The owners of this water park presented its HVAC designers with some tough requirements - 16,000 cfm with a minimum of 3,000 cfm outdoor air and up to 100% outdoor air. A fresh air system with heat recovery and no mechanical cooling turned out to be the solution.

Commercial HVAC projects are typically filled with compromise. In a specialty application like an indoor water park, where air quality, space, and a corrosive environment are key considerations, an engineer must work hard to ensure long-term performance. Ramaker & Associates (Sauk City, WI) made sure no standards were compromised when designing an indoor AHU for Big Splash Indoor Water Park at the Ramada Hotel and Resort in Ocean Shores, WA. Although space was limited and delivery requirements challenging, the engineering firm and the supplier, Des Champs Technologies, provided a customized design that met all of the park's needs.


Space and delivery were major issues for the owner of Big Splash. The park required 16,000 cfm with a minimum of 3,000 cfm outdoor air and up to 100% outdoor air. For optimal efficiency, the AHU design needed to incorporate heat recovery. However, the equipment room, which housed all HVAC, pool, and electrical equipment, was only about 1,000 sq ft. In addition, the park was set to open June 30, 2005, no excuses.

Ramaker faced other design challenges. For one, chlorine is always a concern when designing air systems for indoor pool areas. Because Big Splash is connected through a corridor to the hotel, it was important to maintain a negative pressure inside the park; otherwise, chlorine could penetrate the walls and damage the structure and odors could be pulled into the hotel. Finally, because chlorine is highly corrosive, all air-handling components needed a special coating to ensure lifespan.

The design and equipment also had to be suited to the moist seacoast environment of the Pacific Northwest.

"There is no canned HVAC solution for all natatoriums," said Keith Dunnavant, regional sales manager of Des Champs Technologies. "Climates, building construction practices, and usage vary from one pool project to the next."

Therefore, Dunnavant said, it's important that a supplier take a "systems" approach to each natatorium project, applying the best technologies for controlling space temperature, humidity, and pressure, while providing ideal ventilation with minimal energy usage. For Big Splash, this translated into a fresh air system with heat recovery and no mechanical cooling.

The supplier and engineer developed a highly customized design of Des Champs' X-Pack packaged ventilator to meet the specific needs of the park. The unit provided filtration, energy recovery, supply air, and indirect fired heat all within a footprint of approximately 10.5 ft by 25 ft.


Warm exhaust air from the pool area is used to preheat the outdoor air entering the unit via a high-efficiency, cross-flow, plate-type heat exchanger. The heat exchanger provides only sensible heat, since this application doesn't require any humidity to be reclaimed from the exhaust. An indirect gas-fired heater further heats the supply air to maintain an indoor space temperature of 85


The water park opened on schedule in June 2005. Meeting this deadline helped secure a bonus for the general contractor and kept Big Splash true to its grand opening promotions. For Des Champs, this meant a commitment to build and ship a highly customized unit three to four weeks faster than standard. "Over the years, we have developed more than a dozen different designs for indoor pool applications," said Dunnavant. "It takes experience and flexibility to be successful on a challenging project like this."