April 1, 2010
By Harry Topikian
Thanks to recent technological advancements, indoor waterparks can now have perfect indoor air quality (IAQ) and green environments. However, anyone who is involved in the commercial aquatics industry knows these facilities are capable of the exact opposite—uncomfortable indoor air environments that are not energy efficient.
For example, indoor waterparks are not typical role models for IAQ and energy conservation. When these facilities started to become popular several years ago, many waterparks tended to embrace the ‘pay later’ option in controlling the tremendous humidity generated by 27.7 C (82 F) quick-evaporating pools and a myriad of aerosolizing equipment (e.g. waterslides, water cannons and waterfalls).
Instead of using specialized mechanical equipment to control humidity, the trend over the last decade has been the use of conventional equipment to provide make-up air. This equipment brings in outside air, conditions it by heating or cooling it, then wastefully exhausts it in an attempt to control relative humidity (RH) and prevent the facility from feeling like a muggy rainforest. It is considered the ‘pay later’ option because the equipment requires considerably lower up-front capital costs than mechanical dehumidification equipment. However, as conventional dehumidification methods are significantly less efficient than mechanical dehumidification equipment, operational costs alone can amount to hundreds of thousands—or even millions—of dollars more over the typical 20-year lifecycle of the equipment, thus the pay later terminology.
Not controlling the humidity load with modern dehumidification equipment can result in an uncomfortable atmosphere of 80 per cent RH or higher, which takes its toll on patrons, employees, interior design and, quite possibly, the building’s structural integrity.
Not knowing the future success of the fledgling indoor waterpark trend or the non-interest in long-term investment as a business strategy, many early indoor waterpark facilities across North America employed thrift measures throughout to avoid high up-front capital costs.
Contrarily, the ‘pay now’ option is more environmentally friendly and energy efficient. Instead of the costly process of continually bringing in fresh air, indoor air is recirculated with a reduced amount of outdoor air, which still surpasses American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards.
Instead of exhausting the inherent evaporative effects of a warm body of water, mechanical dehumidification condenses the humidity out of the air via refrigeration coils. In the recirculation process, a comfortable 50 per cent RH airstream is returned to the indoor facility. Additional environmental measures can be applied by using exhaust air (some air must be exhausted to maintain a negative air pressure and compensate for any new outdoor air that is introduced) to preheat outdoor air during wintertime operation with a ‘Smart Saver’ function. In many cases, some mechanical dehumidifier brands allow 100 per cent of the heat recovered from the refrigeration process to be used for heating the pool water. Rather than using a dedicated, fossil-fuel-powered boiler, all the facility’s water heating is free.
Due to the costs of mechanical dehumidification equipment, those with short-term (five years or less) investments in mind might be better off in taking the pay later option and pass on the future exorbitant energy costs to the next owner. However, long-term ownership can save significant energy costs, add a green facility to the local community and provide a more healthy and comfortable IAQ environment for both patrons and employees.
A new breed of waterpark developers are beginning to plan long-term corporate missions of providing better IAQ and employing green principles, while also considering or employing the pay now method.
One example of this is Splash Universe, a Shipshewana, Ind.-based waterpark developer that recently opened two identical 2,323-m2 (25,000-sf) indoor waterparks in Shipshewana and Dundee, Mich. Both facilities feature a green approach and use mechanical dehumidification equipment employing several heat recovery strategies. Each facility’s dehumidifier supplies 18.8 m3/s (40,000 cfm) and has a moisture removing capacity of 256.3 kg/hr (565 lbs/hr). Besides several heat recovery strategies, the units dehumidify the space to 50 RH, supply free pool water heating to maintain 28.8 C (84 F) water temperatures and cool or heat the space to 27.7 C (82 F).
Although Splash Universe paid more money for its equipment up front, dehumidification and recirculation is saving each facility $105,000 US or more annually, according to Paul Joliat, PE, LEED AP, president, Michigan Air Products, a Troy, Mich.-based manufacturer’s representative. Over the 20-year lifecycle of the equipment, Splash Universe will save an estimated $2 million or more, according to Joliat.
Besides operational savings, mechanical dehumidification also has a positive effect on turnstile sales. Rather than subjecting patrons to the rainforest conditions of many indoor waterparks, the Splash Universe facilities provide a comfortable environment.
“Indoor air quality can’t be seen, but it’s definitely felt by patrons,” says chief maintenance engineer, Dennis Rainsberger. “Poor indoor air quality has short-term effects when eyes sting from excessive chloramines and long-term effects where asthmatic and other respiratory conditions occur. Many waterpark operators wrongly think indoor air quality doesn’t affect their businesses. If the patrons don’t have a comfortable experience, they won’t come back, regardless of how cosmetically nice the facility looks.”
Another IAQ advantage Splash Universe employs is gas-phase air purification, marking the first time the technology has been used in a North American indoor waterpark. Chloramines, which are chlorine molecules that attach to human waste products such as urine and ammonia, are removed by gas-phase filtration added as a factory option to the mechanical dehumidifiers.
Chloramines tend to linger in all types of indoor pool environments. They are proven respiratory irritants for patrons and pose long-term dangers for facility employees. The chloramines issue came to the national forefront in 2007 when the U.S. National Swimming Championships in Indianapolis, Ind., were disrupted after swimmers experienced breathing difficulties directly related to excessive chloramines, according to news provider United Press International (UPI).
Conventional air filtration media, regardless of the heating, venting and air conditioning (HVAC) method used, are incapable of trapping gaseous contaminants. Instead, gas-phase filtration uses an environmentally friendly granulated coconut shell-based carbon media, through which the return air stream passes. The carbon media absorbs chloramines produced inside the pool area as well as vehicle emissions, ground-level ozone and other gaseous contaminants introduced by outdoor air requirements. The result is a free-breathing atmosphere void of chloramine buildup.
“Other waterparks typically have a pungent odour,” explained Rainsberger, a former HVAC industry veteran. “However, I think we have successfully created a fresh air environment with gas-phase air purification that is noticeable as soon as you enter the pool area.”
Community, YMCA and school pools have embraced the mechanical dehumidification strategy more easily because they typically have long-term missions early on. Older pools with conventional make-up air equipment are retrofitting to new technology with green and IAQ focuses.
For example, the town of Richmond Hill, Ont., primarily used make-up air equipment and recently retrofitted its HVAC system at the Lois Hancey Aquatic Centre in favour of green heat-recovery mechanical dehumidification equipment. The environmental mission has paid off handsomely with incentives and quick paybacks.
When built in 1991, the facility followed status quo natatorium design, relying on a conventional unit. It provided 7.08 m3/s (15,000 cfm) 100-per cent make-up air and used mixing dampers to control evaporation from the 650-m2 (7,000-sf) wave pool and 65-m2 (700-sf) therapy pool. The HVAC system created economizer-type conditions and saved energy by taking advantage of dry ambient air during winter months. Mechanical engineers involved with the retrofit project abandoned this method in favour of 24-7 dehumidification and energy recycling to better handle peak loads in summer months, which were characterized as uncomfortable.
This system was replaced with the current mechanical dehumidification equipment, which has a moisture-reducing capacity of 258.5 kg/hr (570 lbs/hr) and a greater capacity to recover heat for pool water heating. Its heat recovery system, which reclaims heat from exhaust air, combined with the reduction in electrical demand by using a newly-developed energy-saving multi-fan array, qualified the project for a $100,000 Cdn Municipal Eco Challenge Fund grant from Ontario’s Ministry of Energy and Infrastructure. The new system has cut annual energy costs by $76,000 and reduced maintenance costs by $30,000.
When combining the grant, operational savings and reduced maintenance costs, engineers estimate the dehumidifier’s payback at less than five years.
“We’re much greener now, but we have also improved our indoor air quality. There’s no longer a chlorine odour and humidity is now maintained at a comfortable 50 to 60 per cent year-round,” said Saroj K. Acharya, P.Eng., LEED-AP, CEM, facility systems manager, town of Richmond Hill.
Although these two examples are of an indoor waterpark and a community pool, green technology and IAQ measures can be applied to any indoor pool/spa facility, whether it’s in a residence, hotel, school, fitness club or other facility with aquatic features. It’s not opinion that conventional air conditioning can’t handle the tremendous humidity loads of a natatorium; it’s a fact backed by ASHRAE standards. Mechanical dehumidification, on the other hand, facilitates better health, IAQ, heat recovery, energy savings and environmental consciousness.
Harry Topikian, P.Eng., is vice-president, business development, Dectron Internationale, in Montreal, Que. He has 25 years experience in energy recycling and engineered air treatment solutions. Topikian is a graduate of the building engineering program of Concordia University. He can be reached via e-mail at email@example.com.
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