The history of thermal insulation materials is not as long as that of other materials, but the necessity of insulation is as old as building activity. Prehistoric people built shelters to protect themselves from the elements, originally using organic materials and later more durable substitutes.
However people used not only materials that were found in nature, but discovered others which were suitable for insulating. Processing organic materials produced the first insulated panels in the 19th century: meanwhile an increasing range of artificial materials were developed (rock wool, fibreglass, foam glass, hollow bricks, expanded perlite).
The appearance of plastic foams caused a huge revolution. Although plastic production was well-known in the 19th century, the first plastic foam was not produced until 1941.
Nowadays the most popular insulation materials are plastic foams and mineral wool with only a small amount of natural materials being produced. The overall growth of these products has been substantial due to a wide range of reasons.
From nanotechnology-based thermal insulation materials nano-ceramic thermal insulation coatings are generally considered to be the most critical because of contradictory technical data that could be founded in special literature. Complete agreement had not been already found about the mechanism how does their insulating effect take. In the Laboratory of Building Materials and Building Physics at Széchenyi István University (GyĘr, Hungary) several thermodynamic tests were made in order to find out thermodynamic process inside this material. Several building structures with different order of layers were tested with heat flow meter. Results showed that convective heat transfer coefficient cannot be taken account in usual way using this material as thermal insulation.
In the 21st century, global climate change and the high level of fossil energy consumption have introduced changes affecting all sectors of the economy, including the building industry. Reducing energy consumption has become an important task for engineers because 30% of the total energy consumption is used for heating our buildings. Recycling the huge amount of industrial and agricultural by-products has also become urgent because due to their CO2 emissions, their combustion is not a state-of-the-art alternative. Besides rediscovering some long-known, nature-based insulating materials, there are also several research projects that have resulted in new products. In the last century it was relatively easy to review this product range, but nowadays there are so many kinds of nature-based thermal insulating products, there is a need for systematization, and more in-depth knowledge about them is required. The purpose of this paper is to develop a new systematization of nature-based thermal insulation materials, summarize the main knowledge about them, and indicate the direction of recent research and development.
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