The disclosure relates to a thermosiphon system operable to consistently maintain the permafrost and active frost layer in a frozen condition to adequately support buildings and other structures. During cooler seasons, the thermosiphon system uses a passive refrigeration cycle to efficiently maintain the frozen layers using the cold air. When the air temperature rises during the warmer months, the system transitions into an active refrigeration mode that uses a refrigeration system to minimize thawing or degradation of the permafrost and active frost layers.