The exhibit's dedicated outdoor air systems use an enthalpy energy recovery system to reclaim as much energy from the relief air as possible. An active desiccant wheel ensures very dry air is supplied to the low temperature brine cooling coils, minimizing any required reheat. The units have traditional chilled water cooling supplied from a very efficient district CHW loop. The decision of the exact type of cooling fluid to be used was crucial to the efficiency of the systems and the overall performance for the building. Operating at 15°F (-9°C), this fluid had to be special. There were five possible methods/cooling fluids (Figure 3) that could be used with these air-handling units: 1. Refrigerant (either direct expansion or liquid overfeed); 2. Ethylene glycol; 3. Propylene glycol; 4. Brine water solution; and 5. Potassium formate. Due to the risk to the penguins' heath if a leak occurred, the first two options were eliminated. The pumping energy for propylene glycol would be very high at 15°F (-9°C), and the owner was concerned about the corrosive brine system with the fourth option. Detailed analysis proved the potassium formate was the most efficient cooling fluid for this project. The ride and queue units all use enthalpy wheels to assist in the dehumidification process. A heat recovery system uses the 95°F (35°C) condenser water return to generate all of the hot and defrost water heating needs for the building. Effective maintenance of a building is necessary to achieve designed energy savings. The www.info.hotims.com/54427-53 APRI L 2015 ashrae.org ASHRAE JOURNAL 49