Single layer mortars with microencapsulated PCM: study of physical and thermal properties, and fire behaviour

tPhase change materials are a promising strategy to reduce energy consumption in a wide range of appli-cations including the building sector. Many studies have been done to evaluate the impact of PCM onthermal properties of building materials, however there exists little information on the influence ofPCM on other properties of the support materials. This knowledge is necessary to determine the fea-sibility to apply and use building materials containing PCM. In this paper, the effect of the addition ofdifferent percentages of microencapsulated phase change material on the properties of two commercialsingle layer mortars has been studied. Physical and thermal properties as well as fire reaction have beenevaluated.Peer ReviewedPostprint (author's final draft

Single layer mortars with microencapsulated PCM: study of physical and thermal properties, and fire behaviour

tPhase change materials are a promising strategy to reduce energy consumption in a wide range of appli-cations including the building sector. Many studies have been done to evaluate the impact of PCM onthermal properties of building materials, however there exists little information on the influence ofPCM on other properties of the support materials. This knowledge is necessary to determine the fea-sibility to apply and use building materials containing PCM. In this paper, the effect of the addition ofdifferent percentages of microencapsulated phase change material on the properties of two commercialsingle layer mortars has been studied. Physical and thermal properties as well as fire reaction have beenevaluated.Peer Reviewe

Use of multi-layered PCM gypsums to improve fire response. Physical, thermal and mechanical characterization

The building sector is one of the highest energy consumers representing around 30% of total energy use. One of the recommendations of the IEA (International Energy Agency) to reduce energy consumption in buildings is to enhance the thermal performance of building envelopes. In the present study, PCM (Phase Change Material) gypsum materials have been manufactured using three different PCM inclusion methods and a thin layer of gypsum without PCM is added as external layer with the aim of improving the fire reaction behaviour. By performing a detailed physical, mechanical and thermal characterization, the suitability of the materials to be implemented in the building envelope as inner coating is demonstrated. Results show that also the thermal properties are improved in the three cases by the addition of PCM. Moreover, the negative effect of adding paraffin wax PCM into gypsum against flame can be easily reduced by the addition of a thin gypsum layer, which is a low tech and cheap solution without extra environmental impact.Peer Reviewe

Effect of the curing process on the thermomechanical properties of calcium aluminate cement paste under thermal cycling at high temperatures for thermal energy storage applications

Future perspectives to improve the energy efficiency of concentrating solar power (CSP) plants are focused on increasing temperatures above 600 °C. Among the different components of a CSP plant, the thermal energy storage (TES) medium must withstand high operating temperatures. Concrete was identified as an exciting candidate for its mechanical and thermal properties, needing further experimental research about this specific application. A fundamental concrete element is the cement binder, bringing cohesion to the composite components. As a requisite, the cement needs to be heat-resistant, and calcium aluminate cement (CAC) suits this demand. This cement is characterised by curing temperature-driven crystallisation changes, triggering an alteration of material properties. Considering that at 60 °C, the metastable hexagonal crystallisation is converted into a stable cubic crystallisation, seven curing cases were proposed in this study. After the curing process, thermo-mechanical properties of calcium aluminate cement paste were tested before and after thermal cycles from 290 °C to 650 °C. The results showed that, despite thermal cycling, the immediate hydration at 60 °C results in a higher thermal conductivity and compressive strength than standard curing at 20 °C. © 2022 The Author

Thermo-mechanical stability of supplementary cementitious materials in cement paste to be incorporated in concrete as thermal energy storage material at high temperatures

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. © 2022 Elsevier Lt

Estabilidad termomecánica del hormigón con escorias de acero como árido, tras ciclos térmicos de alta temperatura

Thermal energy storage represents a crucial element to increase solar power dispatchability. Within sensible heat storage in solid media, concrete is considered a low-cost alternative to be further developed and therefore, this has been addressed in this paper. Four concrete dosages were designed, combining each type of considered cement, ordinary Portland and calcium aluminate cement, with each type of considered aggregate, silico-calcareous and a steel slag. Thermo-mechanical properties of concrete were studied before and after 10 thermal cycles from 290 ¿C to 700 ¿C. Maximum operating temperature and heating rates were selected accordingly to the targeted application, a concentrating solar power (CSP) tower plant. At macro-level, results show thermal cycle stability of concrete with steel slag aggregate in both cement types. On the contrary, at micro-level, the petrography analysis shows the lack of bonding between steel slag aggregate and the cement paste. In contrast, concrete mixtures containing silico-calcareous aggregates collapse after thermal cycling.Peer ReviewedPostprint (published version

A method to identify barriers to and enablers of implementing climate change mitigation options

Mitigation option are not yet being implemented at the scale required to limit global warming to well below 2°C. Various factors have been identified that inhibit the implementation of specific mitigation options. Yet, an integrated assessment of key barriers and enablers is lacking. Here we present a comprehensive framework to assess which factors inhibit and enable the implementation of mitigation options. The framework comprises six dimensions, each encompassing different criteria: geophysical, environmental-ecological, technological, economic, sociocultural, and institutional feasibility. We demonstrate the approach by assessing to what extent each criterion and dimension affects the feasibility of six mitigation options. The assessment reveals that institutional factors inhibit the implementation of many options that need to be addressed to increase their feasibility. Of all the options assessed, many factors enable the implementation of solar energy, while only a few barriers would need to be addressed to implement solar energy at scale. © 2022 Elsevier Inc