Tim McGinn, P. Eng., of Keen Engineering realized his client's desire of having a building that promoted wellness and health for all users of the
facility - patients and staff alike. With this in mind, they elected to implement an underfloor air distribution system for the North Community
Services Wing of the health centre. The underfloor system would offer the following advantages compared to a conventional overhead air distribution
- Reduced Staff Relocation Costs
- Increased Thermal Comfort
- Enhanced Indoor Air Quality
- Significant Energy Savings
To assist in accomplishing this design goal, Keen enlisted the services of the local Price office in Calgary and described to Price a rather unique
application for underfloor air distribution. Rather than simply design a traditional passive style underfloor air system, Keen wanted the ability to
add variable volume heating, and deliver it from the floor as well. After some discussions between Keen, Price Calgary, and Winnipeg Application Engineering,
a solution was developed that consisted of the following items. The interior zones of the space were fitted with traditional, non ducted, passive, Price
model ARFTDA floor diffusers. The perimeter zones included several Price model FEBU8000 underfloor fan terminals with filters, hot water reheat coils,
and the Price model UMCB terminal controller. Ducted from both the inlet side and discharge side of the fan terminal were the Price model RFB-HC motorized
damper/boot assembly, mounted beneath the raised floor to the bottom of additional ARFTDA diffusers. The multiple RFB-HCs were easily field wired back to
the UMCB associated with each fan terminal via factory supplied plenum rated modular plug-in control cables.
When the perimeter zone calls for heating, the fan terminal powers up, and each of the RFB-HCs on the discharge side of the fan terminal modulate to close
off the primary air supply from the underfloor pressurized plenum. Simultaneously, the RFB-HCs on the inlet side of the fan terminal will also modulate to
a pre-programmed minimum position, in order to allow a portion of the primary pressurized plenum fresh air to mix with air drawn from the occupied space.
The air is filtered and heated at the fan terminal, and then discharged back into the occupied space through the discharge ARFTDA diffusers (see Figure 1).
The net result is a mixture of fresh plenum air mixed with re-circulated room air, that is filtered, tempered, and discharged back into the room near the
perimeter wall, satisfying zone heat and ventilation requirements.
When the perimeter zone is switched over to cooling mode, the fan terminal is deactivated, while the RFB-HC damper/boots modulate open. This allows supply
air in the underfloor pressurized plenum to enter the space via the ARFTDA diffusers in a fashion typical of a traditional raised floor air distribution
system. (see Figure 2 ) As Tim explained, this method of heating the perimeter of the building using underfloor air delivery was selected to avoid a
conventional perimeter heating system of either radiant panels or finned radiation. "This provides the owner with the ultimate in flexibility in reconfiguring
spaces in the future ", states Tim. From an air distribution perspective, there is no question that delivering the air properly at low levels, directly into
the occupied zone contributes to better indoor environmental air quality for the occupants. Underfloor air distribution systems also provide opportunities for
reducing energy consumption when compared to a traditional overhead air delivery system.
The CHR opened the doors of the Okotoks Health and Wellness Centre to the public in November of 2004. Mr. Les Marles, project manager for the CHR has given
the project his personal endorsement. He states, "In our business where we are trying to promote wellness, the building itself should also be a healthy place
to be. We also wanted to make the building as environmentally friendly and as energy efficient as possible." Due in large part to the overwhelming success of
this project in terms of providing a facility that is healthy for staff, healthy for the public, and healthy for the environment, it has been stated that Okotoks
Health and Wellness Centre will serve as a blueprint for future community health centres under the direction of the Calgary Health Region. Once again, Price has
demonstrated it's commitment to providing leading edge products and services, and is proud to have been selected the "supplier of preference" for such a highly