Comparative analysis of combined cooling, heating and power systems (CCHP) covering data centers energy needs

The Information and Communication Technology (IT) industry has gone in recent years through a dramatic expansion, driven by many new applications and services available on private or public networks. Such growth has obviously needed an equally remarkable growth in energy consumption by data centers, which require huge amounts of power not only for IT devices (servers, network equipment, storage devices), but also for power distribution units (including uninterruptible power sources) and for ventilation and conditioning. It is reasonable to expect that such growth trend will continue in the forthcoming years, given the ever increasingly important role that is being played by IT-related applications and services. It is therefore of the utmost importance to assess the energy consumption of data centers in order to devise possible ways to increase energy efficiency, because in a conventional data center the cooling and power distribution equipment can absorb the same power as the IT equipment itself. An interesting option is the use of distributed generation and combined cooling, heating and power systems (CCHP) designed to meet the whole energy needs of data centers, with absorption chillers used to recover heat discharged by a thermal engine (internal combustion engine or gas micro-turbine) or a fuel cell. Indeed, this would be an almost ideal application of trigeneration, given that electric and cooling power are always required simultaneously, and are not subject to significant daily or seasonal oscillations (with the result of very high utilization factors). Under these circumstances, trigeneration systems can produce relevant benefits for the environment, through reduced primary energy consumption and greenhouse gas emissions, and for data center managers as well, through cost savings related to “lighter” energy bills. In this paper a study is presented offering a comparative analysis of the performance of state-of-the-art trigeneration technologies. In particular, the study compares the energy performance of a conventional data center with the results that can be achieved by generating electric energy by means of CCHP systems based on internal combustion engines and LiBr/H2O absorption chillers. The main results are presented in terms of reduction of primary energy consumption, of greenhouse gas emissions and of annual data center operating costs.