Underground CSP Thermal Energy Storage

2019 ◽  
Author(s):  
Roohany Mahmud ◽  
Mustafa Erguvan ◽  
David W. MacPhee
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Fossil Fuels ◽  
Storage System ◽  
Heat Engine ◽  
Energy Storage System ◽  
Electricity Demand ◽  
Heat Transfer Fluid ◽  
Concentrated Solar Power ◽  
Thermal Sources

Abstract Concentrated Solar Power (CSP) is one of the most promising ways to generate electricity from solar thermal sources. In this situation, large tracking mirrors focus sunlight on a receiver and provide energy input to a heat engine. Inside the receiver the temperature can be well above 1000°C, and molten salts or oils are typically used as heat transfer fluid (HTF). However, since the sun does not shine at night, a remaining concern is how to store thermal energy to avoid the use of fossil fuels to provide baseline electricity demand, especially in the late evenings when electricity demand peaks. In this study, a new method will be investigated to store thermal energy underground using a borehole energy storage system. Numerical simulations are undertaken to assess the suitability and design constraints of such systems using both molten salt as HTF.

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.

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.

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.

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.

scholarly journals The Effect of PCM Capsule Material on the Thermal Energy Storage System Performance

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
R. Meenakshi Reddy ◽  
N. Nallusamy ◽  
K. Hemachandra Reddy
Keyword(s):  
Energy Storage ◽  
Mild Steel ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Supply And Demand ◽  
Storage System ◽  
Internal Heat ◽  
Energy Storage System ◽  
Heat Transfer Fluid ◽  
Capsule Material

Phase change material (PCM) based thermal energy storage (TES) systems are gaining increasing importance in recent years in order to reduce the gap between energy supply and demand in solar thermal applications. The present work investigates the effect of PCM capsule material on the performance of TES system during charging and discharging processes. The TES unit contains paraffin as PCM filled in spherical capsules and is integrated with flat plate solar collector. Water is used as sensible heat material as well as heat transfer fluid (HTF). The PCM capsules are of 68 mm diameter and are made using three different materials, namely, (i) high density polyethylene (HDPE), (ii) aluminum (Al), and (iii) mild steel (MS). The experimental investigation showed that the charging and recovery of stored energy are less affected by the spherical capsules material. The variables, like charging time and discharging quantity, are varied around 5% for the different capsule materials. Even though aluminum thermal conductivity is much higher than HDPE and mild steel, its influence on the performance of TES system is very low due to the very high internal heat resistance of PCM material stored in the spherical capsules.

scholarly journals Preliminary thermal characterisation of an active latent thermal energy storage system using PCM

2021 ◽  
Vol 2116 (1) ◽  
pp. 012045
Author(s):  
A Egea ◽  
A García ◽  
R Herrero-Martín ◽  
J Pérez-García
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Energy Storage System ◽  
Heat Transfer Fluid ◽  
Coriolis Flowmeter ◽  
Thermal Energy Storage System ◽  
Exit Temperature ◽  
Flow Through

Abstract Preliminary results of energy charging/discharging processes in a latent thermal energy storage system are reported. A novel design of a rotative scrapper heat exchanger has been studied. Paraffin RT44HC is employed as a phase change material. A Coriolis flowmeter is employed for measuring the mass flow through the prototype, and PT100 temperature sensors are used for measuring the inlet and exit temperature of the heat transfer fluid.

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