In 2020, the construction of the first mosque in Slovenia was completed – the Islamic Religious and Cultural Center in Ljubljana, designed by the internationally renowned Slovenian architectural firm Bevk Perović architects. The leadership of the complex, which includes a religious school, cultural and office programs, apartments, a restaurant and the central prayer area, aimed to minimize costs and achieve complete energy independence, which could only be achieved with heat pumps. In uncertain times, every saved euro in such a large facility makes a huge difference! Why not invest the saved money back into their activities instead of paying a high heating bill?


Facility size: 14,100 m2

Building construction: 2020

Type of facility: religious and cultural facility

No. appliances: 4 heat pumps Heat source: water/water

Application: heating, cooling, preparation of hot sanitary water

Additional: utilization of the waste heat of the cooling mode


The Islamic Religious and Cultural Center is not only an exceptional architectural achievement, but also a unique example of how smart heating and cooling solutions from our company, Kronoterm, can further contribute to the sustainability of the building, reducing its carbon footprint and operational costs. Below we present how this system was carefully thought out and optimized at every step.


Energy independence and cost minimization

But let’s start at the beginning. Why did the leadership of the Islamic Religious and Cultural Center decide to use the Kronoterm heat pump heating system? Because the building, constructed in 2020, is located in the center of the capital Ljubljana and should have been connected to the town’s district heating system, as planned by the local government. This would have been a “quick fix”, but the leadership of the Islamic Religious and Cultural Center wanted more, something that district heating could not provide: energy independence and cost minimization, which are much lower with the heat pump system.



In such large buildings as a mosque, even a small increase in the price of district heating energy can mean a significant increase in the operating costs of the building. This can be completely avoided with a heating system using heat pumps that exploit their own heat source from the surroundings – whether it be air, water, or the ground. By choosing Kronoterm heat pumps, the Islamic Center will have more money left over for conducting religious and cultural activities and supporting its community, while also providing maximum comfort to users.



The mosque is an excellent example of heating a larger building or complex of buildings without any fossil fuels, meaning that the building is not connected to district heating, and for heating and preparing hot water, it does not use gas or electric heaters – Kronoterm heat pumps take care of everything successfully.


4 Kronoterm heat pumps

In the almost 14,100 m2 mosque complex, four water-to-water heat pumps that exploit the heat from the groundwater take care of heating, cooling, and preparing hot water. The system is based on a pumping or suction well that pumps groundwater from an aquifer at a depth of about 30 meters, and a sinking well through which cooled water returns back to the aquifer.



Water-to-water heat pumps operate in an open system where water flows from one well to another. It is pumped from the pumping well, and cooled, uncontaminated or non-contaminated water is returned back to the underground aquifer through the sinking well.


The system designed for the Islamic religious and cultural center is a two-pipe system that allows for switching from heating to cooling and vice versa. The heat pumps prepare heating water with a temperature of up to 50 °C and sanitary water with a temperature of up to 60 °C, thus preventing the formation of Legionella in the TSV system. Since these are high-temperature heat pumps, it would be possible to heat the hot water to over 70 °C if necessary.


Smart heat pumps that adapt to the building

All four heat pumps are multi-compressor with the ability to adjust power according to the building’s needs. The advantage of using multi-compressor heat pumps is greater reliability of the entire system. The advantage of adjusting the power of heat pumps is greater efficiency of the system, as the operation of the heat pumps automatically adapts to the actual needs of the building – if there is a period of mild winter, the Kronoterm heat pumps will appropriately reduce their operating power compared to the period of the coldest winter. This subsequently means additional cost savings!



The system of four Kronoterm heat pumps is divided into three heating stations with a total nominal power of approximately 1265 kW. The first heating station is for the restaurant area, the second for the residential area, and the third for the central area with the main prayer hall. Depending on the surface area and requirements of each part of the building, the heating stations differ in their nominal power. In the restaurant area, the nominal power for heating is 75 kW, for cooling is 65 kW, and for preparing hot water is 60 kW. In the second, residential area, the nominal power for heating is 50 kW, for cooling is 45 kW, and for preparing hot water is 40 kW. The needs of the central area are the most demanding, so two heat pumps take care of this part of the complex. The first heat pump with a nominal power for heating of 280 kW and for cooling of 250 kW is solely responsible for heating and cooling, while the second one is also responsible for heating the hot water. The nominal powers of the latter are 145 kW for heating, 130 kW for cooling, and 125 kW for preparing hot water.


When you think that additional financial optimization is not possible… Kronoterm is here!

But the advantages of heating with Kronoterm heat pumps for the mosque have not yet ended. Kronoterm has demonstrated that even the best system can be further optimized and upgraded. This applies both to cost reduction and to the environmental friendliness of our systems. The Islamic Religious and Cultural Center proves that every building can always be even more environmentally friendly. Although heating with a heat pump is already one of the most environmentally friendly ways of heating, it is upgraded in the mosque building by utilizing waste heat from the cooling system in the summer and using it for heating hot water.


This makes the entire system perfectly harmonious, as it makes use of heat that would otherwise be wasted. What a brilliant solution! If the sanitary water is sufficiently heated and does not require further heating, and there is excess waste heat from the cooling system, the system is designed to return the waste heat to the environment via groundwater. This ensures maximum efficiency of the system.



The Peak Architecture

The Islamic Religious and Cultural Center is not only an exceptional building from an environmentally friendly, efficient, and optimized heating, cooling, and hot water system operating cost perspective, but also from an architectural aspect. The mosque, designed by the internationally renowned Bevk Perović Architects, is one of the architectural highlights of the last decade in Slovenia. This is confirmed by numerous awards received by the building, such as the Plečnik Award 2020 (the highest professional recognition for achievements in architecture), the ZAPS Golden Pencil Award for excellent execution in 2020, and a nomination for the prestigious Mies van der Rohe international architectural award. In 2023, the building was also awarded the Abdullatif Al Fozan Award, which selected the Islamic Religious and Cultural Center as one of the five award-winning mosques out of 200 around the world.


Why is the building so architecturally fascinating? First of all, the location of the building itself is fascinating, with its biggest feature being, according to the architects, that it is without any specific features. Although located just a stone’s throw from the town center, this area directly adjacent to the railway tracks had been degraded and abandoned for a long time. The realization of the Islamic Religious and Cultural Center was important not only for the Islamic community but also for the further urban and programmatic development of this part of the town. The complex is designed as a micro-urbanism of several independent buildings with different programs (a restaurant, residential building, central religious building, etc.) that surround a common square with a mosque in the center and are connected by an underground garage. Simple, white concrete volumes are covered by a lace-like steel structure reminiscent of abstract Islamic patterns. The interior of the central religious building is marked by a hanging dome woven from celestial blue textile.


We are proud that such a architecturally sophisticated and important building for the community is heated with our heat pumps.


If you want to heat and cool your commercial or industrial building in an ecological and economically favorable way, Kronoterm heat pumps are the right choice for you. For more information, contact us or write to us at

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