Numerical Investigation of Combined Sensible/Latent Heat Thermal Energy Storage With Supercritical Carbon Dioxide As Heat Transfer Fluid at 650°C

2019 ◽  
Author(s):  
Kelly Osterman ◽  
Diego Guillen ◽  
D. Yogi Goswami
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Energy Storage ◽  
Supercritical Carbon Dioxide ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Storage ◽  
Storage System ◽  
Heat Transfer Fluid ◽  
Dry Air

Abstract This paper numerically explores a high-temperature sensible-latent hybrid thermal energy storage system designed to store heat with output temperatures stabilized at approximately 550–600 °C for direct coupling with supercritical carbon dioxide (sCO2) power cycles operating at their design point. sCO2 and dry air at 25 MPa are used as heat transfer fluid (HTF) in a packed bed storage system that combines rocks as sensible heat storage and AlSi12 as latent heat storage. The base model using dry air at atmospheric pressure is compared to similar work done at ETH Zurich; the model is then extended for use with sCO2 to compare the performance of air and sCO2 at similar volumetric flow rates. It was found that sCO2 is capable of storing a significantly larger amount of energy (∼40 kWh) in the same time period as the air system (∼19 kWh), and can discharge that energy much quicker (1.5 hours compared to 4 hours). However, in order to achieve similar degrees of temperature stabilization, the total height of PCM had to be increased significantly, from 9 cm to 45 cm or more.

Numerical Study of Thermochemical Storage Using Ca(OH)2/CaO: High Temperature Applications

2016 ◽  
Author(s):  
Qasim A. Ranjha ◽  
Nasser Vahedi ◽  
Alparslan Oztekin
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Numerical Study ◽  
Storage System ◽  
Packed Bed ◽  
Heat Transfer Fluid ◽  
Operational Parameters ◽  
Storage And Retrieval

Thermal energy storage by reversible gas-solid reaction has been selected as a thermochemical energy storage system. Simulations are conducted to investigate the dehydration of Ca(OH)2 and the hydration of CaO for thermal energy storage and retrieval, respectively. The rectangular packed bed is heated indirectly by air used as a heat transfer fluid (HTF) while the steam is transferred through the upper side of the bed. Transient mass transport and heat transfer equations coupled with chemical kinetics equations for a two dimensional geometry have been solved using finite element method. Numerical results have been validated by comparing against results of previous measurements and simulations. The effect of geometrical and operational parameters including the material properties on overall storage and retrieval process has been investigated. The co-current and counter-current flow arrangements for steam and heat transfer fluid have been considered.

Exergy-Based Optimization of Sub- and Supercritical Thermal Energy Storage Systems

2014 ◽  
Author(s):  
Louis A. Tse ◽  
Reza Baghaei Lakeh ◽  
Richard E. Wirz ◽  
Adrienne S. Lavine
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Heat Transfer Fluid ◽  
Energy And Exergy

In this work, energy and exergy analyses are applied to a thermal energy storage system employing a storage medium in the two-phase or supercritical regime. First, a numerical model is developed to investigate the transient thermodynamic and heat transfer characteristics of the storage system by coupling conservation of energy with an equation of state to model the spatial and temporal variations in fluid properties during the entire working cycle of the TES tank. Second, parametric studies are conducted to determine the impact of key variables (such as heat transfer fluid mass flow rate and maximum storage temperature) on both energy and exergy efficiencies. The optimum heat transfer fluid mass flow rate during charging must balance exergy destroyed due to heat transfer and exergy destroyed due to pressure losses, which have competing effects. Similarly, the optimum maximum storage fluid temperature is evaluated to optimize exergetic efficiency. By incorporating exergy-based optimization alongside traditional energy analyses, the results of this study evaluate the optimal values for key parameters in the design and operation of TES systems, as well as highlight opportunities to minimize thermodynamic losses.

scholarly journals Towards development of a prototype high-temperature latent heat storage unit as an element of a RES-based energy system (part 2)

2016 ◽  
Vol 64 (2) ◽  
pp. 401-408
Author(s):  
J. Karwacki ◽  
K. Bogucka-Bykuć ◽  
W. Włosiński ◽  
S. Bykuć
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Storage ◽  
Heat Transfer Fluid ◽  
Storage Unit ◽  
Latent Heat Storage ◽  
Shell And Tube

Abstract This paper presents an experimental study performed with the general aim of defining procedures for calculation and optimization of shell-and-tube latent thermal energy storage unit with metals or metal alloys as PCMs. The experimental study is focused on receiving the exact information about heat transfer between heat transfer fluid (HTF) and phase change material (PCM) during energy accumulation process. Therefore, simple geometry of heat transfer area was selected. Two configurations of shell-and-tube thermal energy storage (TES) units were investigated. The paper also highlights the emerging trend (reflected in the literature) with respect to the investigation of metal PCM-based heat storage units in recent years and shortly presents unique properties and application features of this relatively new class of PCMs.

scholarly journals PENGGUNAAN PARAFFIN WAX SEBAGAI PENYIMPAN KALOR PADA PEMANAS AIR TENAGA MATAHARI THERMOSYPHON

ROTASI ◽  
2016 ◽  
Vol 18 (3) ◽  
pp. 76 ◽  
Author(s):  
Muhammad Nadjib
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Storage ◽  
Paraffin Wax ◽  
Heat Transfer Fluid ◽  
Sensible Heat ◽  
Latent Heat Storage ◽  
Change Material

Pemanas Air Tenaga Matahari (PATM) konvensional umumnya menggunakan air sebagai penyimpan energi termal. Pemakaian sensible heat storage (SHS) ini memiliki kekurangan, diantaranya adalah densitas energinya rendah. Di sisi lain, latent heat storage (LHS) mempunyai sifat khas yaitu densitas energinya tinggi karena melibatkan perubahan fasa dalam penyerapan atau pelepasan kalor. Material LHS sering disebut phase change material (PCM). Penggunaan PCM pada PATM menarik dilakukan untuk meningkatkan densitas energi sistem. Penelitian ini bertujuan untuk menyelidiki perilaku termal penggunaan paraffin wax di dalam tangki PATM jenis thermosyphon. Penelitian menggunakan kolektor matahari pelat datar dan tangki thermal energy storage (TES) yang dipasang secara horisontal di sisi atas kolektor. Di dalam tangki terdapat alat penukar kalor yang terdiri dari sekumpulan pipa kapsul dimana di dalamnya berisi paraffin wax. Air digunakan sebagai SHS dan heat transfer fluid (HTF). Termokopel dipasang di sisi HTF dan sisi PCM. Piranometer dan sensor temperatur udara luar diletakkan di dekat kolektor matahari. Pengambilan data dilakukan selama proses charging. Temperatur HTF, PCM dan intensitas radiasi matahari direkam setiap 30 detik. Data ini digunakan untuk mengetahui evolusi temperatur HTF dan PCM. Berdasarkan evolusi temperatur ini kemudian dianalisis perilaku termal PATM. Hasil dari penelitian ini adalah bahwa paraffin wax telah berfungsi sebagai penyimpan energi termal bersama air di dalam tangki PATM jenis thermosyphon. PCM memberi kontribusi yang cukup signifikan terhadap kapasitas penyimpanan energi sistem. Efisiensi kolektor lebih optimal karena PCM dapat mempertahankan stratifikasi termal sampai akhir charging. Adanya PCM mampu mengendalikan penurunan efisiensi pengumpulan energi saat intensitas radiasi matahari menurun. Alat penukar kalor yang digunakan cukup efektif yang ditandai dengan kecepatan pemanasan rata-rata antara HTF dan PCM yang tidak berbeda jauh.

scholarly journals Experimental study of solidification of paraffin wax in solar based triple concentric tube thermal energy storage system

2018 ◽  
Vol 22 (2) ◽  
pp. 973-978 ◽  
Author(s):  
Rengarajan Ravi ◽  
Karunakaran Rajasekaran
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Solidification Process ◽  
Energy Storage System ◽  
Paraffin Wax ◽  
Heat Transfer Fluid ◽  
Thermal Energy Storage System

This paper addresses an experimental investigation of a solar based thermal energy storage system to meet current energy demand especially for milk industry in Tamil Nadu, India. A solar based energy storage system has been designed to study the heat transfer characteristics of paraffin wax where it is filled in the middle tube, with cold heat transfer fluid flowing outer tube, inner tube, and both tubes at a time during solidification process in a horizontal triple concentric heat exchanger. In this study, main concentrations are temperature distributions in the energy storage materials such as paraffin wax during solidification process and total solidification time. Three heat recovery methods were used to solidify paraffin wax from the inside tube, outside tube, and both tubes methods to improve the heat transfer between heat transfer fluid and phase change materials. The experiment has been performed for different heat transfer fluid mass-flow rates and different inlet temperatures and predicted results shows that solidification time is reduced.

Heat Transfer Analysis of a Low-Temperature Heat Pipe-Assisted Latent Heat Thermal Energy Storage System With Nano-Enhanced PCM

2018 ◽  
Author(s):  
Mahboobe Mahdavi ◽  
Saeed Tiari ◽  
Vivek Pawar
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Low Temperature ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Heat Pipes ◽  
Energy Storage System ◽  
Heat Transfer Fluid ◽  
Thermal Energy Storage System

In the current study, the thermal characteristics of a low-temperature latent heat thermal energy storage system are studied numerically. A cylinder container encloses a paraffin-based PCM, which is heated via a heat transfer fluid passing through a tube at the center. Heat pipes are incorporated into the PCM to enhance the heat transfer rate between the heat transfer fluid and the PCM. In addition, high thermal conductive nanoparticles are dispersed into the PCM to increase its thermal conductivity. A transient model is developed using ANSYS-FLUENT to simulate the charging process and study the impact of heat pipes and nanoparticles on the performance of the system. The effects of different parameters, such as the quantities of heat pipes as well as the nanoparticles types and volume fraction, are investigated.

Analysis of Transient Heat Transfer in a Thermal Energy Storage Module

2010 ◽  
Author(s):  
S. Kuravi ◽  
J. Trahan ◽  
M. M. Rahman ◽  
D. Y. Goswami ◽  
E. K. Stefanakos
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Cylindrical Tube ◽  
Transient Behavior ◽  
Axial Direction ◽  
Heat Transfer Process ◽  
Heat Transfer Fluid

The transient behavior of a thermal energy storage system was studied numerically. The storage system is composed of cylindrical tube containing the phase change material (PCM) surrounded by the heat transfer fluid (HTF) that flows along the axial direction of the tube. The melting of PCM was solved using specific heat capacity method. The heat transfer inside the tubes was analyzed by solving the energy equation, which was coupled with the heat conduction equation in the container wall. The velocity profile was obtained by solving the annular flow outside the tubes. The parameters that control the thermal behavior were identified. Several numerical simulations were performed to assess the effects of the Reynolds number on the heat transfer process of the system during the melting of a PCM.

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