Geothermal heat pump for tomato greenhouse in Renkovci
Overview
Greenhouses require a large amount of energy to create the adequate environment needed for food production. For instance, particular heat and humidity conditions are required for tomatoes such as the Lust variety grown by the Slovenian producer Paradajz d.o.o.. Since 2013, the greenhouse in Renkovci, Prekmurje, Slovenia uses geothermal heat to generate a significant amount of its required heat.
In 2018, geothermal use has been expanded even further with a geothermal heat pump to cut natural gas uses short and thereby reducing CO2 emissions by up to 50% and cutting costs of up to 72%. Additionally, the geothermal heat pump does not only heat the greenhouse but also provides cooling to the tomato storage, which lowered the investment costs considerably as no cooling device had to be installed. Furthermore, waste-heat from the storage can be re-used for the greenhouse itself.
The Heat Pump
Operated by KRONOTERM, the geothermal heat pump is the biggest of its kind in Slovenia. Its development started in 2017 and since 2018 the heat pump has been installed. It uses wastewater at 30/40 °C and reaches an end temperature of 65-80 °C. It has high efficiency with 2 MW which can be compared to the heat demand of 400 low-energy houses. Further, the working efficiency varies between 5.1 and 6.0, meaning one unit of electricity results in 5-6 units of heat energy. Consequently, the installation became financially viable after just one year, also due to high heating costs of other heater sources.
Summary
Year of commissioning: 2017
Power production: since 2018
Heat production capacity: 2 MW
Operator: KRONOTERM
Well depth: 1483 m
Temperature: 65-80 °C
Emission reduction: at least 50%