Pre-existing mechanical rooms in older aquatic facilities pose a series of challenges for any HVAC replacement team—specifically in terms of access. Indoor pool dehumidifiers are typically very large and, circa the ’90s, architects rarely planned for the day the equipment would need to be replaced. Therefore, many mechanical rooms only have single 813-mm (32-in.) wide or double-access pedestrian doors. While old equipment can be disassembled and carried out, older mechanical room door openings cannot accommodate today’s larger dehumidifiers.
This poses several decisions for a design team:
- Bring in the new system by opening a wall or roof, which could potentially cost tens of thousands, if not hundreds of thousands, in envelope construction.
- Request the manufacturer to factory-disassemble the unit (after factory assembly and testing) and deliver to the site in multiple sections that fit through pedestrian doors for on-site assembly.
- Use a variation on the previous example, whereby gutting the old dehumidifier components, but leaving the shell in place, then requiring the new system’s manufacturer to design a new component configuration for assembly into the old shell.
- Realizing access is problematic in retrofits, some manufacturers have recently designed modular units to fit through standard-sized pedestrian doors for integration into one unit that equals the refrigeration tonnage and cubic feet per minute (CFM) of one large unit.
The CAC design team chose the fourth option for the spectator dehumidifier. The two, 2-m (6.4-ft) long by 1.1-m (3.5-ft) wide by 0.76-m (2.5-ft) four-ton units that were specified were easily dollied through the mechanical room door. Inside, both modular units were integrated in tandem using their factory-aligned connections designed for piggybacking into one small horizontal footprint.
The new system consumes approximately 50 per cent less floor space, making the mechanical room less confined. More importantly, the eight-tons of dehumidifier capacity and revamped spectator section ductwork helped to quadruple the spectator area’s air changes per hour (ACPH) to eight. The additional air changes provide a more comfortable temperature and humidity of 24 C (76 F) and 50 per cent relative humidity (RH), versus the pool area’s 27 C (82 F) and 50 per cent RH.
Further, the modular units have their own compressor, blower, and refrigeration circuit. This configuration allows them to operate in tandem for full capacity situations at swim meets, or as a single-stage unit when few or no spectators are present, which provides significant energy savings for the facility.
