Engineering Sustainable Data Centres - A Techno-Economic Analysis of Data Centres Cooling Technologies, Operating Conditions, Renewable Energy Integration & Waste Heat Recovery Opportunities

Abstract

Data centres are growing to be a crucial industry sector, currently consuming an estimated three percent of the annual electricity supply globally, contributing two percent of total global greenhouse emissions, and half of the energy wasted as dissipated heat. This thesis is focused on reviewing opportunities and technologies for improving the green metrics of data centres. There is currently a lack of comprehensive analysis considering data centres as energy prosumers, integrating renewable energy sources upstream and utilizing waste heat downstream. This study aims to address this gap by providing such a review. It examines advancements in cooling techniques, renewable energy integration, advanced controls, waste heat recovery, district heating connections, real projects, performance metrics, and economic, energy, and environmental analyses. From an extensive review of data centres in district energy systems, the following key findings emerged:1. There is a lack of international standards and processes that can be deployed to manage renewable energy production, data centre operations, waste heat generation, and downstream waste heat utilization.2. Regional studies offer effective insights for optimizing the integration of renewable energy and waste heat recovery technologies to enhance data centres’ energy efficiency.3. It is economically feasible to utilize waste heat from data centres for district heating purposes, provided that a comprehensive technology and market assessment. Recovering waste heat from data centers poses challenges, particularly when dealing with decentralised and low-quality waste heat. Therefore, exploring ways to maximise data centres’ energy efficiency and utilize their waste heat is vital. The study highlights absorption chiller systems as promising for recovering waste heat at ultra-low temperatures. The study delves into the potential of reusing waste heat from data centres and proposes alternatives to enhance the efficiency of waste heat utilisation by data centre operators. It also discusses how liquid coole ddata centres outperform air-cooled ones in waste heat utilisation. The study addresses barriers related to connecting data centres to heat networks and provides suggestions for overcoming these obstacles. Additionally, a framework that can be used as a decision support tool for various stakeholders is presented that analyses the feasibility of waste heat recovery from various source(s) and their accompanying sink(s), the balance of exergy and the temporal availability. The research also comprises of an economic analysis of various technologies that can be used for district heating and how they compare to data centres heat recovery technologies. Theresults demonstrate the economic viability of data centre waste heat recovery, and monetizing environmental benefits further enhances its economic advantages. Moreover, sensitivity analysis reveals that the current carbon price has minimal impact on the project's economy, while operational and maintenance costs and energy costs are key factors. The findings of this study not only offer new insights for energy sustainability but also serve as a reference for decision-makers and investors.