FAQ

Suspended Ceilings

Suspended Ceilings

Why are suspended ceilings not recommended?

They create an unconditioned space that is prone to condensation and corrosion problems. Pools with suspended ceilings are notorious for corroded hardware (‘T’ bars and hangers) and condensation soaked tiles falling into the pool.

Skylights

Skylights

Why are skylights not recommended?

They are prone to condensation problems in colder weather. The quantity of supply air (3-5 CFM per ft2 or 15-25 1/s per m2 of glass) required for condensation control must be sufficient to blanket the entire skylight. Visible ductwork is required to supply this air to the skylight and can cause concerns about aesthetics with the owner.

Duct Design

Duct Design

How important is duct layout?

It is absolutely vital. The total quantity of supply air must be sufficient to provide four to eight air changes per hour (as recommended by ASHRAE) to prevent stagnation and air stratification. Care must be taken to ensure the entire space receives the required amount of air flow and to prevent supply air from short-circuiting to the return inlet.

Heating Whirlpools

Heating Whirlpools

Can a DRY-O-TRON® be used to heat a whirlpool?

The economics of this option make it a good investment, but only for larger whirlpools. A suitable whirlpool is one that represents more than 25 percent of the total evaporation from all pools.

Swim Meets

Swim Meets

What special design concerns mustbe addressed?

A pool that will host swim meets has essentially two modes of operation: normal and swim meets. A swim meet generally has a very large spectator load while the pool swimmer density is less than during normal operations. The Activity Factor for a swim meet should be 0.65 whereas in normal operation it would be 0.8-1.0, (as per the “Activity Factor” table on page 17). The designer should review computer models of each mode to ensure that the size of the selected unit is appropriate for both.

Pool Covers

Pool Covers

Are they recommended for daily use?

Experience shows that unless a pool cover is automatic, it will not be routinely used. A pool cover is important to have at a facility in the event of a power failure when the DRY-O-TRON® is not able to run. The use of a pool cover however, does not affect the size of the DRY-O-TRON® required since it is sized for the load presented by the pool when in use.

Condensate

Condensate

What should be done with the condensate that comes from the unit?

The amount of condensate a DRY-O-TRON® recovers in a year is approximately the equivalent of one entire pool fill. The condensate from our HyPoxy® coated coils is drinking water quality and can be returned to the pool where local codes permit. It is usually reintroduced upstream of the filter or into the skimmer.

Cooling

Cooling

What if more cooling is required thanthe unit can provide?

If the DRY-O-TRON® selected has a capacity close to the minimum required, a unit one size larger would be the most cost effective solution. If the cooling requirement is significantly more than the selected DRY-O-TRON® supplies, the difference can be made up by a separate cooling circuit added either to the DRY-O-TRON® or in the duct.

Air Direction

Air Direction

Should air blow at the water surface?

Air movement at the water surface increases the evaporation rate. The U.S. Olympic Committee (USOC) does however recommend some air movement at the water surface for its facilities because a slightly higher concentration of chlorine (compared to the rest to the space) tends to remain there. The USOC also likes air to be supplied to the water surface to help improve the air quality where the swimmers breathe.

Return Air

Return Air

Should the return air inlet be nearthe spa?

This is not recommended. The air around the spa has the highest concentration of chloramines and is the most corrosive air in the space. This could reduce the lifespan of the ductwork and equipment. An exhaust fan near the spa is recommended.

Wet Deck

Wet Deck

Why use wet deck area in lieu of total deck area to calculate the outdoor air requirement?

The purpose of outdoor air is to dilute the chemicals evaporating from the pool water. A section of deck that will never get wet does not contribute to air quality issues. As outdoor air is expensive to heat, cool and dehumidify, designing the outdoor air requirement to match the wet areas is a means of reducing the operating costs of the facility.

Duct Material

Duct Material

What duct material is recommended?

The recommended duct material is standard galvanized sheet metal, aluminum, 316-grade stainless steel or fabric duct. Painted galvanized spiral ductwork is popular when the duct is exposed. The entire ductwork system must be designed to be dry at all times, and all seams must be sealed with an approved duct sealant. If a below-grade duct system is used, non-metallic or PVC-coated round metal ductwork should be used.

Duct Insulation

Duct Insulation

Is it required?

If the ductwork is located in unconditioned areas (normal temperatures are 65°F-90°F (10°C-32°C)), it should be insulated with at least two-inch (5 cm) fiberglass duct wrap on the outside of the duct. This will prevent condensation and heat gain/loss.

Small Rooms

Small Rooms

What is recommended for a room with only a therapy pool or whirlpool?

These smaller rooms are common in hotels and physical therapy clinics. The small dehumidification load and lower air flow requirement is an ideal application for Dectron’s MAM Series. Contact your local representative for additional information.