Large potential of high-temperature heat pumps
Discover the large potential of high-temperaure heat pumps and how to exploit it.
Acknowledged key technology
High-temperature heat pumps are industrial heat pumps with supply temperatures above 100 °C. They are able to provide heat at highest efficiencies while recovering excess heat and being driven by potentially emission free electricity. Due to the high performances, high-temperature heat pumps are expected to have the most optimal techno-economic performances for a wide range of process heating applications at temperatures far above 100 °C.
These aspects caused high-temperature heat pumps to become an acknowledged key-technology for the transition towards sustainable proces heating. The Danish Counsil on Climate Change has analyzed the pathways for reaching the 70 % CO2 reduction goals in Denmark and suggested that 25 % of the CO2 reductions expected from the Danish industry are to be reached by implementing industrial heat pumps for providing 15 PJ/year. Considering the temperature requirements of the Danish industry, it becomes apparent that this corresponds to a considerable demand for high-temperature heat pumps. The International Energy Agency (IEA) has recently confirmed the large demand for high-temperature heat pumps by the Net Zero by 2050 Roadmap. The report suggested the low/medium-temperature heat demand (up to 400 °C) to be covered by 15 % in 2030 and 30 % in 2050 by high-temperature heat pumps.
These numbers indicate a considerable number of high-temperature heat pumps to be installed in industrial high-temperature application towards 2030. Enabling to cover this high number of applications requires not only the availability of various technical solutions, but also solutions for applications on different integration levels. High-temperature heat pumps have the ability of being applicable close to the production process or further outside on utility or sector level. Both approaches imply several advantages and disadvantages - illustrated below.
Trade-off for integrating high-temperature heat pumps at different integration levels.
Integration at process or unit level
Integrating industrial heat pumps on process or unit level is a promising approach for reaching high performances due to no losses in heat distribution networks. In turn, the heat pump is very dependent on the process dynamics and often subject to varying operating conditions, including part-load and off-design operation. Depending on the specific process, special challenges for the heat exchanger equipment can arise. Furthermore, integration at process level is often subject to tough investment criteria such as low payback times. Overcoming the challenges on process level requires the development of sophisticated process integration systems including buffer tanks and an advanced control integration. To satisfy the investment criteria, the solutions should be based on cost-effective standard solutions such as semi-hermetic compressors produced in large volumes.
Integration at utility or sector level
High-temperature heat pumps can also be integrated further outside the core processes, i.e. on utility level or at sector level. The further outside the integration is realized, the higher the losses are associated with heat distribution networks and required temperature differences, i.e. lower overall efficiencies in standard operation. In turn, heat pumps at utility and sector level are benefiting from more balanced loads from higher number of processes. Furthermore, larger equipment with higher efficiencies and lower specific investment cost may compensate the losses from the heat distribution network from a techno-economic perspective.
Integrating high-temperature heat pumps on utility or sector level has the advantage of requiring no modifications of existing processes and thereby gain higher acceptance from industrial end-users. From an economic aspect, it may be noted that investments on utility level are based on longer planning horizons and may be accepted with larger payback times. However, in order to enable effective integration on utility level, heat recovery and process integration are inevitable.
In the context of this project, sector integration with district heating is found to have a high potential. Integrating district heating by a local high-temperature heat pump to boost the heat from the district heating network to temperatures suitable for process heat demands allows making advantage of the load balancing possibilities implied by the district heating network. Furthermore, the district heating company, which would own and operate the heat pump, can provide local clusters of several heat consumers or industrial symbiosis while recovering heat or providing cooling from other customers. This approach has the potential to facilitate the sector integration between district heating and cooling, while exploiting the synergies between local industries.
Development accelerates market introduction
The degree of freedom arising from the various applications for high-temperature heat pumps as well as the large market potential increase the need for a variety of technical solutions, including competing alternatives and redundancy in supply chains. In this context, it is expected that the development and market introduction of high-temperature heat pumps can be accelerated by developing:
- Competing high-performance technologies and redundant supply chains
(OEMs, system integrators, …) - Standard solutions for different integration levels facilitating uptake in
brownfield applications - Business models for accelerating the integration of high-temperature
heat pumps in industry and facilitating sector integration.