Nematpourkeshteli, Abolfazl (2023) Experimental and Numerical Analysis of the Thermal Performance of PCM in a Solar System with Enhancement PCM Thermal Conductivity Methods. [Tesi di dottorato]

Anteprima

Testo Nematpourkeshteli_Abolfazl_36.pdf Download (11MB) | Anteprima

Abstract

Solar energy, well-known for its inexhaustible and ecologically beneficial features, is one of the most promising energy sources. Solar energy is often captured in the form of heat by a heat medium Heat Transfer Fluid (HTF) and then transmitted to manufacturing and human usage. Solar heating or power supply devices based on Thermal Energy Storage (TES) components that can work constantly and without interruption are required due to the problems of varying weather, climate, and seasons. Latent Heat Thermal Energy Storage (LHTES) employs Phase Change Materials (PCMs) to store and release heat, effectively mitigating the discrepancy between energy availability and demand. Nevertheless, conventional PCMs with low Thermal Conductivity (TC) suffer from prolonged energy storage and release durations, significantly compromising the efficiency of TES components. The primary objective of this doctoral dissertation is to investigate the thermal behavior of a solar system integrated with a composite PCMs. This investigation will employ a combination of experimental and numerical techniques, incorporating Porous Metal Foam (PMF), Nanoparticles (NP), and Optimization Systems (OP). The model incorporates the enthalpy-porosity technique to account for phase change phenomena, while considering the local thermal non-equilibrium assumption for the utilization of foam, and a single-phase equivalent assumption is used for nanoparticles. The research outcomes indicate that the integration of PMF, NP, and OP methodologies can significantly reduce the overall duration required for both charging and discharging the PCM. Simultaneously, these approaches lead to an accelerated rate of energy storage and release. After comparing the numerical outcomes with the experiments herein run, data are shown in terms of liquid fraction, temperature evolution, stored energy, rate of energy storage charge, and a dimensionless parameter that characterizes the phase change process. The findings suggest that the proposed methods for enhancing heat transfer can enhance the thermal efficiency of systems. In one of experimental trials, the results indicate that incorporating the methods nanoparticle, metal foam, and metal foam with nanoparticles, each with porosities of 0.4% and 0.94%, leads to a reduction in melting time by 13.39%, 60.77%, and 71.93%, respectively, compared to pure PCM.

Downloads

Actions (login required)

Modifica documento