By By Richard Lay, P.Eng., Enermodal, a member of MMM Group
Northern Exposure: Churchill Northern Studies CentreBuildings Building Mechanical & Electrical (HVAC) Systems Building Structure
In the summer of 2011 the Churchill Northern Studies Centre moved into its new 2,580-m2 (27,800-sq.ft.) facility. Founded in 1976, the CNSC is an independent, non-profit research and education facility located 23 kilometres east of the town of...
In the summer of 2011 the Churchill Northern Studies Centre moved into its new 2,580-m2 (27,800-sq.ft.) facility. Founded in 1976, the CNSC is an independent, non-profit research and education facility located 23 kilometres east of the town of Churchill, Manitoba.
The new building is designed for 88 visiting scientists and 12 staff who work year-round on sub-arctic scientific research and education.
The centre provides accommodations, meals, equipment rentals, and logistical field support to the scientific researchers. In addition, the centre facilitates educational programming for the visiting public, as well as university credit courses for students.
The building has laboratories, two classrooms, a gift shop, an observation dome, a library, herbarium, and study collections of various animal species. There is also a helicopter landing pad and a garage for vehicles.
The goal for the new facility was to have lower utility and operating costs, and to be a high-performance building that showcases best practice green building engineering design. It also had to meet budgetary and time constraints, not to mention the unique needs of a remote research building in a harsh northern climate.
Prairie Architects of Winnipeg designed a streamlined elevated building intended to shed wind and snow and collect sunlight. The two-storey structure has a long shallow rectangular plan oriented east-west for good daylight penetration and views.
Enermodal Engineering, a member of MMM Group, designed mechanical and electrical services for the building that are appropriate for the difficult climate and lack of municipal services. The systems include heat recovery, intelligent building controls, and good lighting. The kitchen and laboratories are energy efficient, and there are water and wastewater treatment systems, and waterless composting toilets.
Exposed Site: No Services
The site is remote and exposed with only shrubby tundra vegetation and thin gravelly soils over shallow bedrock. There are no piped municipal services for water, sewer, or gas, and no prospect for any in the future. A 1-kilometre power line connects the building to a Manitoba Hydro electrical service, but power is frequently interrupted by winter weather. The building’s own water, wastewater, heat, and power services therefore are essential and have to be highly reliable.
Most northern buildings are located in communities served either with piped services inside utilidors, or they have greater access to water and sewage hauling trucks. It is common therefore for these latter buildings to have inside storage tanks, but what would be considered normal everyday water use means that very frequent fill-ups and pump-outs are needed, sometimes every few days.
The miserly water use in the new CNSC building means its potable water storage should last over a month in winter. And because the sewage treatment tanks can also serve as holding tanks, they offer an equivalent period of independence from the pumpout truck.
The building envelope, designed to be air-tight and well-insulated, consists of R-40 freezer panel construction: an assembly of steel-skinned polystyrene foam insulation, with interlocking gasketed edge joints. Windows are low-e, argon-filled and triple-glazed.
The whole structure is raised about 1.5 metres above grade to control snowdrifts. This feature provides a convenient space under the building for the ventilation openings, where they are protected from snow, minimizing the number of mechanical ventilation louvers and hoods. A few of the newest buildings in Canada’s north have recognized this as an effective way to prevent snow from accumulating on their leeward side.
Efficient and Simple Operations
The four main building ventilation systems have ventilation heat recovery (where incoming, fresh air is pre-heated by outgoing, stale air), which was challenging to accomplish in an environment where heat recovery ventilators (HRVs) are very vulnerable to freezing.
The main ventilation system is an innovative reversing flow heat exchanger made in Manitoba and featuring 85% heat recovery efficiency and no requirement for defrost. The other HRVs, serving the dining room and kitchen, labs, and composting toilets, rely on electric pre-heaters to keep them out of defrost mode and to optimize their heat recovery performance. The reversing-flow heat exchanger supplies up to 1,175 L/s of ventilation, depending on demand, and does not require any preheat.
The building controls are designed for reduced operating costs, yet still are relatively simple and easy to operate. The basic approach is to turn equipment off when not in use. For example, ventilation is supplied by multiple, dedicated units that slow down or stop when any individual unit is not needed. Local controls include occupancy sensors, CO2 sensors, timers, and variable motor speed drives. The project team can access the building automation system for monitoring and trouble-shooting via the internet when they are off-site.
Kitchen and Laboratory Needs
A commercial kitchen serving three meals a day to 100 people can be extremely energy intensive due to the large amounts of cooktop ventilation, hot water use, and energy for appliances. The range hood ventilation at CNSC is low-flow and variable speed, responding to the amount of cooking and providing only the amount of exhaust and make-up air required. The appliances selected have the best available energy and water efficiency.
Solar wall panels pre-heat the large volume of fresh air for the kitchen and cafeteria, and these are supplemented by a dedicated energy recovery ventilator that even recovers heat from the dishwasher exhaust.
There are two oversized grease interceptors – one just for the dishwasher – installed in a cool basement wastewater treatment room, where they serve to heat the room.
The centre’s research activities imposed some special requirements on the mechanical systems. The laboratory areas have to provide for wet-dry and clean-dirty research activities. Some soil and plant samples must be dried for an extended time and the moisture and smell has to be contained, while others must be archived in a room with controlled temperature and humidity. Some experiments also need controlled temperature and humidity, especially in summer during the peak field research activity.
The laboratory fume hoods operate in as energy-efficient a manner as possible, i.e. with controlled exhaust and makeup ventilation, while maintaining good indoor air quality.
Waste heat from the computer room can be circulated to the underfloor plenum for heating, rather than being directly exhausted or air conditioned. The refrigeration compressor waste heat is also recirculated for space heating.
All other spaces have individual thermostat controlled electric baseboard heat. The design heat loss of the building envelope is 145 kW, plus an additional 52 kW for 2,800 L/s ventilation. This load of about 100 W/m2 is about twice that of an energy efficient building in southern Manitoba, but less than a typical Canadian school or office building.
Extreme Water Conservation
The old facility had to truck in water from town 20 kilometres away, then truck back the sewage. Every effort was made to decrease this considerable cost of carbon emissions and money.
The most significant measure is the use of two large composting systems serving waterless toilets and urinals. Wastewater is treated on-site to tertiary quality by two indoor 5,000-litre biofiltration vessels and two outdoor area bed sand dispersal fields. These are made of manufactured sand and woodchip-and-sand layers. The permitted daily design flow is 8,000 litres and design flow is only 68 L/person, compared to the metered 100+ L/person last year in the old building.
An innovative ventilation system using a heat recovery ventilator provides continuous exhaust from the composter. In the washrooms all the exhaust is drawn down thr
ough the toilets themselves. The system is water-and-energy efficient, keeps the washrooms odour-free, and thanks to a healthy population of red wriggler worms, automatic moistening system, automatic compost tea removal, and the aerobic decomposition process, requires very little maintenance.
Lake water is pumped 2 kilometres to the site in summer and treated with settling, simple cartridge filters and ultraviolet light to drinking water quality. Two 13,000-litre tanks can store drinking water trucked from town in winter when the lake is frozen.
To reduce the need for drinking water, untreated lake water is distributed through separate non-potable water piping to flush-type toilets, hose bibs and drain trap primers. Greywater is recycled from the lavatory and shower wastewater, and drainwater heat exchangers recover heat from the showers and lavatories to preheat the domestic hot water.
It is hoped that the combination of ambitious water conservation and on-site treatment will be a model of sustainability for other developments in remote communities. The technologies showcased at CNSC are scalable to larger facilities.
Lighting fixtures are high efficiency, without over-lighting spaces. The average building-wide lighting power density is a mere 7.7 W/m2, which is 30% below ASHRAE 90.1-2007 levels for an office/lab/dormitory building using the building area method.
The dormitory rooms contain a single overhead direct/indirect fluorescent fixture for general lighting, but each bunk bed, four in each room, has a directional, wall-mounted LED light which can be turned on without disturbing other roommates.
The rooftop Aurora Borealis Viewing Dome was outfitted with LED way-finding lights (like emergency exit lights in an aircraft cabin) and a switch to allow users to turn off non-essential exterior lighting for better viewing the Northern Lights. The dome also has a new type of linear fan that directs heated air over the inner surface when “windshield defrost” is required.
The type of innovative yet simple design used at CNSC could be applied to a variety of building types in remote northern locations. It provides the occupants with amenities and services, while giving significant energy and water savings for the owner and environment.cce
Richard Lay, P.Eng, is the senior mechanical designer at Enermodal Engineering, a member of MMM Group, and is based in Kitchener, Ontario.
Owner: Churchill Northern Studies Centre
Mechanical-electrical engineers: Enermodal Engineering, a
member of MMM Group (Richard Lay, P.Eng, Tim Dietrich, P.Eng, Brandon Barroso, CET)
Architect: Prairie Architects
Structural engineer: Crosier Kilgour (Tom Malkiewicz, P.Eng.)
Commissioning: Integrated Designs, Phil Dompierre, EIT
Contractor: Penn-Co Construction