Network auditing for low-cost assessment of networked equipment generated loads in office buildings

The large electricity expenditure of ubiquitous networked equipment within office buildings calls for dedicated load monitoring. Walk-throughs, in situ equipment-level power measurements, and installation of software agents on machines are generally conducted to assess generated loads. Such approaches have cost and time constraints that hinder widespread deployment in many sites if return on investment is not guaranteed. This work proposes to audit non-invasively equipment on virtual local area networks, enabling automated and low-cost assessment of networked equipment loads. Used as a preliminary load assessment, generated figures will be key to motivate further instrumentation. Experiments have been undertaken with the proposed methodology within a University Department comprising more than 850 unique networked machines. Results over a 15-month audit have highlighted that (1) client machines contributed to 18.4% of the Department's daytime power consumption units and to 14.6% of the nighttime power consumption units and (2) server machines contributed to 19.6% of the Department's daytime power consumption units and to 23% of the nighttime power consumption units; uncovering opportunities for important savings and fine-grained monitoring.