Working mixtures for sorption heat pumps, sorption refrigerators and sorption heat transformers

摘要

The patent application proposes various working mixtures consisting of the lower-boiling working material and the higher-boiling absorbent for use in sorption refrigerators, sorption heat pumps and sorption heat transformers. The mixtures known from refrigeration technology, of which ammonia/water and water/lithium bromide are used most frequently, can be used only with limitations in the heat pumps or heat transformers running at higher temperatures. Halogenated alcohols and, from this group of substances, especially trifluoroethanol are mentioned as a working material. These materials are above all distinguished by the moderate vapour pressures and the thermal stability at the temperatures which occur in the heat pumps. Suitable absorbents are organic solvents which are stable at high temperatures and have a boiling point above 260 DEG C. In detail, the following substances and groups of substances are proposed as absorbents for trifluoroethanol: glycol ethers, especially tetraethylene glycol dimethyl ether (E181), phthalates, sebacates, naphthols, naphthylamine, tetraethylenepentamine, diphenylamine, benzophenone and 2-hydroxybiphenyl. The temperature ranges, within which sorption processes with the said working mixtures can be operated, are also indicated.