SHF: Small: Novel Architecture Energy Harvesting for Sustainable Spot Cooling and Energy Management

计算设备功耗的增加导致计算机芯片上的热热点急剧上升，形成恶性循环？较高的温度带来较高的泄漏功率，而较高的功率耗散使温度升高，从而导致热雪崩。为了减少由高温引起的额外的功率耗散和可靠性问题，当前的热管理方法应用冷却机制来积极地去除热量，以及设计动态管理技术，该动态管理技术通过减慢处理器的热量生成来避免热紧急情况。然而，当前的趋势是挤压更多的计算能力，例如，以大型数据中心或移动的设备的形式，与我们减缓对更多能源需求的能力直接冲突。晶体管尺寸的缩小进一步加剧了能量效率降低的问题。在这项工作中提出的解决方案预计不仅可以降低冷却费用和环境温度，而且还可以提高能源利用率，设备寿命和物理空间利用率。这里开发的技术可以应用于各种各样的计算设备，无论大小。如果研究成功，它有可能产生重大的经济效益，并对环境产生重大的积极影响。这是因为在热约束下处理器的性能提高和功耗降低将直接影响大型数据仓库的冷却成本，例如Google，Yahoo，Amazon等。美国的数据中心消耗数百亿千瓦时的电力，产生近十亿公吨的二氧化碳。即使该项目导致现代高性能处理器的能耗提高5%，因此，在数据中心中安装的数百万个这样的处理器中，这本身就可以减少每年释放到大气中的二氧化碳量，并实现数千万美元的能源成本节约。 此外，这种能量收集研究需要在材料工程，VLSI架构，系统架构和机械工程等领域进行跨学科的参与，并将吸引各种学生研究人员。总的来说，工程和科学的贡献也将产生重要的社会影响，包括扩大亚利桑那州立大学？的工程课程，研究生和本科生在研究活动中的参与，创造高中或中学科学项目的潜力，并在科学和工程的目标代表性不足的少数民族的代表性增加。而不是消除热量或减缓热量的产生，所提出的工作将废热转化为可重复使用的能源，用于新的应用，如自供电的局部冷却。该项目的主要目标是设计和实现一个新的架构框架，以创建机制，策略和系统支持，允许有效地收集计算设备产生的废热，以实现更好的能源利用效率。这将通过利用现代计算节点的热特性以及利用热电和热释电能量收集材料来实现。通过在架构级别利用热电和热释电效应，利用计算产生的不同空间和时间的热梯度将处理器废热（否则会耗散）转换为可重复使用的能量。还提出了一种新的应用程序，使用新引入的能量的形式的一个自我维持的冷却系统的处理器。这项工作评估的能量收集材料的适用性，考虑复杂的电性能的材料和异质温度分布的组件上的处理器。所提出的方法是通用的，可以很容易地采用商业上可用的热电和热电能量收集材料。尽管如此，随着材料能量转换效率的突破，所提出的框架可以直接应用，进一步提高收集能量的程度，从而导致更高的系统能量效率。

Increased power dissipation in computing devices has led to a sharp rise in thermal hot spots on computer chips, creating a vicious cycle ? higher temperatures bring higher leakage power, and higher power dissipation increases temperature, thereby leading to thermal avalanches. To reduce the additional power dissipation and reliability concerns caused by high temperature, current heat management approaches apply cooling mechanisms to remove heat aggressively as well as devise dynamic management techniques that avoid thermal emergencies by slowing down heat generation of processors. However, current trends to squeeze more computing power, e.g., in the form of large data centers or mobile devices, stand in direct conflict to our ability to slow down demand for more energy. The shrinking of transistor sizes further exacerbates the problem of reduced energy efficiency. The solution proposed in this work is anticipated to not only reduce cooling expenses and ambient temperatures, but also increase energy utilization, device lifetime, and physical space utilization. The technology developed here can be applied to a broad range of computing devices, large or small. If the research is successful, it has the potential of having a significant economic benefit as well as a significant, positive impact on the environment. This is because performance improvement and power reduction of processors under thermal constraints will have a direct impact upon the cooling costs of huge data warehouses such as those of Google, Yahoo, Amazon, etc. Data centers in the US consume many tens of billion kWh of electricity and generate about nearly a billion metric tons of carbon dioxide. Even if this project resulted in a 5% improvement in the energy consumption of a modern high performance processor and therefore, in the millions of such processors housed in data centers, that itself could reduce the amount of carbon dioxide released into the atmosphere per year, and realize ten of millions of dollars in energy cost savings. Furthermore, this energy harvesting research requires cross-disciplinary engagement in areas such as material engineering, VLSI architecture, system architecture, and mechanical engineering and will attract a diverse set of student researchers. Overall, the engineering and scientific contributions will also have important societal impacts, including the broadening of ASU?s engineering curriculum, the engagement of graduate and undergraduate students in research activities, the potential of creating high-school or middle-school scientific projects, and the increased representation of target underrepresented minorities in science and engineering.This project addresses the heat management problem using an innovative approach ? rather than removing heat or slowing down heat generation, the proposed work transforms the waste heat into reusable energy for new applications such as self-powered spot-cooling. The main objective of this project is to design and implement a novel architectural framework to create the mechanisms, policies, and system support that allow waste heat generated by computing devices to be harvested efficiently, to achieve better energy utilization efficiency. This will be achieved by exploiting the thermal characteristics of modern computing nodes and by leveraging thermoelectric and pyroelectric energy harvesting materials. By leveraging the thermoelectric and pyroelectric effects at the architectural level, the varying spatial and temporal thermal gradients from computations are exploited to transform processor waste heat (that otherwise dissipates) into reusable energy. A novel application is also proposed that uses the newly introduced energy in the form of a self-sustaining cooling system for processors. This work evaluates the applicability of energy harvesting materials by considering the intricate electrical properties of the materials and heterogeneous temperature distribution of the components on a processor. The proposed methodology is generic and can be readily adopted with commercially-available thermoelectric and pyroelectric energy harvesting materials. Nonetheless, with breakthroughs in the energy conversion efficiency of the materials, the proposed framework could be applied directly with a further improved degree of harvested energy, leading to even higher system energy efficiency.