Exhaust structure of sub-boiler of small cogenerator and cover assembly for exhaust channel of sub-boiler of small cogenerator

The present invention relates to an exhaust structure of a sub-boiler (200) of a small cogenerator that includes a Stirling engine (110) producing electricity and being heated by an engine burner (120), and the sub-boiler (200) is disposed on the Stirling engine (110), having a sensible heat exchanger (210) and a latent heat exchanger(220), and making hot water, in which a channel connecting an engine head where an exhaust gas heating the Stirling engine (110) is discharged with the latent heat exchanger (220) is formed, and the channel is formed such that the discharged exhaust gas exchanges heat while flowing from the top to the bottom of the latent heat exchanger (220).