Heat-transfer advances for submerged oceanographic systems

This paper outlines various heat-transfer methods utilizing modern fabrication techniques in conjunction with computer modeling to provide low-risk alternatives for thermal management. It presents details of a particular heat pipe configuration capable of dissipating 400 watts through a 9 1/2-inch diameter, 2-inch-thick grade 5 titanium endcap. Traditional dry contact methods, liquid cooling, and improved geometry are also discussed. The amount of power delivered to cabled systems is on the rise. As all-electric ROVs, manned submersibles, and high-powered cabled seafloor observatories come on line, inevitable inefficiencies mean that these systems must dissipate more heat. The rationale for this effort is multifaceted. Excessive heat is the enemy of solid-state electronics. It affects component longevity and efficiency in addition to introducing undesired drift in instrumentation. Increased component density is creating more heat per volume. Additionally, power conversion modules and improved motor drives are decreasing in form factor and providing less area for heat dissipation. New and improved heat-transfer methods will facilitate a greater selection of appropriate pressure case materials. Titanium, stainless steel, plastics, and ceramics should not be disallowed because they limit heat transfer. Trends in electronic components and material selection can continue to improve system design without compromising overall heat transfer. Thermal engineering needs to be part of the system integration at the onset of a project's design.