Low temperature duct and low temperature control system

The invention provides a low temperature duct and a low temperature control system. The low temperature duct comprises a duct body (10), wherein a first pipeline (11), a second pipeline (12) and a reflux pipeline (13) which are arranged in parallel are arranged in the duct body (10); a heat absorbing cavity (14) is formed in one end of the duct body (10); the first pipeline (11), the second pipeline (12) and the reflux pipeline (13) communicate with the heat absorbing cavity (14); the first pipeline (11) is used for transporting first reaction fluid; the second pipeline (12) is used for transporting second reaction fluid; after being mixed in the heat absorbing cavity (14), the first reaction fluid and the second reaction fluid are subjected to reflux in the reflux pipeline (13); and afterthe first reaction fluid and the second reaction fluid are mixed, an endothermic reaction can be generated. According to the low temperature duct disclosed by the invention, only after the first reaction fluid and the second