Controlled Direct Liquid Cooling of Data Servers

Abstract

We formulate a modelling and control framework aimed at direct liquid cooling of data servers. In our application scenario, the server's heatload is rejected into a liquid cooling circuit that extends to the individual chips. We start with a comprehensive discussion of our modelling derivations and then we show how to manipulate the coolant's flow while 1) regulating the temperatures of any self-heating components within a safe operational envelope, 2) minimizing the coolant supply cost and 3) increasing the server outflow temperature (a key performance objective towards heat reuse systems). We confirm experimentally the benefits of the proposed controlled cooling strategy over several realistic scenarios corresponding to different inlet coolant temperatures and computational loads.