Abstract: Disclosed a heating unit for a portable fuel heater for heating ambient air. In one exemplary embodiment, the heating unit comprises: a first side wall defining an inner space, said inner space forming a combustion chamber; a second side wall arranged outside around said first side wall, said first side wall and said second side wall defining a first annular gap therebetween, said first annular gap forming a cooling chamber adapted to be crossed by a cooling air flow to subtract heat from the first side wall and transfer it to an external environment to be heated; wherein said first side wall forms a first plurality of bosses adapted to promote a thermal exchange of said first side wall with the combustion chamber and with the cooling chamber.

Abstract: A transportable combustion air heater comprises a transportable supporting frame, a housing fixed to the frame, a cylindrical combustion chamber arranged in housing, a cylindrical annular thermal exchange channel formed around the combustion chamber, an external heating chamber defining an annular fume channel around the thermal exchange channel, in which one or more transversal guide walls are arranged in the external heating chamber, which guide walls lengthen flow paths of the fumes in the annular fume channel from fume inlet openings to an exhaust fume opening.

Abstract: A transportable combustion air heater comprises a transportable supporting frame, a housing fixed to the frame, a cylindrical combustion chamber arranged in housing, a cylindrical annular thermal exchange channel formed around the combustion chamber, an external heating chamber defining an annular fume channel around the thermal exchange channel, in which one or more transversal guide walls are arranged in the external heating chamber, which guide walls lengthen flow paths of the fumes in the annular fume channel from fume inlet openings to an exhaust fume opening.

Abstract: Disclosed a heating unit for a portable fuel heater for heating ambient air. In one exemplary embodiment, the heating unit comprises: a first side wall defining an inner space, said inner space forming a combustion chamber; a second side wall arranged outside around said first side wall, said first side wall and said second side wall defining a first annular gap therebetween, said first annular gap forming a cooling chamber adapted to be crossed by a cooling air flow to subtract heat from the first side wall and transfer it to an external environment to be heated; wherein said first side wall forms a first plurality of bosses adapted to promote a thermal exchange of said first side wall with the combustion chamber and with the cooling chamber.