Guest Column - January 2012
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Don't Let Budget Problems Dampen Your Aquatics Program

By Charles Munchell

Managers and administrators of park and recreational facilities need not be reminded that the upcoming year will require belt-tightening, even greater than in past years. Looking for places to trim facility budgets is getting more difficult, and new cuts are hitting primary services more than ever.

Indoor aquatic programs, unlike some departments, require ongoing service and attention. The humidity and space temperature must be continually controlled. Otherwise, occupant comfort will suffer or the facility itself can be dangerously compromised.

Indoor pool facilities need a dehumidification system to remove excessive moisture that continually evaporates off the pool surface. The rate of evaporation increases as water agitation increases and as the water temperature is raised. This air-borne moisture, in many cases combined with chloramines, condenses on cold surfaces. The chloramine-bearing moisture is highly corrosive to metallic surfaces and must be prevented.

Indoor pools usually require heating of both the water and space. The cost of heating is expensive and is further impacted by ventilation code requirements. It becomes more a question of how to maintain the necessary set points at the lowest cost while still retaining occupant comfort and facility protection.

Pool-room environmental equipment is compulsory to effectively balance all the factors necessary for an optimum indoor pool facility. Other than new construction, retrofitting with a new system is practical if your existing dehumidifier is inefficient or prone to costly repairs. The choice of systems can be complex, and, depending on the selections made, can have long-term repercussions.

The first rule is to use only dehumidification equipment designed for indoor pools. Packaged dehumidification equipment built for pools incorporates more sophisticated mechanical design and software compared to conventional systems. They will last longer since most are designed around the corrosive pool environment.

Dehumidifiers using mechanical refrigeration and hot gas reheat are the most frequently used systems and are similar to a conventional heat pump furnace. The dehumidifier collects heat from the excess moisture in the poolroom air during the dehumidification cycle and uses it to temper the pool water and air.

These types of systems have greater first cost, and have higher ongoing maintenance cost due to the mechanical refrigeration system. However, the additional cost can be offset because they will deliver "free" air and pool water heating along with the opportunity to use different control strategies to further lower the cost of operation.

Efficient dehumidification equipment with a high coefficient of performance (COP) means the unit can put out more energy than it uses. As an example, a COP of 5 means the system output energy is five times the input energy. This energy is used to heat the space and/or water, saving on fossil fuel. In many cases the recycled energy will cover the cost of heating, eliminating the need for auxiliary heaters.

Refrigeration-type dehumidifiers can be specified as a basic model for less initial cost or with different features for additional functionality. Base units should be able to recycle energy to heat the pool water and/or air. The addition of an exhaust fan helps with ventilation and negative air pressurization requirements, eliminating the need for a supplemental exhaust fan unit. The inclusion of a purge fan simplifies 100 percent outside air ventilation during pool shocking, saving time and labor.

More sophisticated dehumidifiers include a supply and return fan to better utilize inside and outside conditions. A dual fan system facilitates free cooling, heating and even dehumidification (economizing) when outside air conditions permit. During this cycle compressors are off, saving on energy usage.

Specify High-Efficiency Equipment

High-efficiency dehumidification equipment is not only good for sustainability, it's good for your budget as well. Paying extra in some cases for more efficient components will be a good investment in the long term.

Modulating refrigeration capacity ensures maximum system efficiency and extends the compressor life. Backward inclined airfoil-type fans (BIAF) on blowers move air more efficiently, reducing energy requirements. Use NEMA premium efficiency motors on all fans and blowers. They require less energy for equal loads and deliver longer service life.

Refrigeration-type equipment should have chlorine-free and environmentally-friendly R410A refrigerant that produces more cooling and dehumidifying capacity per kW. And only consider dehumidifiers that have compressors and other critical components outside of the corrosive air stream. Not only will that increase the life expectancy of the equipment, it will increase system reliability.