Developing thermal insulation systems for thermal comfort
Keeping living and working spaces at a comfortable temperature represents a substantial part of the final energy consumption of our buildings.
Materials and structures that provide thermal insulation during the entire lifecycle of a building are preferable to more energy and resource-intensive solutions and should therefore be integrated in green building solutions.
Green building also means raising comfort standards
In the small Russian town of Verkhoyansk, inhabitants experience extreme temperature differences from summer to winter. Just this year, the town registered its highest temperature ever, at 38ºC, while the ledger shows that in the past it once got to a chilling -67.8ºC.
Most people outside this town do not experience such extreme temperatures. Still, turning seasons force us to adjust - from changing our clothes to turning the heater or air conditioner on - as we strive to feel comfortable in our environments.
The challenge of thermal comfort
Thermal comfort is getting harder to achieve. Climate change has increased the frequency of extreme temperatures. At the same time, tropical areas are becoming increasingly urbanized and are expected to be the home of 50% of the global population by 20501.
In Europe, at least 10% of the households are not able to keep their homes warm in the winter, while 20% struggle to keep them cool in the summer2. With climate change, the likelihood of new heat waves as the one that affected Europe in 2003 has doubled, putting more strain on those households.
Let's look into the facts
Thermal comfort changes our behaviour
An uncomfortable environment can have a strong effect on our mental health, for example, by disrupting our sleep quality, increasing our levels of stress and anxiety(3).
Thermal comfort has been linked to productivity by over 100 studies (4). A difference of just 1ºC can bring down productivity by almost two percent (5). The same can be observed in schools, with test scores improving by 4% in classrooms deemed to be comfortable (6).
Thermal comfort is ranked higher in terms of importance than visual and acoustic comfort by building occupants (7) and has been found to have a high influence on the overall satisfaction with any indoor environment (8).
Old and new solutionsHumanity has sought ways of making its dwellings thermally comfortable for a long time, using locally-sourced materials with insulation properties or adapting architectural features to outdoor conditions.
The thick stone walls that can still be found in many older buildings can be explained by the term periodic thermal transmittance. It measures the time gap between maximum outdoors and indoors temperatures. Good insulating materials should be able to achieve a gap of eight to 10 hours.
In the Mediterranean, patio houses from Andalucía to Algeria provide cool air circulation. Adobe, used in structures across every continent, was chosen because it can retain heat during the day to provide warmer temperatures during the night.
But in the past century, there has been a turn to mechanical methods such as heat, ventilation and air conditioning, further adding to the negative effects on the climate.
Towards more sustainable thermal regulation
Instead of relying on air conditioning, we should take note of other building techniques and pursuit thermal insulation as our top priority.
ETICS (External Thermal Insulation Composite System) is a solution for thermal insulation based on panels with the most popular material being polystyrene, mineral wool, and cork.
Ventilated facades is another construction method where a physical separation is created between the outside of the façade and the interior wall of the building, in which mineral wool is also commonly used.
When the facade of the buildings is protected by preservation laws, external interventions cannot go ahead. Instead, working on the internal side of the walls with purely mineral systems that can also adapt to the irregularities of the laying surface.
IMCD on thermal comfort
Hoping to make a contribution to more comfortable interiors while reducing the consumption of energy and resources, IMCD has been striving to find new solutions for thermal insulation.
Our experts explain:
International Product Manager
Why is thermal insulation an important topic for IMCD?
Thermal insulation is a topic that IMCD takes to heart as it contributes to reducing CO2 emissions and therefore counteracting climate change. Thermal insulation also contributes to more pleasing interiors with a direct impact on the well-being of end-consumers.
How do we improve thermal insulation?
Our most recent project is a new, amorphous silica Aerogel powder or grain that is composed of 5% SiO2 and 95% air. The low silica content saves resources and is good news for markets such as Asia-Pacific, where that raw material is becoming scarce.
Aerogel acts as an insulator, with heat becoming trapped in its nanopores. Using merely thermal paint is not enough to achieve the results we desire, so we had to create a system of 3 components – thick mineral plaster, mineral finish (skim coat), and thermal decorative paint – that can be deployed to achieve the highest thermal insulation possible.
This material is extremely light (75kg/m3), hydrophobic, and with a thermal conductivity (lambda) of 0.013 W/m K, making it one of the most insulating on the market. The thermal conductivity (lambda) of the paint declines when the Aerogel content increases. The lower the conductivity the better the insulation. In this case, the best results – the highest thermal insulating or the lowest thermal conductivity - are achieved with 6,4% of Aerogel.
If we want to improve the thermal insulation of a house without changing its exterior we must turn to other solutions. We developing a plaster that has a lambda of 0.04 W/m K. This means we could achieve thermal insulation properties similar to the most popular thermal insulation panels that are used in ETICS without having a thick protective layer on the interior.
What challenges do customers face when creating thermal insulation products?
Using such formulation in a decorative paint as well as in a dry premixed mortar (render and mineral finish) is particularly complicated given the hydrophobic nature of the material, so dispersion in water becomes a challenge.
The correct choice of all the components of the formula and, in the case of paints, the mixing process, are crucial for obtaining the desired result.
IMCD is making an important effort in terms of tests and resources to allow its customers to start any formula development from a solid base, thus addressing their needs quicker.
1 Urban Climate
2 European Environment Agency
3 Journal of Environmental and Public Health
5 Intelligent Buildings International
6 World Green Building Council
7 Building and Environment
8 UC Berkeley Envelope Systems