Aquae Vivae

Energy efficiency

The Aquae Vivae pools are filled with natural, therapeutic thermo-mineral water whose pH value lies between 7.3 and 7.8, making Aquae Vivae’s water ideal for the balance of the organism, the water preserves health and has proven to slow down aging.

The water temperature at the wellspring is 41 degrees, and at our swimming pools it is between 28 and 38 degrees, so that each pool has a different water temperature. The swimming pool with all of its content is open 365 days a year. The water park has a total of 6 pools, 170 water attractions, a 60 meter long water slide, a swimming pool with artificial waves who reach hights of 1.5 meters, a diving pool depth of 4.5 meters, where diving courses are held for all people over the age of 8.

The wellspring of hyperthermal mineral water is a gift of nature to Krapinske Toplice. The water temperature is 41 ° C, it is chemically characterized by calcium, magnesium and hydrocarbon, its ph value is neutral. The first chemical analysis of water in Krapinske Toplice and the comparisons of its water with the thermal water of Europe were made in 1858.

Apart from the fact that the thermal water fulfills its basic task, ensuring the well-being of the human body, we at Aquae Vivae have set a project task that the thermal water passing through the premises of the water park pass on its thermal energy. Therefore, we have designed the water park in a way that it is highly energy efficient and that the needed energy for heating of the premises is drawn from the energy of the hot water and the electric energy needed for the transfer of thermal energy. The premises has a total of 18,000 sqm of which 9,000 sqm is heated space, and 9,000 sqm. is not being heated, and is technical space and these include the terraces.

The first task and goal we had to accomplish was to build an object with a built-in thermal insulation to ensure very low thermal conductivity. The insulation of the external vertical walls was performed in such a way that we achieved a coefficient of heat transfer on the vertical U-shaped walls = 0.26 W / m²K. On the vertical walls there are 60 mm thick glass walls with a very low emission. The heat transfer coefficient through the U-shaped glass walls lies at = 0.9 W / m2K. The roofing is made of laminated wooden structure and is insulated so that its coefficient of heat transfer of the U-shaped roof = 0.2 W / m²K. The glassy roof parts are made of low-emission triple-glazed glass so that in this part the heat transfer coefficient of the roof U-shaped glass = 1.1W / m².


The average annual temperature in Krapinske Toplice is 12 ° C and the temperature within the water park is 28 ° C. Some of the basic Aquae Vivae Park: the surface of vertical walls is 1,600 m² – Pvz = 1600 m². The surface of the vertical glass walls is 800 m² – Psvz = 800 m². The roof area is 8.200 m² – Pk = 8.200 m². The surface of the glassy roof parts is 800 m² – Pksd = 800 m². The average annual temperature difference is ?T = 16 ° C.


The total required annual energy (gE) for heating the premises without the ventilation is: gE = (U-walls x Pvz + glass x Psvz + U-roof x Pk + U-roof glass x Pksd) x ΔT x 365 x 24 gE = 595.942.800 Wh. The total annual energy required for heating the water park is 600 MWh. The ventilation of the premises was designed and executed in such a way that we installed climate chambers with energy recuperators and heat pumps. The recuperators were selected so that at an airflow rate of 2 m / s and an average annual difference in temperature ΔT = 16 ° C they have an efficiency factor of η = 0.79.

When the temperature of the environment drops below 12 ° C, which is the average annual temperature, heat pumps engage which additionally cool the waste – exiting air and simultaneously heat up the fresh – incoming air so that no additional energy is required for ventilation purposes except the electric power for the heat pumps.

Given that the total annual amount of thermal energy required for the Aquae Vivae is 600 MWh, means that the required power is P = 69kW. This strength is gained from the energy of thermal water. The cooling down of 1m3 of thermal water at 41 ° C to 10 ° C, thermal energy in the amount of Te = 36 kWh is released. If thermal energy is released in one hour then the power that the energy emits into the premises is P = 36 kW. It follows that for the heating of Aquae Vivae’s water park energy needs to be subtracted from the water volume of 2 m³ per hour, that in return gives us a 72 kW thermal power.


During the time of the lowest outdoor temperature, which in Krapinske Toplice goes down to -20 ° C, a three times higher power than the average of 197 kW is needed. For this reason, in the AC chambers are built in heat pumps with a total heat output of 200 kW, that engage in levels of 20 kW, depending on the drop of the outdoor temperature.

The system is designed to use a floor heating plate for the heat generator (accumulator) in which 50 km of underfloor heating pipes are installed.

The floorboard is made of concrete, and has a mass of 5000 tons and a volume of 2700 m3.

It is heated during the night when the price of electricity is favorable, up to 33 ° C, and cooled during the day to 30 ° C. In this way, the heat energy is stored at the lowest place in the room, which ensures the circulation of the warm air by a natural way, from the floor to the roof where the air conditioning chambers take in the air and sent it back to the recuperation. With the opening of Aquae Vivae Park, we have made the living water of the Krapinske Toplice accessable to all our visitors.

We can proudly say that the Aquae Vivae water Park has no co2 emissions into the environment. In accordance with the slogan of Jakob Badla from 1867 it honorably serves the homeland and for the benefit of mankind.

Udaljenost do Aquae Vivae
  • Zagreb 50 km
  • Maribor 75 km
  • Celje 66 km
  • Beč 350 km
  • Graz 170 km
  • Munchen - 570 km
  • Trst 220 km
  • Aerodrom Zagreb - 59 km