A Control Strategy for Minimizing Temperature Fluctuations in High Power Liquid to Liquid CDUs Operated at Very Low Heat Loads
A Control Strategy for Minimizing Temperature Fluctuations in High Power Liquid to Liquid CDUs Operated at Very Low Heat Loads
复制标题
一种用于最小化在极低热负荷下运行的高功率液对液 CDU 温度波动的控制策略
DOI：
10.1115/ipack2022-97434
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Jeremy Rodriguez
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文献类型：
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作者：
A. Heydari;Pardeep Shahi;Vahideh Radmard;Bahareh Eslami;Uschas Chowdhury;Chandraprakash Hinge;Lochan Sai Reddy Cinthaparthy;Harold Miyamura;Himanshu Modi;D. Agonafer;Jeremy Rodriguez
对高性能中央和图形处理单元不断增长的需求导致需要更高效的热管理技术，例如直接芯片液体冷却。使用冷板的直接液体冷却是 20 世纪 80 年代以来最有效且经过研究的冷却技术之一。由于计算需求不断增长，主要数据和云提供商正在积极部署液冷数据中心基础设施。液冷数据中心中使用的液对液热交换器也称为冷却剂分配单元 (CDU)。数据中心运营商选择的大多数 CDU 都是基于数据中心的热负载以及该 CDU 的可用磁头。在本研究中，设计和部署了三个 52U 机架，每个机架中有六个基于 TTV 的高功率服务器（热测试车辆）。每台服务器由八个 GPU TTV 和六个 NV 开关加热器组成。采用450kW液冷CDU，冷却剂采用25%丙二醇。典型的 CDU 设计为在额定热负荷的 20% 至 30% 下运行，以实现稳定的二次冷却剂供应温度。本研究将调查 CDU 在极低热负荷下的运行情况，例如 CDU 额定容量的 1% 到 10%。在这些低负载下，观察到次级侧电源温度的大幅波动。这种大的波动可能会导致一次侧 CDU 中使用的三通阀发生故障。本文开发了一种控制策略，结合初级侧的流量控制阀和 CDU 内的 PID 控制设置，在极低负载下将次级电源温度稳定在 ±0.5 °C 范围内。
The rising demand for high-performance central and graphical processing units has resulted in the need for more efficient thermal management techniques like direct-to-chip liquid cooling. Direct Liquid Cooling using cold plates is one of the most efficient and investigated cooling technologies since the 1980s. Major data and cloud providers are actively deploying liquid-cooled data center infrastructure due to rising computational demands. Liquid to liquid heat exchangers used in liquid-cooled data centers is also referred to as coolant distribution units (CDUs). Most of these CDUs selected by the data center operator is based on the heat load of the data center and the available head with that CDU. In this study, three 52U racks with six high-power TTV-based servers (Thermal Test Vehicles) in each rack were designed and deployed. Each server consists of eight GPU TTVs and six NV switch heaters. A 450-kW liquid-cooled CDU is used, and propylene glycol 25% is used as a coolant. Typical CDUs are designed to operate at 20 to 30% of the rated heat load to achieve a stable secondary coolant supply temperature. The present study will investigate the operations of CDU at very low heat loads, like 1% to 10% of the CDU’s rated capacity. At these low loads, large fluctuations in secondary side supply temperature were observed. This large fluctuation can lead to the failure of the 3-way valve used in CDUs at the primary side. In this paper, a control strategy is developed to stabilize the secondary supply temperature within ± 0.5 °C at very low loads using the combination of a flow control valve on the primary side and PID control settings within the CDU.