Abstract: The present invention provides a new heat exchanger element comprising a premix burner with an outward curved or ridged burner surface. The heat exchanger element further comprises a combustion chamber. The combustion chamber is bound on one side by the burner and is further made up of water cooled metal walls which, starting from the burner and in downstream direction, first widen and thereafter narrow down to the width of a customary heat exchanger element. This creates enough space for a proper combustion, avoiding dead angles and recirculation or too early ending of the combustion reaction, thereby reaching low emissions of NOx and CO.

Abstract: The present invention provides a new heat exchanger element comprising a premix burner with an outward curved or ridged burner surface. The heat exchanger element further comprises a combustion chamber. The combustion chamber is bound on one side by the burner and is further made up of water cooled metal walls which, starting from the burner and in downstream direction, first widen and thereafter narrow down to the width of a customary heat exchanger element. This creates enough space for a proper combustion, avoiding dead angles and recirculation or too early ending of the combustion reaction, thereby reaching low emissions of NOx and CO.

Abstract: The present invention relates to a co-cast heat exchanger element intended for a central heating boiler, which heat exchanger element is made from substantially aluminum, the heat exchanger element being provided with walls which enclose a water carrying channel, and with at least one wall which encloses at least one flue gas draft to which a burner can be connected, at least one wall which encloses the at least one flue gas draft being water-cooled in that it also forms a boundary of the water-carrying channel, while one of the water-cooled walls is provided with heat exchanging surface enlarging pins and/or fins which extend in the respective flue gas draft and is also provided with other heat exchanging surface enlarging metallic porous structures.