Industrial high temperature heat pumps are widely recognized as a fundamental technology in the transition to a fossil-free society. To scale this technology to higher temperatures (>100°C) there are a number of challenges that can largely be traced back to the compressor. The compressor exhaust is usually highly overheated which results in problems with thermal expansion (i.e. friction of components) and dissociation of lubricating oil. One solution is to use the heat pump's working fluid as both lubricant and coolant for the compressor. This research proposes an innovative oil-free compressor with liquid injection and hydrostatic bearings to achieve this. Another unique feature is the choice of water/ammonia as the working fluid, which provides an optimal balance between performance, costs, technical properties and environmental impact. This concept and the construction of a test setup are results of a previous project (Upheat-INES 1.0 & 2.0). The next step is to evaluate this compressor concept with experimental results in combination with a specific tailored thermodynamic model. This allows to predict the influence of injection flow rate, injection pressure and water/ammonia fraction on the performance. The model is further used to precisely determine optimal operating parameters and refine the design. Finally, the performance (COP) of an industrial heat pump with this specific technology is calculated in a case study.