Modelling of long-term hygro-thermal behaviour of vacuum insulation panels

Experimental Verification of Theoretical Ageing and Service Life Prediction Model for Vacuum Insulation Panels

“…In addition, a research group of building physics in Belgium reprted on particular type of VIPs with MF2 envelope to determine their Sd-value of the envelope in four different climates for periods up to 4 years and the results showed that the hygro-thermal loading has a small effect on the stability of the envelope (Meersman et al, 2015). In 2018, Batard et al made a prediction model of long-term hygro-thermal behaviour of VIPs and the study was carried out in a constant temperature and relative humidity and found that the result of VIPs thermal conductivity in real condition is not a linear extension of its short-term behaviour (Batard et al, 2018).…”

“…Thus, for the sake of simplicity and without loss of generality, for the rest of this research, λcop and λw are omitted . It is worth noting that since various materials are used as the cores of VIPs, λs has an essential impact on the thermal conductivity calculation ( Simmler et al, 2005b;Alotaibi et al, 2014;Batard et al, 2018). In other words, thermal conductivity is influenced directly by gas pressure, as it can be seen in Figure 2.9, the reduction of air conduction and moisture content are the main variables can provide an decrease on thermal conductivity value Li et al, 2014).…”

“…That is because of the low permeability of the VIP envelope caused a minimal amount of water transmission to the core. Also, an experimental test was done in section 3 to prove this assumption (Simmler et al, 2005b;Alotaibi et al, 2014;Batard et al 2018;).…”

“…2 Swiss Federal Laboratories for Materials Science and Technology = 0.035 × 1.5 + 0.5 × 0.1 ≈ 0.1 (mWm -1 K -1 a -1 ) Equation 18The results determined that the linear model can be reasonable only for the average thermal conductivity, but cannot be applicable for the water content and the pressure (Batard et al 2018). The importance of the external temperature and humidity was observed when the simulations performed in constant conditions.…”

“…For instance, the results proved that in dry conditions, the linear model always underestimates thermal conductivity after 50 years, while overestimated the thermal conductivity in a wet condition for the same time prediction. In all research mentioned that experimental results of initial thermal conductivity and thermal conductivity after ageing can show the long-term performance of VIPs (Kim, 2017;Batard et al, 2018;.…”