Long term measurements and HAM modelling of an interior insulation solution for an office building in cold climate

Abstract

Excessive mould damage was detected in an office building in Northern Europe and thus a renovation need was established. This paper studies a renovation solution using measurements and heat, air & moisture (HAM) modelling. Polyurethane (PUR) foam was used to fill the air gap in masonry while capillary active calcium silicate (CaSi) insulation was used on the interior surface at thermal bridges. During renovation works temperature and relative humidity (t&RH) and heat flux sensors were installed throughout the wall. Nearly 3 years of measurements are presented. Average thermal transmittance (U) of the wall was reduced around 3 times. While the climate was probably not critical during the monitoring, the measured values stayed within hygrothermally safe limits. The paper also compares the measurement data to 2D HAM modelling and discusses the discrepancies. Calibrated models were used to model the wall using real 42-year weather data and give a more thorough assessment of the hygrothermal performance. Although the original wall stayed fairly moist, no performance limits were exceeded and the interior surface became safer in terms of mould risk.

Hygrothermal assessment of four insulation systems for interior retrofitting of solid masonry walls through calibrated numerical simulations

“…The simulation models have all been calibrated with measurements, it is not a validation of the simulation, as this would require complete knowledge of material properties and boundary conditions. The issue regarding the calibrated simulation models exhibiting less RH fluctuation compared to the experimental measurements and often underestimating the RH levels seem to be a common issue for several simulation programs as found in [15], [51]- [57]. The review study by Busser et al [58] similarly found that simulations often underestimate the adsorption processes and/or overestimate the desorption processes.…”

The 4th Industrial Revolution Brings a Change in the Design Paradigm for New and Retrofitted Buildings

“…Speaking about hygrothermal modeling also raises the question of its credibility. Experience [39][40][41] indicates that either co-simulation [42] or verification of material characteristics (calibration) [43] is used. Today, we have three different methods for model calibration:…”