Thermal cycling devices are provided. In one embodiment, a thermal cycling device includes a packed tube comprising an inlet portion defining an inlet and an outlet portion defining an outlet. The packed tube is provided in a double coil arrangement, wherein the double coil arrangement causes radially neighboring turns of the packed tube to have opposing flow directions therethrough. The thermal cycling device further includes a cooling device disposed axially adjacent to the packed tube, and a heating device disposed axially adjacent to the packed tube opposite the cooling device.