resumo
The use of poly(vinyl chloride) (PVC) structural layers incorporating phase change materials (PCM) for latent heat thermal energy storage (LHTES) has become more attractive in the recent years compared to other supporting materials. In this study, PVC layers with different types of PCM were prepared using blending and compression moulding methods. Two types of synthesized PCM, one based on paraffin and calcium carbonate (PCM@CaCO3) and the other on paraffin, silica and graphene oxide (PCM@SiGO) have been developed to enhance the thermal conductivity of the PVC matrix and thus achieve a more effective charging and discharging process. PVC layers prepared using a commercial PCM (PCM@BASF) were also prepared for comparison. SEM images and DSC results reveal homogeneous distribution of the PCM in PVC layers and that most PCM particles are undamaged. The shell material (in the case of PCM@BASF) and the shape stability (in the case of synthesized PCM@CaCO3 and PCM@SiGO) prevent leakage of molten paraffin during the PVC layer production. The thermal conductivity profile of the PVC layer without PCM have a decreasing tendency with the temperature increase when determined using different measurement approaches, the transient plane heat source method (HotDisk Analyser, TPS 2500 S) and thermal flux meter method (steady-state method). However, for PVC layers with PCM the thermal conductivity profile shows a different behaviour when the mean surface temperature of the specimen is below the phase change transition temperature range (increasing tendency). During phase change transition (18-26 degrees C), the thermal conductivity presents two distinct tendencies. Firstly, the thermal conductivity reveals a decreasing tendency as the mean temperature of the specimen rises and afterwards an increasing tendency. Secondly, when the mean surface temperature is above the phase change transition temperature range, the thermal conductivity profile shows a decreasing tendency, independent of the PCM. The mechanical properties of PVC layers were also assessed and the results obtained revealed that the incorporation of PCM into the PVC matrix reduces the mechanical performance of the composites, however for LHETS applications not subjected to high tensile stress levels (over 1 kPa), this is not a significant drawback.
palavras-chave
CHANGE MATERIALS PCMS; CONDUCTIVITY; COMPOSITE; BUILDINGS; PARAFFIN; MICROENCAPSULATION; PERFORMANCE; FABRICATION; STRATEGIES; WALLS
categoria
Thermodynamics; Energy & Fuels; Engineering; Mechanics
autores
Amaral, C; Gama, NV; Mohseni, F; Amaral, JS; Amaral, VS; Marques, PAAP; Barros-Timmons, A; Vicente, R
nossos autores
Cláudia Patrícia Cândido do Amaral
Estudante de doutoramento
João Cunha de Sequeira Amaral
Investigador Auxiliaragradecimentos
This work was developed under the scope of the project: MF-Retrofit - Multifunctional facades of reduced thickness for fast and cost-effective retrofitting [EeB.NMP.2013-1 Grant Agreement to: 609345] and within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES This work was developed within the scope of the project CICECO - Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES and TEMA - Centre for Mechanical Technology and Automation, was supported by the projects UIDB/00481/2020 and UIDP/00481/2020 - FCT - Fundacao para a Ciencia e a Tecnologia; and CENTRO-01-0145-FEDER-022083 - Centro Portugal Regional Operational Programme (Centro2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund. Thanks are due to University of Aveiro, FCT/MEC for the financial support to the research Unit RISCO - Aveiro Research Centre of Risks and Sustainability in Construction (FCT/UID/ECI/04450/2013). JSA acknowledges FCT IF/01089/2015 grant.