The Danfoss ApexxTM VSH compressor and drive package that is honored with the award is the world’s first high-capacity variable speed scroll solution for commercial R-410A air conditioning and heat pumps.
The VSH combines a high efficiency scroll compressor with a specially designed variable frequency drive, and the drive for each package is designed and optimized to specifically match the characteristics of the compressor it is mated with. The drive’s frequency output, from 30 to 90 Hz, controls the capacity delivered by the compressor, and enables the system to always deliver the capacity that meets load demand—no more, and no less.
Air conditioning systems are designed to be able to meet peak demand conditions, but more than 85% of the time, systems work under partial demand conditions. Because Apexx VSH output continuously matches the load, significant energy savings result. Also, much-reduced cycling under partial loads lengthens compressor life, requires less maintenance, and results in enhanced comfort.
Compared to traditional fixed-speed systems, energy savings with a VSH compressor can exceed 20%.
“Apexx VSH achieves much higher efficiency than the next best alternative by supplying, under part load conditions, only the capacity actually needed, but using heat exchangers sized for full load,” said Dr. Mogens H. Rasmussen after receiving the award on behalf of Danfoss. He also pointed out that the application of VSH enables more energy-efficient control strategies for condenser fans, air blowers, and chiller pumps.
“At lower speeds, below 50 Hz, a patented oil injection system eliminates scroll leakage, minimizes efficiency loss, and results in lower discharge pressure. As a consequence, the VSH exhibits high compressor efficiency throughout the speed and capacity range,” Rasmussen added.
Contributing further to energy efficiency, inrush current to a starting Apexx VSH is typically reduced by 70% compared to a fixed-speed compressor, and still more utility savings accrue because the power factor with VSH compressors remains above 0.90 regardless of the load.
VSH compressors cover a design capacity range of 12 to 23 TR (R-410A). Higher capacities are achieved by manifolding or multi-circuiting with fixed speed compressors.
The AHR Exposition Innovation Award was presented to Danfoss at a ceremony in Chicago during the 2009 Exposition. The winning product was selected by a jury of ASHRAE engineers.
“The jury was impressed that VSH users experience better comfort and considerably less operating cost with VSH because there is no wasted capacity as there is with fixed speed compressors and scroll unloading strategies,” said Stephen Gugliotta, director of sales for Danfoss Air Conditioning. “We are proud to receive this Award because it is welcome proof of the continuing Danfoss commitment to energy efficiency achieved through engineering innovation.
In another singular achievement, Danfoss also received the Expo’s 2009 Innovation Award for refrigeration for introduction of the AKD 102 variable speed drive specifically engineered for supermarket refrigeration. Receiving two Innovation Awards in one year is a second singular achievement for the company.