Development of multilayer deposition and micro-texturing techniques for scalable CSP absorbers

Description

Solar energy is a vast and largely untapped resource in Australia, which has the highest solar radiation per square metre of any continent. Recently, central tower Concentrating Solar Power (CSP) technology has received significant attention due to its ability to cheaply store energy and produce electricity in a 24-hour cycle. Vital to the efficiency of central tower CSP technology is the effectiveness of light absorption at the solar receiver.

The central aim of this project is to develop highly efficient, durable, and economical competitive absorber coatings to help transform the CSP industry, which has the potential of becoming an essential part of the renewable energy sector in Australia and worldwide. To achieve the main objective, a multi-scale engineering approach composed of optics modelling, materials science, and ageing testing will be performed. In this project, three main goals are set. The first goal is to model and understand the light trapping mechanism of a micro-textured coating to find the best morphology that optimises light absorption (position 1). The second goal is to improve the durability and light absorption of solar thermal absorbers by developing micro-texturing and multi-layer deposition techniques as well as introducing new materials (position 2). The third goal is to develop and validate accelerated ageing tests that reproduce the extreme conditions of high temperature, radiative fluxes, thermal stresses and fatigue of CSP receivers (position 3).

The objective of this HDR project is to significantly improve the durability and light absorption of solar thermal absorbers by developing micro-texturing and multi-layer deposition techniques as well as introducing new materials. The student will perform a materials design of hierarchical micro- and nano-structured coatings to enhance their optical and thermal properties. Nanocomposite materials will be introduced to improve mechanical and chemical properties. This research stream is highly interconnected with the testing research stream (position 3), while referencing data obtained with the optics modelling (position 1). The base layer design will reduce cation diffusion from the substrate to the absorption layer at high temperatures. Multi-layer deposition will be implemented to reduce thermal stresses under operating conditions. Materials may include combination of low-cost earth-abundant metal-oxides such as CuO and iron oxides, which provide good optical absorption properties, and SiO2, TiO2, SnO2, which provide excellent thermal and chemical stability. It is expected that stabilisation of a porous absorber layer in a robust wide bandgap semiconductor, will lead to tuneable optical and thermochemical properties. The absorption layer design will focus on controlling the properties of the coating by changing the ratio of base/absorption layer thickness. The control of pore size will be achieved by adjusting thermal spray conditions, such as pigment volume fraction, composition, ink temperature, and substrate temperature. Pore size control is essential for the scalability. The top layer design will focus on pre-oxidising the top layer to increase its toughness. The scalability task is focused on building and testing a device that can implement the coating method to large-scale receivers.

Requirements

  • Fundamental knowledge on materials science and characterisation.
  • Analytical and problem-solving skills for experimental design.
  • Time management, planning and organisational skills for experiments.
  • Excellent scientific writing skills.

Keywords

micro-texturing, multi-layer deposition, nanocomposite materials, absorber coatings, solar thermal, concentrating solar thermal power

Updated:  1 November 2018/Responsible Officer:  Dean, CECS/Page Contact:  CECS Marketing