Additional alternatives
New technologies in the HVAC industry, such as modular units, may also help ease equipment installations in smaller mechanical rooms with limited access. Manufacturers have recently developed smaller modular units that can fit through 813-mm (32-in.) doorways, which enables contractors to install a complete unit that is capable of operating at the same capacity of a single, larger system. Essentially, they are separate units but each has a compressor, supply air fans, etc. They can also function together or independently in a staged operation, which can provide energy and redundancy benefits.
This method of installation was used in a retrofit project at the Niles Family Fitness Center—a $14-million, 9290-m2 (100,000-sf) facility built in Illinois in the 1990s. The facility’s original dehumidifier was fairly large and controlled 131.5 kg (290 lbs) of moisture per hour in the building’s 743-m2 (8000-sf) wing which contained the natatorium’s 418-m2 (4500-sf) pool. The consulting engineer opted to stack smaller dehumidifiers designed specifically for modular applications.
Another option is to gut the original unit and install new components, such as compressors, coils, and fans, into the existing shell. This retrofit method was recently used at Stevenson High School (also in Illinois) which hosts various state swim meets at its eight-lane, 50-m (164-ft) pool. The facility is also capable of holding up to 1,000 spectators. The retrofit contractor was challenged with the size of the dehumidifier and its replacement, thus it chose to use the existing shell and build energy-efficient components into it.
Planning for a retrofit during design
Foresight is important when constructing natatoriums and their necessary mechanical rooms as it will help save money in retrofit costs later on. Planning for something that will hopefully only happen in 25 years is not typically at the top of anyone’s priority list, but all equipment will eventually need to be replaced. A little planning in the beginning could generate substantial savings down the road.
Mechanical room space is another restrictive factor. With the high costs of construction (based on square footage), rooms that do not produce revenue, e.g. a mechanical room, are not often built as large as the design engineer would like. A small, restrictive mechanical room will not only create HVAC retrofit challenges later on, but could also potentially affect routine service and maintenance capabilities. One compromise that should never be considered is reducing service access. An inaccessible unit is difficult to maintain and adjust, which will negatively affect performance and ultimately the system’s life expectancy.
Installing HVAC equipment on the rooftop of a facility would be a good consideration in light of the aforementioned mechanical room challenges; however, it comes down to a trade-off between saving indoor mechanical room space, which can range between $100 to $225 per square foot, and the benefits of installing the equipment inside the facility. For example, rooftop locations cannot always be hidden from view to maintain the building’s architectural esthetics or structural integrity. For instance, a gable-style roof design with no flat areas for mounting a large HVAC system makes rooftop installations improbable. Further, the location might also be more remote from the pool, which will increase installation costs. Rooftop units are also more susceptible to heat loss and wear and tear from outdoor elements than their indoor counterparts. When rooftop equipment has poor access or is located in harsh climates, many times their maintenance is more neglected than indoor systems.
