@article{MuellerBrandmayrZoerner2014, author = {M{\"u}ller, Holger and Brandmayr, Sebastian and Z{\"o}rner, Wilfried}, title = {Development of an evaluation methodology for the potential of solar-thermal energy use in the food industry}, volume = {214}, journal = {Energy Procedia}, number = {48}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1876-6102}, doi = {https://doi.org/10.1016/j.egypro.2014.02.135}, pages = {1194 -- 1201}, year = {2014}, abstract = {The research project 'Solar Heat in the Liquid Food Industry' (part of the FORETA Research Network) focused on the development and optimisation of low-temperature heating systems for the liquid food industry. Its main objectives are in energy efficiency, waste heat recovery and the feasibility of a solar-thermal process heating system. Based on the particular simulation results the overall solar-thermal potentials for German breweries and dairies were determined. In this connection a literature review indicated that most of the potential studies on solar-thermal energy use in the industry or related to specific industrial sectors are based on the total use of low-temperature heat. In opposition to these results, the available and mainly limited roof area was found to be a more important aspect for the solar-thermal potential. Hence, the development of a methodology for a site- specific analysis was necessary. The interconnection of only a few defined evaluation criteria resulted in a more realistic estimation of the potential for a solar-thermal heat supply.}, language = {en} } @article{SchwanMohanSchmidetal.2025, author = {Schwan, Hannes and Mohan, Nihesh and Schmid, Maximilian and Saha, Rocky Kumar and Klassen, Holger and M{\"u}ller, Klaus and Elger, Gordon}, title = {Sintering for High Power Optoelectronic Devices}, volume = {16}, pages = {1164}, journal = {Micromachines}, number = {10}, publisher = {MDPI}, address = {Basel}, issn = {2072-666X}, doi = {https://doi.org/10.3390/mi16101164}, year = {2025}, abstract = {Residual-free eutectic Au80Sn20 soldering is still the dominant assembly technology for optoelectronic devices such as high-power lasers, LEDs, and photodiodes. Due to the high cost of gold, alternatives are desirable. This paper investigates the thermal performance of copper-based sintering for optoelectronic submodules on first and second level to obtain thermally efficient thin bondlines. Sintered interconnects obtained by a new particle-free copper ink, based on complexed copper salt, are compared with copper flake and silver nanoparticle sintered interconnects and benchmarked against AuSn solder interconnects. The copper ink is dispensed and predried at 130 °C to facilitate in situ generation of Cu nanoparticles by thermal decomposition of the metal salt before sintering. Submounts are then sintered at 275 °C for 15 min under nitrogen with 30 MPa pressure, forming uniform 2-5 µm copper layers achieving shear strengths above 31 MPa. Unpackaged LEDs are bonded on first level using the copper ink but applying only 10 MPa to avoid damaging the semiconductor dies. Thermal performance is evaluated via transient thermal analysis. Results show that copper ink interfaces approach the performance of thin AuSn joints and match silver interconnects at second level. However, at first level, AuSn and sintered interconnects of commercial silver and copper pastes remained superior due to the relative inhomogeneous thickness of the thin Cu copper layer after predrying, requiring higher bonding pressure to equalize surface inhomogeneities.}, language = {en} }