Design of a Modular Latent Heat Storage System for Solar Thermal Power Plants

2011 ◽  
Author(s):  
Mark R. Campbell ◽  
Marc Newmarker ◽  
Nathaniel Lewis ◽  
Christopher T. George ◽  
Gilbert Cohen
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Heat Transfer Surface ◽  
Change Material

Thermal energy storage systems designed to use phase change material can benefit from accounting for the reduction in heat transfer that results from fouling on the heat transfer surface or employing a system to minimize the amount of build-up on the heat transfer surface. This paper describes the modeling and design of a modular latent heat thermal energy storage system that can use an internal heat exchanger and a mechanical system to increase heat transfer to and from the phase change material. Theoretical heat transfer modeling of a 100 kWht storage system was performed, candidate phase change materials were tested, and mechanical material removal experiments were conducted. The results of this work led to a design that is in construction and will be operated in the future. The system is predicted to be capable of reaching 93% round trip efficiency while providing 2 hours of discharge at a nearly constant temperature.

scholarly journals Numerical Study of Latent Heat Thermal Energy Storage Enhancement by Nano-PCM in Aluminum Foam

Inventions ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 76 ◽  
Author(s):  
Bernardo Buonomo ◽  
Anna di Pasqua ◽  
Davide Ercole ◽  
Oronzio Manca
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Metal Foam ◽  
Storage System ◽  
Melting Time ◽  
Change Material

Thermal storage system (TES) with phase change material (PCM) is an important device to store thermal energy. It works as a thermal buffer to reconcile the supply energy with the energy demand. It has a wide application field, especially for solar thermal energy storage. The main drawback is the low value of thermal conductivity of the PCM making the system useless for thermal engineering applications. A way to resolve this problem is to combine the PCM with a highly conductive material like metal foam and/or nanoparticles. In this paper a numerical investigation on the metal foam effects in a latent heat thermal energy storage system, based on a phase change material with nanoparticles (nano-PCM), is accomplished. The modelled TES is a typical 70 L water tank filled with nano-PCM with pipes to transfer thermal energy from a fluid to the nano-PCM. The PCM is a pure paraffin wax and the nanoparticles are in aluminum oxide. The metal foam is made of aluminum with assigned values of porosity. The enthalpy-porosity theory is employed to simulate the phase change of the nano-PCM and the metal foam is modelled as a porous media. Numerical simulations are carried out using the Ansys Fluent code. The results are shown in terms of melting time, temperature at varying of time, and total amount of stored energy.

scholarly journals Numerical modelling of phase change material melting process embedded in porous media: Effect of heat storage size

2019 ◽  
Vol 234 (3) ◽  
pp. 365-383 ◽  
Author(s):  
Pouyan Talebizadeh Sardari ◽  
Gavin S Walker ◽  
Mark Gillott ◽  
David Grant ◽  
Donald Giddings
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Porous Medium ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Change Material

The aim of this paper is to study the influence of enclosure size in latent heat thermal energy storage systems embedded in a porous medium for domestic usage of latent heat thermal energy storage heat exchangers. A 2-D rectangular enclosure is considered as the computational domain to study the heat transfer improvement for a phase change material embedded in a copper foam considering a constant heat flux from the bottom surface. Different dimensions of the composite system are examined compared with a system without a porous medium. The thermal non-equilibrium model with enthalpy-porosity method is employed for the effects of porous medium and phase change in the governing equations, respectively. The phase change material liquid fraction, temperature, velocity, stream lines and the rate of heat transfer are studied. The presence of a porous medium increases the heat transfer significantly, but the improvement in melting performance is strongly related to the system's dimensions. For the dimensions of 200 × 100 mm (W × H), the melting time of porous-phase change material with the porosity of 95% is reduced by 17% compared with phase change material-only system. For the same storage volume and total amount of thermal energy added, the melting time is lower for the system with a lower height, especially for the phase change material-only system due to a higher area of the input heat. The non-dimensional analysis results in curve-fitting correlations between the liquid fraction and Fo.Ste.Ra −0.02 for rectangular latent heat thermal energy storage systems for both phase change material-only and composite-phase change material systems within the parameter range of 1.16 <  Ste < 37.13, 0 <  Fo < 1.5, 2.9 × 104 <  Ra < 9.5 × 108, 0 <  L f < 1 and 0 <  Fo.Ste.Ra −0.02 < 0.57. Over a range of system's volume, heat flux and surface area of the input heat flux, the benefit of composite phase change material is variable and, in some cases, is negligible compared with the phase change material-only system.

Thermal Energy Storage Through Melting of a Commercial Phase Change Material in an Annulus with Radially Divergent Longitudinal Fins

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Tonny Tabassum Mainul Hasan ◽  
Latifa Begum
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Operating Conditions ◽  
Melting Time ◽  
Bottom Part ◽  
Change Material

This study reports on the unsteady two-dimensional numerical investigations of melting of a paraffin wax (phase change material, PCM) which melts over a temperature range of 8.7oC. The PCM is placed inside a circular concentric horizontal-finned annulus for the storage of thermal energy. The inner tube is fitted with three radially diverging longitudinal fins strategically placed near the bottom part of the annulus to accelerate the melting process there. The developed CFD code used in Tabassum et al., 2018 is extended to incorporate the presence of fins. The numerical results show that the average Nusselt number over the inner tube surface, the total melt fraction, the total stored energy all increased at every time instant in the finned annulus compared to the annulus without fins. This is due to the fact that in the finned annulus, the fins at the lower part of the annulus promotes buoyancy-driven convection as opposed to the slow conduction melting that prevails at the bottom part of the plain annulus. Fins with two different heights have been considered. It is found that by extending the height of the fin to 50% of the annular gap about 33.05% more energy could be stored compared to the bare annulus at the melting time of 82.37 min for the identical operating conditions. The effects of fins with different heights on the temperature and streamfunction distributions are found to be different. The present study can provide some useful guidelines for achieving a better thermal energy storage system.

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.

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