Abstract
The purpose of this work was to quantify the thermal bridge effect of vertical diagonal tie connectors in precast concrete sandwich panels (PCSPs). Special interest was in cases where the use of rigid insulation (e.g. PIR) would leave air gaps between insulation boards and diagonal ties, thus intensifying the thermal bridge. A climate chamber experiment using 5 different joint types was performed to gather reference data for CFD model validation. In the experiment, natural convection was observed in joints where no additional insulation was used, i.e. in air cavities. Significantly larger heat fluxes were measured in these cavities compared to insulated joints. The thermal bridging effect was evaluated for a typical PCSP (thermal transmittance without thermal bridges U = 0.11 W/(m²·K)) using CFD software taking into account 3D heat conduction and convection. Simulation results indicate that diagonal ties without adjacent air cavities increased the average thermal transmittance (U-value) of the envelope by 8%, diagonal ties with a 6 mm air cavity – 19...33% and diagonal ties with a 10 mm air cavity – 45...56%. In conclusion, it was found that the joints in insulation caused by diagonal ties affect the overall thermal performance of the building envelope significantly when efforts are not made to fill the air cavities around the connectors.
Highlights
Global efforts towards improving the energy efficiency of buildings have led to an increasing motivation for using rigid thermal insulation materials in precast concrete sandwich panels (PCSPs)
The current state of PCSP manufacturing in Estonia concerning the issue at hand is satisfactory, for most respondents there was room for improvement
The vast majority of examined insulation joints measured less than 5 mm wide in case of mineral wool or were filled with PU foam for rigid insulation
Summary
Global efforts towards improving the energy efficiency of buildings have led to an increasing motivation for using rigid thermal insulation materials in precast concrete sandwich panels (PCSPs). These materials often exhibit lower thermal conductivity compared to mineral wool, which has been the insulation material of choice for PCSP manufacturers and designers until recently. These are placed vertically between insulation boards typically at 0,6 m spacing as shown on Fig. 1. There is evidence of Estonian PCSP manufacturers not adhering to these guidelines properly (see section 3.1)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.