How to choose the heat pump for your pool ?

Warm up (or cool) the water in your pool at will by capturing the calories free ambient air, represents a revolution in access to the pleasure of prolonging the time of use of this leisure equipment, sometimes also used for therapeutic purposes. The operating costs of swimming pool water temperature regulation systems have long held back the expansion of this practice. The swimming pool heat pump, (PAC), changes the situation to such an extent that the offer becomes bloated! The purpose of this file is to help you gather the best arguments likely to enlighten your personal choice.

7 criteria defining the performance of the heat pump

Installing a heat pump consists of grafting a new accessory onto a set of pre-existing elements. For the graft to take, many interactions predictable must follow each other in an efficient and harmonious manner. The first task therefore consists of making a precise inventory of the technical and environmental characteristics of the equipment in question. These data make it possible, in particular, to assess the foreseeable heat losses, for the calculation of the Powerful of heat pump necessary for the correct balance of the system. So note:

  • The volume approximate size of the pool (average L x W x H of water), expressed in m3
  • The type and the method of manufacture of the swimming pool (above ground, buried, masonry, concrete, stainless steel, wooden structure, synthetic material, etc.). Special attention must be paid to the existence and nature of any pool insulation devices
  • L’exposition the swimming pool (no shade, indoor, outdoor or covered pool)
  • The zone climatithan the site and the risks of strong and/or frequent winds
  • The maximum pool water temperature in degrees Celsius
  • The heating periodexpressed in months
  • The filtration circuit flow rateto adjust the performance of PAC

4 essential technical performance criteria for the pre-selection of your heat pump

The problem consists in sorting out the different models of swimming pool heat pumps compatible with your site and your requirements. This first choice, of a purely technical and functional nature, is based on the criteria published by the manufacturers for each of their productions, namely:

  • The power (in kW), sufficient to provide the calorific needs
  • The COPratio between the quantity of electricity actually consumed and the quantity of calories restored
  • The acceptable noise level
  • Ancillary functions essential to ensure continuity of service, such as the automatic defrost in gel case
  • In the horizontal heat pump, the very cool airflow from the fan blows horizontally. This configuration, very European, turns out to be awkward if the heat pump is placed near the bathing area. It is therefore necessary to carefully define its orientation.
  • In the heat pump vertical, the ventilation blows upwards, which makes it less noisy. On the other hand, it is more cumbersome, often more expensive and exposed to various objects falling into the space of the blades.

Choose the type of swimming pool heat pump

Two types of swimming pool heat pumps with generally the same performance coexist on the market:

Each type exists in variant reversible, to cool the pool water during periods of heat wave. It is the certainty of finding, in all circumstances, a constant temperature of the bath water. For one as for the other, the trendy option is the remote control allowing the heat pump to be moved or hidden without interfering with its use.

Choose the right power rating

The relevant calculation of the power of the pool heat pump is fundamental. This dimensioning depends on the good operating and performance conditions of the system:

Undersizedthe pool water takes a very long time to reach or, depending on the circumstances, does not reach the desired temperature

oversizedthe too rapid rhythm of the cycles of operation and interruption imposed on the compressor, accelerates its aging, causing premature failure.

These two situations generate disproportionate acquisition, installation and operating costs, as well as functional inconveniences that annihilate all or part of the interest of the heat pump. In order to mitigate this difficulty, each machine is capable of working in a power range more or less wide. This allows the use of simple calculation formulas giving a sufficient approximation, such as V x C x Ewhere :

  • V – is the volume of water in the basin in m3
  • C – is the desired temperature rise coefficient
  • E – is the sunshine index of the region concerned

In concrete terms, for a 50 m3 swimming pool, located in Marseille (sunshine index 1.8), a daily temperature rise of 2% (coef 0.12), the nominal power of the heat pump is: 50 x 1.8×012 = 10.8kW

NB : to help the consumer to compare what is comparable, the federation of the professionals of the swimming pool (FPP) and French standards (NF) require manufacturers to display the power of their equipment under the following operating conditions: an outside temperature of 15°C; a pool water temperature of 26°C; a humidity level of 70%.

In practice, the power curve of each device evolves outside this strict framework, in conditions that are specific to it, which complicates the difficulty of choosing the right compromise.

The rise in temperature of the basin is slow. Count from 1 to 3 degrees per day on average depending on the climatic conditions and the presence or not of a nocturnal cover system. To overcome this drawback, some manufacturers offer an electric heater. This auxiliary resistance (integrated into the heat pump or independent) provides additional calories during the temperature rise phase, then turns off. Obviously, during these few hours, the electricity consumption soars! However, this system makes it possible to limit the nominal power of the heat pump and therefore reduces the initial investment and operating costs for the rest of the season. Again, no generalizations apply. the balance sheet relevant is intimately linked to the specific conditions of each installation and the habits of use of the swimming pool.

The coefficient of performance (or COP)

The main originality of heat pumps lies in their power to restore more energy than they consume. The COP is the ratio between the quantity of electricity, in Watts, consumed by machine and the quantity of thermal energy, still in Watts, returned to the heating circuit. By way of comparison, a swimming pool heat pump with a COP of 6 consumes 1 kW of electricity and restores 6 kW of heat, whereas an electric resistance heater that consumes 1 kW restores only 1 kW. The value of this ratio is specific to each material, of which it characterizes the performance. The COP should not be confused with the COPA, a similar ratio, but applied to the entire installation, taking into account the impact of ancillary accessories. The COP and the COPA fluctuate according to the heat pump model, the outside temperature and the desired setpoint temperature.

Given the number and complexity of the elements involved, the use of the services of a professional is strongly recommended for the final calculation of the power adapted to the needs of your installation.

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