Without state-of-the-art HVAC technology and equipment improvements such as advanced motor and drive design, it is doubtful that the RainForest tropical habitat — located within the Cleveland Metroparks Zoo complex — could exist.
The RainForest contains two acres of plants and some 600 animals, similar to that found in rainforests around the world. The natural setting includes birds, monkeys, reptiles, and colorful fish that inhabit lagoons, swamps, and warm rivers. It is a domed, simulated biosphere. Its air handling system conserves water by transferring moisture from inside the biosphere to the dry incoming fresh air on a regular basis.
Despite wide swings in temperature and humidity inhabitants of The RainForest enjoy a nearly constant 76 degrees F and 76% humidity. This is due to a robust HVAC system that has evolved over the years to incorporate components that have improved the system’s reliability.
Direct Air Systems, Inc., with locations in Cleveland and Columbus, Ohio, working in conjunction with Zesco Inc., specialists in electrical-mechanical motion control and based in Cleveland, provided HVAC service to The RainForest.
The RainForest has two air handler units that use 100% outside air. To provide and maintain optimum environmental conditions for the facility, Direct Air Systems installed SEMCO energy wheel systems for the units, one of which has a throughput of 60,000 cfm used primarily for cooling. The other unit, rated at 40,000 cfm, is equipped with a pre-heater and humidifier rack. Both units have side-by-side, 1,000-lb dry desiccant heat wheels, which are necessary to conserve 18,000 pounds of water every day, transferring moisture from the RainForest’s stale exhaust air and giving it to the dry outside air stream once every 2.5 hours.
The fresh air’s temperature and humidity are moderated by the wheels’ slow revolution and the fact that the wheels’ mass and desiccant surface transfers a portion of the heat and moisture collected from the interior. Heaters, when necessary, warm the air before it passes into The RainForests's spacious interior.
The desiccant process was selected for both efficiency and simplicity. Engineers concluded that boilers, z-ducts, heat pipes, and other methods did not compare to the 85% efficiency the heat wheels provide. There were many problems with the original 1-hp ac motor and gearbox equipment in each of the energy wheel systems. At the time of installation, this was a fairly common equipment configuration...read the rest of the story here.