Energy efficiency in office technology

Abstract

This thesis, directed toward a wide variety of persons interested in energy efficiency issues with office technology, explores several issues relating to reducing energy use and improving energy efficiency of office equipment. Chapter 2 compares policies and programs in several European countries and the United States that could enhance the energy efficiency of office technology. Different programs are examined, including federal government programs where in some cases target values for power usage of office equipment have already been set. Large customer procurement programs, industry involvement, with emphasis on voluntary labeling programs, and research projects are also examined. Procedures that provide energy consumption measurements of various types of equipment are important for providing information to emerging procurement programs. Two sets of proposed test procedures for testing energy consumption of copiers, fax machines and printers are examined and compared. In Chapter 3, comparisons are made of the electrical power and energy used by computers, displays, copiers, printers and facsimile machines, both while operating and while idle. Technology options for reduced energy and power consumption and improved energy efficiency are examined. As the capability of office equipment has increased, there has been a trend toward increased electrical power requirements and energy consumption while equipment is in active operation. Computer power continues to grow rapidly. These factors will combine to exert an upward pressure for electrical power. However, some emerging technologies are lessening or in some cases reversing this trend, with little or no penalty in performance or production. The overall balance between increased service and efficiency is uncertain. Chapter 3 also examines the embodied energy of paper and office equipment. I compare it to the total energy required to produce a printed page of information, or required over the lifetime of the machine. Many difficulties were encountered in collecting and comparing data on power requirements of various machines. Procedures for testing the energy usage of office equipment are needed to make valid comparisons between machines. This thesis describes in Chapter 4, modifications to the procedure issued by the American Society for Testing and Materials (ASTM) to test energy consumption in copiers, to account for energy saver modes and double-sided copying. It also presents new procedures submitted to the ASTM committee for printers and fax machines. A fourth procedure is also presented here, one to test the energy consumption of personal computers. Typically, office equipment is not in use for much of the time it is turned on. Use of power management in office equipment can considerably decrease overall energy consumption. While energy saver modes are more prevalent in copiers, those printers that have incorporated this feature achieve more dramatic power reductions. Fax machines do not seem to utilize this technology at all, even though many have high power consumption when they are idle. How energy saving modes effect the overall energy consumption of machines is largely determined by operating profiles of the machines. The effect of operating profiles on energy usage with imaging equipment has not yet been examined. Methods of determining operating profiles of office equipment are presented in Chapter 5. A comparison is made between the energy use predicted by the ASTM procedures, energy use predicted by the ASTM procedures and actual operating profiles, and the actual energy usage of several copiers and printers. For copiers, the ASTM rated energy use per page was from 10-161 % different from the actual measured energy use per page. The use of the ASTM method with the measured operating profiles of the machine gave a 7-22% difference in energy use per page. For printers, the rated values using the ASTM method gave 61-317 % difference from the actual measured energy use per page, while using actual usage profiles with the ASTM method gave 0-6% difference. This thesis provides information on a variety of subject in the area of energy use and energy efficiency in office technology. The results provide information for emerging programs and provide a strong basis for a variety of further research.