Methodology of Regenerator Calculation for Use in Subcritical and Transcritical Organic Rankine Cycle for Low-Temperature Heat Recovery

A comparative study of different Cases (A1, A2, B, C1, C2, D) of regenerator calculating methodology has been carried out for use in subcritical and transcritical organic Rankine cycles(ORCs) driven by low-temperature heat sources. The applicable ranges and conditions as well as influences on thermodynamic performances of different Cases have been analyzed. Results show that, for subcritical ORCs and transcritical ORCs keeping off the critical region(reduced temperature ranging from 0.9 to 1.12), the same results can be achieved with Case C1 and C2 as well as Case B and D. Case D and Case C2 are recommended for subcritical and transcritical ORCs, respectively. The regenerator is adopted on the condition of obtaining appropriate pinch and effectiveness values from techno-economic point of view. Influences of different Cases on heat injection (rejection) and thermal efficiency are below 10%.