Pool Dehumidification | Why use a Fresh Air Pool Dehumidification System?

Pool Dehumidification

The function of a pool dehumidification system is to maintain the room humidity level at a point below the dewpoint of any surface in the building.  This prevents condensation and deterioration of the building structure you can avoid these type of problems by choosing softeners for well water.

There are typically two ways in which you can control the humidity within an indoor-pool enclosure.  One, the traditional mechanical system method, is to use a refrigerated air-conditioning system.  In this system, the air from the pool space is continually recycled over a cooling coil.  The coil condenses water from the air and the pool air set point for humidity is maintained in the space.  The second technique is to control the indoor humidity by diluting the indoor air with drier outdoor air.  In these types of systems, Fresh Air Pool Dehumidification System,  Air-to-Air Heat Exchangers are typically used to recover energy from the pool exhaust air and transfer it to the incoming outdoor air.  Because the outdoor air humidity level changes with the temperature, the colder it is the lower the humidity level is of the outside air.  A pool system is sized to provide adequate dehumidification on a 50-60 deg F rainy day.  Consequently whenever it is colder or drier out than the “balance point” day, less outside air can be brought in for the same amount of dehumidification.

We have supplied both types of equipment over the past 20 years.  We recommend and always prefer to provide a Fresh Air Pool Dehumidification System (see project list).  This is a much more sustainable design.  The units are typically all aluminum and last in excess of 20 years (in a very harsh environment).  Mechanical Systems come complete with condensing units that run all year long.  They are painful to maintain and typically last only 5 to 10 years.

Fresh Air Dehumidification Unit - Nashua Boys & Girls ClubFresh Air Pool Dehumidification System Description: Outside fresh air is brought into the space through a sensible Heat Pipe Heat Recovery Module.  The humid pool air is exhausted through the other side of the heat exchanger.  Over 70% of the heat in the exhaust air is recovered.  On a 0°F design day the heat exchanger will preheat the incoming supply air to 70° to 75°F, before mixing with any recirculated air.  A hot water heating coil, or gas furnace, provides the minimal additional makeup air and space heating.

The modulating Fresh Air Pool Dehumidification System uses modulating recirculation and outside air dampers to regulate the outside air volume to the precise amount required for humidity control.  This conveniently provides minimum outside air flow at the time when heating costs would be highest.  Code ventilation rates are still maintained with a minimum set point on the dampers.  For a typical 10,000 CFM system in New England the humidity set point can be satisfied with as little as 3,125 CFM of outside air on a 0°F design day, and 4,056 CFM on a 32°F day (based on a 50%RH set point on the space humidistat).  The set point on the space humidity can also be reset to 60% as the outside air rises above 55°F and the building surface temperatures rise.  Reheat is added as needed to satisfy the building and ventilation heat load.  The ventilation heat load is typically only a 6-10°F rise.

Fresh Air Pool Dehumidification Unit - Leggs Hill YMCAIn the summer mode the system typically operates at 100% outside air and exhaust.  In buildings with minimal glass loads and sensible heat gains there is no need for any mechanical cooling.  Cooling can be added if necessary with a DX coil, integral or remote air cooled condensing unit and an additional heat pipe coil for free reheat.  With cooling added it only operates when the outside air dewpoint rises above 45°F.  When mechanical cooling is used a reheat air to air heat exchanger is added to precool and reheat the air passing through the cooling coil and provide neutral temperature air to the space above the space dewpoint this and combination of pool, spa & hot tub water enzymes brings very good benefits for your pool´s room and your pool´s water.

Fresh Air Pool Dehumidification System provides the lowest maintenance and operating costs of any pool dehumidification alternative.

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