By Bill Ivey

Principal Consultant

With the push for greater electrification of building systems, electrical energy efficiency has become a hot topic. This article takes a high-level look at four strategies to improve the electrical efficiency of mechanical and plumbing systems in commercial buildings.

1. Variable Speed Drives

Variable speed drives are compact, suitcase-sized devices that control an HVAC system’s motor speed by adjusting the electrical frequency and voltage supplied to the motor. These drives, once expensive, are now much more affordable. By controlling speed, they ensure that pumps and fans use only the necessary power to maintain a set temperature or pressure, improving efficiency and reducing energy consumption.

2. Magnetically Levitated Chillers

Large cooling plants have traditionally relied on water chillers with oil-lubricated centrifugal compressors. A newer alternative, magnetically levitated compressors, suspend the compressor shaft with a magnetic field, eliminating friction. This innovation reduces electrical energy consumption by up to 40 percent compared to conventional compressors, making it a highly efficient choice.

3. Control of Outside Air Flow

Modern building codes require ventilation systems to supply fresh outdoor air to occupied spaces. In both hot and cold climates, outside air significantly affects heating and cooling demands. Precisely controlling outside air flow is crucial to maintaining energy efficiency and minimizing unnecessary heating and cooling loads.

4. Minimizing Air and Water-Pressure Resistance

Air and water delivery systems, such as ductwork and piping, have a major impact on energy costs. Designing these systems with lower friction loss allows fans and pumps to operate more efficiently, consuming less electrical energy while maintaining proper airflow and water circulation.

Ultimately, HVAC systems account for approximately 40 percent of energy use in commercial buildings. Implementing one or more of these strategies can significantly improve electrical efficiency, reduce costs, and contribute to a more sustainable building operation.