Compressors with variable-speed technology can match output to the demand for cooling.

Injection molding and extrusion to form plastic shapes are examples of such processes. Plastic parts in automobiles, for example, are uniform, sturdy, fairly easy to install, and manufactured in temperature-controlled processes. In such cases, industrial chillers control the temperatures of the molds used to make the parts.

There is a bit of irony here. According to Danfoss, compressors that power industrial chillers are themselves often machined by tools whose cutting actions are cooled by industrial chillers. That is the case with the company's Maneurop hermetic compressors.

To optimize chiller capabilities, Danfoss provides industries, including chiller manufacturers, with compressors equipped with variable-speed technology.

Variable speed, when applied to a refrigeration compressor or one used for air conditioning, matches the compressor output to the demand for cooling.

"This ensures the compressor speed runs to reach the target cooling temperature, and no faster," said Jeff Staub, Danfoss application engineering manager. "This saves a lot of energy because the alternative is to introduce hot gas into the cooling circuit to control the temperature, which is simply not the most efficient method."

Variable-speed compressors run throughout the time the machinery is in use. "Although it might seem that running equipment constantly would waste energy, the contrary is true - if little energy is used, or just the right amount, then running the compressor constantly actually extends its service life by eradicating the stresses of stopping and starting."

Danfoss supplies hermetics from 1/10 hp to 70 tons. Staub said that because variable speed makes possible energy efficiency and extended compressor life, the company enhanced the design of many of its compressors to make them suitable for high-efficiency variable-speed operation over an extended capacity range.

For more information, visit www.danfoss.com.

Publication date: 05/02/2005