Subzero System Heating for Outdoor Applications

Edge Compute is pushing compute closer to the sources of data. In some instances, this means Edge equipment will be placed outdoors where temperature extremes may be as low as
$-40\ ^{\circ}\mathrm{C}$
and as high as
$55^{\circ}\mathrm{C}$
(plus solar load). During subzero operation a system could be operating outside of specification if the system components (processor, FPGA, ASIC, etc.) have a commercial temperature rating, i.e. Tease-min
$=0^{\circ}\mathrm{C}$
. To ensure component temperatures are operating within their respective temperature specifications, supplemental heat is required. This paper reviews methods to introduce system heat, the power required to overcome ambient conditions and system thermal inertia under Cold Start and Cold Operation conditions, reliability concerns and cost of implementation.