CONCRETE STORAGE FOR SOLAR THERMAL POWER PLANTS AND INDUSTRIAL PROCESS HEAT

Abstract

Economic storage of thermal energy is a technological key issue for solar thermal power plants and industrial waste heat recovery. Systems using single phase heat transfer fluids like thermal oil, pressurized water, air or superheated steam, demand storage systems for sensible heat. A sensible heat storage system using concrete as storage material has been developed by Ed. Züblin AG and DLR. A major focus was the cost reduction of the heat exchanger and the high temperature concrete storage material. For live tests and further improvements a second generation 20 m³ solid media storage test module was built in Stuttgart and is cycled by an electrically heated thermal oil loop. By end of October 2008 the second generation solid media storage test module had accumulated four months of operation in the temperature range between 300 °C and 400 °C and about 50 thermal cycles with a temperature difference of 40 K. The tests will be continued until June 2009. Application fields for the concrete storage technology are parabolic trough solar thermal power plants; industrial waste heat recovery at elevated temperatures; thermal management of decentralized combined heat and power systems for increased flexibility and other high temperature processes. Especially the wide range of possible working temperatures and the modular structure make the heat storage in concrete attractive.