BITZER US Inc.
4031 Chamblee Road
Oakwood, GA 30566
For commercial-property owners forever on the lookout for ways to reduce their utility bills, a major opportunity arises when it is time to replace old compressors in HVAC systems. When Harrison Property Group, the owner of 10 hotels, needed to replace an aging 60-ton reciprocating compressor in its chiller at the Holiday Inn in Ocean City, Md., it turned to BITZER.
The chiller consisted of five 60-ton recips using R-22 refrigerant. While BITZER screws often are used to replace OEM screws, this retrofit conversion required additional changes to the compressor mounts, piping, and wiring layouts. After the R-22 was recovered and the recips were removed, the system was flushed of residual oil. The frame was modified to accommodate a screw, with BITZER model CSH7551-50Y-2PU installed. Also installed were a new capacity controller, an electronic expansion valve, and liquid- and suction-line dryers. The system then was evacuated and charged with R-134a.
Robert Walter, Harrison Property Group's lead mechanic, found an overall energy reduction of 50 percent, for about $600 a month in savings. BITZER screws offer step-capacity modulation (100/75/50/25 percent) or infinite modulation between 100 and 25 percent. This enables the compressor to precisely match the system load and contributes to the energy efficiency of the HVAC system. A bonus is overall sound reduction.
Upgrading to high-efficiency screw compressors in aging HVAC systems is an effective way to reduce overall power consumption while shortening the investment payback period.