Dynamic modelling of the operating behaviour of adiabatic compressed air energy storage systems
Escrivà García, Ricard Enric (2022)
Diplomityö
2022
School of Energy Systems, Energiatekniikka
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2022120269205
https://urn.fi/URN:NBN:fi-fe2022120269205
Tiivistelmä
The present master thesis presents a simulation model for an adiabatic compressed air energy storage system based on the existing Huntorf facility in Germany. The model comprises a 100MW compression powertrain, a thermal energy storage, a 220MW expansion train and an underground salt cavern. Both compression and expansion trains are formed by two-stage axial turbomachinery, with the compression drive having an intercooler in between the two units. The thermal energy storage technology chosen is a packed bed, which is heated directly by convection from the compression air.
The A-CAES model simulated has three different operating phases during a cycle: compression, idle and expansion. In this work, the cycles have been chosen to have a duration of 24h hours and have been simulated without interruption to assess the behaviour of the system during several consecutive cycles. A single cavern, capable of storing energy in the order of gigawatt days (GWd) will store the air under pressures ranging from 46 to 72 bar. The thesis aims to compare the operational behaviour of an adiabatic compressed air energy storage plant under two different discharge modes. In addition, a loss analysis has been be carried out to determine which components yield the higher energy losses during operation.
Results show that the variable expansion ratio mode can provide higher turnover efficiencies of 1.1% for the start-up cycle and 0.4% for stable operation. The loss analysis performed reveals that turbomachinery entails the highest contribution, followed by the heat exchanger and the thermal energy storage. This loss distribution is maintained for all discharge modes and all cycles.
The A-CAES model simulated has three different operating phases during a cycle: compression, idle and expansion. In this work, the cycles have been chosen to have a duration of 24h hours and have been simulated without interruption to assess the behaviour of the system during several consecutive cycles. A single cavern, capable of storing energy in the order of gigawatt days (GWd) will store the air under pressures ranging from 46 to 72 bar. The thesis aims to compare the operational behaviour of an adiabatic compressed air energy storage plant under two different discharge modes. In addition, a loss analysis has been be carried out to determine which components yield the higher energy losses during operation.
Results show that the variable expansion ratio mode can provide higher turnover efficiencies of 1.1% for the start-up cycle and 0.4% for stable operation. The loss analysis performed reveals that turbomachinery entails the highest contribution, followed by the heat exchanger and the thermal energy storage. This loss distribution is maintained for all discharge modes and all cycles.