The Tropical High Elevation House

The Tropical High Elevation House features orchids and other flora from three high elevation regions in the tropics: the Andes mountains, the Tepuis of southern Venezuela and Mt. Kinabalu in Borneo. Temperatures are maintained at a maximum of 76˚ during the day and 55˚ at night with an average relative humidity approaching 80%. This greenhouse is unique in its use of a mechanical air washer to create a cool humid environment suitable to tropical montane species.

In July the nighttime temperature in Atlanta is usually 70-75˚.One of the biggest challenges faced by staff during the planning and design stages of the Tropical High Elevation House was to address the problem of how to cool a 3600 sq. ft. greenhouse 20 degrees below ambient. Conventional evaporative cooling under humid conditions would probably cool the greenhouse only a few degrees. Air conditioning would be enormously expensive and would create a dry environment. For a solution we turned to the textile industry. Modern textile factories require tight control of temperature and humidity in the production of high grade cotton fiber. The low temperature and high humidity needed to prevent static and breakage of threads is achieved with an industrial air washer.

An air washer uses an enormous fan to draw outside air into a rain chamber. Inside the rain chamber the air is pulled through a large grid of spray bars, each studded with small nozzles emitting fine mist. The source of this water is a 200 cubic ft. reservoir that re-circulates water. At higher cooling stages, as the temperature rises, the water is pre-chilled to 40˚. 

The Fuqua Orchid Center's Tropical High Elevation House is the first greenhouse application of an air washer. The chilly moist air created by the air washer is drawn up from a sub-basement and distributed through the greenhouse via three large air dispersal tubes. The air washing process is monitored and regulated by a computer to maintain the correct environmental parameters.