Solar Thermo Electric Magaldi
The Magaldi patented CST system with thermal energy storage (TES)
CST systems are particularly suitable for industries that require large amounts of heat and for areas with abundant sunlight, helping to reduce CO₂ emissions.
To remain competitive with photovoltaics, concentrating solar thermal (CST) technology includes a thermal storage system to deliver energy on demand.
Magaldi's patented STEM®-CST system, with an expected lifetime of more than 30 years, has all the credentials to play a crucial role in the global decarbonization processes.
Working concept
The STEM®-CST system integrates a fluidized bed TES technology to store and release thermal energy even on cloudy days and in the hours after sunset or before sunrise.
Solar radiation is captured through a heliostat solar field, concentrated on a secondary reflector (beam down), and focused on the fluidized bed receiver. The latter consists of insulated tanks that contain silica sand, fluidized and heated to temperatures above 600 °C. The fluidized bed receiver works as a TES system and effectively stores the solar thermal energy which can be extracted when needed for steam release.
Silica sand vs. molten salts
Generally, the medium of choice in CST plants with TES is molten salts that, however, have some hard limits.
Magaldi based its system on a different material. The use of a cost-effective and locally available storage material like silica sand is a key factor for the STEM®-CST system.
The sand allows overcoming limitations faced with molten salts, thanks to:
- Capacity to reach higher temperatures: sand can operate at both lower and higher temperatures than molten salts, subject to freezing and melting phenomena. Silica sand has a melting point above 1200°C, maintaining its thermophysical properties.
- Compact design: the solar receiver, heat exchanger, and thermal energy storage are all integrated into one device. This results in a compact system with a reduced footprint, ideal for industrial complexes
Main applications
The generated heat can be used in various applications, such as:
- Industrial processes: The green heat is often used to power industrial processes, such as steam generation, drying, distillation, and other operations requiring medium to high temperatures (150°C to 450 °C or more), especially in industries such as food & beverage, chemical and pulp & paper.
- Desalination: In some regions, CST-generated heat can power water desalination plants, a valuable process in arid areas or areas with limited drinking water availability.
