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Eco-lightweight granules for energy efficient applications

Periodic Reporting for period 1 - Eco-LWG (Eco-lightweight granules for energy efficient applications)

Reporting period: 2015-08-01 to 2017-07-31

Buildings in Europe are responsible for more than 40% of total energy consumption and 25% of carbon emissions. This is mainly due to the high number of old housing stock with very poor insulation systems. Such buildings require a huge energy demand for heating and cooling needs, which increases their carbon footprint. Moreover, by 2050 it is predicted that the number of households worldwide will grow by 67% and service sector buildings by 195%.

Developing innovative energy-efficient and low/zero-carbon materials are key areas in which the building sector can meet carbon reduction targets. A possible solution is to use phase change materials (PCMs). These can control temperature fluctuations and increase thermal mass in buildings thanks to their ability to store and release thermal energy during phase change processes (melting and freezing). However, PCMs need to be encapsulated before they can be incorporated into the built environment, to avoid leaking and incompatibilities with the construction matrix which contains them. There are several paths to incorporate PCMs. One existing method soaks commercial lightweight aggregates (LWA) in PCM. Therefore, the amount of PCM that the LWAs can host is limited by the latter’s absorption capacity, which is low.

The overall objective of this EU funded project was to deliver new energy efficient construction materials that can contribute to achieving the 2020 target of nearly zero-energy and highly material efficient buildings, which is an essential target to achieve sustainable growth in the EU. To achieve this, we engineered eco-lightweight granules (eco-LWG) to help mitigate the aforementioned problems.
The eco-LWG developed in this research have high strength and high water absorption, >100 wt.%, and are made from widely available waste materials: recycled mixed coloured glass, clay and limestone. The eco-LWG were used to contain PCM, which use chemical bonds to store and release heat, allowing control of temperature fluctuations. The high level of porosity in the eco-LWG allowed them to absorb and retain much higher levels of PCM than has previously been possible using existing lightweight aggregates. The composition and manufacturing process for both the eco-LWG and the PCM loaded eco-LWG were optimised by statistical design methodology. The main target is to use them to develop new energy efficient construction products. Two impregnation methods were compared to introduce the PCM into the eco-LWG: vacuum sorption, to achieve maximum PCM uptake, and short-term immersion to partially fill the connected porosity. The vacuum method produced innovative lightweight and high heat-storage granules, with higher heat storage capacity than commercially available products. Incorporating PCM loaded granules in mortars and other construction materials will result in novel construction materials.
These novel construction materials can be used for both retrofitting of existing buildings and constructing new buildings. Hence, a potential impact in the construction industry is expected by developing materials with improved energy storage capacity compared with existing commercially-available products.

The developed materials can reduce the energy requirements to heat and cool buildings and improve indoor living conditions by increasing thermal comfort for occupants, by reducing temperature fluctuations. Therefore, the expected socio-economic impact will be to increase people’s wellbeing, reduce energy bills and reduce the carbon footprint of buildings. All these factors are essential to achieve sustainable growth in the EU.