Architectural Thermal Energy Harvesting Opportunities for Sustainable Computing

Increased power dissipation in computing devices has led to a sharp rise in thermal hotspots, creating thermal runaway. To reduce the additional power requirement caused by increased temperature, current approaches apply cooling mechanisms to remove heat or apply management techniques to avoid thermal emergencies by slowing down heat generation. This paper proposes to tackle the heat management problem of computing platforms with a fundamentally new approach - instead of heat removal using cooling mechanisms and heat avoidance using dynamic thermal/power management techniques, this work investigates the mechanisms to recover wasted heat into reusable energy for sustainable computing. Through recent advancements in thermoelectric materials, we allow wasted heat energy generated by computing devices to be recovered, transformed, and harvested as electricity that can be directly used within the system. We demonstrate a real-system setup where we recover 0.3 to 1 watt of power with the CPU running at 70 to 105°C, using a COTS thermoelectric device on top of the CPU. Through this research, we hope to motivate more in-depth efforts to explore heat energy harvesting opportunities on computing devices and inspire plausible solutions to overcome the technical challenges discussed in this paper.