Repurposing Reverse Osmosis Concentrate as a Low-Cost Thermal Energy Storage Medium

The reject of the reverse osmosis water treatment process (aka brine, concentrate, ROC) is a mixture of salts that are dissolved in high salinity water. The ROC is classified as an industrial waste by the U.S. Environmental Protection Agency and can face regulatory limitations on disposal. State-of-the-art of ROC disposal includes deep-well injection, surface discharge to rivers, discharge to the ocean, and evaporation ponds. In this study, the feasibility of using Reverse Osmosis Concentrate as a low-cost Thermal Energy Storage (TES) medium is explored by a techno-economic analysis. The normalized cost of TES (cost per unit volume of stored thermal energy) is estimated through a series of cost analyses and is compared to the cost targets of the U.S. Department of Energy for low-cost thermal energy storage. It was shown that the normalized cost of TES using ROC salt content is in the range of $6.11 to $8.73 depending on ROC processing methods.

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Overview of Seasonal Thermal Energy Storage (STES) Technology

Energy Exploration & Exploitation ◽

10.1177/014459878300200203 ◽

1983 ◽

Vol 2 (2) ◽

pp. 113-122

Author(s):

Charles F. Meyer

Keyword(s):

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Large Scale ◽

Operating Experience ◽

Field Trials ◽

Department Of Energy ◽

Commercial Development ◽

Potential Benefits ◽

The U.S

This paper presents an overview of what seasonal thermal energy storage (STES) is, how it can best be used, and its potential benefits and problems. ATES, the storage of thermal energy in underground aquifers in freshwater, considered to be the most viable form of the technology, is only economic on a large scale, but commercial operating experience demonstrates its technical feasibility, e.g. in China. The U.S. Department of Energy has spent several million dollars supporting research into ATES over the last decade, although field trials are currently curtailed. Despite lack of funding and unwillingness on the part of the private sector to take risks in commercial development, ATES can be shown to be a valuable source of energy, and money, saving, and could be effectively exploited to advantage.

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Performance evaluation and design considerations for a split air-conditioner with built-in thermal energy storage

Building Services Engineering Research and Technology ◽

10.1177/0143624418818228 ◽

2018 ◽

Vol 40 (5) ◽

pp. 560-575

Author(s):

Jehanzeb Ahmad ◽

M Najam Ul Islam ◽

Jawwad Sabir

Keyword(s):

Energy Storage ◽

Phase Change ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Phase Change Materials ◽

Low Cost ◽

Hvac Systems ◽

Air Conditioner ◽

Widespread Application ◽

Air Conditioners

The benefits of thermal energy storage using phase change materials are well documented in the literature. Despite all the potential benefits of thermal energy storage, its commercial and widespread application remains limited. This is due to the high initial cost of phase change materials, extensive rework required in buildings, major modifications in HVAC systems, and the potential for leakage, fire and toxicity hazards. There is a strong need for a simple thermal energy storage solution which can be adopted by large number of consumers. Ductless split air-conditioners are portable, low cost, efficient and account for 70% of all air-conditioning systems sold worldwide each year. The present research provides a novel and low cost solution that incorporates thermal energy storage in these air conditioners, allowing them to run without electricity for 3 h. The paper deals with the detailed design aspects and engineering challenges that arise when incorporating thermal energy storage in these small units. A prototype air-conditioner with in-built thermal energy storage was developed, and all performance parameters presented have been validated through data obtained from the prototype. Our results indicate that thermal energy storage can be incorporated in split units in low cost and with minimal drop in overall energy efficiency of the system. Practical application: Incorporating thermal energy storage in split air-conditioners which enables them to run without grid for many hours has immense practical applications. Since around 50% power in any building is consumed by HVAC systems, being able to provide cooling during peak hours without using grid can significantly reduce load on the grid without compromising user comfort. For developing countries where load shedding is frequent, the users can run these air-conditioners without the use of generators or batteries thus saving costs and the environment.

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vegetable fat: A low-cost bio-based phase change material for thermal energy storage in buildings

Journal of Building Engineering ◽

10.1016/j.jobe.2018.10.022 ◽

2019 ◽

Vol 21 ◽

pp. 222-229 ◽

Cited By ~ 13

Author(s):

Lisa Boussaba ◽

Said Makhlouf ◽

Amina Foufa ◽

Gilles Lefebvre ◽

Laurent Royon

Keyword(s):

Energy Storage ◽

Phase Change ◽

Phase Change Material ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Low Cost ◽

Change Material ◽

Vegetable Fat

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Waste From Metallurgic Industry: A Sustainable High-Temperature Thermal Energy Storage Material for Concentrated Solar Power

ASME 2013 7th International Conference on Energy Sustainability ◽

10.1115/es2013-18333 ◽

2013 ◽

Cited By ~ 12

Author(s):

Nicolas Calvet ◽

Guilhem Dejean ◽

Lucía Unamunzaga ◽

Xavier Py

Keyword(s):

Heat Capacity ◽

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Solar Power ◽

Low Cost ◽

Concentrated Solar Power ◽

Storage Material ◽

Energy Storage Material ◽

Thermal Energy Storage Material

The ambitious DOE SunShot cost target ($0.06/kWh) for concentrated solar power (CSP) requires innovative concepts in the collector, receiver, and power cycle subsystems, as well as in thermal energy storage (TES). For the TES, one innovative approach is to recycle waste from metallurgic industry, called slags, as low-cost high-temperature thermal energy storage material. The slags are all the non-metallic parts of cast iron which naturally rises up by lower density at the surface of the fusion in the furnace. Once cooled down some ceramic can be obtained mainly composed of oxides of calcium, silicon, iron, and aluminum. These ceramics are widely available in USA, about 120 sites in 32 States and are sold at a very low average price of $5.37/ton. The US production of iron and steel slag was estimated at 19.7 million tons in 2003 which guarantees a huge availability of material. In this paper, electric arc furnace (EAF) slags from steelmaking industry, also called “black slags”, were characterized in the range of temperatures of concentrated solar power. The raw material is thermo-chemically stable up to 1100 °C and presents a low cost per unit thermal energy stored ($0.21/kWht for ΔT = 100 °C) and a suitable heat capacity per unit volume of material (63 kWht/m3for ΔT = 100°C). These properties should enable the development of new TES systems that could achieve the TES targets of the SunShot (temperature above 600 °C, installed cost below $15/kWht, and heat capacity ≥25 kWht/m3). The detailed experimental results are presented in the paper. After its characterization, the material has been shaped in form of plates and thermally cycled in a TES system using hot-air as heat transfer fluid. Several cycles of charge and discharged were performed successfully and the concept was validated at laboratory scale. Apart from availability, low-cost, and promising thermal properties, the use of slag promotes the conservation of natural resources and is a noble solution to decrease the cost and to develop sustainable TES systems.

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Thermal Analysis of Elemental Sulfur in a Shell-and-Tube Configuration for Thermal Energy Storage Applications

Volume 6B: Energy ◽

10.1115/imece2016-67389 ◽

2016 ◽

Author(s):

Mitchell Shinn ◽

Karthik Nithyanandam ◽

Amey Barde ◽

Richard Wirz

Keyword(s):

Heat Transfer ◽

High Temperature ◽

Energy Storage ◽

Numerical Model ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Elemental Sulfur ◽

Low Cost ◽

High Energy ◽

Shell And Tube

Currently, concentrated solar power (CSP) plants utilize thermal energy storage (TES) in order to store excess energy so that it can later be dispatched during periods of intermittency or during times of high energy demand. Elemental sulfur is a promising candidate storage fluid for high temperature TES systems due to its high thermal mass, moderate vapor pressure, high thermal stability, and low cost. The objective of this paper is to investigate the behavior of encapsulated sulfur in a shell and tube configuration. An experimentally validated, transient, two-dimensional numerical model of the shell and tube TES system is presented. Initial results from both experimental and numerical analysis show high heat transfer performance of sulfur. The numerical model is then used to analyze the dynamic response of the elemental sulfur based TES system for multiple charging and discharging cycles. A sensitivity analysis is performed to analyze the effect of geometry (system length), cutoff temperature, and heat transfer fluid on the overall utilization of energy stored within this system. Overall, this paper demonstrates a systematic parametric study of a novel low cost, high performance TES system based on elemental sulfur as the storage fluid that can be utilized for different high temperature applications.

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United States Department of Energy Thermal Energy Storage Program

Thermal Energy Storage - Ispra Courses ◽

10.1007/978-94-009-7843-0_18 ◽

1982 ◽

pp. 465-500

Author(s):

J. H. Swisher ◽

W. A. Frier

Keyword(s):

United States ◽

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Department Of Energy ◽

United States Department ◽

States Department

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Low Cost and Marketable Operational Experiences for a Solar Heating System with Seasonal Thermal Energy Storage (SHSSTES) in Hebei (China)

Energy Procedia ◽

10.1016/j.egypro.2015.02.123 ◽

2015 ◽

Vol 70 ◽

pp. 267-274 ◽

Cited By ~ 6

Author(s):

Tao Tao ◽

Fan Zhang ◽

Wei Zhang ◽

Peng Wan ◽

Xiuchuan Shen ◽

...

Keyword(s):

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Low Cost ◽

Heating System ◽

Solar Heating

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Phase Change Material Thermal Energy Storage System Design and Optimization

ASME 2013 7th International Conference on Energy Sustainability ◽

10.1115/es2013-18335 ◽

2013 ◽

Cited By ~ 6

Author(s):

Songgang Qiu ◽

Ross Galbraith ◽

Maurice White

Keyword(s):

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Low Cost ◽

Storage System ◽

Energy Storage System ◽

Stirling Engine ◽

Melt Temperature ◽

Thermal Energy Storage System ◽

Change Material

Thermal energy storage (TES) system integrated with concentrated solar power provides the benefits of extending power production, eliminating intermittency issues, and reducing system LOCE. Infinia Corporation is under the contract with DOE in developing TES systems. The goal for one of the DOE sponsored TES projects is to design and build a TES system and integrate it with a 3 KWe free-piston Stirling power generator. The Phase Change Material (PCM) employed for the designed TES system is a eutectic blend of NaF and NaCl which has a melt temperature of 680° C and energy storage capacity of 12 KWh. This PCM was selected due to its low cost and desired melting temperature. This melt temperature ensures the Stirling being operated at designed operating hot end temperature. The latent heat of this eutectic PCM offers 5 to 10 times the energy density of a typical molten salt. The technical challenges associated with low cost molten salt TES systems are the low thermal conductivity of the salt and large thermal expansion. To address these challenges, an array of sodium filled Heat Pipes (HP) is embedded in the PCM to enhance the heat transfer from solar receiver to PCM and from PCM to Stirling engine. The oversized dish provides sufficient thermal energy to operate a 3KWe Stirling engine at full power and to charge up the TES. The HP arrays are optimally distributed so that the solar energy is transferred directly from receiver to Stirling engine heat receiver. During the charge phase, the Stirling engine absorbs and converts the transferred solar energy to electricity and the excess thermal energy is re-directed and stored to PCM. The stored energy is transferred via distributed HP from PCM to Stirling engine heat receiver during discharge phase. The HP based PCM thermal energy storage system was designed, built, and performance tested in laboratory. The TES/engine assembly was tested in two different orientations representing the extremes of system operation when mounted on sun-tracking dish, horizontal and vertical. Horizontal represents the zero elevation at sun rise and the vertical represents the extreme of solar noon. The testing allows the examination of orientation effect on the heat pipe performance and the maximum charge and discharge rates. The total energy stored and extracted was also examined. The areas for further system refinements were identified and discussed.

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