Energy Management and Conservation

• Introduction
• Potential Savings through Energy Conservation
• Application to Universities
• Summary
• Notes
• Appendix A
• Appendix B

Introduction

Of the total energy used in the United States, approximately 36 percent is consumed by the building sector. Within the commercial building sector, typically 42 percent of the energy is used in the form of electricity for lighting, heating, cooling, and miscellaneous applications. On a nationwide basis, lighting represents approximately 17 percent; cooling, approximately 14 percent; and heating, approximately 41 percent of the source energy used. Although the actual mix of energy varies widely depending on geographic location and type of occupancy (office building, hospital, school, etc.), lighting, heating, and air conditioning generally represent the largest of the energy-intensive operations in commercial and institutional buildings.

Since the mid-1980s, and particularly since 1990, certain types of energy conservation and demand-side management projects have become popular for reducing the utility costs of buildings. Lighting retrofits involving electronic ballasts, reflectors, occupancy sensors, and other forms of lighting controls have gained immense popularity partly because they can be implemented with minimal or no engineering effort and have a high rate of return. Similarly, in the heating, ventilation, and air conditioning (HVAC) area, variable-frequency drives, economizer controls, energy-efficient motors for large HVAC equipment, thermal energy storage (TES), high-efficiency chillers, and direct digital controls (DDC) have been used extensively to enhance the part-load efficiency and control of HVAC equipment. In all likelihood, the drive for reducing utility costs and achieving high energy efficiency will continue unabated through the balance of this century and beyond.