Heat pump for a swimming pool: selection criteria and installation rules

Heat pumps are undoubtedly one of the best inventions in the field of heating systems.It literally makes it possible to extract virtually free energy directly from the air, as well as from the ground or water. If you use a pool heat pump, the cost of heating water can be significantly reduced.

We will tell you how to choose the optimal model for using “green” energy to generate water-heating heat. The article presented for review describes in detail the principle of operation of the system. Here you will learn how to install the unit and how to properly operate it in a domestic environment.

How does this pump work?

Energy is everywhere, even in those objects that seem exceptionally cold to us. This energy just has a low potential. Heat pumps allow you to extract it from the environment and convert it into energy with high potential. In this condition thermal energy can be used for heating.

Heat pumps, like refrigerators, operate according to the Carnot principle. The refrigerator moves thermal energy from the chamber to the surrounding space to create a cooling effect, while the heat pump works in the opposite direction.

Such a system consists of two main parts - external and internal, between them there is a compressor and an evaporator. So, the coolant circulates through a system of pipes that are located outside.At the same time, it absorbs energy dissipated in the thickness of the earth, in water or in the air, depending on the type of pump.

The coolant then passes through the evaporator chamber filled with refrigerant (usually freon). The refrigerant boils at a very low temperature. Heating upon contact with low-potential thermal energy, it turns into a gaseous state and enters the compressor.

This diagram clearly shows the design and operating principle of a heat pump, which collects low-potential heat from the environment and converts it into high-potential thermal energy (+)

Here the gas is heated and moved to the condenser. The refrigerant then cools, returning to a liquid state again, and the heat it has collected goes into the internal heating system, i.e. to the heating system of a house or, in this case, a swimming pool. The cycle is repeated many times.

Of course, for the operation of such a system, namely pumping units, a certain amount of electricity will be required, without access to which the system will not be able to operate.

But the amount of electricity required by a heat pump is about four times less than the cost of heating water directly with an electric heater. With a consumption of less than 2.5 kW of power to operate electricity, a heat pump can generate more than 10 kW of thermal energy.

How to choose the right system?

The design features of the heat pump make it more resistant to high humidity than any other water heating system. But you need to choose the right one heat pump type, i.e. determine the source of low-grade thermal energy.

The more stable the ambient temperature, the more efficient the heat pump operates. Land is considered the best option in this regard, but practical implementation requires the fulfillment of a number of not very simple conditions.

This table allows you to determine the power of your pool heat pump. Calculations were made taking into account the presence of a protective coating from the sun (+)

A spacious plot of land and large-scale excavation work will be required. The pipes through which water circulates will have to be placed deep in the soil; fulfilling this requirement is not always possible or convenient. Ground-to-water heat pumps are rarely used for swimming pools.

A water heat pump is a little easier to install, since water is used as an energy source. The best option is a nearby body of water: pond, lake, river, etc.

Not all land owners have access to such resources. A more affordable solution to the problem is to lower the water pipes into a well or well. This means that an additional water source may have to be built on the site.

Less time and effort will be required to install a heat pump that consumes energy dissipated in the air masses. To organize intensive air exchange, powerful fans are used. There is no need to lay pipes in the ground or drill a new well.

Air-to-water heat pumps allow you to heat a large volume of water in a pool with minimal electrical energy consumption

Of course, the heating efficiency of an air source heat pump may be slightly lower than when using stable energy sources such as earth or water.However, for use during the season from spring to autumn, and not all year round, this model is ideal. Most pools on sites are used during this period.

The heat pump can also be used in conjunction with other heating systems, such as electric heating. To heat a home, such models are sometimes combined with a gas or electric boiler. This is especially appropriate in areas with harsh climates, since at air temperatures below -20 degrees, the efficiency of heat pumps sharply decreases.

A feature of any industrial heat pump model is its high price. You can reduce costs if you build such a device yourself. This is not a very difficult task; many craftsmen have successfully completed it. But industrial models are more reliable, efficient and easier to manage.

According to reviews, the high cost of an industrial heat pump model pays off within the first couple of years of operation, and sometimes in just a few months. In this case, it is very important to choose a model whose power will exactly match the heat needs of the facility.

Heat losses of the object

To choose the right heat pump by power, you need to determine the heat losses of the pool in which the device will be installed.

In the case of a swimming pool, consider:

• the place where the pool is located;
• availability and degree of reliability of the pool;
• volume of the bathing bowl;
• initial water temperature;
• optimal water temperature for swimming;
• the presence of additional factors influencing changes in water temperature: heating the air in an indoor building, air conditioning, etc.

To calculate the heat losses of a structure, some experts recommend using the methodology set out in DBN V.2.5-67: 2013. The pump power should be 30% greater than the heat losses of the pool.

This diagram allows you to get an idea of ​​the possible heat losses in the pool depending on the influence of external factors. The smaller these losses, the more efficient the heat pump will work

These calculations are quite specific; it is better to entrust them to a specialist. Useful recommendations can be obtained from experienced specialists who manufacture or sell heat pumps. When choosing a heat pump, information about the power of the device’s heat exchanger will also be useful.

When choosing an air source heat pump for heating pool water, you should take into account a number of factors that affect the degree of heat loss of the building, for example, the presence or absence of a cover

This indicator reflects the consumption of thermal energy to heat water in the pool over a certain period of time.

In simplified form, the formula might look like:

P = 1.16 X ΔT/t X V (kW)

Where:

• 1.16 – correction factor for heat losses;
• ΔT – the number of degrees separating the initial and final water temperature in the pool, ºС;
• t – operating time of the device until the required water temperature is reached, hour;
• V – volume of the bathing bowl, cubic meters. m.

Of course, this formula does not take into account a number of factors such as the influence of heating in the indoor pool, the presence of air conditioning, the presence of insulation, etc.

But when choosing a suitable heat pump model, such a calculation can be very useful.During the calculations, it is useful to take into account that the optimal air temperature for an indoor pool is 28 degrees, and the water temperature is 24 degrees.

Important points when choosing a pump

When choosing a suitable heat pump, you should focus not only on its power. Other factors are also important. For example, these are the dimensions of a pump that resembles a large metal box.

The installation location is usually chosen in advance; you should make sure that the selected model will fit freely there, while leaving enough space for the person who will install and maintain the device.

The smaller the difference between the air temperature outside and the water temperature in the pool, the more effective the use of a heat pump will be, and the higher its performance.

The automatic control of some models allows you to change the operation of the pump, taking into account not only the outside temperature, but also the rate of cooling of the water in the pool, as well as the ability of the building (if we are talking about an indoor pool) to retain heat.

During operation, the heat pump vibrates and makes noise. The less noise on the site, the better. Before purchasing, you should find a way to evaluate the noise level that different heat pump models produce.

The cost of the unit can be significantly affected by the presence of an automatic control unit. If funds allow, you should not refuse this modern and convenient addition. Firstly, automation increases comfort when using the equipment, since you do not have to constantly be distracted to turn it on, adjust, turn it off, etc.

The automatic control system of modern heat pumps facilitates the operation of the device, increases its efficiency and extends its service life

Secondly, operating the device in automatic mode significantly increases its service life, i.e. lifetime. But breakdowns are still possible. Having correctly completed warranty documents for the device will help to minimize problems associated with the operation of the heat pump.

However, having an official form with a stamp is not enough. Sometimes sellers modestly keep silent about the fact that warranty repairs are carried out only by a specialized enterprise, which is located a hundred kilometers from the installation site of the equipment.

It also happened that the device had to be sent abroad for repair. Such warranty service is extremely inconvenient, since it takes the owner months of time.

Craftsmen who are comfortable with simple repairs of household appliances should study in advance the device features of the selected model and access to spare parts. If the necessary parts are not available somewhere nearby, you will have to special order them, pay for long delivery times, etc. prudence will help avoid such problems.

If the cost of a factory-made heat pump seems sky-high, it can be assemble with your own hands. How a unit is constructed from practically waste starting materials is described in the article we recommend.

Device installation features

The procedure for connecting a pool heat pump depends on the features of the specific model. Therefore, before starting work, you should carefully study the manufacturer’s instructions and strictly follow the requirements and recommendations contained therein. Typically, industrial models are supplied already assembled and with a set of components necessary for installation.

Scheme of operation of a heat pump connected to a pool:
1 — Heat pump for the pool
2 - Remote control device
3 – Clean water for the pool
4 - Circulation pump
5 - Bypass (bypass channel) and control valves
6 - Water supply pipe from the pool
7 - Filter

During the connection, you will need to install a couple of pipes, as well as provide power. The heater is installed in the pool maintenance system so that it is located after the filtration system and before the chlorinator.

As shown in this diagram, the heat pump should be connected after the water filter, but before the chlorination device

It is very important to choose the right place to install the equipment. Usually air-to-water heat pump is an impressively sized unit, reminiscent of the outdoor unit of a split-system air conditioner.

To install the air source heat pump, it is necessary to choose a sufficiently spacious place, which should be protected from external factors, for example, using a canopy

The location for installing such equipment must meet the following requirements:

• good ventilation;
• absence of obstacles to the movement of air masses;
• distance from open fire and other heat sources;
• protection from external environmental factors: precipitation, debris falling from above, etc.;
• accessibility for maintenance and necessary repairs.

Most often, the heat pump is installed under a canopy. For additional protection, you can install a couple of side walls, but they should not in any way interfere with the air flow that is pumped by the fans.

The pump is mounted on a metal frame; the base must be strictly horizontal. This will minimize problems such as vibration and noise during operation of the device, and will also protect the device from damage.

The air source heat pump must be installed on a solid and strictly horizontal base. This will reduce vibration during its operation and reduce the amount of noise.

When installing the heat pump and connecting it to the system, it is important to make sure that all its elements are clean. It wouldn’t hurt to check the inner surface of the pipes used to make the connection.

All pipe connections through which water circulates must be carefully sealed and checked for leaks. To prevent vibration from the heat pump during its operation from being transmitted to the rest of the system, it makes sense to consider connecting using flexible hoses.

Providing power to the heat pump will require special attention. It must fully comply with the rules for installing electrical equipment, taking into account all fire safety requirements.

There is usually a high level of humidity around a swimming pool, and the likelihood of electrical equipment coming into contact with water increases significantly. Therefore, it is necessary to carefully insulate all electrical contacts, additionally protecting them from possible contact with moisture.

In the connection diagram of the heat pump to the power supply, it is imperative to include automatic switches, which are equipped with sensors that respond to temperature increases. You will also need protection devices that will prevent current leakage.

All conductive components must be grounded. To connect cables, both power and control, you will need special terminal blocks. The manufacturer's instructions usually indicate the required cross-section of electrical cables through which the equipment can be connected to the power supply.

These data must be adhered to. The cable cross-section may be larger than recommended, but not smaller.

Installation of a heat pump for heating pool water is carried out in accordance with the manufacturer's recommendations. It is usually installed after the water treatment system, but before the chlorination device, if available.

Homemade heat pump - is it possible?

If you make a heat pump yourself, you can save a lot, but the efficiency of such devices is somewhat lower than that of industrially manufactured models. First, individual pump elements are manufactured, then they are combined into a common system. The evaporator can be made from a large plastic tank. A copper coil is installed inside.

To make a coil, a copper pipe can be carefully wound around a gas cylinder or other suitable cylindrical object to give it the desired shape. Another coil is made in the same way - for the evaporator. This element is placed inside another tank, this time metal, welding work will be required.

The compressor is simply purchased or removed from another device, for example, from a broken air conditioner. When these three devices are ready, they are connected into a common system. The compressor is then charged with refrigerant. All that remains is to connect the evaporator to a fan that blows air, and the condenser to the water heating system in the pool.

Significantly more complex in design water-to-water heat pump. Its construction requires the presence of a river or natural reservoir near the site; if they do not exist, then wells are drilled. However, if it is impossible to obtain energy from the air for technical reasons, this option will also be useful.

Conclusions and useful video on the topic

Practical experience of heating pool water using heat pumps is presented in the following video:

The operating principle of an air source heat pump is clearly demonstrated here:

This video provides a very detailed overview of the operation and design of the air-to-water heat pump model:

A heat pump is a convenient, efficient and environmentally friendly way to heat a pool. With proper use, the cost of the model will pay off very quickly, and proper installation will significantly increase the service life of the device.

Would you like to share useful information on the topic of this article? Maybe you know how to make a heat pump for arranging a private pool with your own hands? Please write comments in the block below, ask questions, share your opinion and thematic photographs.