Building 17-66 Freezer System

31,000 square-foot cold-storage warehouse with a maintained temperature of -10° F

Fourteen (14) automatically controlled evaporative condensers

Four (4) screw-type ammonia compressors, each with its own control panel

Three (3) PLC racks with one ControlLogix processor

SCADA system with three (3) FactoryTalk View stations

4.5 KVA UPS for control power backup

Project Description

The project challenges included maintaining warehouse temperature during the controls upgrade, replacing the existing PLC-5 system with a ControlLogix system, replacing existing SCADA stations with FactoryTalk SE stations, and replacing all four compressor control panels with new controller panels.

The Building 17-66 ammonia refrigeration system provides climate control for the freezer warehouse and adjacent 45°F loading dock area. The warehouse is approximately 31,350 square feet and maintains a storage temperature of -10°F. The warehouse is used for storage of temperature-sensitive materials used in a leading aerospace manufacturer’s production processes and must not be allowed to rise above -5°F to prevent material degradation.

Casne Engineering implemented a carefully planned, phased upgrade and replacement of the Building 17-66 freezer system. The PLC-5 replacement and compressor control panel replacements were performed in phases to reduce system downtime to less than 12 hours per phase. Minimizing downtime was critical to maintaining warehouse temperature and preventing damage to stored materials.

The upgrade included replacement of the existing PLC-5 system, replacement of each compressor control panel, replacement of existing SCADA stations, and addition of a 4.5 kVA UPS system to provide control power backup. In addition to the hardware upgrades, Casne implemented several software improvements to enhance system reliability and performance, including:

Automated shutdown and system startup processes in the event of power loss or a critical alarm event
Anti-cavitation control for the two liquid ammonia pumps
Improved ammonia monitoring, including historical trending and an escalating alarm notification process to notify site emergency response personnel and plant staff in the event of a release