George Drew Complex - Heating Plant, Cooling Plant and Disentanglement


MAT 4Site Engineers was retained to be part of a multi-disciplined team to design and upgrade the government facility: George Drew Complex. The complex consists of three buildings: 25 Grosvenor (20 story commercial building), 27 Grosvenor (multistory parking garage) and 26 Grenville (2 story commercial building). These three buildings operate collectively under many shared mechanical and electrical services: heating, cooling, fire protection, gas service, BAS/controls, plumbing etc. It was decided that 27 Grosvenor and 26 Grenville were to be sold, along with the property they stood upon. Consequently, these mechanical services would have to be separated, or disentangled, and allow 25 Grosvenor to function as a standalone office building.

The existing heating plant (glycol) serving the complex was located in the penthouse mechanical room of 25 Grosvenor. As the complex is downsized, new building load calculations were completed and a new, smaller boiler plant (hot water) was designed and implemented in same location.

The existing chillers serving the complex were located in the second basement of 25 Grosvenor. It’s associated cooling tower was located on the top level of 27 Grosvenor. Retrofitting new chillers in the existing location proved to be challenging and unrealistic, due to limited access in transporting equipment to the second basement. With the reduction of the heating plant footprint, a new location for the chillers was identified and implemented in the penthouse mechanical room.

The scope of the replacement work included the following key elements:

• Installation of new hot water boiler plant (11,400 MBH output) with N+1 redundancy.
• Removal of existing electrical perimeter heating with the retrofit of new hot water perimeter heating.
• Installation of new chilled water plant (800 Tons) with N+1 redundancy, new chiller optimization control system, re-arrangement of piping distribution.
• Installation of new gas service.
• Installation of new snow melting system.
• Investigation/tracing of shared mechanical services in order to disentangle, re-route and install new services to create the standalone facility.


Project services included feasibility planning, detailed engineering, contract administration and close-out.