By Justine Yu, Elizabeth Gao, M.SAME, Kevin Bjella, David Shields, M.SAME, David Christensen, M.SAME, and Rene Parker
The Department of Defense is responsible for ensuring America’s dominance in the Arctic. However, operations at the top of the world are confronted by several challenges, including extreme temperatures and winds, short summers, and large areas of permafrost.
Current rigid wall shelters were not designed for Arctic conditions. To address this, the U.S. Army Engineer Research & Development Center’s Construction Engineering Research Laboratory, along with the Cold Regions Research & Engineering Laboratory, Product Manager Force Sustainment Systems, and Select Engineering Services conducted a field test of an external insulation wrap for rigid shelters: the Mobile Insulation System for Energy Reduction (MISER).
Field testing of MISER was carried out in Fairbanks, Alaska. A pair of rigid wall shelters were placed side by side, with one serving as the baseline and the other the test. Data from power consumption and temperature sensors was collected from November 2021 to February 2022. Temperature readings were taken inside near the ceiling, the floor, and at the 4-ft level. Electrical data and outdoor ambient temperature also were collected.
The demonstration showed that MISER helped maintain a thermostat-controlled 67.4°-F internal temperature, compared to the baseline shelter that reached a maximum of 55.2°-F. Energy consumption was over 35 percent lower than the control.
MISER was also evaluated for durability and ease of use. Despite below-freezing temperatures and snow-covered ground, the system was installed by two people in less than two hours. The durability of its components is excellent, with heavy duty materials tested for use at -60°F. After multiple set-ups and strikes, no signs of wear or degradation were evident.
COLD WEATHER COMFORT
Once outdoor temperatures drop below -5°-F, a standard electric heater cannot maintain a 65°-F indoor temperature, with floor temperatures nearly 30°-F colder. Additionally, when temperatures outside reach -20°-F, below-zero interior temperatures are not uncommon.
The MISER-covered shelter was able to maintain a thermostatically controlled 67°-F average interior temperature. Had the control shelter been able to maintain a 67°-F interior temperature, the difference in energy use would have been even higher.
The Ground Insulative Cover, which was fabricated from the same materials as MISER but designed to fit under the shelter, also demonstrated great potential to insulate the permafrost from heat. While the active surface layer of the permafrost will undoubtedly thaw to some extent during summer, if the ground cover can limit the thawing to a few inches, the terrain will remain stable.
Both systems show promise as a way to expand cold weather performance and allow the shelter to confidently be deployed. While all materials used in the fabrication of the system are rated to meet the extreme Arctic environment, controlled laboratory tests should be conducted to confirm system performance.
Justine Yu is Research Architect/Project Manager, Elizabeth Gao, M.SAME, is Materials Engineer, and Kevin Bjella is Energy Program Manager, Construction Engineering Research Laboratory – U.S. Army Engineer Research & Development Center. They can be reached at firstname.lastname@example.org; email@example.com; and firstname.lastname@example.org.
David Shields, M.SAME, is Mechanical Engineer, David Christensen, M.SAME, is Electrical Engineer, and Rene Parker is CEO/President, Select Engineering Services. They can be reached at email@example.com; firstname.lastname@example.org; and email@example.com.
[This article first published in the September-October 2022 issue of The Military Engineer.]