Waste heat from autoclaves recycled
In the manufacturing industry, high-temperature, high-pressure steam autoclave curing is applied to improve composite materials' strength. As a large quantity of steam is used, after each curing cycle there is excess heat simply released into the environment. EU-funded researchers proposed to recycle the autoclave waste heat to save fuel and reduce operation costs. Within the project ENRSYS (Integrated thermal energy reduction, recovery & re-use in autoclave based composites processing), they developed a prototype system to store and supply excess heat back to the system. Initially, the researchers identified the major sources of recoverable thermal energy. These included heat released while cooling autoclave water and kinetic energy from the release of air pressure. However, heat recovery from the main hull could be substantially higher compared to the recoverable energy from the compressed air. They also generated a large body of knowledge related to heat recovery efficiency, system constraints and operation of composite material curing systems. This work formed part of the research carried out to improve the design of the prototype so that it could be integrated into a real-world operational environment. ENRSYS estimates indicate that heat recovery efficiency could reach up to 77 %, a figure that should translate to cost savings as high as EUR 70 000. Although the actual figures will depend on the weight of the load inside the autoclaves, the payback on recycling waste heat as well as the environmental benefits should be significant.
Keywords
Waste heat, autoclaves, manufacturing, composite materials, ENRSYS, thermal energy
