Devices and methods for mixing fuel and air are presented. A device may include an air pipe extending within a firing tube configured to receive a flow of air: and a plurality of fuel pipes extending within the firing tube in parallel with one another and with the air pipe and configured to receive a flow of fuel: wherein the air pipe includes first apertures configured to release the air from inside the air pipe radially outward from the air pipe. the first apertures arranged around a circumference of the air pipe, and wherein a first fuel pipe of the plurality of fuel pipes includes second apertures configured to release the fuel from inside the first fuel pipe radially outward from the first fuel pipe. the second apertures arranged around a circumference of the first fuel pipe.

A dark radiator includes a burner, a fan and a radiant tube which is connected to an exhaust gas discharge line, wherein the burner is connected to a fuel gas supply, wherein the fan is designed to supply the burner with combustion air, wherein the burner is designed to output a flame into the radiant tube, wherein the fuel gas supply is connected to a hydrogen source.