Performance of a Solar Flat Plate Collector with Integrated Phase Change Storage

The thesis documents the investigation of the time-dependent melting process of paraffin in a solar flat plate collector with integrated heat storage concept. Among all the aspects that affect the phase change, the internal convection effect is in primary attention. The investigation starts with the numerical approach, which provides valuable information to design validation experiments. An apparatus was built to test two reduced scale demonstrators, which are heated up by simulated insolation. To maintain incoming heat flux consistent, the experiments were completed in a laboratory environment where the insolation simulation is applied. The phase transition is recorded and analyzed from the observations and temperature readings in total four melting cycles.

This study validates the feasibility of combining solar energy collection and storage. The general trends of the calculation are confirmed by experiment results, an improved understanding of how the internal convection affects the phase change pattern has obtained. Although the numerical approach models the experiments as much as possible, differences in time response have emerged. Discussions regarding the gaps are made, but some remain inconclusive. To evaluate the comprehensive performances of the passive solar heat storage, recommendations regarding future investigations are made.