In some embodiments, a thermosiphon configured for use within a temperature-regulated storage device includes: a condenser region, including a plurality of evenly spaced condenser channels with horizontally symmetrical bifurcated branches connected to an adiabatic channel, each of the plurality of condenser channels connected at a top position to an upper channel; an evaporator region, including a plurality of evaporator channels, wherein each of the plurality of evaporator channels has a flow channel formed in a serpentine channel pattern and each subunit of the serpentine channel pattern is attached to a vapor return channel at a top of the subunit, and wherein the evaporator region has at least one lowest position connected directly to a vapor return channel; and an adiabatic region including at least one adiabatic channel connecting the evaporator channels and the condenser channels.