RSIndex: an auditable reference-normalized technology-assessment framework for thermal systems

Sustainable thermal technologies require a common useful-service boundary and traceable implementation, environmental, and thermodynamic evidence. This study develops RSIndex as an auditable, reference-normalized screening framework. Implementation burden (NRCI) uses a domain-based codebook, keeping lineage, partial-audit, and pilot-count scenarios separate. Four transcritical CO 2 configurations—baseline (BASE), an internal heat exchanger (IHX5), and dedicated mechanical subcooling (DMS5 and DMS10)—are evaluated at 25–45 °C. IHX5 and DMS5 use 5 K; DMS10 uses 10 K. Under the pilot-count codebook and equal implementation-environment weights, the core order is BASE, IHX5, DMS10, and DMS5 throughout. This order is conditional: the maximum implementation weight allowing DMS10 to outperform BASE rises from 0.057 at 25 °C to 0.162 at 45 °C. Equal-weight TOPSIS reproduces this order through 40 °C but narrowly places IHX5 ahead of BASE at 45 °C. Model-based relative environmental intensity (REI) and COP-based normalized irreversibility index (NII) are nearly redundant within each condition. An experimental dataset from an independent group serves only as an external-source boundary diagnostic. Its nine derived observations yield an across-case descriptive correlation of r = 0.949 and identical within-condition ranks; they are not an independent statistical sample. RSIndex offers transparent screening but does not independently calibrate NRCI or validate the complete composite.