Thermal Management: Heat Transfer Using CoolPlug Cooling

In 2002, CoolPlug technology was introduced to the oceanographic community as a novel approach to removing unwanted heat from electronics used in underwater systems. The CoolPlug is an externally mounted, radially finned plug with an internally mounted heat pipe. The heat pipe is routed to hot-spots in the electronics, similar to what you may find in a laptop computer. This unique combination of appropriate materials, geometry, and technology allows heat to flow through thick barriers and nonconducting materials in a manner that it normally couldn't. Excess heat simply flows through the heat pipe to the CoolPlug and into the water in which the container is submerged. The thermal aspects of each system using CoolPlug cooling described in this paper show excellent long-term success. This paper explains the rationale for proper thermal management. It details concerns and considerations with regard to material selection and geometry. It illustrates the importance of computing by using Finite Element Analysis (FEA) to provide low-risk solutions. This paper goes on to show how the CoolPlug system is implemented for working results, and then presents results on small- and medium-scale CoolPlug use. Discussion in this paper includes cooling for small-scale, high-power modules (e.g., cameras coupled to video processors), and data collection and processing with high-speed computers. It discusses cooling considerations for ocean observatory power transformers and long-term observatories where housing longevity is critical. It also includes a review of the common geometries and cooling techniques used when more effective cooling is not necessary. Case studies include the OceanCube Ocean Observing System developed by Woods Hole Oceanographic Institution (WHOI); vehicles of the National Deep Submergence Facility—WHOI's ROV JASON II, AUV SENTRY, and HOV ALVIN; and the Continuous Particle Imaging Classification System (CPICS) by CoastalOceanVision (COV). The CoolPlug is an effective tool to keep electronics running cool, even when operating in warm, tropical water.