How aquatic facilities can benefit from pump efficiency
With respect to commercial pools, a three-phase pump is a no-brainer as it can save an aquatic facility approximately 35 to 60 per cent on its energy bills in comparison to using a one- or two-speed model.
Further, when combined with a VFD, it increases the pump’s efficiencies, as well as provides better energy savings. Even with a single-phase application, a VFD can be used with a three-phase pump to bring savings to those aquatic facilities as well.
Technological advancements in today’s pool equipment make it imperative for industry professionals to take the time to sit with facility managers to ensure they are achieving the water quality, parameter reporting, and cost controls necessary to keep their facilities operating efficiently.
With many municipal and YMCA-type pools struggling to keep their doors open, the integration of all components in the pump room is paramount to ensuring the lowest possible operating costs. This was the case for one such facility in Woodstock, Ont., with a 331,829-L (87,660-gal) pool built more than 35 years ago. Hollandia Pools and Spas, a commercial design/build and service company based in London, Ont., was called upon to design and renovate the equipment room.
“Having the opportunity to design the pump room for maximum efficiencies allowed us to not only upgrade the existing equipment, but also enabled us to integrate additional technologies to improve the pool’s operating efficiencies and at the same time increase the facility’s cost savings,” says the company’s Richard Deakin.
A big part of the energy savings provided to this particular YMCA was the result of the installation of VFDs on the pumps.
“The facilities where we have installed these units typically see an annual savings of at least $10,000 in operating costs,” says Deakin. “The units are not free, but the return on investment (ROI) is normally less than three years, and some areas are even being given rebates from utility companies, making the payback period even shorter.”
Selecting the right pump
Proper pump selection (sizing) and optimal flow rates (as mentioned above), are additional ways to reduce energy costs. Affinity laws indicate the power demanded by a pump is proportional to the cube of the flow rate. For example, if the pump’s flow rate is doubled, then its power demand is increased by a factor of eight. Therefore, it is important to use the smallest pump that is capable of turning over the entire pool volume in an acceptable amount of time.
During the pump selection phase for an aquatic facility, the auxiliary features (e.g. spray pads, fountains, and waterfalls) should also be considered, as it is common for them to use the pool’s main pump. Some building codes, however, require the use of a multi-speed pump, or in some cases, a separate pump for each auxiliary pool load. Pumps for aquatic facilities are oversized by design, sometimes more than 20 to 40 per cent bigger than they need to be. This is because many architects and engineers look at what is required, then pick the next size up to be sure the pump can handle the job.
Equipment costs versus energy savings
Even with the advantages explained, some homeowners and facility operators still find the cost of a VSP or VFD hard to justify. However, before ruling one out, the price of a new pump should be compared to the expense of doing nothing.
For example, an aquatic facility using a single-speed pump may have operational costs of up to $900 per year. After five years, the facility will have spent $4500 to operate the pump. However, comparable operational costs for a facility with a well-designed circulation system that uses a VSP or VFD may be as little as $200 per year. During the same five-year period, it would cost the facility less than a quarter the amount it would have spent using a single-speed pump. Cost savings will continue to multiply the longer the VSP or VFD is used. (Costs and savings will vary by region). The initial cost of a VSP or VFD can typically be recouped during the second year of operation, especially in poolfacilities that operate year-round.
With the substantial energy-use rebates some local power companies offer, in conjunction with the savings in daily operational expenses, some end-users are getting back approximately 50 per cent of the pump’s cost in less than a year.
Mike Fowler is the commercial marketing/sales manager for Pentair Commercial Aquatics in Sanford, N.C. He has been with Pentair since 1992, starting his career in the technical services department at Purex Pool Products. Fowler has held many managerial roles within the company, including marketing, account management, and product management. He can be reached via e-mail at mike.fowler@pentair.com.
