Thermal Control of Surveillance Systems Using Pulsating Heat Pipes

Abstract

Important applications can be found on surveillance systems using high performance thermal control devices, especially passive ones using heat pipe technology. With the growing need for heat dissipation presented by this type of system, usually hybrid solutions are designed. This is usually applied when the heat source is located far from the heat sink and the use of liquid cooling or any other active thermal control system is not possible. Since most of the surveillance systems being designed today require thermal control devices that operate under adverse orientation, some restrictions apply. Therefore, the technology that is currently used and disseminated for aerospace can find many other applications in surveillance systems for defense purposes. With severe restrictions regarding available space for integration of common thermal control devices, the design and application of pulsating heat pipes (PHPs) becomes the most indicated solution for the present investigation, together with the use of heat pipes for proper heat rejection. Based on this fact, this investigation is focused on presenting the thermal control management of electronic components of a surveillance system being done by PHPs configured as open loops with conventional heat pipes. Despite the relatively high temperature difference observed between the heat source and the sink (up to 25 o C), the open loop PHP was able to transport the rejected heat (up to 40 W) from the electronic components to a remote heat dissipation area, while keeping their temperatures within the required range established by the project (below 80 o C) and relatively high thermal conductances (up to 1.6 W/ o C), as demonstrated by experimental results. The heat pipe has demonstrated the capability of spreading the heat evenly, positively affecting the operation of the PHP. The operation of this combined solution has shown to be stable and reliable.