Johnson Controls has added the Quantech QWC4 Water-Cooled Screw Chiller to its expanded chiller portfolio. The chiller uses variable speed drive technology to reduce energy costs and carbon emissions by as much as 30 percent when compared to traditional chillers. Throughout most locations, the variable speed drive saves energy during 99 percent of operating hours spent at off-design conditions, which include reduced load and/or reduced entering condenser water temperature. Because the Quantech QWC4 screw chiller is capable of handling a higher-pressure lift, it can be used in thermal-storage and heat-pump applications. The chiller utilizes R-134a refrigerant, which has zero ozone-depletion potential.