Abstract
Industrial processes are highly dependent on large amounts of energy in the form of heat. This is traditionally delivered by steam or hot water heated in boilers using natural gas, oil, or biomass. High-temperature heat pumps (HTHPs) are a key technology in the transition towards sustainable energy systems. They may provide highly efficient electricity-based process heat contributing to the de-carbonization of the process industry. The implementation of HTHPs in industrial applications is limited by various operational, technological, and thermodynamic constraints. In contrast to boilers, the efficiency of HTHPs greatly increases when lowering the supply temperature. This yields potential economic savings by lowering the utility temperature of industrial processes. This paper aimed at quantifying the decrease in the levelized cost of heat when lowering the supply temperature of HTHPs. The main boiler was replaced by a HTHP, and the steam temperature was lowered. The changes in Coefficient of Performance (COP), Total Capital Investment (TCI) were observed for several HP cascade cycles, with natural working fluids, including water, hydrocarbons, and ammonia. The results showed that the price ratio between natural gas and electricity and the COP of the HTHP were the main factors for determining financial viability when comparing to a natural gas boiler. The operational cost of a HTHP used for hot utility decreases when lowering the utility temperature. Improved performance was observed for all HTHP configurations, however, it was highly sensitive to the COP and electricity price. A cascade HTHP using R-717 and R-718 as refrigerants delivered 160 ◦C steam at a levelized cost of heat (LCOH) of 46EUR/MWh with 30 ◦C as a source temperature. Varying the delivery temperature with 10 ◦C resulted in a change of 1EUR/MWh to 4EUR/MWh in LCOH depending on the technology and reference point. This indicated the significance of correct design temperatures for process heat supply.
| Original language | English |
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| Title of host publication | Proceedings of ECOS 2022 - The 35th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems 2022 |
| Number of pages | 12 |
| Publisher | ECOS |
| Publication date | 2022 |
| Publication status | Published - 2022 |
| Event | 35th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems - DGI-Byen, Copenhagen, Denmark Duration: 3 Jul 2022 → 7 Jul 2022 Conference number: 35 https://ecos2022.dtu.dk/ |
Conference
| Conference | 35th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems |
|---|---|
| Number | 35 |
| Location | DGI-Byen |
| Country/Territory | Denmark |
| City | Copenhagen |
| Period | 03/07/2022 → 07/07/2022 |
| Internet address |
Keywords
- Heat pumps
- Electrification
- High temperature
- Industry
- Boiler