The companion paper (Huang, 2026) established a three-layer conceptual framework for waste heat thermoelectric recovery in particle accelerators, identifying a cross-disciplinary literature gap at the intersection of accelerator energy management, silicon thermal energy storage, and cryogenic thermoelectric generation. This roadmap document extends that framework by identifying three open research directions that address its most fundamental unresolved challenge — the thermal elevation problem. The three directions are: (A) Directed capture of synchrotron radiation as a stable, continuous high-grade thermal source. LHC synchrotron radiation (~7 kW total) is currently 100% dissipated into cryostat walls with zero energy recovery. Its directionality and continuity make it a candidate for optical collection toward a high-temperature absorber. (B) Intentional thermal extraction at collimator sites. Collimators intercept halo particles and routinely experience local temperatures of hundreds of degrees Celsius, with this heat currently removed entirely by water cooling. A dual-function collimator architecture — fulfilling both beam physics and thermal storage roles — is proposed as a long-term design objective. (C) Dedicated beam energy extraction segment. A purpose-built section of the accelerator ring or bypass line in which a controlled fraction (~1–5%) of circulating beam energy is intentionally deposited as heat in a high-temperature refractory absorber, rather than recovered electrically as in Energy Recovery Linacs. Each direction is characterised by its thermal profile, engineering feasibility, and the specialist communities best positioned to investigate it. Open questions retained from the companion paper — STEG materials across the 1.9 K–1687 K span, CTE mismatch, carrier freeze-out, and exergy accounting — are also summarised. This document is offered as an open invitation to accelerator physicists, thermal engineers, and materials scientists. The author makes no claim to priority on any of the three directions identified. Companion paper: https://doi.org/10.5281/zenodo.18977738
Chan Yen Huang (Thu,) studied this question.