Liquid Cooling for a SeaSonde Transmitter

Acknowledgements Thanks to Nelson Bednersh and Andy Weinberg at the UCSB College of Engineering Machine Shop

Figure 4. The water cooling block with the cover removed resting on top of the testing block, with the RTD in center

Figure 2. The SeaSonde Transmitter stock arrangement.

Figure 5. Final testing set up with radiator, pump, reservoir and heaters.

Future plan Field deployment is scheduled for September 20th, on

Santa Cruz Island, where its effectiveness will be monitored.

Design Criteria

 No modification to the stock transmitter – cooling block fits between amplifier and stock heat sink  Copper tubing used outside of the electronics enclosure to minimize rodent damage or other leaks.

 A non-toxic antifreeze/DI water solution used to prevent corrosion.

 Dissipate enough heat to keep transmitter from shutting off automatically.

 Use less power than an air conditioner.

Figure 3. The heaters connected to the variable transformer

Test Setup:  Simulated the transmit amplifier with an aluminum block connected to three resistance heaters controlled by a variable autotransformer.

 Temperature of simulated amplifier measured with platinum RTD (Resistance temperature detector).

 Temperature differential between simulated amplifier and ambient recorded at steady state.

Abstract We built an aluminum liquid cooling block for use with

a SeaSonde transmitter at a site where limited access to electrical power precludes the use of a typical air conditioner. Test results indicate that the device will cool the transmit amplifier module to about 5oC above ambient, dissipating about 75 Watts of heat, while consuming about 36 Watts of power.

Edward Reams1, Cyril Johnson2, Brian Emery3, Libe Washburn3 U.C. Santa Barbara 1Department of Mechanical Engineering, 2Department of Physics, 3Marine Science Institute

Heater

Radiator

Pump

Water Block

Reservoir

Air Flow

Figure 1. Amplifier and Receiver temperatures (upper), with number of radials measured per hour(lower), showing the loss of data during days with high temperatures (receiver > 40oC)

Pins for extra cooling

temperature sensor

O-Ring

Water Path

Figure 6. The final assembly, integrated onto the transmitter

Test Results Tests were conducted at heat input levels ranging from 60-175 watts, but we conservatively chose 75 Watts as representative of the SeaSonde amplifier. The system cooled the aluminum testing block to about 5oC above ambient. After testing with water only, a 50% antifreeze-water solution was used with identical results.

Heat is generated here, at the amplifier

Stock heat sink

Heaters Variable Transformer