The hot springs with their hyperthermal water are a gift of nature to Krapinska Toplica. The water temperature is 41°C, chemicaly they are characterized by calcium, magnesium and hydrocarbonate, the ph is neutral. The first chemical water analysis in Krapinska Toplica and the comparison of that water with the thermalwaters of Europe was completed in 1858.

Comparisons were made with Bad Gastein (Austria),  Beins-les Bains (France), Johhanisbad (Czech Republic),  Bad Liebenzell (Germany), Bag Ragatz ―at that time called Pfäffers Bad―  (Switzerland), Schlangenbad (Germany), Warmbrunn (Poland), Wildbad (Germany). *springs: “Krapinska Toplica, their hot springs and baths,” author dr. Dominik Bancalari, 1871.

Among this “high circle” of spas are to be found the waters of Krapinska Toplica, already then known for it’s quality.  The waters of Krapinska Toplica have shown themselves to be especially suited for rheumatism, illnesses of the backbone, neuro-musculature problems, diabetes with complications in the joints, post-traumatic conditions before and after orthopedic, surgical and neurosurgical procedures on the motoric functions of the body, cardiovascular illnesses and illnesses of the periphery blood vessels, and for the improvement of post-stroke and post-surgical conditions.

Primarily the water is suitable for keeping oneself healthy and vital.

Our desire was to enrich the offers to tourism, and health tourism in Krapinska Toplica, and so we built the Aquae Vivae water park.

When the Romans passed through this region and noticed the water of the hot springs welling up from the ground and found it to be crystal clear and drinkable, they named it Aquae Vivae, The Living Waters.

The living waters of Aquae Vivae, touch each and every visitor. They pass on their power, energy, and warmth; and due their ph value (which average 7,3 – 7,7 on the PH scale) create a harmony of body and water. They have therapeutic properties and it has been proven that they slow down the ageing process.

The thermal water, besides fulfilling it’s basic role, ensures the well being of the human body.

Here at Aquae Vivae we have set ourselves the undertaking of ensuring that the thermal water, as it passes through the premises of the water park, transfers its thermal energy to our visitors, and not to the ambient environment. We have designed the water park in such a way that it is very high in energy efficiency.  All the energy required for heating the premises is taken directly from the hot springs themselves, as is the electrical energy needed to pump the heat throughout the complex. The premises has a total of 18.000 m² of which  9.000 m² is heated indoor area, and 9.000 m² is unheated outdoor – the technical premises and the terrace.

The primary construction goal that we wanted to achieve was the building of a complex with an integrated thermal insulation which ensures very low thermal conductibility. The insulation of the outer walls was designed in such a way as to achieve a high very coefficiency in the passing of warmth through the wall’s material. This coefficiency is = 0,26 W/m²K.

On the vertical walls we have 60mm thick glass bricks, with a coefficiency of: 0,9 W/m²K.

The roofs are made up of a laminated wood construction and are insulated in such a way that they have a coefficency of: 0,2 W/m²K. The glazed areas of the roof are designed with  triple-glazing  to lower emission so that the coefficiency of the passing of heat in that part of the roof is 1,1 W/m²K.


Krapinske Toplice has an average yearly tempeature of 12 °C, and the average temperature inside the water park is 28°C.


Basic data of the water park Aquae Vivae:

– the surface of the outer walls is 1.600 m² – Pvz =1600 m²

– the surface of the glass bricks on the outer walls is 800 m² –  Psvz=800 m²

– the surface of the roof is 8.200 m˛ –  Pk = 8.200 m²

– the surface of the glazed covered parts is 800 m² – Pksd= 800 m²

The average yearly difference in temperature is 16 ° C.


The total yearly energy (gE) necessary for heating, excluding the ventilation of the premises, is:

gE= (Uwall x Pvz+ Uglass x Psvz+Uroof x Pk +Uroof glass x Pksd) x ΔT x 365  x 24

gE= 595.942.800 Wh

The total yearly energy necessary for the heating of the water park  is 600 MWh.

The ventilation system on the premises was designed and built in such a way that the integrated air conditioning chambers can recuperate energy, they also contain heat lifters. The recuperators were set up in such a way that with the air flow set at a speed of 2 m/s, and the yearly average difference in temperature being only 16 °C, we can have a usability parameter of η=0,79.

When the ambient temperature drops below 12 °C (the yearly average temperature) the heat lifters are turned on, which cools down the outgoing ―waste― air, whilst, at the same time, heating up the incoming ―fresh― air.  So that, for the ventilation, there is no additional energy required beyond the electrical energy needed to operate the heat lifters.

The total yearly amount of thermal energy that is necessasry for the Aquae Vivae water park, 600 MWh, means that the necessary power is P = 69kW.  That power is obtained from the energy of the thermal water.  In the process of cooling down 1 m3  of thermal water from 41°C to 10 °C there is an extrication of thermal energy to the value of Te = 36 kWh. If thermal energy released in one hour is equal to the power of energy that is emitted into the room, this means that P=36 kW. It follows that for the heating of the Aquae Vivae water park, it is necessary to extract the energy from 2 mł of water per hour, in order to give out a thermal energy of 72 kW in power.

During the times when the ambient temperatures in Krapinska Toplica drop to -20°C, the power requirements are three times the average, in other words 197 kW of power. For this reason heat lifters were built in to the air conditioning chambers with the total amount of 200 kW of power.  These are activated gradually, by increments of 20 kW, and they increase in accordance with the fall of the ambient temperature.

The system works in such a way that the heating condensators (accumulators) use the bottom plate of the water park in which 50 km of pipes were built-in for under-floor heating.

The bottom plate 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 prices for electrical energy are at their lowest) to a temperature of 33°C, and during the day it cools off to 30°C.  This way the thermal energy is stored at the lowest part of the premises which ensures the natural circulation of hot air from the floor to the ceiling, where the the air conditioning chambers suck in the heated air and transport it to the previously mentioned recuperators.

With the opening of the Aquae Vivae water park we have brought close the living waters of  Krapinske Toplice to all our visitors.

We can confidently say that the Aquae Vivae water park releases no co2 emissions into the atmosphere, that it is environmentally friendy, and in line with the slogan of Jakob Badl from 1867, “Serve your homeland honourbly, and also for the benefit of mankind.”

In Krapinske Toplice  17.04.2015.