Lendava mesto
3G network
            Facts at one glance
        
        
            
                Status of the project:
            
            Commercially operating
        
        
            
                Operation mode:
            
            Heating network
        
        
            
                Geothermal source:
            
            Medium Depth Geothermal
        
        
            
                Max heat capacity:
            
            1MW - 5MW
        
        
            
                Network generation:
            
            3G
        
        
                
                    Year of operation start:
                
                2007
        
        
            
                Contact:
            
            evgen.torhac@petrol.si
        
    
            Description of the project
        
        
            District heating of Lendava with geothermal energy covers the heating needs of several residential blocks with approx. 610 apartments and several public and other buildings, such as: a health center, a bilingual primary school and a bilingual secondary school, the Mlinska business complex, the Ledava shopping center, the Lendava theater and concert hall, and Cubis Hotel. The total heated area is approx. 60,000 m2.
        
    
                Highlights of the project
            
            
                Geothermal district heating system is built and is operated succesfully with specific, innovative solutions.
Geothermal water flows through heat exchangers with temperature up to 66 °C and transfers heat to secondary medium. Operating heating mode is 60/40 (40 °C is a return T from the users).  
High temperature geothermal heat pump and gas boilers are used for peak load covering. The heat source for high temperature geothermal heat pump is geothermal water after flowing through heat exchangers.
            
        
                The biggest challenges / obstacles
            
            
                Economical utilization of geothermal district heating system with low-temperature geothermal water and relative low (up to 60C)inlet temperature to the radiators.
            
        Detailed characteristic of the project
        Site description
    
        
                Address
            
            
                Mlinska ulica 5, 9220 Lendava, Slovenia
            
        
                Status of the project
            
            
                Commercially operating
            
        
                Year of operation start
            
            
                2007
            
    
                Type of geothermal Heating / Cooling network
            
            
                Heating network
            
        
                Type of geothermal technologies involved
            
            
                Medium Depth Geothermal
            
        
                Are heat pumps used within this project?
            
            
                yes - heat pumps to supply the network
            
        
                Heating network generation
            
            
                3G
            
        
                Number of clients supplied
            
            
                100 - 1000
            
        
                Depth range
            
            
                800-1200
            
        
                Temperature range
            
            
                62-67
            
        
            Involved companies
        
            
                    Owner / operator
                
                
                    Petrol d.d.
                
            
            Types of used geothermal sources
        
        
                Source
            
            
                Depth range
            
            
                Temperature range
            
            
                Purpose
            
        
                Deep aquifers / thermal water - open loop
            
            
                400 - 1500 meters
            
            
                50°C - 80°C
            
            
                Heat extraction
            
        
        System design
    
        
                Heat sources included in the network
            
            
                Bivalent - geothermal is combined with other another heat source (e.g. peak load supply)
            
        
                Max heating capacity supplied by geothermal energy
            
            
                1MW - 5MW
            
        
                Share of geothermal energy
            
            
                80% - 90%
            
        
                Annual operation hours for heating
            
            
                4000 hours - 7000 hours
            
        
                Annual heating production
            
            
                5 GWh - 20 GWh
            
        
                Annual heating production share
            
            
                80% - 90%
            
        
                Energy conversion factor linked to the use of geothermal energy
            
            
                > 20
            
        
                Heat source for peak load supply
            
            
                Fossil fuels
            
        
                Has backup system?
            
            
                Yes
            
        
                Share of fossil fuels for annual gross heat production
            
            
                10 % - 50 %