The thermal budget evaluation of the two-phase closed thermosyphon embankment of the Qinghai–Tibet Highway in permafrost regions

Numerical study of long-term cooling effects of thermosyphons around tower footings in permafrost regions along the Qinghai-Tibet Power Transmission Line

“…Meanwhile, field observations along the QTR, the QTH, and the Chaida'er-Muli Railway, indicate that an "effective cooling distance" of generally less than 2.5 m for a thermosyphon in plateau permafrost soils (J. Wu et al, 2010;Wu et al, 2014;Zhou et al, 2009). Therefore, the thermosyphons around one footing could not considerably influence the foundation soil temperatures of the other two adjacent footings.…”

“…It should be note that, due to the absence of an adiabatic section, external pipe wall temperature did not have any obvious thermal gradient with depth. This is different with temperature distribution along thermosyphon with an adiabatic section; temperatures near the pipe wall under the ground surface has an obvious thermal gradient with the depth (Wu et al, 2014).…”

“…1d-e). Field observations show a satisfactory performance of these applications of thermosyphons: subgrades of the highways and railway have been cooled obviously, with slowed thaw settlement (Jin, 2013;Ma et al, 2012;Pan et al, 2003;Wen et al, 2011;Wu et al, 2014).…”

Thermal performance of a combined cooling method of thermosyphons and insulation boards for tower foundation soils along the Qinghai–Tibet Power Transmission Line

“…The perpendicular distance between the middle and thermosyphon profiles at the location of thermosyphon exceeds "effective cooling distance" of a thermosyphon used in plateau permafrost soils (generally less than 2.5 m (Chen et al, 2011;Wu et al, 2014)). Thus, thermosyphon cannot cool foundation soils in the middle profile directly.…”

Ground-Coupled Natural Circulating Devices (Thermosiphons): A Review of Modeling, Experimental and Development Studies

“…For example, Zhang et al [108] compared calculated and measured outer-wall temperatures at the evaporator section of GCT at left and right embankment shoulders after one year of the construction. Other studies compared spatial distributions of simulated temperature at different depths of the GCT [98,99] and in the ground around the GCT [34,92,94,96,98,182]. In many cases, field data and associated operational information have been used as initial and boundary conditions for numerical models [72,89,96].…”