Innovative Environmental Chamber Construction for Accurate Thermal Performance Evaluation of Building Envelopes in Varied Climates

Abstract

The testing of multi-layer building envelopes was performed using an environmental chamber following the ASTM C1363 and ISO 8990 standards. However, performing such tests in accordance with the standards by an accredited laboratory can be extremely costly, and many laboratories have waiting lists of several months. This is a significant cost for researchers and building material testing companies in the construction industry. Therefore, the goal of this study was to design, construct, and test a portable environmental chamber for building envelopes to validate the accuracy and the efficiency of the built environmental chamber to measure the thermal performance (i.e., R-value) of wall panels at extreme climate conditions (i.e., −20 °C and 80 °C). The results indicated that the built environmental chamber is capable of maintaining the steady state temperature inside the chamber during the hot climate condition test of 65 °C (150 °F) within ±0.5 °C and during the cold climate condition test of −16 °C (3 °F) within ±1 °C, meeting the requirement of the ASTM C1363-19 standard. The results also indicated that the built environmental chamber is capable of measuring the R-value of building envelopes under hot climate conditions with an accuracy of ±0.73 ft2·°F h/BTU (±0.129 m2 °C/W) and under cold climate conditions with an accuracy of ±1.02 ft2 °C·h/BTU (±0.180 m2 °C/W). This university-based testing program allows companies to test several building envelopes at a relatively low cost and minimum wait duration. Additionally, such an environmental chamber can be used for the accurate evaluation of innovative designs to determine promising designs and to refine wall specimen prototypes for manufactured materials.

Assessing Hygrothermal Performance in Building Walls Engineered for Extreme Cold Climate Environments

“…Interestingly, in Figure 8, it appears that during the initial stage of the simulation, there was an hour in the interior surface graph (colored in yellow and circled in red) that bordered on the risk of mold growth, but this situation resolved itself over time. Figures 8,9 and 11 also show that there is no potential risk of mold growth in the interior surface and the exterior plywood layers of the AHWs. However, the double curved lines representing the lowest thresholds on the exterior EPS layer indicate a potential risk of mold growth in the adaptable walls.…”

“…Most of the previous studies have solely focused on evaluating the thermal performance (i.e., thermal resistance or thermal transmittance) of building envelopes [5][6][7][8][9]. One critical factor influencing the thermal performance of exterior wall envelopes is the thickness of insulation along with its orientation relative to sun exposure, resulting in varying solar radiation intensities [10,11].…”