R718 (water/steam) is a well-known heat transfer fluid, and steam compression systems can provide electricity-based solutions at highest efficiencies. Steam compression systems may be integrated at a variety of levels, e.g. directly in the process or at utility level.
R718 as refrigerant
R718 (water) is a well-known and in many regards advantageous heat transfer fluid. It is cheap and environmentally friendly, it has high specific heat capacities, and it is easy to handle with standard equipment. Thereby, it is highly accepted as a heat transfer fluid, and it is widely applied in industries.
Currently, the steam networks are mainly supplied with combustion based boilers. This project aims at developing steam compression systems as replacement for central boilers. In addition to the applications as boiler replacements at utility level, steam compressors may be used at process level as well, e.g. in mechanical vapor recompression applications.
The main focus lies on the development of suitable compressors, which are able to compress steam at high efficiencies and at low investment costs. In this regard, two approaches are followed in the SuPrHeat project.
The first approach is a two-stage system with interstage cooling, which is based on direct driven turbo-compressors. The second approach uses a spindle compressor and thereby a technology based on pumps from oil and gas industries. The two-stage turbo-compressor system is expected to reach temperature lifts of up to 60 K, while the spindle compressor is expected to reach even larger temperature lifts.