Using a high -temperature heat pump for heating greenhousesSarajlić, Almina (Avtor) Avsec, Jurij (Avtor) Novosel, Urška (Avtor) geothermal high- temperature heat pumpgreenhouse heatinggreenhouseheat lossesrenewable energy sourcesGreenhouse heating is associated with high energy consumption and operating costs, particularly during winter conditions. This study investigates the application of a geothermal high-temperature heat pump for greenhouse heating in northeastern Slovenia. A case study greenhouse used for rose cultivation was analysed, to determine heat losses, heating demand and economic feasibility. The heat loss calculations were performed using the greenhouse geometry, the thermal properties of double-wall polycarbonate panels, and the minimum outdoor temperatures recorded between October 2023 and April 2024. The results showed that the maximum heating demand reached 91.31 kW, exceeding the capacity of the existing 80 kW electric heater. Consequently, a Thermeco2 HHR180 high-temperature heat pump was selected, with a heating capacity of 130 kW and a coefficient of performance (COP) of 4.78. An economic analysis indicated annual savings of €29,143.07 and a payback period of 6.55 years. The findings confirm that high-temperature heat pumps represent a technically feasible and economically viable solution for improving energy efficiency and sustainability in greenhouse production.University of Maribor, University of Maribor Press20262026-07-16 08:58:25Znanstveno delo98900UDK: 621.577:631.344.8COBISS_ID: 285004035DOI: 10.18690/jet.19.1.53-68.2026ISSN pri članku: 1855-5748sl