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The incorporation of recycled materials in concrete as a partial replacement of cement is becoming an alternative strategy for decreasing energy-intensive and CO2 emissions imputable to the cement manufacture, while investigating new potential uses of such multifunctional materials for environmental sustainability opportunities. Therefore, low-cost and worldwide availability of by-products materials is being assessed for sensible heat thermal energy storage applications based on cementitious materials. A greater concern is especially required focusing on the thermal stability of cement paste under high temperature cycled conditions. Moreover, compatibility between cement type and supplementary cementitious materials is determinant for the proper performance reliability. In this study, benchmark cement types were selected, i.e., ordinary Portland and calcium aluminate. Six supplementary cementitious materials were added to both types of cement in a content of 10 % and 25 %. Thermo-mechanical properties were studied before and after 10 thermal cycles from 290 to 650 ◦C. Results after thermal cycling showed that calcium aluminate cement paste mixtures maintained their integrity. However, most ordinary Portland cement paste mixtures were deteriorated: only mixtures with 25 % cement replacement with chamotte, flay ash, and ground granulated blast furnace slag remained without cracks. Calcium aluminate cement paste mixtures obtained the highest compressive strength, for partial replacement of cement with 10 % of chamotte, ground granulated blast furnace slag, and iron silicate. The incorporation of supplementary cementitious materials did not increase the thermal conductivity. 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). The authors at University of Lleida 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 and by the Italian project ‘SOS-CITTA’ supported by Fondazione Cassa di Risparmio di Perugia under grant agreement No 2018.0499.026. Laura Boquera acknowledgments are due to the PhD school in Energy and Sustainable Development from University of Perugia. Laura Boquera would like to acknowledge the financial support provided by UNIPG – CIRIAF InpathTES project. The authors also thank the companies that provided the material to make possible this experimental research: Arciresa, Abrasivos Mendiola EDERSA—Masaveu Industria, General Admixtures S.p.A, Mapei, Ciments Molins industrial, and Promsa for the material supplied in this research. Financial support of the UNIPG-CIRIAF team has been achieved from the Italian Ministry of University and Research (MUR) in the framework of the Project FISR 2019: “Eco Earth” (code 00245) and it is gratefully acknowledged.

Abstract This review summarizes and organizes the literature on life cycle assessment (LCA), life cycle energy analysis (LCEA) and life cycle cost analysis (LCCA) studies carried out for environmental evaluation of buildings and building related industry and sector (including construction products, construction systems, buildings, and civil engineering constructions). The review shows that most LCA and LCEA are carried out in what is shown as “exemplary buildings”, that is, buildings that have been designed and constructed as low energy buildings, but there are very few studies on “traditional buildings”, that is, buildings such as those mostly found in our cities. Similarly, most studies are carried out in urban areas, while rural areas are not well represented in the literature. Finally, studies are not equally distributed around the world.

The main objective of this paper is to study the possible use of D-mannitol as phase change material (PCM) for thermal energy storage. PCM are materials that have high phase change enthalpy and this thermophysical property gives them the ability to store energy as latent heat. D-mannitol is a material which has different morphological phases (polymorphism); here were studied b-form and d-form. Different polymorphic forms produce changes on melting point of D-mannitol. For this reason it is necessary to establish a suitable working temperature range for the use of D-mannitol as phase change material. The thermal characterization was performed with DSC analysis using 0.5 K min-1 slow-dynamic method. Polymorphism analysis of D-mannitol was analyzed to associate the thermal behavior obtained by DSC with a specific polymorphic phase. D-mannitol presented three different thermal behaviors: the first one had a melting peak at 167 oC, the second was a double melting peak at 155 oC and 166 oC, and the third a single peak at 155 oC. Due to irregular results, two working range were studied and through the thermal characterization, it was possible to define a working range where Dmannitol could be used as PCM for energy storage: this range is between 135 and 175 oC. Furthermore, it was possible to differentiate two crystalline phases of D-mannitol applying FT-IR analysis and to link them with thermal behavior observed in DSC. The percentage of times each thermal behavior is observed in DSC analysis was calculated. d-form is obtained 15.8% of analyzed cycles, the b-form appears 44.7% of times, and an intermediate transition between the two phases is found 39.5% of cycles.

Fuel moisture limits the availability of fuel to wildfires in many forest areas worldwide, but the effects of climate change on moisture constraints remain largely unknown. Here we addressed how climate affects fuel moisture in pine stands from Catalonia, NE Spain, and the potential effects of increasing climate aridity on burned area in the Pyrenees, a mesic mountainous area where fire is currently rare. We first quantified variation in fuel moisture in six sites distributed across an altitudinal gradient where the long-term mean annual temperature and precipitation vary by 6-15 °C and 395-933 mm, respectively. We observed significant spatial variation in live (78-162%) and dead (10-15%) fuel moisture across sites. The pattern of variation was negatively linked (r = |0.6|-|0.9|) to increases in vapor pressure deficit (VPD) and in the Aridity Index. Using seasonal fire records over 2006-2020, we observed that summer burned area in the Mediterranean forests of Northeast Spain and Southern France was strongly dependent on VPD (r = 0.93), the major driver (and predictor) of dead fuel moisture content (DFMC) at our sites. Based on the difference between VPD thresholds associated with large wildfire seasons in the Mediterranean (3.6 kPa) and the maximum VPD observed in surrounding Pyrenean mountains (3.1 kPa), we quantified the "safety margin" for Pyrenean forests (difference between actual VPD and that associated with large wildfires) at 0.5 kPa. The effects of live fuel moisture content (LFMC) on burned area were not significant under current conditions, a situation that may change with projected increases in climate aridity. Overall, our results indicate that DFMC in currently fire-free areas in Europe, like the Pyrenees, with vast amounts of fuel in many forest stands, may reach critical dryness thresholds beyond the safety margin and experience large wildfires after only mild increases in VPD, although LFMC can modulate the response.

Abstract In order to obtain data on the behaviour of green facades in buildings as a passive system for energy savings in dry Mediterranean Continental climate a long-term work has been performed. This paper presents the first results of two actions developed during 2009. First, the growth of four different climbing plants as well as their ability to provide shadow was studied. Second, monitoring for a year of a real green facade was carried out. The results confirmed the great capacity of green facades to produce shade, reducing the heat on the facade wall of the building. It was also verified that a microclimate between the wall of the building and the green curtain are created, characterized by slightly lower temperatures and higher relative humidity. This means that the green screen acts as a wind barrier and confirms the evapotranspiration effect of the plants. On the other hand, these results did not allow withdrawing conclusions about the insulation effect of green facades.

Aquaculture has become an important sector of animal food production thanks to a fast and continuous growth over the last few decades. Both marine and fresh water fish can be reared in fish farms, and there are species that are mainly produced by aquaculture rather than capture. As most of the reared fish species are sensible to water temperature and its fluctuations, having the control of this parameter in fish farms becomes an important issue that has to be taken into account. In this paper, three different fish farms are studied by simulating the water temperature when a thermal energy storage (TES) system using phase change materials (PCMs) is implemented. The effect and the estimated amounts of PCM required in each particular case are also analyzed. The results show that appreciable effects can be obtained, especially when the TES unit is used in combination with auxiliary sources of energy, such as solar collectors.

Abstract Food transport and storage at low temperatures is a matter worldwide due to changes of the dietary habits and the increasing of the population. The issue of improving food storage applies at different applications such as commercial freezers or refrigerated trucks. The aim of this work is to improve the thermal performance of commercial freezers using phase change materials (PCMs) under door openings and electrical power failure. A commercial PCM was selected (Climsel-18) with a melting temperature of −18 °C, which is contained in 10 mm thick stainless steel panels placed at different locations in the freezer. During 3 h of electrical power failure, the use of PCM maintained the freezer temperature 4–6 °C lower and that of the frozen products remains at acceptable levels for much longer time. With frequent door openings the benefit of the PCM is evident when the temperature of the cabinet is near the melting temperature of the PCM.

Thermal energy storage (TES) using phase change materials (PCM) can be used for load shaving or peak load shifting when coupled to a heating, ventilation, and air-conditioning (HVAC) system such as heat pump. In these systems the PCM is embedded in packages or used in bulk, so the compatibility of the encapsulation materials and the PCM is a key factor to ensure long operational life of the system. Although corrosion caused by salts is known from the chemical industry, when these salts are used as PCM no corrosion data is available, since the salts are used without being in water solution. Producing new corrosion data is essential for PCM utilisation in new applications. In this study the corrosion rate of two metals and two metal alloys when they are in contact with different salt hydrate PCM is evaluated; in total eleven PCM, being four of them commercial PCM, are tested. Since they are PCM to be used for heating and cooling applications they are classified in two different groups to present the corrosion study. Results present the recommendation of using each PCM with the different metals and metal alloys according to the obtained corrosion rate and visual observation of the samples.

In 2008, following its R&D strategy roadmap for Concentrated Solar Power, Abengoa designed, built and tested a unique Molten Salts pilot plant at the representative scale of 8 MWhth, coupled with a trough oil loop. The objectives of this project were based on evaluating the technology at a scale at which the results are sufficiently representative of the real circumstances facing a commercial plant that utilizes this storage technology. To this end, the MS-TES plant was brought into operation on January 19th, 2009, been the first demo plant of indirect double tank storage in operation in the world. Key points such a material corrosion, analysis of possible leakage points, calculation of performance or true efficiency of the storage (including a thorough assessment of thermal losses) and analysis of plant operation are the lines that have been analysed at this plant. Operational aspects such as the mechanical assembling, the pre-heating, the filling up and plant performance were deeply addressed. Key components as the storage tanks, the heat exchanger, the molten salts pumps, the heat-tracing systems or valves and instrumentation were tested. In this first paper, the description and commissioning of the plant is presented together a set of lessons learnt to be applied at the commercial plant scale.

Phase change materials (PCM) are able to store thermal energy when becoming liquid and to release it when solidifying. Latent heat storage has gained importance due the applications towards increasing energy efficiency in several systems. Thus, a correct and accurate thermal characterization of these materials should be achieved. Among all possible thermal analysis methods to determine PCM thermophysical properties, the T-history method presents certain advantages. The T-history method is known to be suitable to obtain fusion enthalpy, specific heat and thermal conductivity for large phase change materials samples. On the other hand, no experimental T-history equipment is commercially available yet. Therefore, the goal of this paper is moving towards a consensus. To achieve this goal, a collection of similar methods previous to T-history are exposed and different proposals based on improving the original T-history method are discussed and reviewed.