Blueprint: Phase-Change Neonatal Warmer — Build and Implementation Specification

Build and implementation specification for a non-electric neonatal warmer consisting of a 2.5 kg paraffin phase-change mattress pack melting near 37 °C, an insulated wrap, and a hot-water recharge tray with a 40 °C guard phase-change material, including dimensions, bill of materials, assembly, recharge and use procedures, modelled hold times by weight class and ambient temperature, and the fail-safe temperature bound. DESIGN BLUEPRINT — SIMULATED, NOT MEASURED — NOT BUILT, NOT CLINICALLY TESTED. Blueprint for the design published as DOI 10.5281/zenodo.24108848.