Suitability of industrial wastes for application as high temperature thermal energy storage (TES) materials in solar tower power plants – A comprehensive review

As variable generation electricity sources, namely wind and solar, increase market penetration, the variability in the value of electricity by time of day has increased dramatically. In response to increase in electricity demand, natural gas “peaker plants” are being added to the grid, and the need for spinning and nonspinning reserves have increased. Many natural gas, and other heat source based, power plants exist as combined heat and power (CHP), or cogeneration, plants. When built for industrial use, these plants are sized and run based on heat needs of an industrial facility, and are not optimized for the value of electricity generated. With the inclusion of new, less expensive thermal energy storage (TES) systems, the heating and electricity usage can be separated and the system can be optimized separately. The use of thermal energy storage with CHP improves system economics by improving efficiency, reducing upfront capital expenditures, and reducing system wear. This paper examines the addition of thermal energy storage to industrial natural gas combined heat and power (CHP) plants. Here a case study is presented for a recycled paper mill near Los Angeles, CA. By implementing thermal energy storage, the mill could decouple electric and heat production. The mill could take advantage of time-of-day pricing while producing the constant heat required for paper processing. This paper focuses on plant economics in 2012 and 2015, and suggests that topping cycle industrial CHP plants could benefit from the addition of high temperature (400–550°C) energy storage. Even without accounting for the California incentives associated with implementing advanced energy storage technologies and distributed generation, the addition of energy storage to CHP plants can drastically reduce the payback period below the 25 year expected economic lifetime of a plant. Thus thermal energy storage can make more CHP plants economically viable to build.

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Study of rock suitability for high temperature thermal energy storage in concentrated solar tower power plants

2015 3rd International Renewable and Sustainable Energy Conference (IRSEC) ◽

10.1109/irsec.2015.7455030 ◽

2015 ◽

Cited By ~ 4

Author(s):

Yousra Jemmal ◽

Nadia Zari ◽

Mohamed Maaroufi

Keyword(s):

High Temperature ◽

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Power Plants

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Evaluation of Annual Efficiencies of High Temperature Central Receiver Concentrated Solar Power Plants with Thermal Energy Storage

Energy Procedia ◽

10.1016/j.egypro.2014.03.081 ◽

2014 ◽

Vol 49 ◽

pp. 752-761 ◽

Cited By ~ 12

Author(s):

B. Ehrhart ◽

D. Gill

Keyword(s):

High Temperature ◽

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Power Plants ◽

Solar Power ◽

Concentrated Solar Power ◽

Central Receiver ◽

Solar Power Plants ◽

Concentrated Solar Power Plants

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Modeling of a High-Temperature Latent Heat Thermal Storage Module for Brayton Cycle Applications

ASME 2012 6th International Conference on Energy Sustainability, Parts A and B ◽

10.1115/es2012-91237 ◽

2012 ◽

Cited By ~ 1

Author(s):

Brian Gehring ◽

Fletcher Miller

Keyword(s):

High Temperature ◽

Energy Storage ◽

Latent Heat ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Power Plants ◽

Relative Concentration ◽

Storage System ◽

Time Shift ◽

Brayton Cycle

Concentrating solar power (CSP) plants with thermal energy storage offer several advantages to plants without storage. Thermal energy storage (TES) allows CSP plants to produce power for longer periods of time each day, making them produce energy more like traditional, fossil fuel power plants. TES also gives the ability to time shift production of energy to times of peak demand, allowing the plant to sell the energy when prices are highest. A CSP plant with storage can increase turbine performance and reach higher levels of efficiency by load leveling production and can remain productive through cloud transients. Power tower CSP plants are capable of producing extremely high temperatures, as they have the ability to oversize their solar field and achieve a greater concentration ratio. Studies have been conducted on variable working fluids, leading to higher working temperatures. This theoretically allows power towers to use more efficient, higher temperature cycles including the recuperated air Brayton cycle, although none currently exist on a commercial scale. This research focuses on developing a model of a high temperature TES system for use with an air Brayton cycle for a power tower CSP plant. In this research we model one module of a latent heat TES system designed to meet the thermal needs of a recuperated Brayton engine of 4.6 MWe capacity for six hours. A metal alloy, aluminum-silicide (AlSi), is considered as the phase change medium. The storage tank is approximately 161 m3, or a cylinder with a 5 m diameter that is 8 m tall filled with AlSi with several air pipes throughout the volume. We model the volume around a single pipe in a 2-D cylindrical coordinate system, for a module size of 0.2 m in diameter and 8 m long. The advantages of using AlSi alloys is that they have variable melting temperatures depending on the relative concentration of the two metals, from 577 C for the eutectic composition of 12.6% silicon to 1411 C for 100% silicon. This attribute is taken advantage of by the TES model as the composition of the AlSi alloy will vary axially. This will allow a cascaded type storage system within one tank and with one material. The use of FLUENT to model this problem is first validated by several analytical solutions including Neumann’s exact solution for a one-dimensional Cartesian geometry and the Quasi-Steady Approximation in a 1-D cylindrical geometry. The model developed will establish charge/discharge times for the storage system, round-trip efficiency of the system, ability of the system to meet the demand of the Brayton cycle, and the validity of using off-eutectic metal alloys in a cascade as a latent heat TES medium.

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