Large-scale heat pumps in Europe : a review of the status quo and the competitiveness of different heat sources

Abstract

Large-scale heat pumps are regarded as a key technology for decarbonizing district heating systems. This work investigates the current status and potential contribution of large-scale heat pumps (LSHP) in European district heating systems under varying conditions of heat source availability and technology portfolios. The core objective is to assess the techno-economic viability of LSHP, particularly focusing on different refrigerants, sizes, and climate conditions.The methodology involves the creation of a database for large-scale heat pumps to assess their current status in terms of various parameters like size, location and temperature levels. It is followed by a scenario development using a district heat supply model. The data collection indicates that the installation of large-scale heat pumps has grown rapidly in recent years,along with an increasing diversity of heat sources in EU member states. Out of the simulated portfolios, large-scale heat pumps can cover from 47% to 68% of the total heat demand under various conditions when industrial process heat is used as a heat source, while this share is more fluctuating for ambient heat sources. Their economic viability is heavily influenced by the type of refrigerant and the scale of implementation, with larger heat pump units having significant economies of scale effects. Additionally, climatic conditions play a crucial role, with southern and central European climates showing higher efficiency and utilization rates compared to northern Europe. In conclusion, large-scale heat pumps are a promising technology for covering a high share of the heat demand in district heating systems undercurrent conditions. Apart from the impact of electricity prices, which is not a focus of this thesis, their competitiveness depends on optimizing the choice of refrigerants, utilizing economies of scale, and diversifying heat sources to ensure reliability under specific climatic conditions.