A two-stage heat transformer with H2O/LiBr for the first stage and 2,2,2-trifluoroethanol(TFE)/N-methy1-2-pyrrolidone (NMP) for the second stage

The two-stage heat transformer (TSHT) is an advanced heat–transformer which can widen the operating range compared to that which can be achieved with a single-stage heat–transformer (SSHT). This paper analyzes three kinds of two-stage heat transformers and puts forward the two-stage heat–transformer with H2O/LiBr for the first stage and 2,2,2-trifluoroethanol (TFE)/N-methy1-2-pyrrolidone (NMP) for the second stage. The results show that it can reach the same high delivered temperature as the two-stage heat–transformer with only TFE/NMP as working–fluid combinations and can achieve a higher system performance than the two-stage heat transformer with TFE/NMP.