Innovative microencapsulated phase change materials for direct-absorption solar collectors

Publieke samenvatting / Public summary

Direct absorption solar collectors (DASCs), in which the heat transfer fluid (HTF) directly absorbs and converts solar energy into thermal energy, have proved to have higher receiver efficiencies than conventional solar collectors. The incorporation of phase change materials (PCMs) in conventional HTFs offers potential to enhance the efficiency even further.

The aim of the project is to introduce and characterize novel microencapsulated PCM slurries (ME-PCMS) for direct absorption solar collectors. The working fluid acts both as the HTF and energy storage medium, following two main purposes:
- to increase the efficiency;
- to increase energy storage capability of the collectors.

Korte omschrijving
The following important issues have to be resolved for the proposed use of ME-PCMs for DACS:
- Preparation and characterization of ME-PCMs: evaluation of their morphology, structure and thermal storage performance. These activities are performed in work package 1.
- Preparation of ME-PCM slurries for developing a suitable HTF to be used for DASCs. This phase also includes investigation of thermal conductivity, specific heat and photo-thermal performance of the novel HTF. The activities are overlapping between work packages 1 and 2.
- One-dimensional transient heat transfer analysis will be used to investigate the effects of particles volume fraction, collector height, irradiation time, solar flux on the solar collector performance. The activities are performed in work package 2.

The outcome of the project is a novel HTF, in which ME-PCMs are incorporated, that both enhances the efficiency of solar energy conversion as well can store thermal energy. In turn, this will lead to DASC systems with overall higher performance in terms of efficiency, cost, and required space etcetera.