Integration at sector level
A casade system using butane and water is used for process heat supply by upgrading heat from district heating.
The second high-temperature heat pump system developed in the project is a cascade system using butane and water with open industrial compressors for supply temperatures up to 160 °C. The system is used to upgrate heat from district heating for process heat supply, and the industrial compressor types can cover applications of several megawatts. The heat demand at the industrial process heat consumers can mainly be covered with hot water and steam at temperatures up to 160 °C, while higher temperatures are expected to be lowered on the customer side by process integration and optimization
First industrial demonstration of compressors
The demonstration system will be based on a cascade system consisting of a hydrocarbon bottom cycle with a steam compression cycle on top. The compressors will be industrial compressors from SRM. The compressor for the hydrocarbon cycle will be a modified and optimized version of their standard portfolio, and the solutions will be able to extend their entire capacity range to higher temperatures. The steam compressor is based on multi-year developments of their screw compressors for steam applications. This will be the first industrial demonstration as the first tests in laboratory environment har recently been finalized.
The system will be designed for a heat supply capacity of 1.3 MW to 1.5 MW (dependent on supply temperatures), and the final application capacities lies between 1 MW and 15 MW to be integrated on utility or sector level.
Challenges
This cascade system consisting of a hydrocarbon and a steam cycle are subject to the same challenges as the pure hydrocarbon cascade system integrated at process level. Additional challenges arise from the applications as this system will be operated by a district heating operator, providing heat to industrial consumers. This means that the consumer demands are controlled independently of the heat pump, which increases the need for a sophisticated load balancing and control system to maintain system operation at high efficiencies even for varying loads.
The choice of heat exchanger poses another challenge as the heat exchanger design must ensure sufficient velocities as an optimal compromise between pressure drop, heat transfer coefficients, and oil return. These challenges will be adressed in the project.
Demonstration principle at sector level
The principle behind this high-temperature heat pump system is to use a standard compressor, which is modified and optimized for butane and higher temperatures, and a special screw compressor for steam for the high-temperature stage.
Overview of heat pump integration at utility / sector level.
Potentials of integration at sector level
In addition to the development of the heat pump technologies, there will be a dedicated focus on developing solutions which enable the full exploitation of sector integration benefits. This includes solutions for heat recovery and supply of process cooling as well as load balancing through the district heating network. The potentials of sector integration, and thereby the resulting business models, will be demonstrated and analyzed as a basis for facilitating the wide application of high-temperature heat pumps.
The main developments of the system include:
- Flexible HTHP System for supply of hot water and steam
- Industrial compressors from SRM
- System by Verdo with support from Multi Køl og Energi
- Demonstration capacity: 1.3 MW to 1.5 MW (dependent on supply temperatures)
- Application capacity: 1 MW to 10 MW
- Process integration ensuring highest efficiencies and load balancing
- Simultaneous heat recovery and supply
- Demonstration of sector integration