Challenge/Solution Case Study: Designing a Custom Cooling System for Large Electric Motor

Nestor Rentas Challenge/Solution Case Studies


EFI Group designed, specified, purchased and supplied all materials for an outdoor, stand-alone, ventilation system to deliver ambient cooling to an 115,000 HP electric motor.

The EFI Group team managed the entire project, including contributions by outside vendors, which minimized freight charges and field installation costs and achieved on-time delivery and performance in excess of client expectations. The client experienced full ROI after just one year.


EFI Group’s OEM client needed a complete, outdoor, stand-alone ventilation system robust enough to operate problem-free at an unmanned station that was subject to drifting snow and airborne debris from adjacent farmlands.

The scope included the design engineering, specification, purchase and supply of all cooling equipment, instruments and fabricated sheet metal and structural steel parts.

All components had to be completely preassembled, with equipment mounted and shipped in as few pieces as possible for efficient field assembly.

The ductwork was installed into an existing building with tight space constraints, and was required to hold a minimum outdoor footprint.


EFI Group decided to approach the project in three phases:

  1. Research/Fieldwork: EFI Group collected enough solid field data for all the design work from a single jobsite visit. Fieldwork included: obtaining relevant building drawings; taking extensive, accurate, as-built field measurements; and photographically documenting the work area.
  2. Design Configuration Options: This phase included the submission of several viable ductwork routing options for client review. From the client’s selection, a full system general arrangement (GA) was developed and approved by all interfacing disciplines. EFI Group minimized field installation costs by utilizing bolted structural connections and minimized freight charges by designing for standard flatbed consolidation.
  3. Final Design: Based on the approved GA, EFI Group developed detailed design drawings consisting of: all subsystems and fabricated components and design calculations for structural supports, system pressure drop, thermal expansion, accumulative tolerances and design conformity. EFI Group guaranteed integrity during fabrication by attaining design/approval of shop drawings for each piece, performing frequent inspections and ensuring adherence to effective quality control practices and documentation.


  • General arrangement and field assembly drawings.
  • Complete fabricated system: inspected, pre-assembled, match-marked, with step-by-step assembly instructions and all assembly parts required.
  • Process description narrative and operation manuals for all equipment and instruments.

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