METHODS OF ACTIVE THERMAL STABILIZATION OF FROZEN GROUND: RUSSIAN DEVELOPMENTS, RESEARCH, AND PROSPECTS
V.P. Melnikov1,2, A.A. Ishkov2,3, G.V. Anikin4,5
a:2:{s:4:"TEXT";s:402:"1Tyumen State University, Tyumen, Russia
2Tyumen Industrial University, Tyumen, Russia
3LLC “RN-KrasnoyarskNIPIneft”, Krasnoyarsk, Russia
4Tyumen Research Centre, Siberian branch of the Russian Academy of Sciences, Earth Cryosphere Institute, Tyumen, Russia
5Autonomous non-commercial organization “Gubernaya Akademiya”, Tyumen, Russia";s:4:"TYPE";s:4:"html";}
Keywords: permafrost soils, ground temperature stabilization systems, carbon dioxide, experimental research, pulsed flow regime, refrigerant
Abstract
This paper provides a detailed review of the methods of active temperature stabilization of frozen soils with an emphasis on stabilization systems with a horizontal evaporator. The experience of Russian and foreign authors in the field of single seasonal cooling devices is presented. The range of seasonal cooling devices applied in Russia and the objects, at which they are installed, are considered. The mechanism of action of both single cooling devices and temperature stabilization systems with a horizontal evaporator is shown. The paper also presents a new experimental installation for thermal stabilization of frozen ground with a horizontal evaporator, on which a number of experiments have been conducted to study refrigerant flows in the circulation circuit of the proposed system under different thermal conditions affecting the evaporator. A description of a full-scale stand is given, and the principle of supplying positive temperature to the evaporator in order to simulate heat removal from the ground and its further dissipation into the atmosphere is described. At present, systems of this type usually use ammonia as a refrigerant; in the proposed system, carbon dioxide is used. It has been shown that the capacity of the installation based on carbon dioxide can be significantly higher than that based on ammonia. The study results make it possible to optimize the configuration of the ground temperature stabilization system with a horizontal evaporator for particular construction sites. The efficiency of the developed system is much better compared to the analogues, which significantly reduces the risk of thawing of frozen ground at operational sites. This is especially relevant at hazardous production facilities working with harmful substances, the ingress of which into the soil imposes a significant ecological trace.
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