Infused Thermal Solutions (ITS) introduces a monolithic integral design with embedded passive thermal control for temperature stabilisation of functional structures, without active heating and cooling systems. Passive thermal control is achieved by embedding phase change material (PCM) in additive manufactured components, which relate on a double-wall design with integrated intermediate lattice. The PCM is embedded between the double walls as macro-encapsulation for thermal energy storage (TES), which yields the ITS technology. Hence the integral design is attributed to additive manufactured monolithic integral structures with integrated lattice and embedded PCM. The PCMs used for TES in the ITS research are limited to organic PCMs (paraffins) due to their high specific latent heat of fusion in combination with the available broad melting temperatures range, which enables ITS model flexibility. This useable effect of the PCM flattens temperature peaks, reduces temperature gradients and damps cooling phases, which then requires less heating power. In this doctoral thesis, the fundamental validation of the passive temperature stabilisation of additively manufactured integral structures with infused PCM is supported by thermal analyses. Additionally, hardware tests are performed with specimen test series and a scaled ITS demonstrator, which is related on the Entrance Baffling Assembly (EBA) instrument structure of the Meteosat Third Generation (MTG) satellite. The MTG use cases are derived from orbit thermal data. The thermal predictions of all test specimens and demonstrator models are modelled in ESATAN and relate on a developed subroutine for thermo-physical modelling of PCM behaviour. This PCM subroutine is generic and fully parametrised. The numeric to simulate PCM behaviour is based on the latent heat storage (LHS) method in combination with hysteresis models to consider technical-grade PCM behaviour with non-interrupted and incomplete phase change cycles. All thermal test specimens, breadboards and the ITS demonstrator are additively manufactured by applying laser powder bed fusion (LPBF), using the highly thermally conductive additive manufacturable aluminium alloy AlSi10Mg. The combination of the synergistic effects of an integrated lattice matrix in between double walls, contributes significantly to the improvement of the effective thermal conductance as well as to stiffen the double walled ITS component as a whole. It is therefore approved that the integrated BCC2 lattice significantly enhances the effective thermal conductivity and thus minimizes the impact of typically very low conductive paraffin. Both the conductive and convective heat transfer modes are analysed and correlated with experimental data. Convective heat transfer can occur under certain circumstances, but compared to conductive heat transfer within ITS structures, it is neither dominant in the measurements made nor does convection lead to unacceptable model deviations. Through systematic TVC steady-state tests the conductive heat transfer model and its thermal modelling concept are validated, both with and without PCM in order to yield the thermal properties of the lattice and PCM. The conductive heat transfer model is fully parameterised. The results of the TVC cycling tests compared to the predictions demonstrate and confirm throughout all specimens and the ITS demonstrator the proposed key features of the ITS passive thermal control capability, which are to damp peak heat loads, to narrow the temperature band and to minimize subcooling phases, which in turn minimizes heater power. The scalability of the ITS technology is validated on the demonstrator model. The predicted and measured temperature curves with embedded PCM of the demonstrator can be correlated with good accuracy and the achieved temperature stabilisation is quantified. The quantification of the achieved temperature stabilisation is provided by metrics, which are integrated in developed software tools for data post-processing, based mostly on MATLAB code. The ITS concept was already awarded to the winner in 2018 for the most innovative technology in the field of mobility and space applications as part of the national INNOSpace Masters initiative (link) of the German Aerospace Centre (DLR). In addition, the ITS concept was awarded the Research Prise of the Aachen University of Applied Sciences in 2020 (link). The findings and results from the ITS research project (funding code: 50RP1975, funded by the Federal Ministry for Economic Affairs and Energy, Germany) have already been published both in scientific papers and extensively in the final scientific-technical success-control-report. The publication of the success-control-report had to be taken place already in January 2023 on the instructions of the German Aerospace Center (DLR) as the funding body, and thus before the completion of this thesis. Furthermore, all publications related to the ITS research and the author Mr. Wild are listed in this thesis.    «

Infused Thermal Solutions (ITS) introduces a monolithic integral design with embedded passive thermal control for temperature stabilisation of functional structures, without active heating and cooling systems. Passive thermal control is achieved by embedding phase change material (PCM) in additive manufactured components, which relate on a double-wall design with integrated intermediate lattice. The PCM is embedded between the double walls as macro-encapsulation for thermal energy storage (TES),...    »