Using data centres for combined heating and cooling: An investigation for London

Data centres consist of data halls, or buildings, containing rows of IT server racks, which are used to store, process and transmit information from connected computer networks. There are estimated to be more than 2 million server racks in the UK. Data centres are large energy users, being currently responsible for at least 1.5% of the electricity demand for the whole of the UK and with increased internet use this is projected to grow by up to 20% per year up to 2020. Electricity is used both to power the IT servers and for the cooling equipment, such as air conditioning systems, which are used to remove the heat generated by the IT servers. This heat is normally discharged to the ambient air; however, if the heat could be recovered and reused, it would represent a significant heat resource. This paper describes the range of approaches available for the cooling of IT servers and their potential for waste heat recovery and reuse. One waste heat recovery application that has been recently proposed, for example by the UK's Department of Energy and Climate Change (DECC), is as a heat source for district heating networks. The use of heat pumps to boost the temperature of the waste heat rejected by data centres, in order to meet the heat input requirements for heat networks is explored in this paper, and the potential energy, carbon and cost savings available are presented. The matching of potential data centre waste heat sources to the heat requirements for a number of London districts is also reported. (C) 2015 Elsevier Ltd. All rights reserved.