Thermal damping (or amplitude attenuation) is an essential concept in the field of energy efficiency and thermal comfort in buildings. It represents the ability of a wall to dissipate a thermal wave and attenuate its intensity. Complementary to effusivity, this criterion plays a major role in the RE2020 summer comfort assessment. So how is it calculated and what does it tell us about the thermal performance of a wall? ?
Thermal damping
The thermal attenuation (or thermal amplitude attenuation) of a wall refers to its ability to dissipate heat and reduce its intensity. It is expressed as a percentage and indicates the proportion of heat dissipated in relation to the incident heat. It is an important characteristic for evaluating the performance of a wall in terms of thermal regulation.
Thermal amplitude attenuation can be evaluated by comparing the heat flow through the uninsulated wall with that through the insulated wall. Higher attenuation means a greater reduction in heat flow and temperature variations through the wall.
However, calculating thermal amplitude attenuation can be more complex in practice, as it may require consideration of factors such as convection, thermal radiation, thermal bridges, and other considerations specific to the wall configuration. In some cases, numerical simulations or more advanced models may be used for a more accurate analysis.
Calculate thermal depreciation:
The percentage of thermal amplitude of a wall (or thermal damping) can be calculated by comparing the maximum and minimum temperature variations across the wall. Here's how to calculate it:
- Temperature measurement: Using appropriate temperature sensors, measure the maximum temperature (Tmax) and minimum temperature (Tmin) across the wall over a given period of time.
- Calculating the temperature range: Subtract the minimum temperature from the maximum temperature to obtain the difference between the two: Temperature range = Tmax – Tmin.
- Calculating the percentage of temperature range: Divide the temperature range by the average temperature (AvgT) across the wall and multiply by 100 to obtain the percentage of temperature range: Percentage of temperature range = (Temperature range / AvgT) * 100.
The average temperature (Tavg) can be calculated by adding the maximum and minimum temperatures and dividing by 2: Tavg = (Tmax + Tmin) / 2.
Interpreting thermal damping data:
Materials with low thermal mass are less effective at regulating temperature fluctuations, which can lead to heat spikes inside the building during hot periods. In contrast, materials with high thermal mass absorb and dissipate heat more effectively, contributing to increased thermal comfort and better energy management.
It is therefore essential to choose building materials with good thermal damping capacity to optimize summer comfort in buildings. In addition to good thermal insulation, this reduces the need for air conditioning and creates a more pleasant indoor environment throughout the year.
Furthermore, the interpretation of the temperature range percentage must be considered in the specific context of the application and the objectives sought. Comfort, energy efficiency, and sustainability criteria may vary depending on the type of building, its intended use, and applicable standards.
In all cases, for an accurate and appropriate interpretation, it is recommended to consult qualified professionals in the field of building thermal engineering or thermal engineering.
Damping and effusivity
If thermal damping is the ability of a material to dissipate a heat wave and reduce its intensity, this criterion complements effusivity. Effusivity characterizes a material's ability to absorb and store energy. These characteristics are linked by the fact that they both influence a material's ability to manage heat. A material with high thermal damping capacity can absorb and dissipate heat efficiently, while a material with low effusivity will have the ability to store and transfer heat slowly.
In building design, it is important to strike a balance between these two properties to achieve optimal thermal comfort and energy efficiency. Certain materials can have both good thermal damping capacity and appropriate effusivity, making them popular choices for wall coverings and thermal insulation.
When heat strikes a wall, it generates a thermal wave that propagates through the materials that compose it. A material with high thermal damping capacity will slow down the propagation of this wave, thus limiting the amount of heat that penetrates the interior of the building. Materials with good thermal damping can help maintain a more stable indoor temperature and improve thermal comfort in buildings.
