scholarly journals Two-Dimensional Model of a Space Station Freedom Thermal Energy Storage Canister

1994 ◽  
Vol 116 (2) ◽  
pp. 114-121 ◽  
Author(s):  
T. W. Kerslake ◽  
M. B. Ibrahim
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Free Convection ◽  
Phase Change ◽  
Thermal Energy ◽  
Heat Engine ◽  
Space Station ◽  
Working Fluid ◽  
Two Dimensional ◽  
Liquid Salt

The Solar Dynamic Power Module being developed for Space Station Freedom uses a eutectic mixture of LiF-CaF2 phase-change salt contained in toroidal canisters for thermal energy storage. This paper presents results from heat transfer analyses of the phase-change salt containment canister. A two-dimensional, axisymmetric finite difference computer program which models the canister walls, salt, void, and heat engine working fluid coolant was developed. Analyses included effects of conduction in canister walls and solid salt, conduction and free convection in liquid salt, conduction and radiation across salt vapor-filled void regions, and forced convection in the heat engine working fluid. Void shape and location were prescribed based on engineering judgment. The salt phase-change process was modeled using the enthalpy method. Discussion of results focuses on the role of free convection in the liquid salt on canister heat transfer performance. This role is shown to be important for interpreting the relationship between ground-based canister performance (in 1-g) and expected on-orbit performance (in micro-g). Attention is also focused on the influence of void heat transfer on canister wall temperature distributions. The large thermal resistance of void regions is shown to accentuate canister hot spots and temperature gradients.

Comparison of Thermal Performance of 3D Printed Shell and Tube Heat Exchanger With Commercial Plate Heat Exchanger for Thermal Energy Storage (TES) by Incorporating Phase Change Materials (PCM)

2020 ◽  
Author(s):  
Ashok Thyagarajan ◽  
Nandan Shettigar ◽  
Debjyoti Banerjee
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Heat Exchanger ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Working Fluid ◽  
Temperature Differential ◽  
Shell And Tube ◽  
Dry Cooling

Abstract Wet cooling is predominantly used in thermoelectric power plants for condensing steam from the turbine owing to their low system cost and for their ability to render lower turbine back pressure (in comparison to dry cooling). However, the implementation of wet cooling in arid regions is costly while implementation of dry cooling in arid regions can degrade operational reliability (while also increasing both capital costs and operational costs). As a result, alternate technologies are needed to wean power plants from using fresh water resources while also enhancing the operational reliability of dry cooling. Air cooled heat exchangers installed in arid climates are inoperable on certain days during summer as the ambient air temperature can exceed the temperature of the steam at the turbine exhaust and may lead to power plant shutdown, in-turn, causing instability in the electric supply grid infrastructure (thus compromising reliability). In order to combat these shortcomings, supplemental cooling options may be needed. Thermal Energy Storage (TES) platforms can provide an attractive option for supplemental cooling. Phase Change Materials (PCM) are often used as viable options for Latent Heat Thermal Energy Storage Systems (LHTESS) as they have small footprint owing to the high latent heat values of PCM. The objective of this study is to analyze the performance of various LHTESS platforms by utilizing different configurations of the Heat Exchangers (HX) that are filled with PCM. The scope of this study is limited to using an organic Phase Change Material (PCM) and two different HX configurations are explored in this study: (a) a Shell and Tube Heat Exchanger that was fabricated using Advanced Manufacturing (AM) technique (i.e., “3D Printing”); and (b) a conventional Chevron Plate Heat Exchanger (PHX) that was procured commercially from a vendor. The thermal response and performance characteristics (e.g., power rating and HX effectiveness) of the two HX configurations are measured experimentally in order to ascertain their efficacy for melting and solidification of the PCM for different flow rates and inlet temperature values of the working fluid. The working fluid is called the Heat Transfer Fluid (HTF). The HTF used in this study is tap water. The PCM used in this study is PureTemp 29 (commercially procured from Pure Temp Inc., Minneapolis, MN). The propagation of the melt and the freeze fronts were monitored and tracked based on the nature of the transient temperature profiles recorded by an array of thermocouples. The array of thermocouples were strategically mounted at different locations within the HX containing the PCM. For the 3D-Printed HX (Shell and Tube HX), the thermocouples were located at different radial and axial locations within the shell containing the PCM. For the PHX, the thermocouples were located at different heights (for different plates containing the PCM). The transient values of the power and capacity ratings for the HX were estimated based on the time-history of the transient values of the temperature differential for the bulk temperature of the HTF flowing between inlet and outlet ports of the HX (and this was correlated with the transient profile and location as well as the propagation of the solid-liquid interface within the HX). The performance characteristics of both HX, analyzed from the experimental data, show that the average power rating for the melting-cycle is consistently higher than that of the solidification-cycle due to the dominance of free convection during melting (resulting in higher values of the effective heat transfer coefficients for the same temperature differential values); while the solidification process is dominated by transient conduction (resulting in lower values of the effective heat transfer coefficients for the same temperature differential values).

scholarly journals Analysis of Thermal Energy Storage Material With Change-of-Phase Volumetric Effects

1993 ◽  
Vol 115 (1) ◽  
pp. 22-31 ◽  
Author(s):  
Thomas W. Kerslake ◽  
Mounir B. Ibrahim
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Space Station ◽  
Two Dimensional ◽  
Transfer Resistance ◽  
One Dimensional ◽  
Thermal Energy Storage Material ◽  
The One

NASA’s Space Station Freedom proposed hybrid power system includes photovoltaic arrays with nickel hydrogen batteries for energy storage and solar dynamic collectors driving Brayton heat engines with change-of-phase thermal energy storage (TES) devices. A TES device is comprised of multiple metallic, annular canisters which contain a eutectic composition LiF-CaF2 phase change material (PCM) that melts at 1040 K. A moderately sophisticated LiF-CaF2 PCM computer model is being developed in two stages considering first one-dimensional and then two-dimensional canister geometries. One-dimensional model results indicate that the void has a marked effect on the phase change process due to PCM displacement and dynamic void heat transfer resistance. Equally influential are the effects of different boundary conditions and liquid PCM free convection. For the second stage, successful numerical techniques used in the one-dimensional phase change model are extended to a two-dimensional (r,z) PCM containment canister model. A prototypical PCM containment canister is analyzed and the results are discussed.

scholarly journals Latent Heat Phase Change Heat Transfer of a Nanoliquid with Nano–Encapsulated Phase Change Materials in a Wavy-Wall Enclosure with an Active Rotating Cylinder

2021 ◽  
Vol 13 (5) ◽  
pp. 2590
Author(s):  
S. A. M. Mehryan ◽  
Kaamran Raahemifar ◽  
Leila Sasani Gargari ◽  
Ahmad Hajjar ◽  
Mohamad El Kadri ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Phase Change ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Wavy Wall ◽  
Governing Equations ◽  
Stefan Number ◽  
Change Material

A Nano-Encapsulated Phase-Change Material (NEPCM) suspension is made of nanoparticles containing a Phase Change Material in their core and dispersed in a fluid. These particles can contribute to thermal energy storage and heat transfer by their latent heat of phase change as moving with the host fluid. Thus, such novel nanoliquids are promising for applications in waste heat recovery and thermal energy storage systems. In the present research, the mixed convection of NEPCM suspensions was addressed in a wavy wall cavity containing a rotating solid cylinder. As the nanoparticles move with the liquid, they undergo a phase change and transfer the latent heat. The phase change of nanoparticles was considered as temperature-dependent heat capacity. The governing equations of mass, momentum, and energy conservation were presented as partial differential equations. Then, the governing equations were converted to a non-dimensional form to generalize the solution, and solved by the finite element method. The influence of control parameters such as volume concentration of nanoparticles, fusion temperature of nanoparticles, Stefan number, wall undulations number, and as well as the cylinder size, angular rotation, and thermal conductivities was addressed on the heat transfer in the enclosure. The wall undulation number induces a remarkable change in the Nusselt number. There are optimum fusion temperatures for nanoparticles, which could maximize the heat transfer rate. The increase of the latent heat of nanoparticles (a decline of Stefan number) boosts the heat transfer advantage of employing the phase change particles.

scholarly journals Experimental and Computational Investigations of Phase Change Thermal Energy Storage Canisters

2000 ◽  
Vol 122 (4) ◽  
pp. 176-182 ◽  
Author(s):  
Mounir Ibrahim ◽  
Pavel Sokolov ◽  
Thomas Kerslake ◽  
Carol Tolbert
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Radiation Heat Transfer ◽  
Convection Heat Transfer ◽  
Melting Time ◽  
Radiation Heat ◽  
Space Experiments

Two sets of experimental data for cylindrical canisters with thermal energy storage applications were examined in this paper: 1) Ground Experiments and 2) Space Experiments. A 2-D computational model was developed for unsteady heat transfer (conduction and radiation) with phase-change. The radiation heat transfer employed a finite volume method. The following was found in this study: 1) Ground Experiments, the convection heat transfer is equally important to that of the radiation heat transfer; Radiation heat transfer in the liquid is found to be more significant than that in the void; Including the radiation heat transfer in the liquid resulted in lower temperatures (about 15 K) and increased the melting time (about 10 min.); Generally, most of the heat flow takes place in the radial direction. 2) Space Experiments, Radiation heat transfer in the void is found to be more significant than that in the liquid (exactly the opposite to the Ground Experiments); Accordingly, the location and size of the void affects the performance considerably; Including the radiation heat transfer in the void resulted in lower temperatures (about 40 K). [S0199-6231(00)00304-X]

Solid/Liquid Phase Change Heat Transfer in Latent Heat Thermal Energy Storage

2009 ◽  
Author(s):  
D. Zhou ◽  
C. Y. Zhao
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Calcium Chloride ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Metal Foams ◽  
Chloride Hexahydrate

Phase change materials (PCMs) have been widely used for thermal energy storage systems due to their capability of storing and releasing large amounts of energy with a small volume and a moderate temperature variation. Most PCMs suffer the common problem of low thermal conductivity, being around 0.2 and 0.5 for paraffin and inorganic salts, respectively, which prolongs the charging and discharging period. In an attempt to improve the thermal conductivity of phase change materials, the graphite or metallic matrix is often embedded within PCMs to enhance the heat transfer. This paper presents an experimental study on heat transfer characteristics of PCMs embedded with open-celled metal foams. In this study both paraffin wax and calcium chloride hexahydrate are employed as the heat storage media. The transient heat transfer behavior is measured. Compared to the results of pure PCMs samples, the investigation shows that the additions of metal foams can double the overall heat transfer rate during the melting process. The results of calcium chloride hexahydrate are also compared with those of paraffin wax.

Latent Heat Storage: Container Geometry, Enhancement Techniques, and Applications—A Review

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
S. Arunachalam
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Latent Heat ◽  
Thermal Energy ◽  
Heat Exchangers ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Low Thermal Conductivity

Energy storage helps in waste management, environmental protection, saving of fossil fuels, cost effectiveness, and sustainable growth. Phase change material (PCM) is a substance which undergoes simultaneous melting and solidification at certain temperature and pressure and can thereby absorb and release thermal energy. Phase change materials are also called thermal batteries which have the ability to store large amount of heat at fixed temperature. Effective integration of the latent heat thermal energy storage system with solar thermal collectors depends on heat storage materials and heat exchangers. The practical limitation of the latent heat thermal energy system for successful implementation in various applications is mainly from its low thermal conductivity. Low thermal conductivity leads to low heat transfer coefficient, and thereby, the phase change process is prolonged which signifies the requirement of heat transfer enhancement techniques. Typically, for salt hydrates and organic PCMs, the thermal conductivity range varies between 0.4–0.7 W/m K and 0.15–0.3 W/m K which increases the thermal resistance within phase change materials during operation, seriously affecting efficiency and thermal response. This paper reviews the different geometry of commercial heat exchangers that can be used to address the problem of low thermal conductivity, like use of fins, additives with high thermal conductivity materials like metal strips, microencapsulated PCM, composite PCM, porous metals, porous metal foam matrix, carbon nanofibers and nanotubes, etc. Finally, different solar thermal applications and potential PCMs for low-temperature thermal energy storage were also discussed.

Sign in / Sign up

Export Citation Format

Share Document