This article was published in HPAC Magazine April 8, 2025, written by Ali Sajjadi.
Two new Victoria area schools fed by central geothermal plant.
Insultated PEX played a significant role in a multi-process retrofit of two adjacent schools seeking LEED V4 Gold certification. (Photo: Sooke School District)
With an influx of young families to the western communities of Greater Victoria, the local Sooke School District needed to build more schools to accommodate some 1,200 elementary- and middle-school age students.
In September 2022 the area opened up PEXSISEN Elementary—meaning “the opening of hands,” as named by the Songhees First Nation — closely followed by the opening of the Centre Mountain Lellum Middle School — meaning “house” and “the idea of community, where we raise our children” as named by the Beecher Bay Nation.
The new adjacent schools were seamlessly integrated into the existing landscape and were designed to be earth-friendly in every way. This included optimizing energy efficiency by targeting LEED v4 Gold certification.
To achieve this goal, the project incorporated elements such as photovoltaic panels on the roof, strategically positioned and designed windows and a geothermally-boosted HVAC system. As the schools are in close proximity, the planners decided upon a district heating model, with a central plant collecting and distributing energy between the two schools. Heating and cooling can be produced simultaneously by the central water source heat pump, with additional heating provided by electric boilers as needed.
The water is delivered through underground piping to terminal units at each school, where it is used by local HVAC systems to provide heating and cooling.
Pre-insulated PEXa piping saves energy and provides labour and material savings. (Photo: REHAU)
According to Michael Hladky, principal of engineering firm SMcN Consulting, the key in these distribution piping or energy transfer piping applications is to keep the heating or cooling energy from escaping while it travels to the schools, maintaining temperatures.
To meet the challenge, the team specified pre-insulated PEXa pipe as the basis of design. Transferring energy from the central plant to each school is 4.9 in. (125 mm) diameter pipe. The middle school uses 2,200 ft. (671 m), while the elementary school uses 600 ft (183 m). The flexible pipe consists of PEXa O2 barrier pipe surrounded by foam insulation and a corrugated polyethylene (PE) outer jacket.
Technical details
The central district energy plant provides heating and cooling for both schools. (Photo: Sooke School District)
The engineering team needed to do a lot of number-crunching and run many “what-if” scenarios to determine the optimal pipe sizing and other specifications for the project. “We were using a very low-temperature/high-efficiency heating water system with water at only 115F (46C), so we couldn’t afford to lose much heat in the trip through the pipe from the heating plant to the buildings,” said Hladky.
Easy to install
Once specified and in the field, installers noted impressive aspects of the product. “Larger bore pipes are generally more challenging to work with, but the hydraulic tool REHAU provides does it all for you,” said Gord McLaren, division manager of mechanical contractors at Professional Mechanical Ltd. “Once you get the hang of it, it’s easy to make the connections.”
“You literally can’t put the pipe and fittings together wrong; the tool won’t let you misposition anything,” noted project installer Joe Bell.
Choosing PEXa piping that is already pre-insulated further streamlined the installation process. Metal piping must be manually insulated on the jobsite, which becomes costly, labour-intensive and can lead to performance issues if there are assembly errors. As a secure one-piece solution, the pre-insulated PEXa pipe reduces material and labour cost while ensuring performance.
Plus, because of the flexibility of PEXa installers could navigate bends or obstacles without extra fittings or couplings, minimizing potential leak points. Bell remarked, “We put in thousands of feet of pipe and had no leaks at all.”
McLaren was also impressed with the hands-on assistance he and his team got from the supplier reps in the field. “There are always numerous ways to skin the cat, and it’s great to have an expert there to bounce off ideas as far as different ways to lay the pipe, work the joints, connect spools, terminate the pipe and other aspects,” he said.
Supporting district heating education and awareness
The central plant is designed to be a learning hub for the industry and public. (Photo: REHAU)
According to Hladky, the central plant was designed in a way that provides educational value to others. The project team will implement the central plant as a learning hub for upcoming engineers and trades workers, including features such as colour-coded pipes and a TV dashboard that displays plant data, energy consumption and GHG (greenhouse gas) savings.
While central plants are often concealed, this project prioritizes visibility with windows at the front of the building, so industry professionals and the public can learn more about the inner workings of district heating applications.
The schools now have a high-performing district heating application that facilitates a high-quality learning and working experience for students and teachers. The schools are contributing to a more sustainable future in their community, while also supporting the development of the next generation of engineers and trades workers.
By Ali Sajjadi