A data center is cooled through hydronic convection mechanisms, geothermal mechanisms or combinations thereof. The individual computing devices of such a data center are cooled through a thermally conductive interface with a liquid. The liquid's container can extend to a cooling apparatus located physically above such computing devices to provide hydronic convection cooling, or it can extend into the earth, either in the form of a heat pipe, or in the form of conduits through which the liquid is actively pumped. The hydronic convection cooling and geothermal heat pipe cooling operate via temperature differentials and consume no external electrical power. Geothermal cooling avoids heat soak by utilizing multiple different sets of conduits extending into the earth, where at least some of those sets of conduits are not utilized for a period of time. Combinations of hydronic convection mechanisms and geothermal cooling can also be utilized.