3, January 2022

ESA Open Invitation to Tender: 1-10695
Open Date: 21/12/2021 14:46 CEST
Closing Date: 01/03/2022 13:00 CEST

The objective of the activity is to design, manufacture and test an engineering model of a highly efficient heat exchanger for a loop heat pipe condenser coupled to heat pipe radiator panel. Targeted Improvements:- Improved overall conductance of the loop heat pipe plus radiator system by 30%;- Increased reliability of the system against micrometeorites;- Reduced volume of the compensation chamber.Description: Loop heat pipe (LHP) condensers function by either direct or indirect condensation. For direct condensation, the condenser piping needs to be distributed across the entire radiator panel. This creates long pipes and requires a large size compensation chamber to be accommodated on the spacecraft. In addition, if the power to be transported changes, the radiator needs to be re-sized, which affects the volume of the compensation chamber as well as the LHP design for each application. Indirect condensation requires the condenser to be bolted to a heat pipe network where the connection creates a thermal gradient. Indirect condensation is less performant but gives a better reliability and better flexibility when resizing the radiator, since only the length of the heat pipes would need to be adjusted. Having a compact heat exchanger that is directly interfacing with heat pipes would greatly improve the performance, reduce the compensation chamber size and increase the reliability of the heat transport system. The heat exchanger design would allow heat to be exchanged at a much higher heat flux density compared to the conventional design, since it would provide an increased contact surface area with the fluid within the heat exchanger. Standard axial grooved heat pipes would be welded to the heat exchanger in order to increase the heat exchange, but without exchanging directly fluid between the loop heat pipe and the heat pipes. The design of the heat exchanger would be generic and allow the possibility of welding heat pipe profiles in close proximity. The activity will focus on developing a new inner capillary structure in the compact condenser area in order to greatly improve the overall condensing heat transfer coefficient, which is one limiting factor in the performance of an LHP. At least three breadboards shall be built and characterisation tests shall be performed. Based on the breadboard test results, an engineering model shall be designed, developed and manufactured, having a loop heat pipe with a compact heat exchanger interfacing directly with heat pipes that are both embedded into a radiator panel. Tests shall be conducted to measure the end to end performance improvement of the overall system.

Directorate: Directorate Telecom Integrated Applica
Estabilishment: ESTEC
ECOS Required: No
Classified: No
Price Range: > 500 KEURO
Authorised Contact Person: Florence Odette Jeanne Glandieres
Initiating Service: TIA-TTS
IP Measure: N/A
Prog. Reference: E/0534-01G – CC-AT 4.0.1
Tender Type: Open Competition
Technology Keywords: 21-A-II-Capillary-Driven Loops
Products Keywords: 2-O-3-g-High temperature CPL/LHP (Capillary Pumped Loop/Loop Heat Pipe)

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