Immersion cooling and heat storage

高性能计算机使用大量的能源来保持冷却和高效运行。英国的建筑物需要大量的能源来保持居住者的温暖。今天，用于加热和冷却的能源是碳密集型的，在全国范围内，加热和冷却的供应占英国温室气体的1/3。冷却HPC系统产生的热量可以用于其他地方的空间加热，并且热存储可以存储多余的热量，并在需要时将其取回。该提案旨在做到这一点：高效冷却HPC系统，并研究将由此产生的多余热量存储在被淹没的煤矿中-英国过去采矿业的遗留资产作为零碳未来的零碳热存储。在这里，我们将研究结合互补能源需求的可持续能源潜力-在不牺牲地球成本的情况下研究社会能源需求。目前英国的大型HPC系统都使用直接液体冷却（DLC），冷却液通过管道输送到计算节点内的散热器上，热量被提取，然后通过热交换器交换，然后释放到大气中。这些系统可以消耗多兆瓦的功率。浸入式冷却是技术的自然发展，它涉及将经过特殊调整的服务器完全浸入传热液体（通常是矿物油）中，从而从所有组件（不仅仅是CPU）中去除热量，简化服务器设计（没有风扇，热管和减少嵌入的二氧化碳）。然后在更高的温度下从系统中提取热量。该技术仅使用5%的功率来处理废热，远远优于DLC系统的约20%和风冷系统的40-100%，从而显著节省了功率。目前英国HPC数据中心没有任何直接使用这种相对较新的技术的经验，因此，我们建议在达勒姆大学的数据中心安装一个商用浸没式冷却槽（它还托管EPSRC BEDE N8 Tier-2系统）。这个浸入式测试台系统将成为一个国家测试设施，供其他数据中心工作人员访问，以获得这项技术的经验，并供供应商展示其服务器技术。我们将分析托管在此罐内的套件的性能，并调查流体温度和服务器能耗等属性。浸没式冷却的另一个好处是，废热处于比传统系统更高（更可用）的温度。达勒姆是这样的设施的理想位置，目前托管国家ExCALIBUR硬件和使能软件系统和Tier-1和Tier-2 facility.We还建议研究数据中心余热再利用，通过调查存储HPC余热在废弃的和淹没的煤矿工作的数据中心网站下面。通过储存废热，它可以在需要时重新使用。这需要在矿井工作区钻几个钻孔来提取水，增加/减少热量，并将其重新注入矿井。简而言之，我们将研究如何将矿井作为一个热电池。这个提议很及时，因为它与大学目前在校园内安装供热网络的计划非常吻合。该网站将被用作一个活生生的实验室，并为其他潜在的系统树立榜样。

High Performance Computers use substantial quantities of energy to keep them cool and operating efficiently. Buildings in the UK require substantial quantities of energy to keep their occupants warm. Today, energy for heating and cooling is carbon intensive, and nationally the supply of heat and cooling is responsible for 1/3 of the UK's greenhouse gases. Heat from cooling a HPC system can be used for space heating elsewhere, and heat storage can store excess heat, retrieving it when required. This proposal seeks to do just that: efficient cooling of HPC systems, and investigating storing the resulting excess heat in flooded coal mines - legacy assets from the UK's mining past acting as carbon-zero heat stores for a zero-carbon future. Here we examine the sustainable energy potential of combining complimentary energy demands - examining societal energy needs without costing the Earth.Current UK large HPC systems all use direct liquid cooling (DLC), where a cooling fluid is piped onto heat sinks within compute nodes, heat extracted and then exchanged via a heat exchanger before being released into the atmosphere. These systems can consume multiple Megawatts of power. Previous air-cooled systems were even less efficient.Immersion cooling is the natural progression in technology which involves fully immersing specially adapted servers in a heat transfer liquid, typically a mineral oil, which removes heat from all components (not just CPUs), simplifying server design (no fans, heat pipes and reduced embodied CO2. Heat is then extracted from the system at higher temperature. This technology uses as little as 5% of power for dealing with waste heat, much better than the ~20% for DLC systems and 40-100% for air-cooled systems, yielding a significant power saving.Current UK HPC data centres do not have any direct current experience with this relatively new technology, and therefore it is seen as a significant risk for adoption in new HPC systems.We therefore propose installing a commercial immersion cooling tank in Durham University's the data centre (which also hosts the EPSRC BEDE N8 Tier-2 system). This immersion test bed system will become a national testing facility for other data centre staff to visit to gain experience with this technology, and for vendors to demonstrate their server technologies. We will analyse the performance of kit hosted within this tank, and investigate properties such as fluid temperature and server energy consumption. A further benefit of immersion cooling is that the waste heat is at a higher (more usable) temperature than from conventional systems. Durham is the ideal location for such facility, currently hosting national ExCALIBUR hardware and enabling software systems and both Tier-1 and Tier-2 facilities.We furthermore propose to study data centre waste heat reuse, by investigating storing HPC waste heat in the abandoned and flooded coal mine workings beneath the data centre site. By storing the waste heat, it can be reused when required. This requires drilling several boreholes into the mine workings to abstract the water, add/subtract heat to it, and re-inject it back to the mine. In short, we would be investigating using the mine workings as a heat battery.This proposal is timely, since it fits well with the university's current plan to install a heat network across its campus.The site would be used as a living lab and exemplar for other potential systems.