Development of structural layers PVC incorporating phase change materials for thermal energy storage

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 °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.publishe

Experimental and numerical analysis of the thermal performance of polyurethane foams panels incorporating phase change material

The potential thermal regulation effect of rigid polyurethane (RPU) foams can be enhanced by the incorporation of phase change materials (PCM). The main goal of the present work is to evaluate the thermal characteristics of RPU panels using two different types of PCM (a commercial one and another based on paraffin and calcium carbonate) and to quantify their potential as thermal regulators of indoor spaces. The experimental results obtained revealed that the RPU panels incorporating PCM can lead to a thermal amplitude reduction of about 3.5–1 °C (peak maximum temperature – peak minimum temperature). Furthermore, it was demonstrated that the performance of the RPU panel with PCM was enhanced when the external and internal mean temperature were closer to the melting peak temperature of the PCM. Additionally, it was also verified that the thermal amplitude reduction due to the PCM is more significant for the RPU panel incorporating PCM. In brief, the results showed that the efficiency of the RPU panels incorporating PCM is not exclusively dependent on the presence and quantity of PCM (equivalent in wt% in all cases) but it is also affected by the imposed temperature profile and the PCM thermal properties.publishe