George Mackie Library Roof Top Heat Pump Project
E-Factor Engineering completed the replacement of an aging primary rooftop unit (RTU) at 8440 112 Street in Delta, BC in 2011. The existing Trane RTU was replaced with a 25 Ton Heat pump unit. This was the largest variable volume Heat Pump in the Voyageur series and was custom order. The building has several fan power boxes and reheat coils and a boiler for air heating and radiation. The final project included the following scope and energy saving measures:
- Replacement of aging standard efficiency RTU with premium efficiency air-to-air heat pump equipped with supply fan VFD and enthalpy economizer control,
- Reducing boiler and pump hours of operation (only enabled above 10 C),
- Considering potential savings from replacement of motorized mixing terminal boxes with non-motorized VAV boxes,
- Installation of a building-wide DDC system to control RTU, boiler, and all or a selection of terminal mixing boxes.
Optimum sizing and energy consumption of the RTU was done based on analysis of energy history for the building. The impacts of these measures are covered in this audit report as cost estimates.