Advances in high-temperature heat pump technologies for industrial process applications with large temperature glides: assessing the potential for carbon dioxide as a refrigerant

Kurzfassung

Industrial process heat users face great uncertainty due to the cost and complexity of transitioning to renewable energy sources. High-temperature heat pumps offer a promising solution due to the high COPs that can be achieved compared to electric heating. However, it can be difficult to identify which heat pump systems are most suitable for which applications. This is particularly true for transcritical heat pumps where the temperature glide in the gas cooler (equivalent to a condenser) is very high. This paper aims to quantify the potential decarbonisation impact that could be realised from the development of new CO2 high-temperature heat pump cycles with large temperature glides (>100 °C). To this end, this study identifies potential process applications, including suitable sink and source streams to supply the heat pump system, and discusses the opportunities and barriers for HTHP implementation. Thermodynamic models of three CO2 heat pump cycles were used to estimate the COPs and the carbon abatement potential for the identified applications. Drying applications such as for producing milk powder, starch and instant coffee, were identified as suitable applications and the COPs estimated based on the required process temperatures and available waste heat.