AIRLIGHT – High-Temperature Thermal Storage System for Concentrating Solar Power

Partners: external page ALE Airlight Energy SA, external page SUPSI-iCIMSI
Funding source: external page BfE - Swiss Federal Office of Energy

Background – Concentrated solar power (CSP) technology, coupled to thermal storage systems, enables continuous dispatchability of solar electricity. One of the simplest and yet most cost-effective and efficient storing mechanisms with air as working fluid is based on a packed bed of rocks: The rocks are heated as hot air from the solar field flows through the packed bed during the day and the energy is extracted during the night by pumping air at ambient temperature through the hot packed bed.

Fig. 1: A solar power plant operation scheme a) during the day and b) during night

Fig. 2: The storage unit at Airlight in Biasca, Switzerland

Objective – The project is aimed at the design, fabrication, testing, modeling & validation, and optimization of a thermal storage system.

The project encompasses the following phases:

Thermal Storage Modeling: Formulation of a dynamic heat transfer model to simulate the transient operation of the storage system. Validation with experimental results from previous campaigns.
Thermal Storage Design and Construction: Design and fabrication of an improved 100 kW thermal storage system using information obtained from the simulations and previous experiments.
Experimental Demonstration: Experimental campaign with the complete system comprised of the solar concentrator, solar receiver and thermal storage. Evaluation of the thermal performance according to its (solar-to-heat) thermal efficiency.
Model Validation and Optimization: Validation of the heat transfer model by comparison with the results of the experimental campaign. Parametric study to optimize the design and operation, and for scale-up of the thermal storage unit.

Project-related Publications