Modelling of a large scale High-Temperature Thermal Energy Storage System

Student thesis: Master thesis (including HD thesis)

  • Kristian Kristensen
  • Søren Søndergaard Batz
4. term, Energy Engineering, Master (Master Programme)
The share of the Danish energy demand covered by renewables has increased steadily since the 1990's.
Because of this, energy storage is becoming a more viable solution for peak shaving and a key component for transitioning to renewable power generation.

Thermal Energy Storage (TES) utilises a packed bed of rocks to store high temperature thermal energy originating from fluctuating sources such as wind power. When needed, heat is extracted and converted to electricity using a steam Rankine cycle.

A TES resembling a cone section is dynamically modelled to investigate the heat transfer- and pressure loss characteristics. A parametric study is conducted to identify the governing parameters of the TES performance. Two steam Rankine cycles are modelled as a part of the auxiliary system to identify efficiencies and heat exchanger areas.

It is concluded that a TES with a volume of 175,000 m3 effectively utilises only 40.5% of the storage volume. A rock diameter of 3 cm is selected as the optimum size.

Energy and exergy efficiencies for thermal cycling of the TES are, for most cases, above 98%.

A single pressure steam Rankine cycle is able to produce 35.34 MWel at a discharge rate and temperature of 221.2 kg/s and 873 K respectively, with an energy efficiency of 32.2%.
SpecialisationThermal Energy and Process Engineering
LanguageEnglish
Publication date14 Jun 2017
Number of pages111
ID: 258801774