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Cryogenic cooling of infra red detectors is a well know requirement and need for many instruments in space application. The need for higher performance and long-life cryogenic cooling system, along with already stringent requirements for vibration, compactness, and mass, is self evident in spacecraft instruments especially for long space missions. It is therefore an object of this study to provide a system that has the potential to meet these challenges. A new absorption based cryocooler is presented and studied. Different absorption working fluids are selected and studied. Thermodynamic state performance and major items of the design specifications are described and presented. The main characteristics of the absorption system in this study are the lowest temperature that could be reached in the evaporator side and the nature of the working fluid mixture. A maximum of 100 W cooling capacity in the evaporator side is considered.

Nanofluids have been recently investigated as new working media for two-phase thermal control systems. However, conflicting reports have emerged, in which contradictory effects of the nanoparticles on the working performance of heat pipes have been described. Some studies have shown that gold or silver nanoparticles significantly improve heat transfer performances of heat pipes. Other studies have provided evidence that metal nanoparticles have no particular effect. This study is aimed at determining whether nanofluids are good candidates as heat carriers in a Loop Heat Pipe (LHP) system. Here, a nanofluid consisting of well-characterized citrate-stabilized gold nanoparticles in water is examined. The metallic nanoparticles are functionalized with citrate ligands in order to be soluble and stable in water at room temperature. An LHP hardware set-up was developed for this investigation.

Heat pipes, loop heat pipes and capillary pumped loops are heat transfer devices driven by capillary forces with high-effectiveness & performance, offering high-reliability & flexibility in varying g-environments. They are suitable for spacecraft thermal control where the mass, volume, and power budgets are very limited. The Canadian Space Agency is developing loop heat pipe hardware aimed at understanding the thermal performance of two-phase heat transfer devices and in developing numerical simulation techniques using thermo-hydraulic mathematical models, to enable development of novel thermal control technologies. This loop heat pipe consists of a cylindrical evaporator, compensation chamber, condenser along with vapor and liquid lines, which can be easily assembled/disassembled for test purposes. This laboratory setup is especially designed to enable the visualization of fluid flow and phase change phenomena.