Thermal evaluation of a highly insulated steel stud wall with vacuum insulation panels using a guarded hot box apparatus

2020 ◽  
pp. 174425912098003
Author(s):  
Travis V. Moore ◽  
Cynthia A. Cruickshank ◽  
Ian Beausoleil-Morrison ◽  
Michael Lacasse
Keyword(s):  
Thermal Resistance ◽  
Air Temperature ◽  
Building Code ◽  
Interior Surface ◽  
Vacuum Insulation ◽  
Industry Standard ◽  
Thermal Bridging ◽  
Standard Calculation ◽  
Wall Assembly ◽  
Steel Stud

This paper presents the results of a Guarded Hot Box (GHB) experiment on a wall assembly made up of both steel stud framing and an external insulating assembly which incorporates vacuum insulation panels (VIPs) for which knowledge of the composition of the VIP barrier foil is not readily available. The purpose of the tests is to provide an experiment result for thermal resistance of a wall assembly containing several sources of thermal bridging, including those due to the barrier foil at the edge of and joint material between the VIPs and the condensation potential on the interior surface due to the steel studs. The steady-state GHB experiments were completed in accordance with ASTM C1363 for an interior air temperature of 20.9°C and an exterior air temperature of −34.9°C; this resulted in a thermal resistance for the wall assembly of 6.8 ± 0.8 m2 K/W. Surface temperature measurements on a VIP in the wall assembly indicated that increased levels of heat transfer were occurring at the edges of the VIPs as compared to the center of the panel confirming thermal bridges were present at the panel edge. Measurement of the temperature on the interior surface of the sheathing board around the steel stud indicated that the external insulation effectively minimized the risk of condensation due to the steel studs. Determining the thermal resistance and condensation risk for a wall assembly which contains VIPs for which knowledge of the barrier film is not readily available demonstrates the potential for use of such a wall assembly according to energy and building code requirements. The wall assembly and test details can also be used to compare industry standard calculation methods and detailed 2D and 3D simulations to the GHB test result. The comparison can be used to inform on the validity of using calculations and simulation methods in lieu of testing for energy and building code compliance. The comparison of calculations and simulations is not the scope of the work presented in this paper and will be explored in future publications.

Determining the thermal resistance of a highly insulated wall containing vacuum insulation panels through experimental, calculation and numerical simulation methods

2020 ◽  
pp. 174425912098003
Author(s):  
Travis V Moore ◽  
Cynthia A. Cruickshank ◽  
Ian Beausoleil-Morrison ◽  
Michael Lacasse
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Effective Thermal Conductivity ◽  
Edge Effect ◽  
3D Simulation ◽  
Simulation Methods ◽  
Zone Method ◽  
Vacuum Insulation ◽  
Thermal Bridges ◽  
Wall Assembly

The purpose of this paper is to investigate the potential for calculation methods to determine the thermal resistance of a wall system containing vacuum insulation panels (VIPs) that has been experimentally characterised using a guarded hot box (GHB) apparatus. The VIPs used in the wall assembly have not been characterised separately to the wall assembly, and therefore exact knowledge of the thermal performance of the VIP including edge effect is not known. The calculations and simulations are completed using methods found in literature as well as manufacturer published values for the VIPs to determine the potential for calculation and simulation methods to predict the thermal resistance of the wall assembly without the exact characterisation of the VIP edge effect. The results demonstrate that disregarding the effect of VIP thermal bridges results in overestimating the thermal resistance of the wall assembly in all calculation and simulation methods, ranging from overestimates of 21% to 58%. Accounting for the VIP thermal bridges using the manufacturer advertised effective thermal conductivity of the VIPs resulted in three methods predicting the thermal resistance of the wall assembly within the uncertainty of the GHB results: the isothermal planes method, modified zone method and the 3D simulation. Of these methods only the 3D simulation can be considered a potential valid method for energy code compliance, as the isothermal planes method requires too drastic an assumption to be valid and the modified zone method requires extrapolating the zone factor beyond values which have been validated. The results of this work demonstrate that 3D simulations do show potential for use in lieu of guarded hot box testing for predicting the thermal resistance of wall assemblies containing both VIPs and steel studs. However, knowledge of the VIP effective thermal conductivity is imperative to achieve reasonable results.

scholarly journals Simplified Infinite Fin Method to Model the Heat Transfer Associated with Slab Edges and Balconies

2021 ◽  
Vol 2069 (1) ◽  
pp. 012022
Author(s):  
Mehdi Ghobadi ◽  
Alex Hayes ◽  
Travis Moore
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Numerical Simulations ◽  
Convective Heat Transfer Coefficient ◽  
Mitigation Strategies ◽  
Additional Heat ◽  
Thermal Bridges ◽  
Thermal Bridging ◽  
Wall Assembly ◽  
The Impact

Abstract As building codes become more stringent in terms of thermal performance of building envelopes, and higher insulated wall assemblies are becoming more common, the heat flow due to major thermal bridges can contribute to a significant portion of the total heat transfer through a building façade. Characterizing different thermal bridging elements is essential not only to capture the thermal resistance of wall assemblies and understand the thermal efficiency of buildings, but also in terms of understanding the impact of each thermal bridging element and mitigation strategies that can be used. Numerical simulations are used widely to characterize different thermal bridging elements. However, not all designers have access, technical skills or time to complete numerical simulations to calculate the heat transfer loss through thermal bridges. In this study we propose an analytical method to integrate the effect of adding a slab edge/balcony/eyebrow into a clear-field wall assembly. The additional heat transfer due to the slab edge is calculated by considering the slab edge to be an infinite fin. The additional heat transfer is integrated into the clear-field as a quasi-convective heat transfer coefficient. The overall thermal resistance of the wall assembly is calculated by employing the parallel path method. Comparing the results obtained from this method with the numerical simulations which were benchmarked against guarded hot box results, an overall deviation of 1 to 8 percent was observed.

scholarly journals Experimental and numerical investigation of thermal bridging effects of jointed Vacuum Insulation Panels

2016 ◽  
Vol 111 ◽  
pp. 164-175 ◽  
Author(s):  
Alice Lorenzati ◽  
Stefano Fantucci ◽  
Alfonso Capozzoli ◽  
Marco Perino
Keyword(s):  
Numerical Investigation ◽  
Vacuum Insulation ◽  
Thermal Bridging

Study of the edge thermal bridging effect in vacuum insulation panels: steady and unsteady-state approaches using numerical and experimental methods

2021 ◽  
pp. 111821
Author(s):  
Márcio Gonçalves ◽  
Nuno Simões ◽  
Catarina Serra ◽  
Inês-Flores-Colen ◽  
Kenny Rottenbacher ◽  
...  
Keyword(s):  
Experimental Methods ◽  
Unsteady State ◽  
Vacuum Insulation ◽  
Thermal Bridging

A Simulation and Monitoring Based Case Study Regarding the Dynamic Thermal Conditions in Non-Used Attic Space

2019 ◽  
Vol 887 ◽  
pp. 467-474
Author(s):  
Radoslav Ponechal ◽  
Renáta Korenková ◽  
Daniela Štaffenová
Keyword(s):  
Thermal Resistance ◽  
Air Temperature ◽  
Thermal Conditions ◽  
Adjustment Factor ◽  
Solar Absorption ◽  
Roofing Material ◽  
Dark Color ◽  
The Mean ◽  
The Difference

This study solves a problem of the dynamic thermal performance of the residential attic space in moderate climatic zone. Heat loss into the attic space is difficult to be accurately determined by the quasi-stationary method. It depends on the thermal resistance of the ceiling, thermal resistance of the roof, ventilation characteristics and other details, such as the solar absorption of the roofing material or roof orientation. The paper presents results of some parametric simulative calculations, which were calibrated with measurements of air temperature in the attic space during the summer, winter and transitional season. It compares the mean air temperature in the ventilated and non-ventilated attics. The difference between the use of bright and dark color of the roof cover is also compared. An alternative with half thickness of thermal insulation was also simulated. Based on measurements and then the simulation the adjustment factor adjustment factor for heat transfer coefficient was quantified..

Experimental Analysis of Heat Transfer From Ice Rink Floors

Solar Energy ◽  
2006 ◽  
Author(s):  
Jung Mun ◽  
Moncef Krarti
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Thermal Insulation ◽  
Air Temperature ◽  
Experimental Analysis ◽  
Experimental Results ◽  
Water Ice ◽  
Set Up ◽  
Time Required ◽  
The Impact

This paper describes an experimental set-up to evaluate the refrigeration loads for ice rink floors under controlled conditions. The ice-rink set-up was instrumented to measure the temperatures along various locations within the ice-rink floor including the water/ice layer. In addition, the energy used to freeze the water is monitored over the entire charging cycle to evaluate the performance of the ice rink floor for various insulation thermal resistance values (or R-values). Four floor insulation configurations are considered in the experimental analysis of R-0 (no insulation), R-4.2, R-6.7 and R-10 (in IP unit: hr.ft2.°F/Btu). The impact of the air temperature above the ice rink is also evaluated. The experimental results confirm that the addition of the thermal insulation beneath the ice-rink floor reduces the refrigeration load, decreased the time required to freeze the water above the ice rink, and helps maintain lower average ice temperature.

scholarly journals Comparison of Steady-state and In-situ Testing of High Thermal Resistance Walls Incorporating Vacuum Insulation Panels

2015 ◽  
Vol 78 ◽  
pp. 3246-3251 ◽  
Author(s):  
Christopher Baldwin ◽  
Cynthia A. Cruickshank ◽  
Matthew Schiedel ◽  
Brock Conley
Keyword(s):  
Steady State ◽  
Thermal Resistance ◽  
In Situ Testing ◽  
Vacuum Insulation ◽  
High Thermal Resistance

In Situ Experimental Validation of therm Finite Element Analysis for a High R-Value Wall Using Vacuum Insulation Panels

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Matthew J. Schiedel ◽  
Cynthia A. Cruickshank ◽  
Christopher M. Baldwin
Keyword(s):  
Finite Element ◽  
Thermal Resistance ◽  
Experimental Validation ◽  
Department Of Energy ◽  
Test Facility ◽  
Element Analysis ◽  
Theoretical Evaluation ◽  
Vacuum Insulation ◽  
R Value

This paper details the method used for a theoretical evaluation of Team Ontario's, U.S. Department of Energy Solar Decathlon 2013 entrant, high R-value wall using vacuum insulation panels (VIPs). The purpose is to determine a theoretical whole-wall thermal resistance to be used for energy modeling. Theoretical simulations are performed in therm, a two-dimensional finite element heat transfer modeling program, and an in situ experimental validation is conducted in Carleton University's Vacuum Insulation Test Facility located in Ottawa, Ontario, Canada. The theoretical model is refined based on the experimental study, and a whole-wall thermal resistance of Team Ontario's wall design is determined to be 9.4 m2·K/W (53 h·ft2·°F/Btu) at an exterior design temperature of −18 °C (0 °F).

scholarly journals Thermal resistance of masonry walls: a literature review on influence factors, evaluation, and improvement

2021 ◽  
pp. 174425912110095
Author(s):  
Maysoun Ismaiel ◽  
Yuxiang Chen ◽  
Carlos Cruz-Noguez ◽  
Mark Hagel
Keyword(s):  
Energy Consumption ◽  
Literature Review ◽  
Thermal Resistance ◽  
Influence Factors ◽  
Masonry Wall ◽  
Thermal Design ◽  
Masonry Walls ◽  
R Value ◽  
Thermal Bridging ◽  
Code Compliance

Increasing the thermal resistance of masonry wall systems is one of the effective ways to reduce energy consumption in the operation of masonry buildings. This increase is also demanded by newer, more stringent energy codes. However, the effective thermal resistance ( R-value) of masonry walls is affected by many factors, such as thermal bridging, which occurs in places where highly conductive structural components penetrate insulating materials. Thermal bridging is common when connecting masonry veneers to structural backup walls. Furthermore, quick and precise methods for estimating the R-value are needed for thermal design improvements and code-compliance calculations. This study presents a comprehensive literature review on key factors that influence the overall thermal performance of masonry walls, methods to effectively estimate and measure R-values, and improvements in thermal design. In addition to identifying the main technical and practical challenges and the corresponding progress made on each front, key design considerations, such as code compliance, material properties, insulation types, and location, as well as special ties and shelf angles types, are also discussed. This study summarizes critical information and recommendations that will help improve the thermal design of masonry walls, hence reducing the energy consumption of buildings.

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