Managing Peak Loads With Variable-Speed Equipment

With energy demands continually rising throughout the country, the HVAC industry bears a particular responsibility for implementing energy-saving measures. This can be achieved through improved efficiency, better equipment, and features and components that make better use of the energy consumed to produce heating and cooling. Air conditioning, for example, can account for as much as 60 percent of all energy used during peak hours. By using variable-speed equipment to produce heating and cooling, energy use can be significantly reduced with little or no impact on the quality of indoor comfort.

Stress on the Power Grid

HVAC equipment produces considerable stress on the local power grid. Cumulatively, extra use of local power grids produces significant amounts of demand on overall power resources nationwide. Older furnaces and air conditioners are particularly troublesome as energy consumers since they typically have much lower efficiency levels and do not contain the improved components of newer systems. During peak-use times, heavy use of the local grid can increase energy costs for consumers while making brown-outs or blackouts more likely. Efficiency-boosting equipment and components are easily and readily available for use in modern furnaces and air conditioners. As part of a community improvement initiative, the HVAC industry could partner with electric utilities, HVAC professionals, and consumers to promote the use of variable-speed equipment that helps save energy, aid the environment, and cut high-cost excess use of local power supplies.

Benefits of Variable-Speed Equipment

Variable-speed equipment relieves stress on the local power grid by reducing the amount of energy used by individual furnaces and air conditioners. For example, a variable-speed component will operate at its highest levels only in response to actual demand. This is in direct contrast to single-speed components and equipment that always function at their highest and most energy-intensive level every time they switch on. Since variable-speed equipment works at this high level on energy consumption only when necessary, it runs at lower energy-saving levels more frequently. The benefits of variable-speed equipment also can be very apparent within a commercial building or home. Variable-speed components can:

• Reduce energy consumption, which lowers energy bills
• Reduce energy loss, which eliminates paying for energy you didn’t need or use
• Improve the “green profile” of your HVAC equipment while reducing emissions, energy waste, and other factors that can harm the environment and impair conservation of limited natural resources.

Variable-Speed Equipment and HVAC Components

Two of the most common types of variable-speed equipment for your HVAC system are variable-speed blower motors and two-stage compressors.

Variable-Speed Blower Motors

Blowers or air handlers are the system components that distribute the conditioned air produced by an HVAC system. They force conditioned air out of the furnace or air conditioner, into the system’s ductwork, and out at registers and vents placed throughout a building. A variable-speed blower motor is designed to start at a lower speed, then increase speed if more heating or cooling is needed to meet temperature settings at the thermostat. If less air circulation is needed, they drop to the lower speed. In general, variable-speed blower motors can reduce energy consumption by as much as 60 percent over standard single-speed motors.

Two-Stage Compressors

Variable-speed or two-stage compressors let an air conditioner produce the most cooling only when outside temperatures are high enough to warrant it. Most of the time, these compressors work at a lower level, which produces sufficient cooling for most residential settings. Because the compressor runs longer at a lower level, the unit wastes less energy during on and off cycles that typically consume large amounts of power. An additional benefit of two-stage compressors is that they can usually use newer, more environmentally friendly refrigerants. They are also quieter and more effective at humidity removal.

Our goal is to help educate our customers about Plumbing, HVACR, Fire Protection and Alarm Systems in Mechanical, Commercial and Residential settings. For more information on making the best use of variable-speed equipment and components in your air conditioner or heating system, or to view projects we’ve worked on, visit our website!