Nebula Public Library

The knowledge bank of ESA’s R&D programmes

Chemical Compatibility and Wettability of various Materials with various Working Fluids for Two-Phase and Heat Pump Systems

Programme Reference
Prime Contractor
University of Limerick
Start Date
End Date
Chemical Compatibility and Wettability of various Materials with various Working Fluids for Two-Phase and Heat Pump Systems
Investigate and test the chemical compatibility and wettability of several working fluids with various materials as well as bi-metallic junctions
Material compatibility with ammonia is critical for the performance and lifetime of Two-Phase equipment. The generation of non-condensable gases can severally impact the performance of the two-phase equipment. Material compatibility testing is mandatory in all the development of two-phase equipment which uses new materials. However, the compatibility results are not publish and it remains at the manufacturer, hence it cannot be used by another manufacturer. In addition, the introduction of additive layer manufacturing, which allows to create innovative two-phase components requires to use other materials than the conventional ones, such as alsi10mg. Hence, for activities that uses ALM components, the compatibility testing with ammonia and other fluids, need to be conducted.
Furthermore, bi-metallic junction would allow to change the type of material within a two-phase loop. As an example, the loop heat pipe evaporator could use stainless steel and the condenser area would use aluminium in order to increase the performance as well as to simplify the mounting by using extruded aluminium profiles. Bi-Metallic junctions are being used by some Two-Phase equipment manufacturer but there are questions regarding the long term generation of non-condensable gases over the 15years of operations.
Moreover, Mechanical pump systems use various materials within the loop. It is known individual material may be compatible with ammonia, but when combined with another material, they become non-compatible. This is an aspect that requires further investigation and testing. Ammonia is the common fluid used in Two-Phase equipment since its performance is greater than other fluid within a certain temperature range. Other fluids as Toluene for high temperature applications can be investigated as well.. Hence compatibility testing of these new fluids with heat pump components is required.
This activity encompasses the following tasks :
- Requirements consolidation
- Test Plan
- Manufacturing of Samples
- Wettability measurements
- Chemical Compatibility testing and Non-Condensable Gas testing
- Sample analysis e.g. Micro-sectioning, corrosion detection,
- Reporting
Application Domain
Technology Domain
21 - Thermal
24 - Materials and Manufacturing Processes
Competence Domain
2-Structures, Mechanisms, Materials, Thermal
2-Space Segment - Platform
Initial TRL
Target TRL
Public Document
Executive Summary
Final Presentation