Water Heating: The Idea of Ev Zin

Water heating

In the early days of the pool market, water heating was seen as an added gadget and an almost extravagant luxury.

 But as habits changed, the pool stopped being used exclusively for swimming and is now a way of life.

 After all, as the various water heating equipments are now more stylish and affordable and easy to install, they have succeeded in being regarded as a reliable and practical means of extending the ideal swimming season.

 Of course, the construction of an isothermal cover is the best solution for increasing the efficiency of heating equipment and reducing the cost of additional enjoyment. We tend to say that the temperature of 28 °C is the most suitable for swimming in the pool. Heating systems help to maintain this temperature throughout the year.

 Especially if the pool is indoor, heating is mandatory.

There are numerous techniques for pool heating that work with different forms of energy.

      Equipment that runs on natural gas, propane, or oil allows the water to be heated with the help of a specially adapted boiler or by using a heat exchanger connected to the domestic heating boiler.

 

 The electricity is used to use the heat pump or water heaters. The big advantage of the heat pump is that it consumes less energy (20%) during operation and over-delivers heat (80%).

Heaters use a large amount of energy to heat water.

 

     Alternative forms of energy, such as solar or geothermal, serve to achieve a heating difference of up to 50 . In this case the pool is heated with the help of solar panels or pre-installed water circulation pipe systems.

The surface, the size, the installation of the pool in or out of the ground, the desired water temperature, the way of use, the climate zone, the existence of a canopy, the exposure to the wind, the altitude, the availability of energy, are some of the parameters that are taken into account when choosing the most economical heating method as well as the one that best suits the needs and the space in which the pool is installed. Obviously, when choosing the heating method, the long-term performance of this investment should be taken into account. For example, an electric heater costs less than a heat pump, but consumes more energy, so its use turns out to be more expensive.

Water cannot be kept hot all the time. There are heat losses which we must reduce in order to limit heating costs. 94% of heat loss occurs at the surface of the pool: 60% from evaporation, 17% from water movement and 17% from radiation. The isothermal cover is therefore essential for those who want to prevent the phenomenon of evaporation and retain heat.

 It halves the power we use to heat the pool, and thus the total costs. The isothermal cover is necessary during the night, this equipment can be used just as often during the day when the pool is not in use, maintaining the heat but also protecting both from micro-contamination factors (leaves, dust, etc. ) as well as from the growth of microorganisms due to solar radiation.

There are various types of covers that take on this function such as isothermal covers for the summer season.

 Domed canopies of telescopic type, easy and quick opening and closing, high or low coverage.

 Automatic covers with automatic or manual floats.

 Some types have solar absorption blades that heat the pool while it is covered.

 The following example shows by numbers the importance of the cover if you decide to heat your pool.

Fuel prices refer to the period up to May 2008 and PPC electricity

They are about current usage.

   

Swimming pool 4×8 m

Surface 32m2

Depth 48 cubic meters

Altitude 50 meters

Filtering 16 hours/day

Use from May 15 to September 15

Wind exposure: moderate

Pool temperature 15 oC

Desired temperature 28 oC

Natural Gas (18241 kWh x €0.043): €784

Propane (1416 kg x €1.37): €1940

Household oil (1926 liters x €0.59): €1136

Electric Heater (16417 kWh)

Peak Hours (€0.107 /kWh): €1757

Off-peak hours (€0.065/kWh): €1067

Average peak hours: €1412

Heat pump (HEAT PUMP) (3148 kWh)

Peak Hours (€0.107 /kWh): €357

Off-peak hours (€0.065/kWh): €205

Average peak hours: €271

Natural Gas (9535 kWh x €0.043): €410

Propane (740 kg x €1.37): €1014

Household oil (1007 liters x €0.59): €594

Electric Heater (8581 kWh)

Peak Hours (€0.107 /kWh): €918

Off-peak hours (€0.065/kWh): €558

Average peak hours: €738

Heat pump (1650 kWh)

Peak Hours (€0.107 /kWh): €177

Off-peak hours (€0.065/kWh): €107

Average peak hours: €142

You can, if you wish, use the boiler of the house to heat the pool water. For this heating method you will need a heat exchanger which is placed in a deviation of the hot water network intended for the interior space. In the exchanger, two thermal networks circulate against the current: the water of the boiler, therefore, dissipates the heat in the water of the pool. The expansion power of the exchanger, which is placed near the filtration and near the boiler, determines the heating of the water. One of the main advantages of the exchanger is based on its efficiency: using the entire power of the boiler, it guarantees an immediate increase in temperature, a fact that is particularly appreciated by owners of country houses who swim at weekends.

The cost of this equipment depends on its form, its functions and its power: for a 20 kW device the price starts from €900. It is not an expensive investment as the installation costs are relatively modest.. As for the running costs, this depends on the energy used to heat the house. It is customary to say that the use of natural gas is the best solution for this installation. However, if you use the pool sparingly, using oil or propane are generally not the worst solutions.

However, it should be taken seriously that the boiler should be located relatively close to the pool to avoid heat loss during the flow.

In this case you can buy and install a boiler exclusively for heating the pool water. Made of rust-resistant materials, it is equipped with an exchanger that produces water hot at 70/90 oC capable of heating the pool. The heating is produced by the heat transfer in the exchanger. Connected directly to the refining network, this equipment allows rapid temperature rise.

These boilers run on natural gas and propane. Some manufacturers also recommend oil boilers which are also very efficient. However, the disadvantage of this equipment is that it is expensive: €3500 we calculate for a boiler that can heat a 100 cubic meter pool and which works with gas and €1000 if it works with oil. You should also be aware that some boilers on the market are perfectly adapted for indoor pool heating as they have a dual network option that allows them to heat water and air at the same time.

Available everywhere and easily accessible, electricity allows everyone to install an electric heater, which is also small in size, easy to install and not an expensive purchase. But this time operating costs come into play.

Consisting of copper pipe and heated plates, the heater is simply installed in the piping after the filter. The heat is dissipated through the electrical resistance found in the water. Once the installation is complete, it is sufficient to set both the thermostat to the desired temperature and the filter to either raise the temperature or maintain it. Depending on the normal temperature of the pool, we now have 2 to 5 days to reach the temperature of 28oC. The electric heater is among the most economical water heating tools and with a low installation cost. We can for example find numerous models on the market from €700-€1400 depending on the power of each model. However, in this case, it is the electricity that costs quite a lot. Operating costs will therefore depend on time of use (peak or off-peak) and power. We therefore conclude that the electric heater is more suitable for small pools that are not used much during the year.

The heat pump is a thermodynamic system, which quite simply shakes heat from the air and transfers it to the pool water. It consists of an air compressor, an evaporator and a water vapor condenser. At the heart of this equipment circulates a cryogenic liquid which changes state (either liquid or gas) depending on the pressure it experiences in each part of the circuit. This change in the nature of the liquid leads to heat absorption on the one hand and heat release on the other. Therefore, the operation of the heat pump, which is usually installed outdoors, is similar to that of a refrigerator or air conditioner.

The heat pump is particularly loved by private individuals as the operating costs are very low. Of course it runs on electricity which is very expensive, but consider that for one kWh of electricity it consumes, it produces 2,3 and 4, sometimes even 5 depending on the models and climate conditions. As a measure of comparison, we can say that an electric heater produces 1 kWh for 1 kWh it consumes. Thus, the use of the heat pump costs less than the electric heater, the boiler and the heat exchanger as a whole, while the cryogenic liquid circulating inside it makes it an environmentally friendly solution. Of course, this does not mean that it is the right investment for everyone. The heat pump is mainly interesting for frequent and prolonged use of a swimming pool, in order to quickly amortize its purchase which approaches €2500-€5000 depending on the model for a 30-50 cubic meter pool (the models that can operate all seasons and in -10oC they usually cost more).

For the sake of accuracy, we should mention that in some cold regions, the heat pump can lose its efficiency very quickly, as winter approaches. For this reason, it is rarely used to heat water in indoor pools which are used all year round. Finally, it is important to mention that the heat pump needs 2 to 5 days to regulate the temperature of the pool.