AIR WATER HEAT PUMP

AltSourceTM

The only high-volume electric boiler on the market and the perfect complement to renewable energy. This combination boiler-storage tank for residential use serves as a back-up energy source to the primary system in order to maximize output. Thanks to its T2 UltraSmart® controller, the boiler provides improved comfort through precise temperature control.

Typical installation with standard features thermo2000.com keep the buffer tanks at the set point temperature (105F/41C).” Because it’s a really tight building, it allows for a low supply temperature. The heat loss calculation at design temperature of -30C was 128,000 Btu/h (37.5kW) for the building envelope, and Haines says their calculations show they could have gone as low as 95F (35C).

Perfect for optimizing the performance of many types of heating systems.

AltSourceTM with the optional copper coil heat exchanger is shown.

As designed, not all three heat pumps are operating at once, as Haines describes, they are set up so there is one master heat pump and then the other two are slaves, and that process rotates among the three.

Cold Climate Logistics

The plumbing and mechanical systems were installed by Candor Plumbing and Heating of Ottawa. In operation for over 35 years, the company has a history of working with Armstrong at his previous Nunavut projects. Fortunately, the crew took lessons from that experience when planning for this job.

“We had to load everything in three shipping containers here in Ottawa— that includes every elbow, every valve—and it was all packed in a way that it could be removed in the order of installation,” says Trevor Johnson, who helps run Candor along with his father Kim and brother Cory.

Johnson recalls how this process was better than the last time when they found themselves cutting blocks of snow off of crates in the middle of the dark Arctic winter searching for the parts they needed.

Working on an island in the middle of Hudson Bay presents many challenges. Getting the crew on-site alone required flights connecting through either Winnipeg or Montreal, with the real prospect of cancellations and having to rebook days later.

In total the team took five trips, starting in January of 2022 when they were using a generator for temporary heating (because it was minus 30 inside) and watch- ing a thermometer waiting for it to rise to where the glue for the ABS would cure.

“We also lost the power to the building where we were staying that January,” recalls Johnson. During a blizzard they needed to crane the generator from the worksite—that was keeping that building warm—to heat up their sleeping quarters, and then start all over again the next day.

“And then we all got COVID,” says Johnson, who adds that things only got better from there.

Heat Distribution

The primary loop from the heat pumps to the buffer tanks is all in 2-1/2-in. copper that was insulated. The Candor team prefers to use press tools wherever possible. The heating distribution system uses infloor heating on the upper two floors as well as heating coils in the air handling units of two ERV ventilation systems.

There isn’t any type of mechanical cooling the space, but the building is ducted to allow free cooling using outdoor air. “Duct work is not something I do every day, so I was leaning heavily on Jamey Mackenzie of Mack Metal, our subcontractor for installing the duct work,” notes Johnson.

Each room in the building is its own zone. When a thermostat calls, a zone valve opens and a low-power variable speed ECM circulator near the buffer tanks recognizes the opening and sends heat to that zone. There is a pump for each floor, and a third installed for redundancy. Those tanks are piped in parallel using circuit balancing valves. There are also two totes of glycol in the system. “You take no chances when temperatures can dip to -40C,” says Johnson.

No concrete is used in this cold climate project, so the team used radiant panel flooring, a high-density polystyrene that comes with an aluminum heat transfer sheet on top and pre-set grooves for the PEX piping. The panels were secured on top of an additional layer of insulation board that was placed on top of the subfloor, which was made of a well-insulated SIP panel. “There’s no shortage of insulation,” confirms Johnson.

Vinyl flooring was used on top of the radiant panels. There are also three entry way force flows for heating as well as a unit heater in the mechanical space.

Domestic Hot Water

The heat pumps have a double-wall desuperheater which is used for pre-heating the domestic hot water. That system leads to a 50-gallon storage tank with integrated electric boiler that holds the preheated domestic water that runs through a copper coil at 70F or greater, and then the domestic water goes through a second coil in another 50-gallon tank where it is brought up to a minimum of 140F.

As a back-up for the entire system, there is also an oilfired boiler in the mechanical space that ties into the DHW tank, and it is also piped-up to supply the heating distribution system if necessary.

Net Zero

Mechanically, the building was ready to go and operational last fall and has performed well over one winter. Currently, the electricity for the community is driven by diesel-fuelled generators. To offset some of that carbon-burning power the building has installed solar panels on the roof, and the owners anticipate tapping into a community wind turbine project on the island to get completely carbon free. “Their net zero capabilities are still a work in progress, but they shouldn’t have a problem getting there,” says Johnson.

And Haines agrees: “There’s a lot of wind up there, so that’s why the model was so positive towards net zero.” He adds that when looking to go net zero, everyone seems to be moving towards heat pumps and in-floor heating. “It’s one of the best systems to use because of the size of the heating area so you need very low temperatures which allows the heat pumps to operate at a very high efficiency.”

Johnson hopes that by sharing this project with the industry others will find inspiration in the simple possibility of achieving net zero in an arctic region. <>