High-temperature heat pumps

Overview of the status and impact of the innovation



High-temperature heat pumps (HTHPs) can deliver heat at temperatures between 90°C and 150°C (Arpagaus et al., 2018), although there is no consistent definition of an HTHP. 10 Research efforts are currently underway to increase HTHPs’ temperature range to up to 200°C (de Boer et al., 2020).


It is crucial to make HTHPs commercially available because that will allow electrifying many more applications, especially in industry. Since many industrial processes require temperatures above 100°C, heat pumps that can deliver heat above 100°C will be able to electrify a large share of the industrial demand. In Europe, for example, industry would be able to meet 26% of the total EU process heat demand (or 508 terawatt hours/year) using heat pumps (de Boer et al., 2020). Figure 6.4 shows the industrial processes that might be electrified using heat pumps. For many processes, such as pasteurisation and drying, electrification also leads to important energy savings. So far, however, HTHP technology is not considered mature and only a limited number of suppliers exist.

BOX 6.2 Marienhütte steel and rolling mill

The Austrian steel and rolling mill Marienhütte in Graz, Austria, installed two large heat pumps that can supply heat at up to 95°C with a heating capacity of 6-11 MW. As a source, the pumps utilise the mill's waste heat at a temperature of 30°C to 35°C, using energy that would otherwise be dissipated to the environment. The heat pumps enable the mill to avoid using 46 GWh each year from fossil fuels, thereby reducing annual CO2 emissions by 11 700 tonnes (de Boer et al., 2020).


Innovation 2
Source: (Sauer, 2018).

FIGURE 6.4 Temperature ranges for different industrial processes and heat pumps

Source: (Arpagaus et al., 2018).
Notes: HP = heat pump; HTHP = high-temperature heat pump; VHTHP = very-high-temperature heat pump.

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