Data Center Server Room Cooling HVAC System Replacement


For several years, the client had been renting four portable AC units and two supplemental diesel generators, totaling 50 tons of cooling capacity to keep server rooms operational. There was no effective method of heat removal, and in the summertime, the dry coolers were kept online with sprinklers. Improper maintenance of CRAC systems led to a dependence on the rented units, reducing energy efficiency while increasing costs and the frequency of emergency HVAC calls. Eventually, the CRAC systems could no longer reliably support mission-critical server rooms.


Donnelly Mechanical won the competitive bid and was awarded the replacement and maintenance project, which included:

  • Proper cleaning of all dry coolers
  • Installing return ducts from hot aisles to CRAC units for improved heat removal
  • Installing 30 tons of permanent back up air conditioning units
  • Replacing an overworked 30-ton dry cooler with a more efficient model
  • Properly maintaining all CRAC units on an ongoing basis


With precision and expediency, Donnelly delivered the CRAC construction project on-time and on-budget. Through expert planning and coordination, Donnelly minimized downtime to keep mission critical systems operational. Cooler now than it has ever been, the server room no longer requires costly rented systems and generators to protect the equipment and ensure uptime. Donnelly now provides preventative maintenance, ensuring that the CRAC systems are properly maintained and functioning optimally to efficiently remove heat from the server room. Donnelly’s client hit their ROI targets for the project, reducing costs and increasing efficiencies and uptime.

“Donnelly has done an excellent job for us over the past year, working on computer room & data center projects. These projects have included all required turnkey scopes of work involving demolition and protection for our live computer room equipment and modifying supply and return ductwork in a live environment. I have always found Donnelly and their employees to be excellent in working with other trades and various inspectors on our projects. This has always been helpful when working to achieve our critical scheduling goals. Donnelly has always provided us with the very best service and knowledge it has taken to get our projects done professionally.”

Director, Data Center Services 

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