NUMERICAL COMPARISON AND SIZING OF SENSIBLE AND LATENT THERMAL ENERGY STORAGE FOR COMPRESSED AIR ENERGY STORAGE SYSTEMS

2016-11-17
Compressed Air Energy Storage is a promising large-scale storage system in part because of its high power rating during discharge. But it is not the cleanest way of storing energy due to the necessity of an external heat source (typically the combustion of natural gas) to heat the air at the turbine inlet. This problem can be overcome with Thermal Energy Storage by storing the thermal energy of air at the compressor exhaust in order to be used for heating air before turbine. In this study, a numerical transient heat transfer model of Thermal Energy Storage is developed and the performance of Thermal Energy Storage is investigated based on heat storage capacity, required time to store unit amount of energy and air temperature profiles at the outlet of Thermal Energy Storage during discharge for the system. High heat storage per volume is necessary for more compact systems. Required time to store unit amount of energy is desired to be short for a fixed volume Thermal Energy Storage in order to maintain continuous operation; on the other hand, air at the outlet (turbine inlet) should be at a high temperature for the longest time possible to supply hot air to turbine. In order to investigate the effects of operating parameters, different volumes of Thermal Energy Storage tank filled with different storage mediums of various sizes are explored. Latent Heat and Sensible Heat Thermal Energy Storage systems are compared using magnesium chloride hexahydrate, paraffin, myristic acid and naphthalene as phase change materials and rock as sensible storage medium. Results show that Latent Heat Thermal Energy Storage gives a better performance than Sensible Heat Thermal Energy Storage. Among phase change materials, magnesium chloride hexahydrate provides the highest heat storage per volume. Required time to store unit amount of energy are comparable among the phase change materials. Magnesium chloride hexahydrate seems promising considering the discharge temperature profile at the Thermal Energy Storage outlet. Capsule size should be kept as small as possible which can be challenging in terms of manufacturing.

Suggestions

Numerical Comparison and Sizing Of Sensible ve Latent Thermal Energy Storage For Compressed Air Energy Storage
Kaya, Mine; Tarı, İlker; Baker, Derek Keıth (null; 2016-11-17)
Compressed Air Energy Storage is a promising large-scale storage system in part because of its high power rating during discharge. But it is not the cleanest way of storing energy due to the necessity of an external heat source (typically the combustion of natural gas) to heat the air at the turbine inlet. This problem can be overcome with Thermal Energy Storage by storing the thermal energy of air at the compressor exhaust in order to be used for heating air before turbine. In this study, a numerical trans...
Numerical investigation of bubbling fluidized bed to be used as high temperature thermal energy storage
Hiçdurmaz, Serdar; Tarı, İlker; Department of Mechanical Engineering (2017)
A thermal energy storage unit designed to be used in a solid particle concentrated solar energy system is analysed with the help of a commercial Computational Fluid Dynamics tool. Hydrodynamics of the bubbling fluidized sand bed of which dimensions are 0.28 m x 1 m x 0.025 m to be used as direct contact heat exchanger are modelled and validated. Geldart B type particles with diameter of 275 micron and density of 2500 kg/m3 are used in modelling of bubbling fludized sand bed. Syamlal O’Brien drag model with ...
Numerical comparison and sizing of sensible and latent thermal energy storage for compressed air energy storage
Kaya, Mine; Tarı, İlker; Baker, Derek Keıth; Department of Mechanical Engineering (2015)
Intermittent and variable characteristics of renewable energy systems can be compensated by energy storage systems (ESS). There is a wide range of ESS specialized for different applications. Compressed Air Energy Storage (CAES) is often used for wind power plants due to high power rating at the discharge and long discharge duration. CAES takes ambient air and pressurizes through a compressor and stores compressed air in a volume when supplied energy is greater than demand. If demand exceeds supply, CAES is ...
Numerical investigation of a stand alone solar hydrogen energy system effects of PEFC degradation
Ender, Ozden; Tarı, İlker (null; 2015-08-12)
An existing stand-alone solar energy system producing hydrogen for energy storage is numerically investigated focusing on the degradation of Polymer Electrolyte Fuel Cell (PEFC) and its effects on the overall performance of the system. The system consists of Photovoltaic (PV) panels, polymer electrolyte based electrolyzers, H2 and O2 storage tanks and a commercial PEFC stack. A PEFC is numerically investigated both as new and as degraded (for about two years). Using a variety of observed degradation pattern...
Proposal of a Novel Gravity-Fed, Particle-Filled Solar Receiver
JOHNSON, Evan; Baker, Derek Keıth; Tarı, İlker (2016-10-14)
Solar Thermal Electricity power plants utilizing solid particles as heat transfer and storage media have been proposed by several research groups, with studies citing benefits of increased thermal efficiency and lower cost. Several types of solid particle receivers have been proposed, with leading designs consisting of particles falling or suspended in air. A new solid particle receiver is proposed here, consisting of a receiver fully packed with particles flowing downward with gravity. Particle flow rate i...
Citation Formats
M. Kaya, İ. Tarı, and D. K. Baker, “NUMERICAL COMPARISON AND SIZING OF SENSIBLE AND LATENT THERMAL ENERGY STORAGE FOR COMPRESSED AIR ENERGY STORAGE SYSTEMS,” 2016, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/54353.