Long-Term Deployment of Liquid-Cooled High Frequency (HF) Radar

A liquid cooling system has been incorporated into a 5 MHz (long-range) SeaSonde HF radar system from CODAR Ocean Sensors. The cooling system consists of commercially available heat exchangers, connected in series and applied to various heat sources within the system. These include the central module within the transmitter chassis, as well as four locations within the receiver chassis. In addition, heat exchangers were also installed on the processor, northbridge, and hard drive of the Apple Mac mini computer used to govern the system. Bench testing showed that these heat exchangers are sufficient to effectively dissipate the roughly 200 W of heat generated by the radar equipment. We also designed and built a cooling reservoir for the dissipation of this heat to the external environment. In order to minimize power consumption, a passive cooling reservoir was developed. Four 55 gallon high-density polyethylene barrels are used to store the water, which is cooled by ambient air and wind. Water is circulated through the system by a single 39 W pump operating off of 24 VDC. This system was field-deployed for one year at Matagorda Island, located in Texas off the coast of the Gulf of Mexico. This is a remote site at which commercial power is unavailable. Instead, the system is powered by a photovoltaic array. Air conditioning at this site would more than double the total power requirements of the installation. In contrast, the water cooling system requires less than 20% of the total electrical power. From August 2008 to August 2009, the system operated with high reliability, producing surface current radial data which was transmitted in near real-time via a cellular signal to the National HF Radar Network and is publically available via the World Wide Web.