Plumbing and pump size
Plumbing is critical to the overall performance of a perimeter overflow pool. The old mantra of ‘big pipes and small pumps’ is very appropriate. Proper pipe sizing and precise edge tolerances allow the pool to run off of a single VFD pump set to low revolutions per minute (RPMs) for energy-efficient operation.
Failure to provide sufficient hydraulic capacity (both pressure and drain lines) in the design, along with poor edge tolerances, will significantly alter the performance of the pool and lead to a large increase in energy consumption. The more narrow a pool’s perimeter-overflow edge is, the less water and pump power is required to maintain the wet edge (all pool coping is underwater).
A simple experiment, comprising a garden hose used as the surge tank water source, can be performed to test the pool’s edge tolerance. First, fill the pool to the point of spill over; then, place the garden hose in the pool and turn the water on. If the edge maintains a wet profile the pool is perfectly level. The more accurately the perimeter edge is constructed, the less water is required to maintain the wet edge, thus reducing energy costs. Engineered designs take the guesswork out of perimeter overflow systems, allowing the pool to operate properly and efficiently at startup.
Automation
A 32-zone automation system was installed to help the client operate all of the pool’s functions and features, while automatic timers are set to limit pump operations and maintain energy efficiency.
‘Smart’ pools are inherently efficient, as they do not rely on human interaction for operation. For instance, when the pool cover is closed on the therapy pool, the perimeter overflow system automatically turns off and the water circulates internally similar to a typical pool. This reduces heat loss and water evaporation that would occur if the perimeter overflow system was operating 24-7.
Different shades of ‘green’
There were a number of similarities and differences between this project and ‘Canada’s Greenest Pool.’ For instance, the latter project was constructed using a retractable pool enclosure. These structures can be extremely efficient provided the pool owner operates the roof and energy-efficient systems correctly (e.g. the HVAC system can be turned off for the majority of a typical pool season). This project, however, had many of the same ‘green’ systems in place but with a more standard, although energy-efficient, fixed-roof building. Both projects offer the owners long-term sustainability, safety and smart operating systems.
Many of the construction techniques and ‘green’ systems employed on these projects can be implemented on either standard projects, or complex installations. Pool, spa and water feature designers/builders should offer more energy-efficient solutions to their clients to increase the number of smart, sustainable and safe projects being installed.
Author note: A number of industry experts consulted on and contributed to this project, including: Gary Scott (Zodiac Pool Systems Canada Inc.), Fred Breen (Colbree Enterprises), Jake Hamoen (JTH Best Engineering Inc.), Steve Hamoen (Zonelife Inc.), Alan Thorne (Ocea U.K.) and Elena Danke (Aquafin Inc.).
Barry Justus is the owner of Poolscape Inc., a landscape contractor and pool designing and building company based in Burlington, Ont. He can be reached at barry@poolscape.com or by visiting www.poolscape.com.
