Effect of damaging on the thermal properties
The plots of Fig. 7 present the evolution of the specific heat of non-damaged PCMs in comparison with the damaged ones. One can see that in the two configurations, the Cp tendencies are quite the same, namely the damage of PCMs would have not influenced the evolution of the specific heat versus the temperature. How- ever, if we take a look at the quantitative analysis of the specific heats values recorded in Table 4, one can see that the damaged PCMs exhibit lower heat capacities than the reference ones. A deviation of nearly 28% between the damaged and non-damaged case is recorded in the estimation of the heat capacity of PCMs before their melting. This result could be explained by the leakage of the paraffin active compound from the capsules after the damage of PCMs, for example and/or the deterioration of the thermal transfer conditions due to the rupture of the shell exchange surfaces which could be relevant to preserve the proper- ties of PCMs and to ensure their stability from a thermal point of view. It shall be emphasized that the thermal response of the PCM samples is strongly dependent on the wax paraffin component and that the contribution of the polymer shell is negligible because of its small mass proportion in PCM, on the one hand and its lower specific heat with regards to the wax on the other hand. This finding highlights the damage effect of PCMs and the importance to take it into account to faithfully estimate the PCMs thermal properties. From an operational point of view, this means that by introducing the PCMs at the first stage of the mixing process during the manufacture of the PCM-material, a loss in the energy storage, gained both by sensible and latent heats of PCMs, could be attained. Accordingly, the thermal inertia of the PCM-material composite is deteriorated and the energy efficiency target is not really achieved. Thus, it shall be emphasized that the processing of the PCM-material shall be carefully planned and optimized.
ผลของการทำลายบนคุณสมบัติความร้อนThe plots of Fig. 7 present the evolution of the specific heat of non-damaged PCMs in comparison with the damaged ones. One can see that in the two configurations, the Cp tendencies are quite the same, namely the damage of PCMs would have not influenced the evolution of the specific heat versus the temperature. How- ever, if we take a look at the quantitative analysis of the specific heats values recorded in Table 4, one can see that the damaged PCMs exhibit lower heat capacities than the reference ones. A deviation of nearly 28% between the damaged and non-damaged case is recorded in the estimation of the heat capacity of PCMs before their melting. This result could be explained by the leakage of the paraffin active compound from the capsules after the damage of PCMs, for example and/or the deterioration of the thermal transfer conditions due to the rupture of the shell exchange surfaces which could be relevant to preserve the proper- ties of PCMs and to ensure their stability from a thermal point of view. It shall be emphasized that the thermal response of the PCM samples is strongly dependent on the wax paraffin component and that the contribution of the polymer shell is negligible because of its small mass proportion in PCM, on the one hand and its lower specific heat with regards to the wax on the other hand. This finding highlights the damage effect of PCMs and the importance to take it into account to faithfully estimate the PCMs thermal properties. From an operational point of view, this means that by introducing the PCMs at the first stage of the mixing process during the manufacture of the PCM-material, a loss in the energy storage, gained both by sensible and latent heats of PCMs, could be attained. Accordingly, the thermal inertia of the PCM-material composite is deteriorated and the energy efficiency target is not really achieved. Thus, it shall be emphasized that the processing of the PCM-material shall be carefully planned and optimized.
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