Pool dehumidifiers: how to choose and calculate the optimal dehumidifier

High humidity is a characteristic feature of rooms with artificial reservoirs, associated with intense evaporation of water.As a result, moisture condenses abundantly on the walls, glazing, handrails, and ceiling.

Condensation creates conditions for the settlement of harmful microorganisms and destroys building structures. Properly selected pool dehumidifiers will help eliminate the negative effects of excess moisture. We will tell you how to choose the right drying equipment and introduce you to typical installation diagrams.

Specifics of the classification of dehumidifiers

Air conditioning systems, designed to create an optimal microclimate in private swimming pools, do not cope with the task of eliminating excess humidity.

Even air conditioners equipped with this function are not able to completely rid the room of water floating in the air and settling on surfaces. Only dehumidifiers operating independently or in conjunction with ventilation can solve the problem.

Division by principle of action

In the fight against excess moisture, two methods have traditionally been used:

• Heating of supply air. Supplied by ventilation system or air heating The air is preheated, which reduces humidity and increases moisture capacity. The vapors prepared in this way for assimilation are connected to the air flow and removed with it outside the room.
• Adsorption. Over-humidified air is sucked into a device with an adsorbent filler, for example, silica gel. The substance absorbs excess moisture, which is then removed from it by calcination.

Both methods can hardly be classified as economical. In the first case, too much energy is spent on processing the air, which is then easily discharged into the atmosphere. In fact, there is an expensive heating of the street without tangible results in terms of drying.

Drying devices operating on the principle of heating the air mass with subsequent assimilation of vapors spend too much energy on heating the air discharged to the street without rational use of heat

The second option is not pleasing with the impressive energy losses spent on adsorption with moisture condensation and subsequent calcination of the adsorber. However, it is more practical.

Systems operating on the basis of adsorption are produced, for example, by the Swedish company Munters, but they are used mainly for the arrangement of public sports complexes, industrial and food warehouses, and production workshops.

The action of adsorption air dryers is based on the ability of a substance located inside the housing to absorb and retain water molecules

The high cost and senseless energy losses of the two outdated methods forced us to look for more affordable economic and technological ways to equip private swimming pools.

As a result, new dehumidifiers have been developed that operate on the same principle as standard air conditioners. Drying machines are slightly different from them in design and require equal care and maintenance.

The dehumidifier models currently in use are equipped with a fan, compressor, hydrostat, and radiators. Their action is based on the principle of condensation. A fan built into the device captures moist air from the pool room and directs it to the condensing unit.

The air freed from condensation is discharged back into the room, and the condensate separated from the moist air mass is collected in a pan and discharged through the drainage channel.

If the dehumidifier design includes an additional heat exchanger, then it can perform the work of heating the air in the room being treated. When connected to a water heater or hot water supply, such models allow you to reduce the number of radiators or not eliminate them at all

Devices that remove excess moisture through condensation operate in full or partial recirculation mode. Complete recirculation involves the cyclical movement of air flow within a room without changing its composition.

Such dehumidifiers cope well with air treatment in small private pools that do not require constant updating of the air composition.

If you want to improve the quality of the air flow or there is a need to increase the oxygen content and reduce the proportion of carbon dioxide due to the length of bathing sessions, then it is better to purchase a dehumidifier that is connected to the ventilation system or directly to the street.

It will provide the opportunity to update the composition of the air by periodically mixing a fresh portion into the dried air flow.

The range of dehumidifiers includes modifications with water heat exchangers connected to the pool water heating circuit. They transfer the heat generated during the drying process to the heating system, thereby significantly reducing the cost of maintaining an artificial reservoir.

In addition to the ability to mix portions of outside air, a number of dehumidifier models are complemented by the functions of heating water and the air itself, and perform filtration and ionization actions. The dehumidified air flow is heated by a water or electric circuit. The first one will be cheaper both to purchase and to operate.

If you are interested not only in normalizing the humidity level, but also in creating the most comfortable conditions, then you should study the functionality of several units in advance in order to select and give preference to the position that has the required capabilities.

Duct drainage systems are equipped with a significantly larger number of functions. For example, Variheat brand systems, in addition to their main work, at the same time mix in fresh air, stabilize its temperature, prevent leakage of air masses into adjacent rooms and heat the water in the pool bath (+)

Design and installation differences

We found that the predominant number of market offers in the segment of air drying machines for artificial reservoirs is represented by condensing devices.

According to the installation method, they are divided into:

• Mobile. Small monoblock machines, buy them for small-sized pools and saunas, if the water surface area does not exceed 40 m². These are mainly compact floor-mounted varieties or wall-mounted modifications with the ability to be installed on the floor.
• Stationary. These are duct systems designed for air treatment in swimming pools with an evaporation area of ​​over 40 m². Large-sized floor units that can be installed both in a separate ventilation room and in a swimming room.

When installed in a separate compartment, a ventilation chamber, duct dehumidifiers are connected to an air duct system built into the walls or ceiling of the pool. Taking into account the specific environment in installation of air channels it is advisable to use plastic structures.

You can install a ventilation chamber for a ducted dehumidifier in the basement of a house with a swimming pool or in the attic.

Duct dryers are connected to air ducts. The unit itself is most often placed in a utility room (+)

Note that the division by processing capabilities is quite arbitrary, because among compact devices there are dehumidifiers capable of treating pools with an evaporation area of ​​70 - 100 m². And if such a wall & floor unit is built into a partition, it automatically goes into the category of stationary systems.

Monoblock dehumidifiers are available in wall-mounted, floor-mounted or combined versions. Most models are suitable for both floor and wall mounting (+)

Typical layouts

Systems for ensuring a favorable microclimate in a room with a swimming pool are arranged in accordance with one of the standard schemes.

Option #1. The simplest and cheapest way to reduce the level of humidity in a pool is to install monoblock wall-mounted or floor-mounted dehumidifiers in an amount of 2 to 5 pieces, depending on the actual evaporation area.

This solution is perfect for small rooms with low traffic volume. Where it is much easier and more reasonable to ventilate periodically than to install an expensive duct system (+)

Option #2. A scheme operating on the principle of partial recirculation, i.e. with the intake of a fresh portion of air from the street, which is mixed with the dried and heated air mass captured in the pool.

It is used in facilities with a high level of traffic that require a constant supply of oxygen and removal of carbon dioxide. To discharge excess air mass, an independent exhaust system is constructed (+)

Option #3. Channel systems installed in separate compartments are used. Dehumidifiers are combined with supply and exhaust ventilation, which guarantees complete air exchange in the pool room.

The installation performs several functions simultaneously. It removes 50% of the exhaust air from the pool, captures a portion equal to the removed portion outside, mixes them and dehumidifies them to the required parameters (+)

Option number 4. The scheme uses wall-mounted, built-in or simply mounted dehumidifiers, the operation of which is not related to supply and exhaust ventilation. The dehumidifier turns on when the humidity level set by the pool owner is exceeded.

The air flow is supplied in the lower part of the room, almost at the level of the water surface. The air flow is extracted through exhaust openings mounted in the ceiling (+)

Option #5. Wall-mounted monoblock dehumidifier works in tandem with supply and exhaust system, performing partial drying of the air mass in the pool.

The monoblock dehumidifier is activated only if the ventilation circuit cannot cope with the task of lowering the humidity level (+)

Based on the standard solutions proposed for consideration, you can choose the best option for arranging your own pool or improve one of the most suitable ventilation options according to specific technical conditions.

Features of installation of dryers

Before installing any model of dehumidifier, you should thoroughly study the instructions supplied by the manufacturer with your product. The cooling system of machines operating on the principle of condensation of excess moisture is filled with refrigerant.Despite assurances that the substance is safe, leaks and discharge into the environment must be prevented.

The installation location of the device, regardless of its design features, must take into account:

• access for maintenance and repair work;
• all risks associated with a possible emergency leak of refrigerant;
• permissible distance from objects that pose a threat of direct contact of the electric machine with the flow of water.

Such objects include the pool itself, a whirlpool bath, a shower, a fountain, and a container of water. According to European standards, there must be a minimum of 2 m between the water source and electrical equipment.

In the event of a refrigerant leak, the impact must be minimized. If detected, artificial ventilation should be strengthened and supplemented with natural ventilation methods.

The accumulation of the substance occurs in the lowest places, poorly covered by circulating air flows. Due to stagnation and accumulation, refrigerant concentrations can reach dangerous levels.

Direct contact of the refrigerant with a hot surface and an open flame is unacceptable, because when heated, the substance breaks down into toxic components. It is necessary to prevent it from coming into contact with exposed skin and eyes. Spilled refrigerant should not be allowed to flow into the sewer system, so as not to create gas plugs in the pipeline - a common cause of water hammer.

If a minor leak is detected, the substance should simply be allowed to evaporate. If a serious release occurs, it is necessary to increase the intensity of ventilation, localize the refrigerant with sand or at least ordinary soil and call repairmen.

Installation of a monoblock wall model

Most modifications of wall-mounted dehumidifiers are available in versions used for floor installation and hanging for their intended purpose on a vertical surface. In the first case, the legs are screwed to the body, and the equipment acquires the status of a mobile dehumidifier. In the second, everything is extremely simple - the housing is fixed to the wall with M8 screws through mounting loops.

Installation of monoblock modifications of dehumidifiers can be done either using a wall-mounted design or mounted in a partition through the use of ventilation chambers

Let's look at the specifics of installing a wall-mounted model from the HldROS SBA series. Let's consider the installation option of being built into a partition using dryable chambers.

We will do it as follows:

• We attach two ventilation chambers to the dehumidifier body from above and below so that their working side is turned towards the surface to be treated. We use Ø 3.5 screws to fix the cameras.
• We dismantle the machine body to connect water pipes and install electrical connections.
• We connect a coil designed to heat water and a drainage hose designed to drain condensate.
• We connect the power cable to the terminal board located in the control box.
• We carry out all grounding connections specified by the dryer manufacturer.
• We check the quality of the generated nodes and the performance of the system.
• We assemble the body and fix its parts in their original places.

The dehumidifier should be serviced regularly, every six months.

During scheduled maintenance, you need to check the operation of safety and control units, monitor for water leaks from the coil and refrigerant from the cooling system.It is necessary to check the condition of the air filters, measure them if necessary, and check the balancing of the fan blades.

At the end of the season, maintenance is carried out in the above order, but is supplemented by the mandatory drainage of the water circuit.

Construction of a channel modular system

Installation of modular systems with duct dryers must be carried out according to a pre-developed project. During development, the optimal route for laying air ducts and the best location for installing the machine are selected. Let's look at the device options using the Calorex Variheat III brand systems as an example.

Duct drainage systems made on a modular principle are arranged in accordance with the architectural and technical features of the room, as well as the wishes of the customer (+)

The equipment is produced in the format of prefabricated modules, which makes it possible to:

• Vertical installation of the dehumidifier with the supply duct located at the top in the area of ​​the upper ceiling, behind the suspended ceiling or along the line between the ceiling and the adjacent wall.
• Vertical arrangement of the drying machine with installation of the supply duct at the level of the radiators under the window openings. Air intake for processing is carried out at the level of the upper module of the dryer.
• Horizontal arrangement of the main unit of the system with lateral connection of air ducts. Air intake for drying and delivery of the processed mass is carried out almost at the same level.

The optimal layout of equipment and air ducts is selected in accordance with the individual characteristics of the main and utility rooms of the pool.

Design and calculations for equipment selection

For proper selection of equipment, it is necessary to calculate the evaporation rate. Calculations are carried out according to the formula regulated by the European standard VDI 2089.

The formula was developed by a community of German engineers to determine a dehumidifier with the necessary and sufficient capabilities

Let's calculate the evaporation rate for a small private pool with a water surface area of ​​30 m². Let us take the temperature of the water in the pool bath to be +28ºС, the air temperature in the swimming hall +29ºС, the value of the water vapor pressure in the room R_B Let's take 33.6 mbar. Let's assume that the recorded air humidity is 65%.

First we need to calculate *R_L – the magnitude of the partial pressure of evaporating water. We find the value to calculate it R_L100 (at humidity parameters of 100%) according to the table of gradation of elasticity of saturated water vapor.

This elasticity depends on the temperature of the water in the pool bowl. According to the conditions we have adopted, this is 40.07 mbar, which must be multiplied by 0.65 (the humidity value normalized to unity).

Table with experimentally determined average values ​​of air elasticity at a conventional humidity level of 100%

R_L100 (value at 100% humidity) × 0.65 (65%) = 40.07 × 0.65 = 26.05 mbar

W = e × A × (P_B - R_L) = 15 × 30m² × (33.6 mbar – 26.05 mbar) = 3397.5 g/hour ≈ 3398 g/hour = 3.398 kg/hour

Based on the example data from 1m² 0.11 kg of moisture will evaporate from the water surface in the pool.

This is a simplified scheme for calculating evaporation rates, but if you wish, you can use another method used in the UK.

The Byazin-Krumme formula is most often used when calculating the evaporation rate of private and public swimming pools in the UK (+)

Conclusions and useful video on the topic

Video #1. Purpose and principle of operation of the device for dehumidifying air in the pool:

Video #2. How monoblock dehumidifiers work:

Video #3. What is a duct drying unit:

Choosing a device for drying air in a pool is a serious matter that should be approached thoughtfully and thoroughly. The information we offer will certainly be useful to the owner of a swimming pool who wants to ideally, but without extra costs, equip his beloved property. Wisely selected equipment will work perfectly and serve well.

How did you choose and install air drying equipment in your pool? Share the technical criteria that justified the purchase and installation details that will be useful to site visitors. Please write comments in the block below, post photos, ask questions.