estimated that the proposed technology will deliver 60% of domestic energy requirements and provide 20% reduction in energy costs and greenhouse gas emissions compared to the best existing low carbon energy technologies. To reach the main objectives, the first step consist in providing information on features of architecture of domestic and small business residential buildings and their annual energy demands for different countries such as: Spain, France Germany, Italy, and United Kingdom. This will include detailed building information of envelopes (walls, roof, lofts, etc.), structure, fabric, and results of energy demands (domestic hot water, space heating and electricity) for the abovementioned countries. This information will be used as input data during the development of this technology as it will point out the potential benefits of the system in different countries, climates, and building typologies. ; This study has received funding from European Union's Horizon 2020 research and innovation programme under grant agreement Nº723596 (Innova MicroSolar) and Nº 657466 (INPATH-TES), from the European Commission Seventh Framework Programme (FP/2007-2013) under grant agreement Nº PIRSES-GA-2013-610692 (INNOSTORAGE). The work is partially funded by the Spanish government ENE2015- 64117-C5-1-R (MINECO/FEDER), ENE2015-64117-C5-3-R (MINECO/FEDER) and (ULLE10-4E-1305). GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940.

Solar thermal energy has been adopted in medium and long‐term energy strategies within EU countries for increasing the energy efficiency of buildings. In this context, the overall objective of this project consists in developing an innovative high performance and cost effective hybrid system (solar heat and electrical power). The initial application is to be implemented in residential buildings for on‐site electricity and heat generation using solar thermal energy. The proposed technology is expected to deliver 60% of domestic energy requirements (heating and domestic hot water) and provide 20% reduction in energy costs and greenhouse gas emissions compared to the best existing low carbon energy technologies. A benchmark on the energy demand for the different types of residential buildings in Europe serves as reference scenario to evaluate the potential applicability of the different existing renewable technologies and to establish a comparative framework in terms of quantitative values. Thus, the specific aim of this study consists in performing a state‐of‐the‐art on the different building typologies, which can host this technology, and their energy demands for heating and domestic hot water, as well as their associated CO2 emissions. ; This study has received funding from European Union's Horizon 2020 research and innovation programme under grant agreement Nº723596 (Innova MicroSolar) and Nº 657466 (INPATH‐TES). The work is partially funded by the Spanish government ENE2015‐64117‐ C5‐1‐R (MINECO/FEDER) and ENE2015‐64117‐C5‐3‐R (MINECO/FEDER). GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). Alvaro de Gracia would like to thank Ministerio de Economía y Competitividad de España for Grant Juan de la Cierva, FJCI‐2014‐19940.

The building sector accounts for one third of the global energy consumption and it is expected to grow in the next decades. This evidence leads researchers, engineers and architects to develop innovative technologies based on renewable energies and to enhance the thermal performance of building envelopes. In this context, the potential applicability and further energy performance analysis of these technologies when implemented into different building typologies and climate conditions are not easily comparable. Although massive information is available in data sources, the lack of standardized methods for data gathering and the non-public availability makes the comparative analyses more diffcult. These facts limit the benchmarking of different building energy demand parameters such as space heating, cooling, air conditioning, domestic hot water, lighting and electric appliances. Therefore, the first objective of this study consists in providing a review about the common typologies of residential buildings in Europe from the main data sources. This study contains specific details on their architecture, building envelope, floor space and insulation properties. The second objective consists in performing a cross-country comparison in terms of energy demand for the applications with higher energy requirements in the residential building sector (heating and domestic hot water), as well as their related CO2 emissions. The approach of this comparative analysis is based on the residential building typology developed in TABULA/EPISCOPE projects. This comparative study provides a reference scenario in terms of energy demand and CO2 emissions for residential buildings and allows to evaluate the potential implementation of new supply energy technologies in hot, temperate and cold climate regions. From this study it was also concluded that there is a necessity of a free access database which could gather and classify reliable energy data in buildings. ; This study has received funding from European Union's Horizon 2020 research and innovation programme under grant agreement Nº723596 (Innova MicroSolar). The work is partially funded by the Spanish government (RTI2018-093849-B-C31). Julià Coma would like to thank Ministerio de Economía y Competitividad de España for Grant Juan de la Cierva, FJCI-2016-30345. José Miguel Maldonado would like to thank the Spanish Government for his research fellowship (BES-2016-076554). This work is partially supported by ICREA under the ICREA Academia programme.

Rapid expansion of solar thermal energy for increasing energy efficiency of buildings has been adopted in short/medium and long-term energy strategies of EU countries. Within this context, the overall objective of this work is to develop an innovative high performance and cost effective hybrid solar heat and power system. The initial application is to be implemented in individual dwellings and small business residential buildings for onsite electricity and heat generation using solar thermal energy. It is estimated that the proposed technology will deliver 60% of domestic energy requirements and provide 20% reduction in energy costs and greenhouse gas emissions compared to the best existing low carbon energy technologies. The aim of this study consists in performing a comparative analysis of the different building typologies, which can host this technology, and their energy demands for heating and domestic hot water, as well as their CO2 emissions. ; This study has received funding from Eurepean Union's Horizon 2020 research and innovation programme under grant agreement Nº 723596 (Innova MicroSolar) and Nº 657466 (INPATH-TES). The work is partially funded by the Sapnish government ENE2015-64117-C5-1-R (MINECO/FEDER) and ENE2015-64117-C5-3-R (MINECO/FEDER). GREA is certified agent TECNIO in the cathegory of technology developers from the Government of Catalonia. The authors would like to thanks the Calatan Governmnet for the quality accreditation given to their research group (2014 SGR 123). Alvaro de Gracia would like to thanks Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940.

The improvement of thermal energy storage systems implemented in solar technologies increases not only their performance but also their dispatchability and competitiveness in the energy market. Latent heat thermal energy storage systems are one of those storing methods. Therefore, the need of finding the best materials for each application becomes an appealing research subject. The main goal of this paper is to find suitable and economically viable materials able to work as phase change material (PCM) within the temperature range of 210-270 ºC and endure daily loading and unloading processes in a system with Fresnel collector and an organic Rankine cycle (ORC). Twenty-six materials have been tested and characterized in terms of their thermophysical conditions, thermal and cycling stability, and health hazard. Two materials out of the 26 candidates achieved the last stage of the selection process. However, one of the two finalists would require an inert working atmosphere, which would highly increase the cost for the real scale application. This leads to a unique suitable material, solar salt (40 wt % KNO3/60 wt % NaNO3). ; This work was partially funded by the European Union's Horizon 2020 Research & Innovation Programme under Grant Agreement 723596 with reference name Innova MicroSolar. This work was partially funded by the Ministerio de Economía y Competitividad de España (ENE2015-64117-C5-1-R (MINECO/FEDER) and ENE2015-64117-C5-3-R (MINECO/FEDER)). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. José Miguel Maldonado would like to thank the Spanish Government for his research fellowship (BES-2016-076554). Aran Solé would like to thank Ministerio de Economía y Competitividad de España for Grant Juan de la Cierva, FJCI-2015-25741. Alvaro de Gracia has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 712949. Angel G. Fernández would like to acknowledge the financial support provided by GIZ "Programa de pasantía en el extranjero en tecnologías de concentración solar para investigadores" and CONICYT/FONDAP 15110019 "Solar Energy Research Center" SERC-Chile.

To preserve food nutrients, texture, and taste, as well as to prevent its putrefaction, food is frozen and kept at around −20 °C. Refrigerators and freezers are highly energy demand systems which can suf- fer a considerable decrease in operational efficiency due to frost growth on the evaporator. Defrost pro- cesses are launched periodically to avoid the frost built-up, consuming a relevant part of the total energy demand. To control the defrost launching and to improve the energy performance of the refrigeration system an accurate measurement of the frost level is required. Many frost detecting methods are expen- sive, not feasible due to their size, or simply they cannot measure the frost stacking precisely enough to swerve mal-defrost phenomena. This study provides an accurate parameter to indirectly estimate the frost layer built-up on the evaporator. The new parameter called thermal variation easiness (TVE) was experimentally tested and validated by comparison with another frost leveling method, T method, on a walk-in freezer unit. Then the TVE was successfully tested on a multi-cold room refrigeration system, proving its applicability on both walk-in freezers run by remote condensing units and multiple cold rooms fed by a rack of compressors. The novelty of this parameter lays on its capacity to work on refrigeration facilities which are used to feed several walk-in fridges and refrigerated displays in big installations, such as supermarkets. ; This work was partially funded by the Spanish government through CDTI project with reference code IDI-20160143. José Miguel Maldonado would like to thank the Spanish Government for his research fellowship (BES-2016-076554). The project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 712949 (TECNIOspring PLUS) and from the Agency for Business Competitiveness of the Government of Catalonia. Pere Moreno would like to thank Ministerio de Economía y Competitividad de España for Grant Torres Quevedo, PTQ-15-08025. GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). This work is partially supported by ICREA under the ICREA Academia programme.

Heat removal is the most extended method for food preservation in food manufacturing industry by lowering food temperatures to stop microorganisms growing, which might spoil the product and could cause toxicity. Therefore, walk-in freezers are used for that purpose consuming a relevant part of the energy on service sector. The compression refrigeration system of the walk-in freezers can be blocked by the frost accumulated on the evaporator. For that reason a defrost process, which requires an important part of the energy consumption, has to be launched from time to time. In this paper, the schedule which manages the defrost process is investigated to limit its activation only when it is necessary. Moreover, different fan operation strategies were tested regarding the energy efficiency of the whole refrigeration system. This study has provided a system control strategy both for defrost and fans operation, depending on the frost built up on the evaporator. The control improves the energy performance of the whole refrigeration system. ; This work was partially funded by the Spanish government through CDTI project with reference code IDI-20160143. Alvaro de Gracia would like to thank Ministerio de Economía y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940. Pere Moreno would like to thank Ministerio de Economia y Competitividad de España for Grant Torres Quevedo, PTQ-15-08025. 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.

Solar energy is widely considered as one of the most attractive renewable energy source to curb CO2 emissions at residential level where micro-cogeneration has a very interesting potential. One promising application of solar energy is in combination with Organic Rankine Cycle (ORC) plants due to the ability to utilize low-medium temperature heat sources. However, because of the intermittent availability of solar energy, thermal energy storage (TES) systems are required to improve the performance of such systems and assure their prolonged operation. At medium temperatures, latent heat thermal energy storage (LHTES) systems allow to effectively store and release the collected thermal energy from the solar field. However, room for improvements exists to increase their efficiency when in operation. For this reason, in this work the authors have numerically investigated the performance of a 2 kWe micro-solar ORC plant coupled with an innovative LHTES system that is going to be built and tested under the EU funded project Innova MicroSolar. The novel LHTES, developed and designed by some partners of the Consortium, is subdivided into six modules and consists of 3.8 tons of high-temperature phase change material. In this study the effect of the storage volume partialization on the performance of the integrated plant is evaluated using a fuzzy logic approach. Main aim of the storage management is to achieve a reduction of the thermal losses and improve the plant overall efficiency. Annual dynamic simulations are performed in order to determine the optimal storage volume needed in different operating conditions. Results clearly show a remarkable annual increase in electric and thermal energy production of 8 % and 6 % respectively, in comparison with the configuration without fuzzy logic control: this achievement was obtained decreasing the working LHTES modules in winter and conversely increasing them in summer. ; This study is a part of the Innova MicroSolar Project, funded in the framework of the European Union's Horizon 2020 Research and Innovation Programme (grant agreement No 723596).

In this paper, the smart management of buildings energy use by means of an innovative renewable micro-cogeneration system is investigated. The system consists of a concentrated linear Fresnel reflectors solar field coupled with a phase change material thermal energy storage tank and a 2 kWe/18 kWth organic Rankine cycle (ORC) system. The microsolar ORC was designed to supply both electricity and thermal energy demand to residential dwellings to reduce their primary energy use. In this analysis, the achievable energy and operational cost savings through the proposed plant with respect to traditional technologies (i.e., condensing boilers and electricity grid) were assessed by means of simulations. The influence of the climate and latitude of the installation was taken into account to assess the performance and the potential of such system across Europe and specifically in Spain, Italy, France, Germany, U.K., and Sweden. Results show that the proposed plant can satisfy about 80% of the overall energy demand of a 100 m2 dwelling in southern Europe, while the energy demand coverage drops to 34% in the worst scenario in northern Europe. The corresponding operational cost savings amount to 87% for a dwelling in the south and at 33% for one in the north. ; This research was funded by European Union's Horizon 2020 Research and Innovation Programme, grant number 723596. The APC was waived for this invited paper

Reducing the energy consumption in the building sector, as well as its associated CO2 emissions, is one of the main environmental concerns at worldwide level. In developed countries, the building sector means 41% of the total energy consumption and 40% of the total greenhouse gases emissions. To improve the energy efficiency of residential buildings, several energy strategies were carried out in European countries to encourage the development of active energy saving systems; such as the solar thermal energy. The presented study is in the frame of the Innova MicroSolar European project, which is sponsored by the European Union's Horizon 2020 research and innovation programme. The main goal of this project is to develop an innovative concentrated solar heat and power system for residential buildings, which supplies 2-kWelec and 18-kWth. This technology includes a concentrated solar system, a high performance micro organic Rankine cycle (ORC) turbine, and an enhanced latent heat thermal energy storage (LHTES). The solar system is based on linear Fresnel mirrors which are considerably easier and cheaper to manufacture than their parabolic equals. Also, the mirrors are led by a sun tracking mechanism so they are always focusing the absorber tubes, heating up to 295ºC the heat transfer fluid (HTF) flow. The total area of the real scale prototype solar field is 140 square metres, which could provide from 80 to 15 kWth. The micro ORC technology is equipped with a high speed permanent magnet AC alternator able to supply 2.3 kWel. The ORC block has to be fed with 22 kWth. Finally, the TES tank consists of two main blocks, the PCM tank and the enhanced heat sink. Both blocks are connected between them by reversible heat pipes as heat carrier. The storage is designed to supply 25 kWth during four working hours. The whole system will supply 60% of the total building energy demand, reducing the energy cost up to 20%, as well as the greenhouse gases emissions when comparing against the best renewable energy technologies available on the market. This study shows the first experiments of the whole systems. The HTF (Therminol 62) is heated up to 270ºC with the solar field, then the HTF is lead to the ORC evaporator and the organic fluid (cyclopenthane) evaporates and runs the turbine. The TES tank is charged when the solar field reaches maximum power levels. Once the solar production cannot run the ORC, the solar field is bypassed and the TES tank successfully becomes the main energy supplier. ; The research leading to these results has received funding from the European Union´s Horizon 2020 Research & Innovation Programme under Grant Agreement 723596 with reference name Innova MicroSolar. This work was partially funded by Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER)). José Miguel Maldonado would like to thank the Spanish Government for his research fellowship (BES-2016-076554). Alvaro de Gracia has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 712949 (TECNIOspring PLUS) and from the Agency for Business Competitiveness of the Government of Catalonia. 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.