Problem Solver - August 2008
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Reducing Costs at Your Aquatic Facility

With the rapid rise in energy costs, and an economy that is causing many recreation directors to restrict their spending, pool owners and operators are looking for creative new ways to reduce their costs by conserving energy. Simple steps are sometimes all it takes to reduce energy expenditures—and savvy pool managers can reap the rewards for a long time to come.

Q: How can we reduce energy costs for our pool?

A: One of the most rewarding changes you can make to your pool is to add a variable frequency drive. How does this work? Most pools are covered by regulations that require pumps that are sized for the worst-case scenario to ensure that things will operate smoothly, even when the pump is challenged to keep up. But what that means is that most of the time—when your bather load is at normal levels and your systems are not challenged—your pump is actually oversized, and that means it's using more energy than necessary.

Compatible with a variety of pumps, a variable frequency drive is computer-controlled and installed in line with the power source for your pump. They work to regulate variable and constant torque operation on the pump, controlling pump speed based on your system's needs. In other words, the variable frequency drive ramps things up when operating conditions call for more power, but slows the motor back down when normal conditions return.

Q: How much energy will I save?

A: When motors run slower, power is reduced. Even a modest reduction in motor speed can deliver energy savings. And when pump speeds are reduced by half, energy use is just one-eighth of what was previously used.

Over time, you can reduce what you're spending on electricity by 30 percent to 40 percent. That means your system will pay for itself in anywhere from six to 12 months, depending on the operating conditions at your facility.

In fact, one manufacturer offers a commercial variable frequency drive that actually displays the time remaining until the drive pays for itself. That means you'll know exactly when your investment starts providing returns.

Q: Will this also help extend the life of my pump?

A: Yes. Variable frequency drives can help minimize motor noise and heating. One model features an adjustable switching frequency modulation function, which adjusts the switching frequency automatically in relation to the motor. As speed is reduced, the switching frequency increases to ensure lower noise and to reduce motor heating.

In addition, variable frequency drives can include features that provide a rapid acceleration of pumps to a desired minimum speed, at which point the normal ramp takes over. This prevents damage to thrust bearings and overheating of the pump.

And finally, a pump that is running at full speed all the time will wear out much quicker than a motor that "rests" in between peak speeds.

Q: What other steps can I take?

A: There are many steps you can take to reduce energy costs and save money at your aquatic facility.

For example, you can reduce heat loss by using a pool cover and by placing cabanas, fencing or another obstacle to shelter your pool from prevailing winds.

Cleaning your pool and filter on a regular basis will also reduce energy consumption, as your system will not be strained by clogged drains and filters.

For a full list of steps you can take to reduce your energy expenditure and improve the functioning of your pool, you should talk with various manufacturers to find out what solutions are available. With the growing focus on green technology, many aquatics manufacturers are investing in new developments that will serve to lower your costs in the long run.

Q: My pump is oversized for my facility. What can I do to downsize?

A: By installing a variable frequency drive, you can match the gpm to your demand. This process requires a premium efficient motor, matched to the variable frequency drive. At an average KWH (kilowatts per hour) cost, your drive investment could be paid for in electrical savings within approximately eight to 10 months.

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