Cooling of a pulsed energy-storage rep-rated Yb:YAG laser disk by heat sink

2008 ◽  
Author(s):  
Lin Chen ◽  
Shaobo He ◽  
Dingxiang Cao ◽  
Jianguo Liu ◽  
Yong Liu ◽  
...  
Keyword(s):  
Energy Storage ◽  
Heat Sink ◽  
Laser Disk

Development of Integration Methods for Thermal Energy Storages Into Power Plant Processes

2016 ◽  
Author(s):  
Clemens Schneider ◽  
Sebastian Braun ◽  
Torsten Klette ◽  
Steffen Härtelt ◽  
Alexander Kratzsch
Keyword(s):  
Energy Storage ◽  
Power Plant ◽  
Thermal Energy ◽  
Heat Sink ◽  
Energy Supply ◽  
Power Plants ◽  
Thermal Power ◽  
Test Facility ◽  
Thermal Power Plants ◽  
Load Reduction

Germany’s current energy policy is focused on the replacement of the conventional powered electrical energy supply system by renewable sources. This leads to increasing requirements on the flexibility for the conventional thermal power plants. Larger differences between energy supply from renewable energy sources and energy demand in the grid lead to high dynamic requirements with respect to the load change transients. Furthermore, a reduction of the required minimum load of existing thermal power plants is necessary. The existing power plants are indispensable for securing the network stability of the power grid. Accordingly, activities to improve the flexibility of existing power plants are required. By the use of thermal energy storage (TES) it is possible to increase the load change transient. Furthermore, it is possible to temporarily provide an increased generator power and reduce the minimum technical load of the unit. Currently, there is no closed methodical approach for the load profile-dependent and location-based dimensioning and integration of TES into thermal power plants. The aim is to generate contributions for the development of a universal design method. This requires the provision of characteristics for dimensioning and integration of TES into thermal processes. For this purpose, it is necessary to derive quantifiable information on the required capacity, performance and stationary and dynamic operating conditions. Starting from analyzing the anticipated, site-specific load profiles the derivation of concepts for technical implementation, feedback on the process and cost of the thermal storage unit takes place. In order to investigate the technical feasibility, the implementation of storage and the associated control concepts as well as to validate the developed design models, the test facility THERESA has been built at the University of Applied Sciences in Zittau (Germany). The acronym THERESA is the abbreviation for thermal energy storage facility. This test facility includes a reconstructed thermal water-steam process, similar to a power plant with integrated TES. The test facility is unique in Germany and enables the delivery of saturated steam up to 160 bars at 347 ° and superheated steam up to 60 bars at 350 °C with an overall thermal power of 640 kW. The design, planning and construction of the facility took 3 years and required an investment volume of 3 mill. Euro. The facility includes two preheater stages, steam generator, super heater, direct TES with mixing preheater and a heat sink. The TES with a volume of 600 L as well as the mixing preheater are prototypes which developed for the special requirements of the facility. Based on this facility, it is possible to investigate methods for the flexibilization of thermal power plants with TES under realistic parameters. Furthermore, the test facility allows the development of control and regulatory approaches as well as the validation of simulation models for process expansion of thermal power plants. Initial investigations show the impact of a simulated load reduction at the heat sink on the system behavior. Here, the load reduction takes place from the heat sink in the storage without changing the steam production. The development and construction of the test facility were funded by the Free State of Saxony and the European Union. The further work on the development of the integration methods are funded by the European Social Fund ESF.

Small-Scale Thermal Energy Storage With Capillary Conductivity Enhancement

2016 ◽  
Author(s):  
A. Hays ◽  
E. Borquist ◽  
D. Bailey ◽  
D. Wood ◽  
L. Weiss
Keyword(s):  
Energy Storage ◽  
Heat Source ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Sink ◽  
Large Scale ◽  
Heat Pipes ◽  
Small Scale ◽  
Conductivity Enhancement

Thermal energy is a leading topic of discussion in energy conservation and environmental fields. Specifically for large-scale applications solar energy and concentrated solar power (CSP) systems use techniques that include thermal energy storage systems and phase change materials to harvest energy. However, on the smaller centimeter scale, there have been historically fewer investigations of these same techniques. The main goal of this paper is to investigate thermal energy storage (TES) as applied to a small scale system for thermal energy capture. Typical large-scale TES consists of a phase change material that usually employs a wax or oil medium held within a conductive container. The system stores the energy when the wax medium undergoes a phase change. In typical applications like buildings, the system absorbs and stores incoming thermal energy during the day, and releases it back to the surrounding environment as temperatures cool at night. This paper presents a new TES unit designed to integrate with a thermoelectric for energy harvesting application in small, cm-scale applications. In this manner, the TES serves as a thermal battery and source for the thermoelectric, even when originating power supply is interrupted. A unique feature of this TES is the inclusion of internal heat pipes. These heat pipes are fabricated from copper tubing and filled with working fluid, mounted vertically, and immersed in the wax medium of the TES. This transfers heat to the wax by means of thermal conductivity enhancement as an element of the heat pipe operation. This represents a first of its kind in this small-scale, thermal harvesting application. As tested, the TES rests atop a low temperature (60 °C) heat source with a heat sink as the final setup component. The heat sink serves to simulate thermal energy rejection to a future thermoelectric device. To measure the temperature change of the device, thermocouples are placed on either side of the TES, and a third placed on the heat source to ensure that the energy input is appropriate and constant. Heat flux sensors (HFS) are placed between the heat source and the TES and between the TES and heat sink to monitor heat transferred to and from the device. The TES is tested in a variety constructions as part of this effort. Basic design of the storage volume as well as fluid fill levels within the heat pipes are considered. Varying thermal energy inputs are also studied. Temperature and heat flux data are compared to show the thermal absorption capability and operating average thermal conductivities of the TES units. The baseline average thermal conductivity of the TES is approximately 0.5 W/mK. This represents the TES with wax alone filling the internal volume. Results indicate a fully functional, heat pipe TES capable of 8.23 W/mK.

Methodology for Designing a Hybrid Thermal Energy Storage Heat Sink

2000 ◽  
Author(s):  
Ning Zheng ◽  
R. A. Wirtz
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Sink ◽  
Thermal Response ◽  
Performance Model ◽  
Loading Constraints ◽  
Model Predictions ◽  
Heat Loading

Abstract A thermal response model for designing a hybrid thermal energy storage (TES) heat sink is developed. The stabilization time and maximum operating (hot side) temperature-to-transition temperature difference are used to characterize the performance of the heat sink. The thermal properties of the PCM employed in the design are investigated. Integration of a design optimization algorithm into a thermal performance model of the TES-hybrid heat sink results in determination of a best design subject to geometric and heat loading constraints. A prototype based on this best design is build and used to benchmark the performance model. The performance measured is consistent with the simulation model predictions of performance.

A Hybrid Thermal Energy Storage Device, Part 1: Design Methodology

2004 ◽  
Vol 126 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Ning Zheng ◽  
R. A. Wirtz
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Sink ◽  
Thermal Response ◽  
Performance Model ◽  
Storage Device ◽  
Loading Constraints ◽  
Model Predictions

A thermal response model for designing a hybrid thermal energy storage (TES) heat sink is developed. The stabilization time and maximum operating (hot side) temperature-to-transition temperature difference are used to characterize the performance of the heat sink. The thermal properties of the PCM employed in the design are investigated. Integration of a design optimization algorithm into a thermal performance model of the TES-hybrid heat sink results in determination of a best design subject to geometric and heat loading constraints. A prototype based on this best design is build and used to benchmark the performance model. The performance measured is consistent with the simulation model predictions of performance.

Numerical Characterization of Anisotropic Heat Sink Composites

2010 ◽  
Vol 654-656 ◽  
pp. 1500-1503 ◽  
Author(s):  
Thomas Fiedler ◽  
Graeme E. Murch ◽  
Timo Bernthaler ◽  
Irina V. Belova
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Sink ◽  
Composite Structures ◽  
Phase Change Materials ◽  
Void Space ◽  
Change Material

This work addresses the numerical analysis of anisotropic composite structures for thermal energy storage and temperature stabilization. The basic idea of heat sink composites is the combination of metallic matrices for fast energy transfer with phase change materials for thermal energy storage. Anisotropic matrices, such as lotus-type structures, allow for increased control of the thermal energy flow, without the necessity of additional thermal insulation. As an example, thermal energy can be directed towards a surface cooled by convection and excess energy is stored in the phase-change material. Computed tomography data of copper lotus-type material is used for the generation of the numerical calculation models. Due to its particular meso-structure, this material is characterised by strongly anisotropic properties. The void space of this cellular metal is filled with the phase-change material paraffin in order to enhance the energy storage capacity. A recently extended Lattice Monte Carlo method is used to evaluate the anisotropic thermal properties of these promising materials.

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