Radiant to convection transition for fired equipment

Fired equipment comprising:

• a radiant section configured to absorb thermal energy primarily via radiation from a burner flame within the fired equipment;
• a convection section configured to absorb thermal energy via radiation from the burner flame and convection from combustion gases flowing through the fired equipment, the convection section axially aligned with the radiant section and reducing in interior cross-sectional area in a downstream direction of the combustion gases flowing through the fired equipment;
• a transition section having an input dimension substantially the same as an output dimension of the radiant section, the transition section further having an output area substantially the same as an input area of the convection section, and the transition section axially aligned with the radiant section and the convection section and connecting the radiant section to the convection section without a target wall;
• and
• a circuit of pipes configured to flow fluid through the fired equipment and absorb thermal energy generated within the fired equipment into the fluid, wherein a first portion of the circuit of pipes resides substantially about an interior periphery of the radiant section, wherein a second portion of the circuit of pipes substantially fills an interior volume of the convection section.