Liquid Metal Dynamic Thermal Management Suit (LM-DTS)

Ensuring diver safety and performance in extreme underwater environments requires advanced thermal management solutions. Current diving suits, such as neoprene wetsuits and immersion suits, suffer from significant drawbacks, including compression-induced loss of insulation at depth, restricted dexterity, and limited adaptability to varying temperatures. To address these limitations, Hawai‘i Innovation Inc. (HII), in collaboration with North Carolina State University (TPACC- Textile Protection and Comfort Center), proposes the Liquid Metal Dynamic Thermal Management Suit (LM-DTS), an active heating and cooling system designed to sustain core body temperatures of 95–99°F and extremity temperatures above 53.6°F in water ranging from 28–99°F for up to 10 hours. The LM-DTS integrates three core innovations: (1) Compression-Resistant Insulation using aerogel-foam composites that retain =80% thickness under 6 bar pressure to prevent heat loss at depth, (2) a Hybrid Heating/Cooling Reservoir, incorporating Phase Change Materials (PCMs) and optional thermoelectric elements to store and regulate heat energy, and (3) a Biomimetic Fluid Network, utilizing liquid-metal or advanced dielectric coolants in a capillary-inspired tubing system to transfer heat efficiently while minimizing bulk. The system enables both heating and cooling by dynamically circulating the working fluid between a heat source (PCM release or resistive heating) and a heat sink (PCM absorption or thermoelectric cooling), depending on mission conditions. The suit supports both tethered and untethered operation, reducing diver load in surface-supplied missions or enabling extended independent operations with onboard thermal storage (3–5 lbs PCM and a 200–300 Wh battery, total weight: 16–25 lbs). The system is designed to regulate diver temperature based on real-time thermal sensor feedback autonomously, ensuring optimal comfort and performance during extended underwater missions. In Phase I, HII will develop and test sub-scale prototypes, integrating compression-resistant insulation with the hybrid fluid circuit. TPACC will conduct Sweating Guarded Hotplate (ISO 11092) tests to evaluate R-value performance in wet and dry states, chemical durability assessments (ASTM D1141) to validate contamination resistance in oil-laden seawater, and glove thermal comfort testing to ensure manual dexterity at 35–40°F. The Phase I outcome will be a torso-only LM-DTS prototype, validated for thermal efficiency, durability, and operational feasibility. The LM-DTS is designed for Navy divers conducting salvage, reconnaissance, and search-and-rescue missions and has significant dual-use applications in offshore energy, scientific exploration, and extreme-environment diving. The project will transition into Phase II by expanding to a full-body suit prototype, followed by operational field tests in collaboration with NAVSEA and special operations diving teams.