Metered energy consumption and analysis of energy conservation techniques in desktop PCs and workstations

Abstract

This thesis investigates potential energy savings due to the application of power managed PCS, monitors, and workstations. The basis of this effort includes electric metering of such equipment at six preliminary and one primary location, a large business office in Boston, Massachusetts. Metering there occurred over an 8 week period, using an in-line metering device, and at a resolution of one minute intervals. The results of this study show that many problems exist in the field today which prevent any energy savings from being realized. These include both software and hardware incompatibilities. It was found that either the equipment was not enabled from the beginning; that various problems caused inadvertent disabling of the energy saving features, or that lack of knowledge about specific power management techniques caused the user to intentionally disable the features. Since this work began, the EPA's Energy Star Computers and Monitors Program updated their requirements such that energy saving features are now enabled when they are shipped from the manufacturer. All computers tested in this investigation were installed before the application of this condition, which was October 1, 1995. However, many problems exist other than those remedied by this requirement, including: computers which disengage from the network environment upon entering the lowest power management levels, various software incompatibilities, problematic methods of achieving power reduction, and little to no training of users or even prior negative experiences with power managed equipment There is a need for manufacturers to develop suitable or standard methods of achieving power management In addition, computer procurement employees or users must be taught about power management methods, and must have an opportunity to voice questions or concerns to manufacturers regarding power managed equipment. More research needs to be focused on network incompatibilities. Specifically, many computers are disconnected from their network upon engaging the lowest power level. This is due to either unacceptable power management methods or "stand-alone" power manageable computers which are placed on a network. Users purchasing computers intended for network use should be informed about whether the energy saving features are compatible with their type of network. This thesis is divided into two parts, the first for PCs and the second for workstations. The primary metering site for workstations was the Massachusetts Institute of Technology, which contains both Energy Star compliant and non-compliant machines. Opportunities for energy conservation in workstations are compared and contrasted to those of desktop PCs and monitors. In addition, current and future trends in workstation manufacturing and their impacts on energy conservation are explored.