Abstract
The IT sector has seen rapid growth in recent decades due to the demand for higher capacities in cloud-based services. This growth has been reflected in data center (DC) cooling demands due to higher heat output and leading to increased energy consumption. Though the temperature range of DC heat output is low compared to that of other industrial processes, recovering the waste heat using Waste Heat Recovery (WHR) units can still be feasible. This study presents the analyses, technical and economic, of WHR applications on the component level to better understand the impacts of implementing such systems in DCs. A transcritical CO2 WHR system was proposed for a DC located in Sacramento, CA. A transcritical refrigeration cycle was developed and optimized to reach a coefficient of performance (COP) of 4.45 prior to the addition of a WHR system. A WHR heat exchanger was developed to recover waste heat from the DC hot aisle to function as a gas precooler in the refrigeration cycle loop. The implementation of the DC WHR heat exchanger into an existing transcritical CO2 cooling system demonstrated a higher COP of 4.63, a return on investment (ROI) of 27%, and a payback period (PBP) of 4 years for a large-scale DC.