Introduction

A modular prefabricated element made in concrete for heat absorption and storage at high temperature and method to make it. The casting, curing and degassing phases are carried out in a controlled environment. It consists of cement, with the inclusion of plastic and metal fibres, and a thermal exchange tube. Multiple elements are assembled together to create complex systems.

Technical features

Current technologies for medium temperature heat storage show some problems: low energy density, high volumes and costs. A widely available and recyclable concrete would allow a low-cost solution. It needs improved physical characteristics: low water/cement ratio (<0.4), thermal conductivity higher than 2W/m°K and operating up to 400°C. It is the basis for a simple, flexible, scalable and cheap thermal storage element. The latter has a prismatic shape and contains, immersed in the concrete, a heat exchanger, consisting of a coil whose ends are on the same side. The invention provides a method for construction (casting of the concrete into a mould containing the exchanger, its curing and degassing) as well as scalability and maintenance of this kind of thermal storage. Potential users will have a low-cost system that can be integrated with any medium temperature application using renewable energy sources or waste heat.

Possible Applications

• Concentrated solar power plants;
• Solar thermal plants with evacuated tubes;
• Biomass or hybrid plants;
• Recovery of industrial waste heat;
• District heating;
• Energy storage from electricity to heat conversion for wind, photovoltaic or similar systems.

Advantages

• Conceptual simplicity;
• Prefabrication in a controlled environment;
• Scalability, systems with variable thermal capacity;
• Economics based on low-cost materials;
• Ease to install;
• Low environmental and social impact;
• Recyclability of materials