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 %