HVAC Designs for Arctic Applications
The northern Canadian climate poses unique challenges for the design of mechanical systems for buildings. Even though in Edmonton we face long and cold winters, we have highly accessible resources and a variety of heating equipment technology to not only heat but do it efficiently.
The Yukon Territory, Northwest Territory and Nunavut bring many different obstacles for engineering and construction. In the north, fuel costs are extremely high, fuel options are limited, the construction season is short, and the consequences are dire if systems breakdown with no contingency plan. The number of heating degree days1 below 18 deg C outdoors can reach 12,594 annually in Resolute, Nunavut. For comparison, it is typical for Edmonton to experience 5,782 and Vancouver about 3,000. (Good Building Practices Guideline, Second Addition December 2005). For all these reasons, engineering design for these areas utilizes certain practices to ensure project success.
Typical energy source options include propane, fuel oil, diesel, electrical (from grid or generator depending), and wood pellet. For building projects, this fuel decision is most often made based on price and availability to the location. For example, the fuel options in Yellowknife will be quite different than in Pangnirtung, Nunavut. There are no natural gas utilities or grid electricity to many northern communities, generator power is relied on and stocking fuel that arrives via barge in the summer will have to last all winter.
In Edmonton, it is usually the most cost-effective to purchase natural gas-fired equipment for each use in a building and distribute fuel throughout the whole building. There are endless options for efficient natural gas-fired equipment which are accessible all over Alberta, and design of gas distribution piping is safe, common, and well known. There are not nearly as many equipment options designed for safe use with fuel oil, diesel, or propane and distribution systems for other these fuel types in occupied spaces results in several complications. Therefore, it is advantageous to design all building heating systems to operate from a boiler heating plant with a single location for fuel input.
There are various boiler options that work well with alternative fuels, which is the starting point for northern HVAC design. From a correctly sized heating plant using a glycol mix to mitigate freezing risks, a whole building heating system can be operated. Envelope heating can be met with terminal units such as baseboard radiators, cabinet heaters, ceiling panels, force flows or unit heaters depending on the building type. Ventilation heating loads can be taken care of with coil heat exchangers within airside equipment. Hot water heating can be delivered using storage tanks with a coil heat exchanger. Reheat distribution boxes such as VAV’s can be equipped with reheat coils for additional occupant comfort. It is best practice for any application to provide a second boiler meeting full load requirements to alternate through providing contingency in the event one boiler is down. Depending on the facility type and desired contingency, a third emergency electrical boiler can be included, and steps can be taken to upgrade envelope design R-values for slower heat dissipation
A good design also takes into consideration the operation and maintenance needs of the system. This is a large factor in equipment selection and building controls design. The availability of parts is limited, if not impossible, for certain northern locations in the winter seasons and there may not be the required trades accessible for repairs and troubleshooting of complex systems. During design, it is crucial to work with the surrounding community and building occupants (which may not be the client) to mitigate risks and provide proper system documentation and any required training.
Switch Engineering is passionate about energy-efficient solutions within every design. For northern projects, efficiency is crucial, any resource that is not fully utilized is a huge financial burden for our clients. This also means that any fuel reductions implemented create huge savings. The carbon footprint associated with burning fuel oil, propane, or diesel is greater than natural gas, to begin with, and that is before considering the carbon impacts of transportation. This is an opportunity in northern projects to determine building loads in detail, optimize controls to modulate equipment performance on an as-needed basis and to consider options such as Heat Recovery Ventilators, pellet fired equipment and solar installations in each project to offset where feasible. As always design optimization is a collaboration between disciplines. Using processes such as The Whole Building Design Guide (https://www.wbdg.org/), or LEED’s Integrated Design Process (ttps://www.usgbc.org/guide/bdc) is a necessity to achieve a balance between use, loads, and equipment.
Switch Engineering is building a portfolio in northern projects and we are equipped to address the unique needs of these communities. If you are curious about HVAC design and how it can assist your business in saving money and increasing efficiencies contact us today!