Many people have a dream - to build their own pool. Having a home, such people have a choice of its location. If you plan to build on the street, then you should be aware of the nuances of its systematic cleaning from environmental factors.
The dehumidifier provides high-quality air exchange
Why does the pool need air cleaning?
When the pool is located in the house, the risk of rapid contamination is reduced. But there is another problem. Water tends to evaporate. This is due to temperature differences. Water turns into steam, which accumulates in the room.
Moisture condenses on all surfaces of the room: furniture, windows, walls, floors, etc. The constant impact of water on the objects of the surrounding space, negatively affects their condition. Properly executed swimming pool ventilation completely solves this problem.
The problem of excessive moisture in the pool
Proper operation of a private or public pool includes a large number of activities related to: cleaning, disinfection, revision of sewer parts, replacement of filters, etc. When the pool is located indoors, it is important to reduce the evaporation of water and dispose of the accumulated steam. High humidity is the cause of several problems.
What is the danger of high humidity in the pool
- Condensation accumulates on the surfaces of the building and existing furniture. This causes the formation of: rust on metal elements, mold and decay of objects of use surrounding a person.
- Humidity in the pool can harm the structure itself. Its long and regular impact on the walls causes their destruction.
- Even if the building is new and, according to external signs, nothing threatens it, the humidity in the pool can cause cracks in the floor and walls in a short period of time. Condensation accumulates in these formed spaces.
- Finishing building layers begin to mold and slowly collapse.
- The evaporated water flow, settling on the surface of the building, creates ideal conditions for the development of bacteria harmful to the human body. Inaction in solving such a problem leads to various diseases.
The photo shows a conditional scheme of supply and exhaust ventilation in the pool
But all of these problems can be solved. Ventilation in the pool of a private house can reduce the risk of negative impact on surrounding objects and the human body.
Advantages of installing a ventilation system in the pool
Dehumidifying the air in the pool is an important factor in the proper operation of this facility. One cubic meter of water can convert up to 250 ml of liquid into steam in one hour. One can only imagine how difficult the air becomes to breathe.
Even the smallest pool of 10 cubic meters of water releases more than two liters of its component into the air in 1 hour. It is dangerous to be in such conditions. The issue of vapor concentration in the air also depends on other factors, such as: the size of the room, the temperature difference between water and air, the size of the pool and the volume of water in it.
But for any indicators, smaller or larger, the negative impact on the person, structure and furniture plays an important role. Ventilation of the pool in a private house or in any other room will reduce all indicators of such an impact.
Now it is not a problem to buy special equipment. Anyone is given a huge selection of devices of various types and the principle of their work. For a private pool, there is equipment with dehumidifiers, without them, and supply and exhaust devices. Each of these has its own advantages and disadvantages.
Why installing only an exhaust hood is not enough for air purification
An exhaust unit of any type cannot solve some problems on its own. These include:
- The difficulty of draining the room in the warm season. The evaporation of water in the pool is a constant process, and the air temperature outside the room may vary. In summer, the process of evaporation of moisture from the earth's surface reaches its maximum rate. The air becomes humid and the pool dehumidifier does its job less efficiently.
- When a large amount of precipitation falls in the form of rain, the outdoor air is supersaturated with evaporation. A dehumidifier for the pool is not advisable to use during such periods. It will not perform its functions. Even the installed supply and exhaust ventilation for pools will not be able to significantly reduce the humidity index. Such a device will allow you to remove stagnant volumes of steam from the room and bring new, no less humid ones into it.
- A large and efficient pool ventilation unit is volatile and powerful. The installed type of equipment or their complex increases the cost of electricity.
Having determined the shortcomings of air drying and its replacement with fresh masses, it is possible to determine the efficiency factors of the equipment used. These include:
- Quality air exchange. Air handling units must be as efficient as possible. The best indicator is 70 cubic meters. meters of fresh air per person.
- Ventilation in a private pool is most effective when using dehumidifiers. These devices come in a variety of capacities. There are no restrictions on certain volumes of air.
- Dehumidifiers for swimming pools are selected from the personal desire of a person. It is only necessary to pay attention to some design issues.
The dehumidifier for the pool is selected based on the desires and requirements of the owner
Selection of drying equipment
If a person cannot decide on the exact model or does not know how to choose a dehumidifier, he should pay attention to the design of the equipment. Stationary or wall-mounted dehumidifiers are in constant contact with humid air. Potential buyer, it is better to choose models:
- With galvanized body. You should pay attention to how this structural element is made. If hot, then the ends of the body will be reliably protected from corrosion. Cold - the case begins to rust after several years of use.
- With sealed knots. The design of the device should not have places where moisture accumulates. All nodes must be firmly connected and sealed.
- With smooth pipe surfaces. Corrugation such serves as a place for the accumulation of water droplets.
- With an additional layer of enamel on the surface of the case. He is protective. Its presence will significantly increase the life of the device.
When it comes to the technical component, everyone chooses a dehumidifier at their own discretion.
The principle of operation of drying equipment
The arrangement of the pool ventilation system is impossible without a complete understanding of its principle of operation. This is especially true for those who install the drying equipment with their own hands. Conventional hood, fans or supply and exhaust type of ventilation - their principle of operation is clear. Such devices are necessary for independent or forced removal of heated air, and sometimes replacing it with a new, fresh stream.
Feature of pool ventilation equipment
The scheme of the device and the installation of the dehumidifier is completely different from the usual, often used means of ventilation. Its operation is based on the principle of condensation. Humid air streams are drawn into a special chamber - the evaporator with the help of a fan. Here it goes through the process of cooling and dehumidification. The incoming mass of recycled air is pushed out through a separate outlet.
Design features of the pool ventilation system
Designing pool ventilation requires the right choice of device. Sufficient equipment power and its location are important issues for the owner of the pool. The correct selection of drainage equipment is initially made from the surface area of the pool. The stationary most powerful device processes air with a water layer size of not more than 40 sq.m.
If this figure is higher, the ventilation system in the pool is supplemented with another device. Sometimes experts recommend installing a dehumidifier as a structural part of the general house ventilation or air handling unit. Such models are expensive, and it is difficult to install equipment on your own.
How to choose a ventilation system for your pool
For pools up to 50 sq.m. suitable wall-mounted type of drying equipment. In cases with a larger water surface area, such a ventilation system will be ineffective. The advantage of a floor or mounted dehumidifier is its ease of installation. Such devices do not require a separate room and are located directly in the same room as the bath.
And if there is already ventilation in the same room, then it is these types of drying devices that are most appropriate to use. The disadvantage of mounted and outdoor equipment is considered to be occupying a certain place in the room. The dehumidifier cannot be hidden or decorated. A pool ventilation project with a built-in dehumidifier eliminates this problem.
The air exchange rate of the dehumidifier located inside the ventilation pipe is higher than that of floor and hanging devices.
The intensity of air processing increases due to the properties of the supply and exhaust equipment. General ventilation of this kind performs two functions at once - air replacement and dehumidification. Also, the advantages of this are: sound insulation, small size and saving space in the room.
Types of drying equipment devices
There are three types of dehumidifiers for domestic and public pools:
- condensing and refrigeration type;
- adsorption type;
- assimilation type.
Each of these has its own advantages and disadvantages.
Refrigerators
Condensing units are often used in floor and mounted types of equipment. The work of such is based on the cooling of the heat exchanger. Air, getting into such a chamber, condenses on the walls. Water flows into a special drainage and is completely removed from the device. The dried and cooled air is supplied to the second chamber - the heating one. It is from this that it is fed back into the room with the help of a fan.
adsorption dryer
An adsorption dryer works differently. The working chamber of the device is filled with a special substance that extracts a large amount of water from moist air, drying it.
Assimilation dryer
Assimilation dehumidifiers are rarely used for swimming pools. This is due to the high cost of electricity. In such a device there is a heating chamber. The air is heated to a certain temperature and condenses.
All types of equipment are highly efficient. Modern models can process up to 120 liters of moisture in 1 day.
The nuances of the configuration and electronics of the dehumidifier models
Pool ventilation calculation is a system of actions that includes monitoring of all the nuances of the equipment used. These include:
- choice of location;
- type of hood and dehumidifier;
- calculation of the required power of devices and their efficiency;
- equipment installation;
- ease of use of devices.
Modern models of ventilation equipment are equipped with an additional set of functions that facilitate or improve the operation of the device itself. Dehumidifiers are no exception. The main functions of the drying equipment are:
- Maintaining and regulating the level of air humidity.
- High multiple of air exchange intensity. The higher the multiplicity - the more air the dehumidifier processes per unit of time.
- Purification of air masses from harmful impurities (salts, metal, etc.).
Device functionality as a selection criterion
How to choose a dehumidifier for the pool, additional features can also help. Modern technology is often equipped with a number of interesting and effective options, such as:
- additional air heating;
- built-in temperature and humidity sensors with display of the indicator on an electric display;
- removable filters for cleaning and washing from harmful substances;
- air ionization;
- microprocessor automatic control;
- air humidity and temperature regulators;
- drainage containers or special hoses.
Devices for dehumidifying the air in the room are constantly being improved. Manufacturers are introducing new technologies into their manufactured models, making the use of the dehumidifier convenient, easy and practical.
Tips for buying and operating a dehumidifier
- A dehumidifier is an important detail in arranging your own pool. It is necessary to carefully study the market and the characteristics of the models before making a purchase. It is important to consider the size of the home pool. For a small area of \u200b\u200bthis, a stationary type of device is suitable. These are wall and floor.
- The capacity of this type of equipment is designed for a pool area of up to 25-50 sq.m. If the home reservoir is larger, use a common ventilation system with a built-in dehumidifier.
- Swimming pools over 150 sq.m. rare at home. For such sizes, industrial dryers are used. They are installed in public pools and indoor sports-type ponds.
- It is also important to consider device performance. Correctly selected equipment for 1 hour of its work should be turned on at least 3 times and no more than 6 times for air processing.
Long-term drying with one or two cycles of its operation adversely affects the condition of the device itself.
The engine may overheat. If it does not have time to cool, system failures and various breakdowns may occur.
High humidity is a “painful” problem of rooms with swimming pools, the cause of which is intensive evaporation. To solve it, there is an air dryer - a set of freon installations assembled in one housing, the purpose of which is to extract moisture from the air masses and maintain its optimal level.
Purpose of the device
Excess moisture results in the accumulation of condensate on the walls, ceiling, windows, and also contributes to the development of microbes, the appearance of mold and corrosion in enclosed spaces with an artificial pond. This phenomenon threatens with an uncomfortable environment for visitors, because the preservation of a waterlogged microclimate can cause people who are prone to cardiovascular diseases, asthma attacks or shortness of breath. In addition, there is a high probability of contracting various diseases due to the multiplication of harmful microorganisms in these places.
Excessive humidity leads to wear and tear of the equipment and the destruction of the decoration of the rooms, which will eventually require repairs to the building.
For these reasons, it is advisable to install dehumidifiers in rooms with a swimming pool. They provide control and maintenance of an optimal level of humidity, absorb condensate and give out dry and warm air.
Sometimes the question arises: why this task cannot be dealt with by applying air exchange or ventilation? Firstly, it is energy-consuming, and secondly, they will not be able to create favorable conditions in such premises, namely the optimal temperature of water (25-29°С), air (27-30°С) and humidity level (50-60 %). Therefore, it is better to take care of the dehumidifier even during the design of the pool.
You can get acquainted with the scope and features of the use of dehumidifiers from this video:
Principle of operation and technical characteristics
Most often, in buildings with a swimming pool, a freon type of dehumidifier is used, which is based on two heat exchangers: cold (evaporator) and hot (condenser), located in series. When air saturated with moisture enters the equipment, the fan transports it to the evaporator, in which condensate is removed and drained into a specially designated container, and then discharged into the sewer. The dried cold atmosphere, passing through the condenser, is heated to the set temperature and brought back to the room.
The hygrostat built into it helps to turn on the device in time. It controls the maintenance of the humidity level in the room in accordance with the set indicator on the equipment and, when it rises, it is activated, and when the microclimate reaches the norm, it turns off.
How a dehumidifier works, you can see in this diagram:
When choosing a dehumidifier for the pool, you should pay attention to its specifications:
- Humidity and temperature range.
- Dehumidification capacity (l/day).
- Type and amount of refrigerant used (kg).
- Consumption (loss) of air (cubic m / h).
- Power supply: current consumption (A) and power (kW).
- Noise level (dB).
- Cycle of continuous work.
- Degree of protection.
The main characteristic of the device is its performance - the amount of moisture that it is able to absorb per day. This indicator is calculated for a certain area of the water mirror and varies from 100 to 300 liters.
It is important that the equipment provides for the possibility of adjusting the mode, intensity and time of drying, the power allows, if necessary, to work continuously up to 24 hours, the noise level during its operation is minimal, and the protection class meets all requirements. You need to pay attention to the material from which the case is made, as parts of the device may be subject to corrosion.
Types of devices: advantages and disadvantages
Dryers are divided into two types: stationary(they have high power and are suitable for rooms with artificial reservoirs) and portable(devices on wheels that allow you to move them around the building, but are more used for eliminating leaks or for finishing work).
Dehumidifiers for swimming pools, depending on the principle of their work, are divided into:
- Assimilation- are based on the elimination of moist air from the room, replacing it with dry air extracted from the outside of the building. They are rarely used, since the performance of such equipment is much less than its energy consumption, which makes the use of such dehumidifiers not rational.
- Adsorption- the removal of moisture from air masses is carried out through the use of an adsorbent - a substance with a high ability to absorb various liquids on its surface, which is located in the rotor of the device.
This process is ensured by the operation of two or three fans: the first sucks in air from the hall and moves it to the rotor, where the adsorbent, entering into a chemical reaction with it, removes moisture. Further, the dry atmosphere enters the distribution chamber, where it is divided into regeneration and exit back.
The regeneration air mass is heated in a separate chamber and redirected by the second fan back to the rotor, where condensate is blown out of it, which is either discharged outside or collected in a tank. The work of the third fan is to remove dry air back into the room.
The main advantages of this type of dehumidifiers are:
- power;
- high performance;
- can work at a temperature of -20 C (but no more);
- the air temperature remains unchanged;
- can reduce humidity by more than 30%.
The disadvantages of adsorption dryers are as follows:
- high price for equipment;
- some models (household) can produce air 5-7 degrees higher than the initial temperature;
- there is a need to bring a hose to accumulate fluid and bring it out into the street.
- - with the help of a fan, humid air enters the device and moves to the refrigeration circuit containing a heat exchanger, which, interacting with the heat of the air masses, heats up. A refrigerant enters it through pipes, passing from a liquid state to a gaseous state, and cools it. As a result of the temperature difference, condensate forms on the heat exchanger, and the refrigerant moves to the compressor, where it returns to a liquid state during compression. The heat released at the same time heats the dried atmosphere, after which it enters back into the room. Continuous operation of the equipment will be able to dry all the air in the room without major changes in the microclimate.
Benefits of condenser dryers:
- acceptable price;
- equipment power;
- low power consumption;
- functionality.
The main disadvantages of this type are:
- temperature restrictions (from +15 to +30 degrees);
- cannot reduce the humidity to more than 40%.
When selecting and buying a dehumidifier for the pool, you need to choose the way it is placed:
- Wall used in cases where you need to save floor space. Among the advantages are low cost, optimization of hidden condensate drain, the ability to paint the device to match the interior. The disadvantages are the lack of fresh air. One device will not be able to maintain the required humidity, so it is recommended to place several devices at once.
- Floor attractive in that you can allocate a place near the pool and, if necessary, move the device to another.
- ducted suitable for rooms with a large area, it is often installed in an adjacent room, and air is removed and supplied through channels located around the perimeter of the room. Among the advantages of such equipment are high productivity, no noise during operation due to the need to be placed in a separate technical room, as well as the possibility of adding a fresh air intake system. Among the disadvantages are the high price of the device, the complex installation process and the need for regular maintenance.
The use of dehumidifiers for swimming pools, whether ducted, refrigeration or absorption, has a number of advantages: they are easy to operate and will delight you for many years of service, while they are considered environmentally friendly devices and are able not only to control the level of moisture, but also to purify the air from dust, microbes, dilute with a fresh atmosphere from the outside. However, you should not get too carried away with drainage, because it can cause various colds in visitors.
Overview of popular models
There are several brands of dehumidifiers for swimming pools with a worldwide reputation:
- Dantherm is a Danish manufacturer with many years of experience, specializing in mobile and stationary dehumidifiers. This equipment has high power and productivity (up to 200 liters per day), while pleases with silent operation. The models listed below have the option of wall and floor mounting, the kit also includes a hose for supplying and removing condensate, which makes this type of dehumidifier universal.
Among the common models of this manufacturer are:
- CDP75
- CDP125
- CDP165
- Calorex- an English brand used for premises with a large area of artificial reservoirs. This type of installation is able to automatically control all the necessary parameters in the building (air exchange, water and atmosphere heating) and provides a comfortable environment for visitors.
The widely used models are:
- DH44A
- DH110
- MYCOND is an English manufacturer who has invested many years of experience in the creation of high-quality and energy-efficient installations for optimizing the level of humidity in rooms with a swimming pool. They have high performance and an automated control system, which greatly facilitates their use.
The most sold are the following models:
- MyCond MBA7A
- MyCond MBA12A
- MyCond MBA17A
Before making your choice in favor of some type of dehumidifier, it is worth analyzing the purpose of its installation: what functions it should perform, the size of the pool area and the room, the possibility of additional functions, etc. This will be the criterion that will help you make the right choice.
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Nowadays, a pool in a private house has ceased to be something extraordinary.
Increasingly, at the design stage, customers are laying a separate room under the pool, where you can have a good time. However, for a comfortable stay, it is necessary to think in advance about controlling the microclimate in the room.
When designing pool ventilation, attention is mainly paid to maintaining the temperature and relative humidity of the air.
High humidity creates the effect of "heavy air". Discomfort can also be caused by improper temperature conditions, the presence of drafts, or vice versa, the lack of the necessary supply of fresh air.
Incorrectly selected equipment, in addition to affecting the well-being of a person, can also have an adverse effect on the structure of the building - the lack of ventilation can lead to the destruction of the finish, wetting the walls. Prolonged high humidity is fraught with the formation of condensation on the windows, ceiling and the appearance of mold.
The best solution is a combination supply and exhaust ventilation and dehumidifier. In this article, we will take a closer look.
How dehumidifiers work
Pool dehumidifiers are freon units. Designed to maintain the level of humidity by dehumidifying the air in the room. Level control is carried out using a built-in humidity sensor, according to which the controller turns the compressor on and off.
Moist air through the grate on the panel enters the evaporator, where the freon takes heat and reduces the moisture content in the air. Condensate released during heat transfer is removed from the equipment with the help of a drain pipe. The cooled air, passing through the condenser of the same refrigeration circuit, heats up, its relative humidity becomes low, and then the air is returned to the visitor. This creates additional heating due to the dissipation of electrical power supplied to the compressor.
How to choose a pool dehumidifier
For the correct selection of dehumidifiers, it is necessary to take into account such factors as:
availability of ventilation, supply air flow rate, air exchange rate, room volume, pool surface area, actual and required indoor air parameters, evaporation rate, air temperature and relative humidity, water temperature.
It often happens that the customer does not know all the conditions, so we offer you Simplified selection of FRAL dryers.
Under the most typical conditions - relative humidity of 80%, air temperature of 30°C and water temperature in the pool of 28°C and the absence or small number of people in the pool, 0.12 kg / h of moisture is released per square meter of surface.
If the pool does not have a protective screen that covers the water surface during unused hours, then dehumidification is required around the clock, therefore, when determining the performance of the dehumidifier, it is necessary to multiply the pool area by 0.12 kg / h and 24 hours a day.
For example:
With a water surface area of 40 sq.m.: 40 x 0.12 x 24h = 115.2 kg / day.
The suitable model in this case is the FSW 140, since its nominal capacity at an air temperature of 30°C and a relative humidity of 80% is 115 kg/day.
The calculation of dehumidification in pools with hot water in treatment centers, salons, massage will be different.
At a higher water temperature, 30-32 °C, water evaporation will increase by about 30% more than in the previous case. We will assume that in this case, 0.16 kg/h of moisture per square meter of surface is released in the pool.
For greater clarity, below is a table of quick selection of dehumidifiers.
Table 1. Private pools
| Pool area, m2 | Required output | Dehumidifier t 30С, Humidity 80% |
Price 2017, EUR | |||
| 1 | 10 | 28,8 | 1 | 52 | 2317 | |
| 2 | 15 | 43,2 | 1 | 52 | 2317 | |
| 3 | 20 | 57,6 | 1 | 52 | 2317 | |
| 4 | 25 | 72 | FSW 96* / FSW 100 | 1 | 80 | 3504 / 3515 |
| 5 | 30 | 86,4 | FSW 96* / FSW 100 | 1 | 80 | 3504 / 3515 |
| 6 | 35 | 100,8 | FSW 140 / FSW 63 (2pcs) | 2 | 115/104 | 6720 / 4634 |
| 7 | 40 | 115,2 | 1 | 115 | 6720 | |
| 8 | 45 | 129,6 | FSW 63 + FSW 96* | 2 | 132 | 5821 |
| 9 | 50 | 144 | FSW 96 (2pcs)* | 2 | 160 | 7008 |
| 10 | 55 | 158,4 | FSW 96 (2pcs) / FSW 63 (3pcs) | 2/3 | 160/156 | 7008 / 6951 |
| 11 | 60 | 172,8 | FSW 96* + FSW 140 | 2 | 195 | 10224 |
| 12 | 65 | 187,2 | FSW 96* + FSW 140 | 2 | 195 | 9325 |
| 13 | 70 | 201,6 | FSW 140 (2pcs) | 2 | 230 | 13440 |
| 14 | 80 | 230,4 | FSW 140 (2pcs) / FSW 96 (3pcs) | 2/3 | 230/240 | 13440 / 10512 |
| 15 | 90 | 259,2 | FSW 63 (2pcs) + FSW 96 (2pcs) | 4 | 264 | 11642 |
| 16 | 100 | 288 | FSW 63 + FSW 96 (3pcs) | 4 | 292 | 12829 |
Table 2. School swimming pools
| Pool area, m2 | Required performance | Dehumidifier t 30С, Humidity 80% |
Number of dehumidifiers per pool | Rated capacity | Price 2017, EUR | |
| 1 | 150 | 432 | 4/6 | 460/480 | 26880 / 21024 | |
| 2 | 160 | 460,8 | FSW 140 (4pcs) / FSW 96 (6pcs) | 4/6 | 460/480 | 26880 / 21024 |
| 3 | 170 | 489,6 | FSW 96 (6pcs) | 6 | 480 | 21024 |
| 4 | 180 | 518,4 | FSW 96 (6pcs) + FSW 63 / FSW 63 (10pcs) | 7/10 | 532/520 | 23341 / 23170 |
| 5 | 190 | 547,2 | FSW 140 (4pcs) + FSW 96 | 5 | 540 | 30384 |
| 6 | 200 | 576 | FSW 140 (5pcs) | 5 | 575 | 33600 |
Table 3. Pools with hot water in treatment centers, salons, massage
| Pool area, m2 | Required performance | Dehumidifier t 30С, Humidity 80% |
Number of dehumidifiers per pool | Rated capacity | Price 2017, EUR | |
| 1 | 10 | 38,4 | 1 | 63 | 2317 | |
| 2 | 15 | 57,6 | 1 | 63 | 2317 | |
| 3 | 20 | 76,8 | FFSW 96* / FSW 100 | 1 | 100 | 3504/3515 |
| 4 | 25 | 96 | FSW 96* / FSW 100 | 1 | 100 | 3504/3515 |
| 5 | 30 | 115,2 | FSW 140 / FSW 63 (2pcs) | 2 | 140/126 | 6720/4634 |
| 6 | 35 | 134,4 | 1 | 140 | 6720 | |
| 7 | 40 | 153,6 | FSW 63 + FSW 96 | 1 | 163 | 5821 |
| 8 | 45 | 172,8 | 2/3 | 200/189 | 7008/6951 | |
| 9 | 50 | 192 | FSW 96 (2pcs)* / FSW 63 (3pcs) | 2/3 | 200/189 | 7008/6951 |
| 10 | 55 | 211,2 | FSW 96 (2pcs)* | 2 | 200 | 7008 |
| 11 | 60 | 230,4 | 2/4 | 240/252 | 10224/9268 | |
| 12 | 65 | 249,6 | FSW 96 + FSW 140 / FSW 63 (4pcs) | 2/4 | 240/252 | 10224/9268 |
| 13 | 70 | 268,8 | FSW 96 (2pcs) + FSW 63 | 3 | 263 | 9325 |
| 14 | 75 | 288,0 | FSW 96 + FSW 63 (3 pcs.) | 4 | 289 | 10455 |
| 15 | 80 | 307,2 | FSW 63 (5pcs) | 5 | 315 | 11585 |
* All FSW 96 models can be replaced by FSW 100 as they have comparable performance. The cost of the FSW 100 model is slightly higher due to the more modern design.
What determines the cost of the dryer
Cost primarily depends on performance models . Dehumidifiers for the pool differ from household models in higher power, resistance to moisture, resistance to chemical corrosion.
About Fral dryers have a capacity from 52 to 140 liters per day depending ondepending on the size, temperature and relative humidity of the air.Dehumidifiers with high moisture removal will be more expensive.
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The body material is also important - low capacity dehumidifiers are made of plastic, which reduces the cost, but reduces the durability of the body. All FRAL dryers of the FSW series are made of galvanized sheet, powder-coated
polyurethane paint resistant to high temperature and humidity in the pool.
The design of the equipment plays an important role, as the model FSW 100 (3515€) at comparable performance with model FSW 96 (3504€) has a great value.
Combination of dehumidifier and ventilation
It is important to remember that dehumidifiers work as closers, without supplying additional fresh air into the room, so using only dehumidifiers will not achieve comfortable conditions in the pool. It is necessary to combine fresh air supply and dehumidification. At the same time, it should be borne in mind that ventilation itself removes some of the moisture from the pool room. The air parameters in the pool must be maintained the same throughout the year, while the temperature in the room should be 1-2 degrees higher than the water temperature in the pool, that is, about 27-30 degrees. For greater efficiency, the heat of the outgoing air is used and a heat exchanger is installed, which will give off the heat of the exhaust air to heat the supply air during the cold season. This will reduce the power of the heater several times.
For such purposes, for example, supply and exhaust units with an additional external duct plate heat exchanger SR or monoblock air handling units ALFA 95, .
Consider the calculation of the dryer with y evenohm ventilation:
Need to know moisture content supply and indoor air, on the I-d diagram, this parameter is denoted as d or x and is measured in g/kg. Do not confuse relative humidity φ, % and moisture content pressure d, g/kg.
Relative humidity is the ratio of the current absolute humidity of the air to the maximum possible absolute humidity at the same temperature, and moisture content is the amount of water vapor in one kilogram of dry air.
W temperature and relative humidity, from file I-d charts We get the moisture content, take the difference between the moisture content of the indoor and supply air and multiply by the flow rate of the air supplied to the room. This will be the amount of moisture that the ventilation will remove.
Calculation example:
In the pool room, a water mirror of 35 m2.
Air consumption of forced-air and exhaust ventilation - 800m3/h.
Options indoor air: 30C / 80% - moisture content 23.2 g / kg or 24.8 g / m3 at an air density of 1.07 m3 / h.
Options supply air in summer: 30 C / 70%, - moisture content 20.2 g / kg or 21.7 g / m3 at an air density of 1.07 m3 / h.
Moisture difference ra n ia : 2 4.8 -2 1 , 7 = 3.1 g/m3
Dehumidification by ventilation : 3.1 g/m3 * 800 m3/h = 2480 g/h = 2.48 l/h = 59.5 l/day
With pool area 3 5 m2 must be rented 1 00,8 l / day of moisture, thus ventilation reduces the load on the dehumidifier by almost 2 times.
Instead of the dryer FSW 100, you can take the FSW 63.
The pool is a source of high humidity. Air saturated with water during prolonged action can adversely affect both the well-being of people and the walls, ceiling of the building, and the operation of its engineering communications. Therefore, in almost every pool, a dehumidifier is used. There are various models of it; they differ depending on the features of the building, its size, the area of the water surface itself and other factors.
To make the most correct choice, you need to understand how the dehumidifier for the pool is arranged, what is its principle of operation and what parameters should be taken into account first of all when making a decision.
Components of the device and the principle of operation
The very principle of operation of the dehumidifier is simple - it is based on the condensation of moisture from the air when it hits a cold surface, just as moisture condenses in clouds and falls to the ground in the form of precipitation.
Any pool dehumidifier is an engineering system consisting of the following elements:
- Air distribution grille that collects humid warm air;
- Ventilation chamber providing air suction into the mine;
- Freon unit that cools the incoming air.
Schematically, it is shown in the figure below.
The air circulation sequence is as follows:
- The air in the pool comes from the surface of the water upwards, under the ceiling, because it is warm and humid.
- Under the very ceiling there is a grate that sucks in air flows due to the operation of the fan and delivers it to the cooling stop.
- Its mechanism of operation essentially coincides with how the refrigerator works. The refrigerant (colorless freon gases) in the tank absorbs heat from the environment, due to which the surface of the mechanism is constantly in a cold state. Colliding with it, the air is greatly cooled, and almost all moisture condenses (passes from a gaseous to a liquid state).
- Further, the moisture turned into a liquid flows down the inclined tank into a container or leaves through the drainage.
- The dehumidified air goes back into the room and the cycle starts again.
Recently, similar mechanisms have often been used in homes in areas with a very humid climate (seaside regions). However, unlike them, a pool dehumidifier:
- has great power - it is able to extract up to 110-120 liters of liquid from the air in one day;
- made of corrosion-resistant materials;
- has additional protective coatings from waves, which are always in the pool.
You can learn more about the principle of operation of the mechanism using the example of a household dehumidifier from the video.
Types of dehumidifiers
Pool dehumidifiers are classified according to the degree of mobility:
An example of a stationary device for a small pool looks like this; the figure shows only a ventilation grill built into the wall, and all internal communications are hidden behind it.
In this case, the device can be mounted in other parts of the room:
The first two options are used in small pools (for example, in children's or saunas). And if the area of the water surface (mirror) is more than 70 square meters, then the channel type of air dryer for the pool is more often used.
In addition, the condensation of moisture from the air in different mechanisms is carried out according to different principles. In addition to the already considered freon installation, the following are also used:
- Adsorption - in this case, moisture is absorbed not due to cooling, but with the help of a special water-absorbing substance (adsorbent). The adsorbent is placed in a special chamber that creates two air streams - one dries the air with hot jets, and the other pushes it back into the room. The devices are of high performance.
- Assimilation - in them, the air, on the contrary, heats up, and does not cool. When hot, it absorbs moisture from the space around, due to which dehumidification occurs. Such dehumidifiers are used much less often, because they spend too much energy with a small capacity.
Additional device features
In addition to its main purpose, a pool dehumidifier is useful in that:
- heats the room, allowing you to maintain a constantly warm temperature inside (25-27 degrees);
- shows important parameters of the air environment (temperature, humidity, pressure);
- in some cases it has a microbial filter, due to which the air is disinfected;
- allows you to adjust all key parameters as needed.
Modern models of dehumidifiers have an electronic control system, as well as a display with which you can easily control the microclimate of the room. Most often, the device automatically turns on if there is too much moisture in the air.
Air circulation, which ensures the balance of temperature, is carried out according to the supply and exhaust scheme of operation shown in the figure.
A more detailed description of the operation of the dehumidifier can also be viewed on the video.
How to make the right choice
Before starting to consider specific pool dehumidifier models, you should carefully analyze the main parameters of the device and the room where it will be used.
Power
When choosing this option, first of all, you need to consider:
- area of the water surface of the pool;
- the volume of the room;
- whether there is forced ventilation and how well it works;
- whether the building is heated well, what are the optimum temperatures and humidity.
Typically, indicators of the state of indoor air in the pool should be in the following ranges:
- air temperature from 25 to 29 degrees;
- water temperature 27-28;
- humidity within 60-65%.
Based on these data, as well as the volume of the room and the area of \u200b\u200bthe pool mirror, the required power of use is easily calculated.
The optimal number of complete cycles of air passing through the dryer should be 5-6 per hour. In accordance with this, the power is determined by the formula:
W = E*S*(psaturated–punsaturated)
Here S is the mirror area, psaturated–pprust is the difference in vapor pressures between saturated and unsaturated air, and E is the heat transfer coefficient. Usually, special online calculators are used for the calculation, which can be easily found on the relevant sites.
Other technical parameters
In addition to power, when choosing a dehumidifier for a pool, it is necessary to take into account the degree of its protection from negative environmental factors (high humidity, water splashes, warm air). It is necessary to pay attention to the features of the material from which it is made, how well the joints between different parts of the structure are made:
- The case material must be made of plastic, which is not subject to corrosion in principle, or, in the case of a metal version, coated with a special protective paint.
- The surface of the device must be completely smooth, without external defects, the pipes must form a completely sealed system, there must be no gaps at the joints.
- If possible, it is better to choose a device with the simplest possible configuration (i.e. with a minimum number of bends, zigzags, etc.).
- Preference should be given to dehumidifiers equipped with a display and an automatic adjustment system. Not only are they convenient to use, but they tend to be more durable as they turn on only when needed and thus save energy.
Brand
Finally, the manufacturer of the device is not the last to make decisions. European brands have proven themselves best on the market:
- DANTHERM;
- General Climate;
- Euronord;
- neoclima.
Price Factor
The price factor when making a decision to buy a product such as a dehumidifier for a pool, most often fades into the background. Of course, when the choice has already settled on a particular model, you should try to find stores that offer it at the lowest price.
IMPORTANT. If you initially proceed from the cost, then you can buy a completely inappropriate model. This is a long-term, profitable investment, so the budget must be planned accordingly. Moreover, against the background of general investments in the creation and maintenance of the pool, the price of a dehumidifier will not seem too high.
Models and prices
Some models with parameters and approximate prices for them are shown in the table below (first there are devices from the manufacturer Neoclima, then Dantherm).
An overview of some models is presented in the video below.
Accessories
In addition to the installations themselves, the manufacturer often offers accessories necessary for their installation and further maintenance:
anti-vibration mounts
brackets for wall mounting
thermostat
humidistat
duct
Device maintenance
Like any other engineering system, a pool dehumidifier needs scheduled maintenance and ongoing repairs. The table shows the activities carried out at different intervals without fail.
| periodicity | Events |
| once a month |
|
| once every 1.5 - 2 months |
|
| once every 4 months |
|
| semiannually |
|
| once a year |
|
IMPORTANT. Also, once every two years, it is advisable to check the fastening and condition of the filters that are designed to dry freon gas. In case of extreme wear, it is better to replace them, otherwise the entire drainage system can quickly fail, and it will take more money and time to restore it.
Air dehumidifiers at home
It is not necessary to visit large pools if the house is small, but your own. If there is such an opportunity at home, then a dehumidifier is a must. A person does not spend much time in the pool, so moisture is unlikely to have a detrimental effect on his health. But constant evaporation from the water surface will affect the walls and ceiling of the room for a long time, and some time later, damage to the materials from which they are made can be noticed.
In what cases are they used
In addition, the use of the device is often necessary in:
- bathroom, toilet;
- home or professional greenhouses;
- basements and attics;
- kitchen;
- pantries;
- home laundries;
- gyms and locker rooms in them;
- rooms with large aquariums.
IMPORTANT. If your home is located in an area with a hot and at the same time humid climate (usually these are regions located near warm seas), and at the same time, you have been increasingly experiencing inexplicable ailments (frequent and rapid fatigue, weakness, dizziness, pressure surges) , mood swings, decreased vitality), be sure to consult a doctor. A very likely reason is the increased humidity in the apartment. In this case, purchasing an inexpensive dehumidifier will significantly improve your well-being.
Most often, household dehumidifiers operate on the condensation principle (intake of moist air and extraction of moisture on a cold surface).
Schematically, it looks like this.
Household dehumidifiers are most often compact and inconspicuous - they look elegant and operate almost silently.
Choosing a home dehumidifier
There are several factors to consider when purchasing a home appliance:
- The volume of an apartment, room, country house or other premises. It is easy to calculate it by multiplying the total length of the apartment by its width and height.
- In addition, it is important to choose the most energy-efficient devices that consume as little energy as possible.
- Finally, the noise level in the apartment is of particular importance.
IMPORTANT. Despite the huge amount of information available on the network, it is best to check how loud the dehumidifier works right in the store - the fact is that each person has individual habits, and what is loud to one may not be heard by another. In addition, quantitative indicators of loudness (in decibels) cannot always be clearly presented in practice until you hear them with a really working device.
- If you live in a region with high humidity and at the same time arid, where there is little rainfall, then it is better to choose dehumidifiers with a drainage system. In this case, all moisture from the air will be supplied through special drains to a reservoir, from which it can be used for household needs (for example, watering plants).
As for the manufacturer, everything that has been said about professional dehumidifiers is also true for home ones. European brands have successfully established themselves in this market, moreover, they always give a long-term guarantee of trouble-free operation of the mechanism.
Some models are shown in the table below.
A video review of the Ballu BDH 30L is shown below.
As you can see, the prices for the devices are quite affordable. Basically, they depend on the performance of the device, and that - on the volume of the serviced premises. It is from this factor that you need to proceed in the first place.
DIY air dryer
If there is an opportunity and desire, then you can make it yourself, using simple materials and mechanisms for this.
You can see detailed instructions in this video.
There is also an option based on the use of an unnecessary freezer. If you have changed the refrigerator to a new one, do not rush to throw out the old one. Based on it, you can make a good dehumidifier. To do this, in addition to a properly working camera, you will need:
- two fans;
- fixing nuts and screws;
- electric heating device;
- rubber tube;
- organic glass with dimensions corresponding to the freezer.
The sequence of actions will be as follows:
Making the device does not take much time. However, if this is not possible and you want to use a reliable device, then it is best to purchase a dehumidifier in a store.
Water is the cradle of life. Probably everyone remembers this banal phrase, plunging into the cool water of the pool on a hot summer day. And in winter, when the transparent dome of the pool is wrapped in snow, you can imagine yourself in it for at least 45 standard minutes in a summer pond or sea. Water sports also remain popular - parents are happy to send their children to the swimming section, boys fight in water polo, girls perform skillful synchronized swimming pirouettes. What about pool parties? In recent years, this option of recreation, previously known only from Western films, is also popular in our country.
It would seem that there is nothing complicated: built a pool and enjoy all these delightful pleasures of life. But in fact, understanding people know that everything depends only on the designers. And the centerpiece of any swimming pool, whether it is a huge sports complex or a small private space for recreation on the water, is the air conditioning system. And it is on whether it is correctly thought out by the designers that the durability of the structure, its ergonomics and other useful qualities depend.
Humidity is a major headache for any body of water designer. For sports pools, the best air temperature is 27-28°C or slightly lower. This is due to the recommendations of doctors to maintain the air temperature at about 1 ° C above the water temperature. Evaporation from the water surface is minimal, and floating is convenient and comfortable.
However, many pool owners want to use them not only for sports and fitness, but also for various parties. In this case, it is necessary to maintain a comfortable temperature in the pool that is normal for living quarters. The job of the designer is to convince them not to. At a high water temperature, a large positive difference in the temperatures of water and air will occur, as a result of which the intensity of evaporation from the surface of the pool will sharply increase. It is possible to combine the most comfortable values of air and water temperature only with the help of the correct selection of equipment that ensures the reduction of air humidity to the required level.
What to do about humidity?
To maintain comfortable conditions and a reasonable level of water evaporation, the humidity in the pool room should be 50-60%. In this case, at an air temperature of 28-30°C, the dew point temperature is between 16°C and 21°C (Graph 1). This is much higher than in conventional air-conditioned rooms, where the air temperature is maintained at 24°C, the humidity is 50%, and the dew point is at 13°C. In indoor pools, the absolute moisture content of the air can be up to 3/4 higher than in conventional air-conditioned rooms. The designer must take this into account and take measures to reduce moisture condensation on the surfaces of the building envelope.
The situation is further complicated by the fact that heat and humidity do not disappear when people leave the pool. You can't just "turn off" the pool at night. Of course, if water surface covers are used during non-working hours, the amount of evaporated moisture can be significantly reduced. But these devices are rarely used for a long time, despite the best intentions of pool designers, manufacturers and operators.
How can a designer deal with such a difficult situation?
Continuous moisture production (24 hours a day, 7 days a week) is reduced when there is no one in the pool. Although an empty pool produces 25-35% less moisture than a filled one, the load on the equipment designed to reduce humidity still remains. In the pool, the temperature cannot be reduced at night, because the lower air temperature only increases evaporation from the surface of the pool. Designers and owners must understand that the climate equipment should never be turned off in the pool.
Constant air circulation must be maintained 24 hours a day. In a conventional swimming pool, it is enough to turn off the dehumidifier for only 20-30 minutes, so that the relative humidity rises to 80-85%. To reduce energy costs when the pool is empty, you can stop the fresh air supply and implement dehumidification in recirculation mode. However, outside air can also be used if the local climate and weather permit.
What to breathe?
In addition to maintaining a stable level of humidity, the designer must also think about air quality. Indeed, chemicals are added to the pool water in order to ensure sanitary and hygienic requirements by neutralizing various organic substances and microorganisms that remain from swimmers. These chemicals can cause air pollution, which in turn can contribute to various irritations in swimmers. Therefore, to maintain normal conditions in the pool, ventilation is needed to ensure the assimilation of chemical excretions from the surface of the water, in addition to the usual human metabolic excretions.
To maintain acceptable indoor air quality, ANSI/ASHRAE 62.1-2004, "Ventilation for acceptable indoor air quality," recommends a ventilation rate of 2.4 l/s per m2 of pool area, including floor area. Due to the increased temperature and humidity in the pool, this increases the load on the heating equipment and, in certain circumstances, on the dehumidifier. If the pool is maintained at 29°C, any forced outside air below 29°C lowers the pool air temperature, thereby increasing the load on the heating equipment, more so the colder it is outside. However, if the dew point temperature of the outdoor air is lower than that of the pool air, this helps to reduce humidity. On the other hand, if the outside air dew point temperature is higher, the inflow of outside air increases the load on the dehumidifier.
Where to supply air?
As recommended by 2003 ASHRAE Handbook - HVAC Applications, art. 4.6-4.8, the optimal air exchange rate is from four to eight. Such a wide range of recommended values is due to differences in the intensity of use of the pool, its attendance and the type of equipment installed. The personal experience of the authors shows that the air distribution scheme used is more important than the air exchange rate. There are systems that provide triple air exchange and still work great.
At first glance, it is easier to take in more air from outside than to design efficient air distribution systems. But this path is fraught with high costs for the owner of the pool: he will have to constantly pay for excessive energy consumption.
It is very important that the conditioned air goes exactly where it is really needed, and not go where it wants (arrows painted on the walls are unlikely to help). Determining where air needs to be supplied is not at all higher mathematics: the obvious places are spectators and surfaces that need to be cooled. Above the surface of the water, it is also necessary to have limited air mobility.
The main objective of the design of the air distribution system is to achieve an effective reduction of humidity and an acceptable air quality in the pool. Simply increasing the air flow through the dehumidification equipment will not solve the problem of condensation and stagnant areas where "bad" air will accumulate. In the pool, due to the high dew point temperature, there are many places where sufficient air flow is required to maintain air quality or to prevent condensation.
Here are some considerations to ensure proper pool air distribution:
The surface of the water. The flow of air above the surface of the water must be kept to a minimum to avoid excessive air movement in the navigation area. In addition, this reduces evaporation, which increases with increasing air speed. At the same time, the air flow rate should not be zero: if there is no weak but stable air flow above the water surface, various gases released from the water will begin to accumulate above the surface. This can cause eye irritation and breathing problems for swimmers. Complaints about uncomfortable conditions in the water are often caused precisely by poor air distribution and the fact that chloramines are not removed from the surface of the pool.
Usually, the designer of the dehumidification equipment is blamed for such problems, but he is not responsible for the design of the air distribution system.
The formation of the necessary flow above the water can be hindered by the location of the inlet openings at a high height (4.5-9m), but the well-thought-out location of the exhaust openings can help.
Supply and exhaust openings. Usually in swimming pools the ceilings are higher than in office premises. Ceiling-mounted inlet diffusers often cannot handle the flow down to the water and floor. To avoid complex directional adjustments, the air supply is often carried out at floor level (with the flow "covering" the coldest surfaces). This scheme is especially often used where, due to the cold climate, heating is required. But wherever the supply diffusers are located, you need to take care of the air grilles to direct the flow to the desired surfaces.
At first glance, the simplest solution is to position the exhaust vents at the same level as the intake vents. This error leads to the fact that when the supply air enters the air intake without mixing with the air of the air-conditioned room, a short circuit of the air flows occurs. This can happen by itself if the supply and exhaust openings are incorrectly positioned and the flow from the supply diffusers is not properly distributed.
Incorrect location is often added to the insufficient size of the exhaust grilles. The fact is that they are noisy and look unattractive, so, naturally, they are trying to make them smaller, or even just put them out of sight. This leads to nothing: the air moves through the small exhaust holes at a higher speed, and the noise only becomes louder, and the formation of stagnant zones becomes an unpleasant side effect. Meanwhile, properly sized can virtually eliminate this noise and reduce static pressure loss in ducts. If you properly calculate the project, then you can easily find a sufficient number of places to place exhaust grills of the "correct" size.
In a warm hot tub or paddling pool, the exhaust grille should be placed close to the water to reduce the effect of increased evaporation. You can not limit yourself to this, making mistakes in determining the required performance of the dehumidification system by supplying more humid air to it than the average for the pool. Sometimes in such areas it is worth using an additional exhaust fan.
Tribunes for spectators
Spectators in the pool want to feel comfortable. They crave coolness - and it does not matter to them that the swimming area and the spectator area cannot be kept at different temperatures without a separating barrier. In order to create an additional air flow in the spectator area with a large influx of people, it is necessary to install auxiliary equipment. Particular attention should be paid here to the choice of installation locations for supply diffusers. For example, you can direct the flow of dry air directly to the audience by installing exhaust grilles at the back of the stands.
locker rooms
Changing rooms should not be connected to the pool dehumidification system. They need their own air supply and exhaust systems. Care must be taken with open openings: a rarefaction in the locker room provokes an influx of air saturated with chloramines from the pool, which leads to an unfavorable sanitary and hygienic situation in the locker room and corrosion of the equipment installed in it. This problem can be solved by installing airtight doors between the pool and changing rooms.
Pressure distribution
To prevent the overflow of high humidity and the smell of chloramines from the pool to other rooms, it is necessary to maintain a negative pressure in the pool in relation to the adjacent rooms and the external atmosphere. It's not as easy as it seems. Many rooms adjoin the pool - locker rooms, halls, lobbies and so on. In addition, conditions can vary significantly depending on the number of people present in the pool. One thing is obvious: the pressure in the pool room must be coordinated with adjacent areas where there is its own air exhaust, for example, with the same locker rooms.
But the main thing is not to overdo it with a decrease in pressure. Doors will be difficult to open: they have a large area, and a slight pressure difference is enough to create difficulties. Cracks can start to make a whistling sound, and air from changing rooms can create odor problems. Cold air seeping through the gaps in the doors can cause frost to form on the inside surfaces of the doors even at a pool temperature of 28°C.
air ducts
Proper air distribution largely depends on the quality of the installation of air ducts, which should be installed in such a way that condensation does not form in them. All joints of supply and exhaust air ducts must be tightly sealed, including their connections with supply grilles, fans, exhaust grilles. Particular attention should be paid to exhaust ducts operating under vacuum. When gaps appear in them, air from unconditioned rooms is sucked in, resulting in condensation and disruption of the normal operation of the dehumidification equipment. If the air ducts are laid outside the air-conditioned room, they must be placed in thermal insulation. Air ducts for swimming pools are made of materials that are resistant to corrosion caused by chlorides, and their joints must be sealed, wrapped and covered with mastic.
Water, water everywhere
When determining the climatic conditions in a typical pool, first of all, they proceed from the comfort for bathers, that is, from the water temperature and air temperature, which determine the intensity of evaporation.
Created by Willis Carrier more than 70 years ago and still used today, the equation for calculating the intensity of evaporation is not always correct. The modified equation (1) proposed by the 2003 ASHRAE Handbook - HVAC Applications (p. 4.6) better reflects the different basin conditions.
p = 0.1A(p - pa) Fa.(1)
p is the rate of water evaporation in ounces per hour,
A is the surface area of the pool tub in square feet,
p is the saturation vapor pressure at the water surface temperature in inches of mercury,
pa is the saturation vapor pressure at the dew point temperature, in the same units,
Fa - activity factor.
The 2003 ASHRAE Handbook (page 4.6) provides a table of factor values for different basin types. This table does not represent all options for activity in the pool and therefore ASHRAE Technical Committee 8.10 Dehumidification Equipment and Heat Pumps is currently working to update existing information.
Raising the temperature of the water in the pool to the temperature of the air (by only 1°C) can increase the evaporation rate by 15-20%. Reducing the relative humidity of the air in the pool by 10% can increase the evaporation rate by more than 30%. Therefore, it is important to know how the pool will be used and what air and water parameters are desired.
The ventilation ratios (fresh air consumption per unit of total pool area) recommended by Standard 62.1-2004 to maintain acceptable air quality can cause a significant increase in humidity loads in summer. However, as already mentioned, ventilation can help reduce humidity if the outside air's dew point temperature drops below that of the pool air. When choosing equipment for dehumidification, it is necessary to proceed from the maximum possible humidity, although fresh air with maximum humidity may be quite rare.
Of course, water surface coatings can reduce the evaporation rate, but only if they really cover the pool - the effect of their use decreases with increasing hours of operation of the pool. It also happens that the staff forgets to install them. Public pools often have many hours of operation, and part of the off-hours is used to purify the water by super-chlorination, further reducing the time the water is covered. It is very likely that the pool cover will not be used regularly unless it is automatic. In any case, during working hours the water surface is not covered, and the designer must proceed from this.
All these factors lead to uncertainty about how much moisture must be removed from the pool, since at extremely high loads the microclimate in the pool will not be able to be controlled, which is especially critical for large, frequently used pools.
Where does the water go?
The water vapor contained in the air becomes liquid when the air cools below its dew point temperature. Moisture condenses and falls out in the form of droplets. This condensation can damage wood, paper, accelerate paint peeling and rust. In indoor pools, chloramines (by-products produced by chemicals used in water sanitation), together with air moisture condensing on cold surfaces, form chloride solutions that are corrosive to most metals, including some stainless steels.
If serious attention is not paid to the issue of reducing humidity in the design and construction of the pool, excessive condensate forms inside the room, which causes, among other things, sagging of the ceiling, wetting of thermal insulation, the formation of fungus and mold, destruction of masonry, corrosion and even destruction of building structures.
Cold surfaces
If any surface is cooled to a temperature below the dew point of the surrounding air, moisture begins to condense on it. Potentially cold surfaces include northern exterior walls, windows, window and door frames, and skylights. Single glazed windows, metal window and door frames, and roof fasteners create thermal bridges between the cold air outside and the humid air inside. It's good that most designers understand how important it is to install warm windows. Even double glazing may not be enough - after all, the temperature outside can be very high or, on the contrary, very low. Unfortunately, some projects do not provide for the installation of frames with thermal barriers. We have seen many structures where the windows themselves were clean, but the frames were covered with moisture.
Another common mistake is when an architect installs steel structures over windows and doors that go through the wall but do not have thermal barriers.
Most pools have at least one emergency exit - and there should be a thermal barrier here as well. Other places that are commonly overlooked are door sills and locks. The authors have seen buildings, the doors of which were, it would seem, poured over with a hose, and the door frames were covered with ice from the inside.
Moisture can also condense on the glazed openings of the pool that open into the interior of the building, especially if the air flow from the air conditioner hits them from the outside. Here again, at a minimum, double glazing should be used.
Skylights are the same as windows, only they are located in more unfavorable places in terms of the presence of condensate. Warm, moist air rises, where the airflow under the ceiling is usually very weak. Therefore, the humidity level near the skylight will be higher than anywhere else. In some buildings, opening skylights or movable ceilings are installed to provide natural ventilation. On the one hand, this solves the problem of condensate to a certain extent, but on the other hand, it is more difficult to seal them, and many of them use mechanisms with insufficient thermal insulation.
Generally speaking, skylights of any kind are not a good idea for a pool. If they are to be used, then the climate system designer should be involved in the development of the architectural part of the project at an early stage in order to ensure normal air exchange. He is obliged to provide for the installation of additional equipment in order to maintain the necessary air circulation near the surface, and to provide for the possibility of blocking the dehumidification equipment when hatches are opened - in order to save energy.
vapor barrier
Pools should be built as vapor tight as possible. In this case, the vapor barrier must be laid directly behind the internal wall covering. Then moist air and steam will linger inside the pool, and not pass into the colder porous walls. All joints of the vapor barrier must be sealed, a simple overlap is not enough. The vapor barrier, in turn, must also be hermetically attached to the ceiling and floor panels so that moist air does not pass through the joints into the walls and ceiling. All joints around electrical switches and sockets must be sealed to prevent moisture ingress. The continuity of the vapor barrier is important.
Dew point
The key parameter is the dew point temperature. Since the temperature of the dew point of the air in the pool is high, being due to the specifics of this structure, this must be taken into account when designing all elements of the building. The recommendation is for the coldest surface to be at least 3°C above the pool dew point (2003 ASHRAE Handbook, pp. 4.6-4.8). However, on a winter day, it is not so easy to maintain the temperature of all surfaces at 21-24°C. Here the air distribution scheme can play an important role, as we have already mentioned.
Air dehumidification
In most cases in North America, chlorination is used to disinfect water, which negatively affects the operation of process equipment installed inside the pools.
So, in order to extend the life of dehumidifiers, designers have to take additional measures to protect them, using special materials to coat the internal metal parts. It is also important to provide anti-corrosion protection for electrical and cooling elements.
With that said, pool owners should keep in mind that installing conventional air conditioners in pools is impractical and should pay attention to more expensive, but also more functional specialized equipment in this case.
Pool dehumidifiers are different from standard air conditioners. They are designed to remove significantly more moisture from the air. The dry heat factor (Sensible Heat Ratio, SHR), determined by the ratio of sensible and latent heat performance, for air dryers is about 0.5-0.6, significantly different from the dry heat factor of standard air conditioners, reaching up to 0.8. The cost per unit volume of treated air is higher for this equipment. At the same time, the sensible heat capacity of air dryers is much lower than that of standard air conditioners, which seriously affects the dimensions of the equipment.
Given the fact that the climatic equipment of swimming pools operates in difficult atmospheric conditions 24 hours a day, seven days a week, it needs regular and professional maintenance. Service can be simplified by installing modern units with direct fan drive and phase-frequency control of the speed of the drives. Nevertheless, in this case, regular checks of the condition of the air dryer are also necessary, so the designer must provide easy access for maintenance personnel to the climate equipment.
In some cases, to maintain the required degree of vacuum inside the room, separate ventilation units are installed that use outside air.
Supply and extract fan configuration. There are two fans inside the unit. The exhaust fan provides negative static head in the exhaust duct, while the supply fan creates a positive static head in the supply duct. The vacuum in the room can easily be achieved by changing the speed of the exhaust fan, the supply fan, or both. The three-valve mixing section allows for 100% outside air or the minimum amount required from a hygienic point of view. This configuration typically uses two filter sections, one for the supply air and one for the exhaust air.
Configuration with supply fan and separately installed exhaust fan. The supply fan provides the necessary negative static pressure on both the fresh air inlet and the intake duct of the recirculation circuit. A separate exhaust fan can be located both inside the special section of the dehumidifier and outside it. This configuration allows only a limited amount of fresh outside air to be introduced (typically about one third of the total flow). This requires one small filter section for outdoor fresh air. For the correct operation of the dehumidifier, it is necessary to synchronize the operation of the separately installed exhaust fan and the outdoor fresh air control valve.
Configuration with supply fan, separate exhaust fan and additional fresh air fan. This configuration is similar to the previous one, but with the addition of a separately installed supply fan, which, together with the main fan, can supply up to 100% fresh air from outside. Typically, this fan allows fresh air to be supplied to at least two-thirds of the total system flow. In this case, a separate filter section is required to clean the entire outside fresh air flow, as well as an additional outside fresh air control valve.
Condensing type dehumidifiers are widely used in swimming pools (2004 ASHRAE Handbook - HVAC Systems and Equipment, p. 47.1). They are specially designed to remove large amounts of moisture, have a low dry heat factor and use the standard chiller cycle. These dehumidifiers are equipped with several separated condensers. This allows, while maintaining the set air temperature and dew point in the pool, to provide, in addition to air dehumidification, cooling of the room and / or use of the waste heat to heat the air and water in the pool.
There is a constant leakage of heat in the pool: through the walls, ceiling, with ventilation air and due to the cooling of water during evaporation, therefore, constant heating of water and air is necessary. It does not matter what type of equipment is used to dry the air. If this equipment allows you to use the heat removed during the dehumidification process to heat the water in the pool, energy costs can be significantly reduced. The power of additional water heaters installed in the pool is calculated taking into account heat losses during evaporation of water from the surface and when adding cold water. The additional water heater must also have sufficient power to heat the entire pool to operating temperature in a reasonably short period of time after it has been refilled.
In conditions where the dew point of the outdoor air is low enough, equipment using 100?% outdoor air is becoming increasingly popular. In such installations, heat recuperators are used to ensure efficient heat exchange between the exhaust air and the supply air. Heat pipes or air-to-air heat exchangers are used as heat recuperators. If the dew point temperature of the outside air is above 15-20°C, then, as a rule, its additional dehumidification is required, since air exchange in an acceptable amount is insufficient to maintain humidity at the required level. When the outdoor air temperature is above 24 °C, it becomes impossible to maintain the required indoor temperature, taking into account internal and external heat gains. In this case, air cooling is necessary, while in winter it needs additional heating.
Recuperative air-to-air heat exchangers are used to transfer energy from exhaust air to supply air, and this reduces additional heating. When selecting such equipment, the designer must take into account the factor of high humidity of the exhaust air. With high-efficiency heat exchangers, at low outside temperatures, condensation and icing can form in the warm arm. If the heat exchanger is of low efficiency, then its benefits are minimal and more intensive additional heating is required. "Enthalpy wheels" are not used in pools - there is no need to increase the humidity of the supply air.
The selection of equipment for dehumidifying the air in the pool is carried out, first of all, based on the required level of humidity. The air exchange rate, outdoor air parameters and architectural features of the room are also taken into account. For example, a large area of glazing on the south side of the pool or large skylights additional cooling loads.
The dew point temperature characterizes the actual amount of moisture in the air (absolute humidity), as shown in graph 2. This indicator is stable and independent of other external factors. On the other hand, as shown in Graph 2, relative humidity can change significantly with a small change in dry bulb temperature. For a more stable operation of the pool dehumidifier control system, it is important that the system works to maintain the desired dew point temperature, and not relative humidity. The user, of course, usually does not know what dew point temperature to set. Therefore, the pool climate control system must allow the input of nominal air temperature and relative humidity values in order to automatically convert these data into dew point temperature.
Thus, it turns out that the designer has a difficult task of ensuring the comfort and convenience of pool users and the success of its owners. The main thing is to remember that this task is completely solvable, and to strive for this solution in the most effective way.