Advanced Concrete Steam Accumulation Tanks for Energy Storage for Solar Thermal Electricity

Steam accumulation is one of the most effective ways of thermal energy storage (TES) for the solar thermal energy (STE) industry. However, the steam accumulator concept is penalized by a bad relationship between the volume and the energy stored; moreover, its discharge process shows a decline in pressure, failing to reach nominal conditions in the turbine. From the economic point of view, between 60% and 70% of the cost of a steam accumulator TES is that of the pressure vessel tanks (defined as US$/kWhth). Since the current trend is based on increasing hours of storage in order to improve dispatchability levels in solar plants, the possibility of cost reduction is directly related to the cost of the material of pressure vessels, which is a market price. Therefore, in the present paper, a new design for steam accumulation is presented, focusing on innovative materials developed specifically for this purpose: two special concretes that compose the accumulation tank wall. Study of dosages, selection of materials and, finally, scale up on-field tests for their proper integration, fabrication and construction in prototype are the pillars of this new steam accumulation tank. Establishing clear and precise requirements and instructions for successful tank construction is necessary due to the highly sensitive and variable nature of those new concrete formulations.

Multi-Parameter Optimization for the Wet Steam Accumulator of a Steam-Powered Catapult

Selecting the optimal parameters for wet steam accumulator of steam-powered catapult is an important task, due to launching safety. There is no literature on the topic of the parameters optimization for wet steam accumulator of steam-powered catapult. The genetic algorithm (GA) was used to determine the optimal wet steam accumulator in this article. The sink-off-the-bow (SOB), angle of attack and rate of climb were used to create the objective function. The multi-objective optimization can be converted to single-objective optimization, which is subject to angle of attack and rate of climb. Moreover, the simulation model of the steam catapult system was built by creating a thermodynamics model of steam-powered catapult, a mathematical model of traction release device, a statics model of tensioning, a statics model of full takeoff power, a mathematical model of catapult force build-up with holdback, a model of release, a dynamics model of power stroke, a dynamics model of free deck run and a dynamics model of fly away. Finally, the optimal combination of the wet steam accumulator was obtained via numerical simulation. The GA method can effectively find the optimal parameters of wet steam accumulator, and its optimized parameters can increase the safety of catapult launch process.

A hybrid energy storage concept for future application in industrial processes

The efficiency of many industrial processes, applying steam as heat transfer medium, can be increased by integrating Ruths steam accumulator. This component makes it possible to store surplus steam for consumption at later time, whereby high loading and unloading rates can be realized with this storage type. For improving this storage type in terms of storage capacity and application range a hybrid storage approach is presented. The concept combines a Ruths steam storage with phase change material and electrical heating elements. For a first analysis of the interaction between the Ruths steam accumulator and the phase change material, which surrounds the steam storage vessel, a dynamic model was created. Also, an example which consist of a charging, storing, and discharging phase is presented. The simulation results show a positive impact in terms of storage capacity. Therefore, the hybrid storage concept is a promising approach for integration in industrial processes.