In addition to heat transfer, economic considerations, strength and stability, the choice of the right thermal insulation for a building should also take into account optimal performance and minimised environmental impact. There are several different types of thermal insulation on the market, ranging from the most commonly used glass wool, rock wool, EPS and XPS to natural materials such as wool, hemp, cellulose, flax, etc., which have different technical characteristics such as thermal and acoustic insulation, fire performance, ability to control ambient humidity and carbon footprint.
The master's thesis deals with three natural insulations, sheep wool, cellulose insulation (wood wool) and hemp insulation, which have the advantage of a relatively low environmental impact, a contribution to indoor comfort by reducing air pollution and good fire resistance, either due to the material properties themselves or due to the addition of flame retardants. The proximate analysis of these samples was determined using TA methods, namely EGA, TGA, DTA, DTG. The thermal stability of the three thermal insulation samples was determined using TA methods depending on variation of the mass of the sample and the thermal changes in the sample during the thermal loading of the sample. The EGA method, which combines a thermogravimetric analyser (TGA) and a quadrupole mass spectrometer (QMS), was used to determine the composition of the volatile components of the samples. The aim of the research is to determine which of the natural insulations considered is the best choice in terms of proximate composition, thermal stability and cost, taking into account also the carbon footprint (GWP) and embodied energy (EE) of each insulation sample.
The results of the thermal analysis methods showed that sheep's wool, wood wool and hemp insulation and decompose in a three – step process. The first stage involves the loss of moisture, the second stage the formation of volatile components or pyrolysis gases, the third stage the combustion of fixed carbon and the residue after thermal treatment is ash. The first two mass changes of the sample take place in an inert atmosphere (argon) and the third in an oxidising atmosphere (argon and oxygen) in a temperature range from 40 °C to 900 °C, recording the thermal decomposition components of the sample.
The findings showed that hemp insulation had a higher thermal stability due to the higher pyrolysis gas generation temperature and the lowest (negative) carbon footprint (GWP). Wool insulation had with the highest ash content, the highest thermal stability and the lowest cost. Wood insulation, on the other hand, had the most thermally stable fixed carbon and the lowest embodied energy (EE).
|
