Supplement Feature - May 2020
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Aquatic Pros Talk Equipment

Aquatic Systems & Mechanical Design Considerations

By Joe Bush

What should operators know about pool heaters?

Luecker: There are three types of swimming pool and spa heaters that run on propane and natural gas: atmospheric units, which are standard air induction heaters; sealed combustion Low NOx heaters; and new high-efficiency heaters. The efficiency ratings on these types of heaters vary from 82% efficiency up to 98% efficiency. Low NOx units are now required to comply with increased air quality standards in some areas.

Fowler: [They should understand] what heaters are best for the application they have, and what's involved with properly performing heaters—flow, gas pressure, ventilation—and also how improper chemistry and ventilation can cause great damage to a heater.

White: Just like newer pool pumps, newer heaters are now also designed to be much more efficient.

Aquatic facilities can also reduce operating costs by upgrading to a new, high-efficiency heater. Older models from seven to 10 years ago may have started out being about 78 to 85% efficient. However, over time, the same heaters will only be about 60% efficient, as heat exchanger tubes fill with buildup and the burners get clogged too.

That said, newer models have higher efficiencies. Today's heaters range in the low-to-mid 90% efficiency range, and some direct-fire models have efficiencies up to 95%. As a result, these units consume less energy and will immediately lower electricity bills. Additionally, newer heaters are easier to operate and produce lower emissions, resulting in better air quality in the pool environment.

Builders today are more energy-conscious in their construction of commercial pools. In my opinion, heated water is best returned to the bottom of the pool instead of the top of the pool, since heat rises and quickly disappears if it is returned just three feet below the water line. So, heaters work harder and longer if the heated water isn't returned to the bottom of the pool.

In my opinion, this is a design flaw that we find in many commercial pools. But designers are getting better at creating more efficient systems of heating, and even if a facility is simply replacing an old heater with a new pool heater, the higher-efficiency heater will heat the water better and use less energy doing so.

What should aquatic facility operators know about chlorination systems and automation/controllers?

Fowler: [They should understand] the proper size of pool is in reference to the capacity of the controller. Make sure operators are aware of what local health departments want for chemical levels. Know about maintenance of the systems. If they're using a salt system, make sure to check with local jurisdiction to see what the requirement is for salt chlorine output per thousands of gallons of water.

White: Chlorination systems need to be supported by complete automation. Traditionally the industry has used pH and ORP (oxidation reduction potential) controllers, which are essential to run commercial pools indoors or outdoors for consistency of control and keeping a well-run pool when you may not have an operator looking at it all the time.

Today there are even more technologically advanced controllers that control pH, ORP and more, and these controllers adjust chemicals as bather loads change and chemical levels fluctuate. Some states require these controllers, and in my opinion, controllers are truly a must for commercial aquatic facilities.

What should aquatic operators know about secondary disinfection?

Luecker: Secondary disinfection systems treat pool water supplementally through systems like ozone, ultraviolet, and new advanced oxidation process (AOP) hybrid systems. All of these systems will improve overall facility water quality, and some will help reduce chemical consumption by lessening the demand for the addition of the sanitizers.

Fowler: [You need to understand] when it's needed and what products qualify through the National Sanitation Foundation as a true secondary sanitizer.

White: Ozone and UV is a trend and a change that has come into our industry. They are both very valuable choices for commercial and public pools. Contamination of pool water with known illnesses such as Cryptosporidium and Giardia make it essential that pools and spray parks have a strong secondary disinfection system as an added second layer of consistent protection.

They are not separate from sanitation using chlorine or bromine, but very essential for big commercial pools. This is particularly important with a high bather load. These systems work behind the scenes and not only improve water quality but also help combat the poor air quality caused by chloramines in these same pools with high bather loads.

What are some of the systems that will help aquatic facilities operate more efficiently?

Fowler: Using more energy-efficient pumps, such as those with built-in VFDs or high-efficiency heaters, will help the facility operate more efficiently. Making sure you're getting the most energy-saving potential out of your equipment and maintenance program will aid greatly with a facility operating efficiently.

Luecker: Heaters, pumps, VFDs and supplemental treatment technologies, as mentioned before, and the use of a chemical controller will help to consistently maintain the chemical residual in the pool or spa water. The use of a pool cover will reduce the radiation of pool heat into the air for an outdoor pool and into the indoor air in an indoor facility. The use of an automatic vacuum will reduce the need to use staff to spend time vacuuming your pool. These units usually pay for themselves in less than a year.