Ceramic Canisters for Lithium Fluoride Thermal Storage Integrated with Solar Dynamic Space Power Systems.

LIF is one of the most suitable thermal energy storage (TES) materials for space applications because of its high heat of fusion of approx. 1044 kJ/kg at a melting temperature of 848 degrees centigrade. The high corrosivity and the large volume change during melting/freezing of approx. 22 % cause problems with metallic canisters. Enforcement of the canisters leads to a disadvantageous phase change material/containment (PCM/CTM) ratio besides the high costs of machining. A containment made of graphite was developed which cannot suffer from corrosion because it is not wetted by molten LIF. In order to match the forces caused by the volume change, a dV mechanism was integrated into the wall through which heat transfer takes place. The volume compensation is based on the capillary depression which experiences LiF due to the nonwettability of graphite by the liquid in a channel-like structure. Tests of the volume compensation which was developed exclusively for space application, showed promising results under gravity conditions. A problem of graphite is its open porosity through which gaseous LiF can permeate, leading to a significant loss of PCM with time. Preliminary tests with coatings on the outer walls of the containers have been carried out with encourageing results

EXPERIENCES from the PROJECT COURSE in GEOINFORMATICS

The aim of this paper is to share our experiences and thoughts about a project course in geoinformatics. The course has been organised annually since 2017. We hope that this article provides ideas about when new project-based courses are designed or existing ones are renewed. We wanted to increase students' motivation by providing assignments from companies or other organisations as well as cooperation with them. Working with real clients makes the project work much more interesting than projects without a real-life connection. We provide topics from various fields of geoinformatics, such as geoinformation technology, geodesy, photogrammetry, laser scanning and remote sensing. The students worked in small groups that were supported by an advisor and a facilitator. The advisor helps with substance and the facilitator assists with reflection and improving working process, i.e. not only to complete the task but also to learn about capabilities for project work, self-directive teamwork and learning to learn (metalearning). To sum up, during the course students increase their knowledge and expertise on geoinformatics, learn skills for client-centered project work and learn how to support their learning through self- and peer-reflection. In other words, the course aims to develop skills that are useful throughout the students' forthcoming careers.Peer reviewe