In a fast growing and interconnected world, the world needs easily accessible, cheap, and reliable energy. However, burning fossil fuels to produce heat and electricity pollutes the atmosphere with greenhouse gases, assuring climate catastrophe. With the growing use of zero-carbon, but intermittent, renewable energy resources such as wind and solar, and the concomitant need for energy storage, there remains the question of how to effectively transition currently fossil fueled industries and urban heating and cooling districts to zero-carbon renewable energy. Therefore, the use of stored heat, generated from wind and solar power, for heating, cooling and electrical power generation, is certain to grow in the coming decades. Current large capacity, high temperature thermal energy storage systems, until now mostly used in conjunction with concentrated solar power systems, often utilize molten salt. The mixed success of these systems shows that molten salt is an untrustworthy material due to its susceptibility to freezing, leaking, decomposition and corrosivity. As an alternative methodology for high-temperature thermal storage, axial flow packed-beds have utilized axially flowing fluid for heat-transfer. However, these axial-flow systems are not ideal because the large surface-to-volume ratio of the storage repository allows heat leakage to the environment, thus decreasing the round-trip efficiency of energy storage. Therefore, power systems require the development of a long duration, geographically and spatially agnostic, cost competitive energy storage technology, especially if this technology makes use of the legacy infrastructure associated with formerly fossil-fueled technologies and delivers heat as well as electricity on demand.
Researchers at the University of New Mexico and CSolPower LLC have developed an efficient thermal energy storage system, capable of converting legacy fossil-fuel powered plants into zero-carbon renewable energy storage facilities. Unlike traditional methods of thermal energy storage, the proposed thermocline storage system uses an innovative dome-capped packed bed configuration, which utilizes inexpensive rock, gravel, and sand-like materials to store high-temperature heat for extended periods. The design achieves optimization of charging, storage and discharging. The described dome-shaped repository has a low-permeability cap, composed of temperature resistant materials such as clay, rock, recycled glass, and sand. The storage system uses radial thermoclines, which are more reliable and yield lower costs than current airflow techniques, and the configuration minimizes thermal loss due to the buoyancy of heated air.
Name: Andrew Roerick