Project Overview: Great Gulf's Active House Power Sub-metering Solution


By: Chris Lange

The idea is simple: if you know where energy is being used, you have the ability to cut energy consumption and related costs. This is the idea that drove the opportunity for Mircom to provide a sub-metering solution for the world’s first Active House built by Great Gulf.

Great Gulf's Active House
Great Gulf Active House

With an impressive track record of 40,000 homes in 35 years, Great Gulf has earned the reputation as one of Ontario’s premier new home developers. Great Gulf is also a founding member of the global Active House Alliance.

The Active House Alliance is an organization which supports the vision of developing buildings that create healthier, more comfortable lives for residents, without having a negative impact on the climate and environment. They provide a label for homes that meet certain criteria related to comfort, energy use, and environmental impact.

Accounting for about 40% of global energy use, buildings are a main target for reducing energy use and improving energy efficiency, which is why the Active House label has a scoring system on annual energy demand and annual primary energy performance. Although power sub-metering is not a requirement for the active house label, it has many benefits that align with the Active House vision. In addition to showing where energy is being used, sub-metering creates the opportunity for preventative maintenance, improved energy efficiency and cost savings. For example, a power spike on an air conditioning circuit could be a sign of a faulty compressor, which could be fixed prior to complete failure. With respect to the Active House label, sub-metering allows home owners to monitor their current status so they can be sure they are staying within the Active House specifications.

The project scope involved the installation of current sensors on each of the homes’ circuit breakers, along with the necessary controllers to process and send the data to the TX3 InSuite Touch Station. A front end user interface was designed to allow any home owner to quickly view energy use on each of their homes circuits. Great Gulf emphasizes design as one of their three core values, so it was an inherent requirement that this sub-metering solution looked clean and professional.

Screenshot of User Interface
User Interface Screenshot

Typical power metering solutions become messy with current sensor wires running wild, so Mircom designed an enclosed solution, with side panels being installed on either side of any home’s breaker panel. In addition to current, it is also necessary to measure voltage in order to determine power and energy use. Current sensors are inherently safer, since they work based on the Hall Effect principle, and they are not directly connected to the circuit they are measuring. Unlike current sensors, voltage measurement creates more concern with respect to safety, since it involves connecting high voltage directly into the measurement device.

Side Panel Configuration
Side Panel Configuration

Safety authorities, such as The Electrical Safety Authority (ESA), have strict rules in order to improve electrical safety, and it became apparent that Mircom would need to work closely with ESA during the design phase. It was determined that the high voltage wires needed for voltage measurement could safely be run through the side panels, as long as they were sufficiently isolated from the low voltage current sensor wires and run through a fuse before terminating at the measurement device. The only caveat was that, until the solution and required devices were UL listed, a site by site ESA inspection would be required.

The Active House is currently home to a family, so it was important for on-site work to be minimal. In anticipation of software updates between installation and completion dates, remote desktop software was installed on a small server, allowing for remote updates to both device firmware settings and user interface software. The remote access control significantly decreased site visits, provided time to ensure the system was stable, and even created extra time for the front end software development.

With energy use increasing and concerns on the environmental impact continuing to grow, power sub-metering is becoming a necessity, and Mircom has developed a sleek solution that fits with modern demand.