How to choose the right pool water heater

Basic Rules

Heating of water in an outdoor pool must be organized in accordance with certain rules:

• 
  maintaining temperature within certain limits;

• the use of devices or equipment that receive thermal energy from external sources or are built into the circulation system;
• heating equipment should not change the composition of the water or allow contaminants or harmful components to enter it.

First of all, it is necessary to ensure a comfortable water temperature.

Different conditions are preferred for different age groups:

• for adults, 23-26° is enough;
• children aged 7 years and older - approximately 29-30°;
• For children under 7 years of age, heating to 32° is desirable.

Pool heat loss

To select the power of the heat source, it is necessary to calculate the heat loss of the pool. Of course, such a calculation should be made by a heating engineer, but for a general idea of ​​​​the order of numbers, we present an empirical table of pool heat loss. With its help, you can easily determine the required power of the heat source:

It should be noted that the initial heating of the pool may take several days, so do not worry if the initial heating of the pool takes a long time.

Heat source options for heating a pool

Let's consider the main heat sources for heating the pool and compare their technical and economic indicators:

Solar collectors are beneficial for open-type swimming pools when the pool is used in the summer and off-season. In combination with a backup source of thermal energy, it is an excellent solution for ensuring a comfortable water temperature in the pool.

Electric boiler - very high operating costs do not allow us to recommend this type of heating for a pool.

A gas boiler is a compromise solution, but operating costs are still high, therefore, taking into account other disadvantages, it is not recommended for heating a pool.

Biomass boiler (wood, pellets) - this option is not as economical as it is more difficult to maintain, therefore, the person who equipped the pool is unlikely to want to spend his precious time on constant maintenance of the boiler. Based on the above, it is not recommended for heating a swimming pool.

A heat pump is an excellent solution for heating a pool. Autonomy – You can start the heat pump from your smartphone and upon your arrival the heat pump will raise the temperature in the pool to a more comfortable one. There is no need to clean or check anything, everything works automatically, plus it’s much cheaper than heating with gas, wood or electricity. Can be used to heat both indoor and outdoor swimming pools. For outdoor pools, we recommend a combination of solar collectors and a heat pump, since during the main operating time - in the summer - only solar collectors will work. Therefore, maintaining the pool will be practically free on sunny days, and when there is no sun, the heat pump will provide protection and you will always be able to plunge into the warm water of your pool in the morning, afternoon and evening.

Does it matter?

Heating water is a physical process that occurs under certain conditions. They can promote or hinder the heating of water, since the transfer of thermal energy is always interconnected with all surrounding objects or factors.

Planning for the creation of a heating system must be done taking into account the characteristics of the pool and its specific properties.

Bowl type

The type and design of the bowl can affect the heating mode in a very direct way. For example, the depth of the pool determines the effectiveness of heating using solar rays.

In addition, if the pool is deep, then the volume of water that needs to be heated increases. For this, more thermal energy is consumed, i.e. a higher power heater is required.

There are conventional and frost-resistant pool designs.

The former must be drained and stored indoors at the end of the swimming season (most often such models are bought for a summer residence), the latter can be left filled with water for the winter.

The walls of the bowl in frost-resistant species are more durable, assembled from several layers. They are able to resist the effects of low temperatures and frosty expansion of water.

Frost-resistant bowls retain thermal energy better, which makes it possible to reduce the power of heaters.

Manufacturer

The heating method does not depend on the manufacturer (be it Intex, Bestway or any other company), since in any case there is a certain volume of water. Only the enclosure of the bowl changes, which practically does not affect the temperature inside.

Characteristics of heat pumps

The main indicator by which the efficiency of a heat pump is assessed is the heat conversion coefficient, abbreviated as CPT (in the English abbreviation COP). It has nothing to do with the efficiency that is familiar to us - the efficiency factor. KPT (COP) shows how many kilowatts of energy the pump pumps per kilowatt of electricity it receives. Depending on the operating conditions, the CFC of a heat pump can range from 3 to 5, which, without further discussion, confirms the economic benefits of its use.

The most stable performance indicators are demonstrated by soil and water installations, since the temperature of water and soil does not fall below zero degrees. Units that collect heat from the air depend on its temperature. When the thermometer reaches sub-zero levels, their productivity decreases by an average of 40-50%.

The second operating parameter is power in kilowatts. It is selected based on the amount of heat loss of the building.

How to quickly heat it up outside?

Many years of use of frame pools contributed to the development of several methods of heating water. Let's look at the most effective of them.

Sun blanket

The sun cover is a special accessory for a frame pool. It is a kind of awning with a cellular multilayer structure that covers the surface of the water.

The bedspread has a dual function:

• During the day, it receives solar heat and transfers it to water. The temperature rise occurs much faster than normal heating from the sun's rays.
• At night, the blanket allows you to retain heat , serving as a cut-off layer from contact with cool outside air.

The disadvantage of a solar blanket is its dependence on weather conditions. If the sky is overcast, water heating stops.

Heater

The use of flow-through heaters allows you to obtain the desired water temperature. You can change the heating mode to achieve the most comfortable feeling. Typically, such heaters are built into a filtration system that operates on the principle of water circulation.

There are different designs:

• electrical;
• gas;
• operating on liquid or solid fuel.

All types differ in the source of thermal energy. They are used in the same way - connected to the circulation system (usually immediately after the filter). The water passes through the heat exchanger and is heated, after which it enters the pool bowl.

The process takes place continuously, but it can be regulated or stopped temporarily.

Heat pump

The design of the heat pump is based on the operating principle of a refrigerator, but another arm is used for heating - a capacitor is used as a heater. The transition of the coolant from a gaseous to a liquid state is accompanied by the release of thermal energy , which is used to heat the water.

To organize the process, it is necessary to create high pressure and cool the freon pumped into the system. The pressure is increased using a compressor, and the cooling element is water from the pool. It circulates through the condensation chamber and heats up, after which it is discharged back into the pool.

To organize heating, it is necessary to connect the condensation chamber of the pump to the water circulation system.

The best option is serial connection after the filter . Water will pass through the chamber and receive thermal energy, cooling the freon.

The process can be regulated, although in practice, maximum efficiency of the complex is most often required.

It must be taken into account that this heating method does not give quick results - it will take 9 hours to raise the water temperature in a pool with a diameter of 4.57 m by 5°.

A heat pump is a rather expensive device, and for its operation it will require a connection to the power supply and connection to the circulation system.

Heating mat

This method is one of the options for heating water using solar energy. A black rubber mat is used with a hose fused inside , bent in the shape of a spiral or zigzag.

This allows you to increase its length so that the water has time to heat up during its passage. The mat is connected to the filtration system, water is passed through to fill the mat, and they wait for a while.

When it heats up, they start circulation and gradually raise the temperature of the water.

For large pools, several of these mats can be connected in parallel.

Shelters

This method is, rather, a way to protect water from loss of thermal energy. The temperature does not increase, but its cooling slows down. For protection, a special cloth is used, similar to a solar blanket.

It is placed on the surface of the water and cuts it off from the cold air. In the morning, remove the sheet and use the pool as usual.

Firewood

A flow-through heater, which is a firebox with a coil built into it . It is connected to the filtration system.

Firewood is loaded into the firebox and set on fire, and the filtration system is started at a certain speed.

During circulation, the water heats up and flows back into the pool. This method is quite effective , but requires the use of fire, which poses a certain danger.

Kettle

This method is only suitable for small pools. Take an ordinary kettle, fill it with water, which is brought to the highest possible temperature. It is poured into a bowl, and the procedure is repeated until the desired result is obtained.

Care must be taken not to pour boiling water onto the film. In addition, there should be no people in the pool during the procedure.

Snail from a hose

This method of solar heating is almost the same as using a mat. There are ready-made designs, but more often they make homemade heaters . Take a rubber (or PE) hose of sufficient length. The darker it is, the better.

Roll it into a spiral or lay it in a zigzag so that the walls of the hose fit more tightly to each other. This allows you to more efficiently absorb solar heat. The hose is connected to the filtration system and turned on. Heated water begins to flow into the pool, and cool water leaves it and enters the warm hose.

Pool maintenance costs

As an example, consider a pool with a 3x7m mirror and the costs of its operation, depending on its type and heating source, taking into account current energy tariffs:

• *120 days (summer 90 days, 15 days spring, 15 days autumn) x 24 = 2880 hours
• *150 days (summer 90 days, 30 days spring, 30 days autumn) x 24 = 3600 hours
• *365 days x 24 = 8760 hours

Having the cost of 1 kW of thermal energy and the total heat loss, you can easily get the total cost of maintaining the pool in terms of heating (without taking into account other funds and maintenance). Consider an indoor pool (water temperature +20℃, room temperature +23℃) - 16556 kW of heat per year.

As can be seen from the table, the amount of pool maintenance can vary significantly depending on the selected heating source. Therefore, the main advice is to carefully weigh everything and choose the golden mean. A more detailed calculation of the cost of 1 kW of thermal energy is here

Scheme of operation of a heat pump for heating a swimming pool

The operating diagram of a heat pump for heating a pool is quite simple and includes the following elements:

• Primary heat source - air, water, soil or technological process
• Heat pump
• Heat exchanger
• Pool water circuit
• Filtration system (not shown for simplicity)

As a rule, the circuit contains a shell-and-tube type heat exchanger. Shell and tube heat exchanger is easy to maintain and durable. This type of heat exchanger is most often used to heat a swimming pool.

It is important to choose the right heat exchanger for a heat pump - Be sure to consult with specialists

Properly selected equipment and high-quality installation are the key to success when implementing a pool heating system using a heat pump.

How to make heating with your own hands?

For DIY, it is best to use one of the most efficient and economical designs - a wood-burning stove with a coil. Let's consider the procedure for assembling the heating system:

Tools and materials

For assembly you will need:

1. Sheet steel. You will need stainless steel with a thickness of 2 mm (for the firebox it is better to find sheets from 4 mm).
2. Metal pipe. Stainless steel is optimal, but you can use a copper tube.
3. Grinder with cutting wheel.
4. Welding inverter with electrodes.
5. Pipe bender
6. Measuring tools - ruler, tape measure, square.
7. Welder suit, eye, face and hand protection.

Only the required minimum is listed; depending on the complexity of the design, other tools may be needed.

Manufacturing process

The oven is assembled in stages:

1. 
   Making a coil. You can make a flat version by welding the pipe with a “snake”, or make a figure in the form of a spatial spiral (spring). To do this, use a pipe bender, grinder, or welding inverter.

2. Manufacturing of body walls. Using a pre-prepared development, the walls are cut out and welded in the required order.
3. Installation of the coil inside the housing , connecting the inlet and outlet pipes.
4. Installation of door and chimney . It is recommended to make the pipe high enough so that sparks from it cannot cause harm.

After completing the assembly, check the coil for leaks, connect the furnace to the filtration system and do a test run of the heating system.

Wood-burning pool water heater MSK

Introducing the new generation of wood-burning spiral water heaters of the Fenix ​​series. Phoenix MOSCOW is a modular, easy-to-assemble water heater consisting of:

— a stainless coil of 20 dense turns, width/depth 550 mm, height 660 mm. (Coil material: stainless steel pipe AISI 304 32*2 mm, coil length: 34 meters) - prefabricated stand with legs - perforated grate - apron body with a bottom airflow system - top cap with a sliding top feed firebox - pipe for installing a chimney 115 mm with a wall thickness of up to 2 mm - rear pipes for connecting the pump and draining water 1″ outer. thread.

The main difference from all other models is that the coil is located higher in relation to the grate, which allows for the most efficient use of the surface of all turns of the spiral (the spiral is located in the place where the flame has the highest temperature).

Thanks to its modular, collapsible design, the water heater is easy to move and install. The body is painted with heat-resistant paint in blue and black colors. A water pump of at least 0.5 Bar and a capacity of no more than 2 cubic meters per hour is required. It is recommended to use an adjustment valve to obtain the optimal outlet temperature, regardless of the model of your pump. Resistant to high internal pressure. Recommended for medium and large pools. Color: charcoal (color), heat-resistant Fuel type: firewood, briquettes, linear and lump wood waste, charcoal.

Summary table of average performance of Phoenix water heaters:

Effective thermal insulation to retain heat

Thermal insulation of a pool is a layer of backing that cuts off the contact of the film with cold concrete or soil. Different materials are used, from ordinary polystyrene foam or more reliable penoplex to liquid polyurethane foam.

It is a liquid that is applied by spraying. In air, the composition foams and hardens, forming a continuous hard layer of insulation. The procedure is quite complicated and requires the use of special equipment. However, the result gives maximum effect.

Such thermal insulation can last 50 years or more.

Making your own heat pump

Considering the fairly high cost of this equipment, many DIYers are tempted to assemble it with their own hands, using improvised units and components. What should be said about this?

This work includes two main stages: preparing the external circuit and assembling the heat pump installation itself. You can dig trenches for laying pipes on your own. It is unrealistic to make a 50-meter well for installing a probe without special equipment. Surface installation of the collector, according to experts, is unprofitable because it does not provide enough heat for stable operation of the installation.

Now let's see if it is possible to assemble a heat pump with your own hands. This requires the practical experience of a refrigeration technician, since a beginner will not be able to fill the system with freon and pressurize it.

Manufacturing an installation based on units from an old refrigerator or air conditioner can be considered only as a demonstration option, which has no practical value due to low efficiency.

A manual for assembling a heat pump based on a compressor from an air conditioner, a stainless steel container (condenser) and a plastic barrel (evaporator) is being replicated on the Internet. Having told how to screw copper tubes onto a cylinder and mount the compressor on the wall, the author ends his story with advice, after completing the assembly, to contact a specialist who will agree to carry out commissioning and correct all the “jambs” made by the home-made man. This instruction cannot be called a serious aid for independent work.

Pool heating with solar collectors

Heating a swimming pool using solar collectors

Using solar energy is the cheapest and most promising form of energy. You don’t have to pay money for this, all you need is a clear sunny day. The solar collector looks like large flat segments. It consists of numerous small diameter tubes, which are made of black polypropylene. It is in these small tubes that the water is heated using solar radiation.

This pool heater is built into a water filtration system. Due to constant circulation, the water in the pool can become significantly warmer in a short period of time. Such solar panels are installed on the roof or in the pool area. They are oriented towards the south or southwest to absorb more solar heat. There is manual and automatic adjustment of water temperature. The power of the batteries is selected depending on the cubic capacity of the pool.

Advantages of using heated floors in swimming pools

Tiles are used to decorate the floors in swimming pools. And this material is classified as cold, so even when the room is warm, walking barefoot on ceramics is uncomfortable. And if the bypass paths are heated by heated floors, it’s much more pleasant to step on them.

Another point is that open water constantly gets on the tiles. And this leads to two things:

• humidity in the room increases;
• Walking on wet tiles is dangerous - there is a risk of slipping.

Warm floors also solve these problems - water evaporates from a warm surface faster, so the room becomes much drier. And it’s safer to walk on dry tiles.

Tile floors

Additional advantages of heating include the possibility of heating water with floors in the pool bowl. Typically, special equipment is used for this, including heating elements. However, no one bothers you to lay water pipes for heated floors along the bottom of the bowl with your own hands.