scholarly journals Experimental Investigation of PCM Spheres in Thermal Energy Storage System

2013 ◽  
Vol 367 ◽  
pp. 228-233 ◽  
Author(s):  
N.A.M. Amin ◽  
Azizul Mohamad ◽  
M.S. Abdul Majid ◽  
Mohd Afendi ◽  
Frank Bruno ◽  
...  
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Packed Bed ◽  
Energy Storage System ◽  
Heat Transfer Fluid ◽  
Experimental Result ◽  
Small Scale ◽  
Storage Unit

This paper presents the experimental result of a small scale packed bed of random spheres with encapsulated PCM being charged and discharged. A vapor compression refrigerator and heated room with fan heater were used to supply constant heat transfer fluid at a minimum temperature of -28°C for charging and 16°C for discharging. Even though the temperature differences were not fixed in the experiments, the performance of the thermal energy storage is depicted in the form of effectiveness values. Different results were obtained for charging and discharging the thermal storage unit. The differences are expected to come from natural convection and super cooling. The super cooling during the charging process was as high as 6°C.

scholarly journals Performance investigation of a 100-kWhth thermocline packed bed thermal energy storage system: Comparison between synthetic oil and vegetable oil

2020 ◽  
Vol 12 (4) ◽  
pp. 168781402090574
Author(s):  
Ahlem Bouguila ◽  
Rachid Said
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Rapeseed Oil ◽  
Storage System ◽  
Packed Bed ◽  
Energy Storage System ◽  
Heat Transfer Fluid ◽  
Thermal Energy Storage System

Thermal energy storage has been considered as an important solution to extend the operation of a concentrated solar power plant by meeting the peak demand of power in the time period from sunset to night, or providing power during cloudy days. Discussed in this work is a thermocline thermal energy storage system with a solid filler material. For this reason, a one-dimensional single-phase model is developed and validated with experimental data to investigate the thermal behavior of such thermal energy storage. The described model is further applied to design a 100-kWhth thermocline thermal energy storage system with a packed bed of quartzite rocks and oil as the heat transfer fluid. A synthetic oil (Therminol VP-1) and a vegetable oil (rapeseed oil) are the two candidates to be used as the heat transfer fluid. Their thermal and economic performances are calculated and compared. The results show that rapeseed oil is more cost-effective than Therminol VP-1 offering a lower energy cost (€18.3/kWhth vs €92.925/kWhth for Therminol VP-1).

Computational Analysis of a Pipe Flow Distributor for a Thermocline Based Thermal Energy Storage System

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Samia Afrin ◽  
Vinod Kumar ◽  
Desikan Bharathan ◽  
Greg C. Glatzmaier ◽  
Zhiwen Ma
Keyword(s):  
Energy Storage ◽  
Molten Salt ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Computational Analysis ◽  
Storage System ◽  
Flow Distribution ◽  
Energy Storage System ◽  
Heat Transfer Fluid ◽  
Case Scenario

The overall efficiency of a concentrating solar power (CSP) plant depends on the effectiveness of thermal energy storage (TES) system (Kearney and Herrmann, 2002, “Assessment of a Molten Salt Heat Transfer Fluid,” ASME). A single tank TES system consists of a thermocline region which produces the temperature gradient between hot and cold storage fluid by density difference (Energy Efficiency and Renewable Energy, http://www.eere.energy.gov/basics/renewable_energy/thermal_storage.html). Preservation of this thermocline region in the tank during charging and discharging cycles depends on the uniformity of the velocity profile at any horizontal plane. Our objective is to maximize the uniformity of the velocity distribution using a pipe-network distributor by varying the number of holes, distance between the holes, position of the holes and number of distributor pipes. For simplicity, we consider that the diameter of the inlet, main pipe, the distributor pipes and the height and the width of the tank are constant. We use Hitec® molten salt as the storage medium and the commercial software Gambit 2.4.6 and Fluent 6.3 for the computational analysis. We analyze the standard deviation in the velocity field and compare the deviations at different positions of the tank height for different configurations. Since the distance of the holes from the inlet and their respective arrangements affects the flow distribution throughout the tank; we investigate the impacts of rearranging the holes position on flow distribution. Impact of the number of holes and distributor pipes are also analyzed. We analyze our findings to determine a configuration for the best case scenario.

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.

Experimental Study of Thermal Energy Storage Using Natural Porous Media

2017 ◽  
Author(s):  
A. J. Al Edhari ◽  
C. C. Ngo
Keyword(s):  
Experimental Study ◽  
Porous Media ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Thermal Storage ◽  
Heat Transfer Fluid ◽  
Storage Unit ◽  
Storage Media

Thermal energy storage has been an area of research interest due to the need to store solar energy or excess energy for later use in many applications including district heating. The focus of a lot of research is on exotic and expensive storage media. This paper presents an experimental study of thermal energy storage using porous media readily available and commonly found in nature such as sand, soil, pebble rocks and gravel. This study also considers a simple and inexpensive thermal storage system which could be constructed easily and examines what could be done to increase the thermal storage performance. The thermal storage system examined in the present study was a thermal energy storage unit with embedded horizontal pipes carrying water as the heat transfer fluid for thermal charging. Different thermal storage configurations were examined by adjusting the thermal charging temperature and using different storage media. The temperature distribution within the storage media was monitored for 10 hours using a data acquisition system with K-type thermocouples. The results indicate that a thermal storage system using sand as storage media is slightly better compared with gravel or pebble rocks as storage media.

Experimental Investigation of Latent Heat Thermal Energy Storage System Enhanced by Annular and Radial Fins

2021 ◽  
Author(s):  
Saeed Tiari ◽  
Addison Hockins ◽  
Samantha Moretti
Keyword(s):  
Energy Storage ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Energy System ◽  
Energy Storage System ◽  
Heat Transfer Fluid ◽  
Charging Time ◽  
Thermal Energy Storage System

Abstract In the current study, the thermal characteristics of a latent heat thermal energy storage system enhanced with annular and radial fins are investigated experimentally. Rubitherm RT-55 is used as the phase change material (PCM) and is enclosed within a vertical cylindrical container. Water is used as the heat transfer fluid (HTF) which is circulated in a copper pipe that passes through the center of the container. The hot HTF is circulated through the system until the entire mass of solid PCM inside the container is melted. Twelve k-type thermocouples are inserted into the container at different levels to monitor the PCM temperature during the charging processes. A thermal imaging camera is used to take thermal images of the latent heat thermal energy system as it operates. The effects of different number of annular and radial fins attached to the central pipe on the thermal performance of the latent heat thermal energy storage system during the charging processes have been studied. It was found that the inclusion of 10 and 20 annular fins decreased the charging time by 79.5% and 82.8%, respectively. The two radial fin designs of 4 fins and 8 fins were assessed and found to decrease charging time by 81.9% and 86.6%, respectively.

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