SECTIONAL HEAT EXCHANGER FOR USE IN A HEAT CELL

A sectional heat exchanger for a condensing heat cell comprises two end segments and one or more than one intermediate segment(s). The one or the more than one intermediate segment(s) and the two end segments are assembled in the heat exchanger. A combustion chamber is provided in the sectional heat exchanger. Each of the one or the more than one intermediate segment(s) comprises at least one water flow channel for water to be heated. Between each two consecutive segments at least one flue gas flow channel is provided, extending from the combustion chamber. The one or the more than one intermediate segment(s) each comprise a horizontal row of ribs extending into the flue gas flow channel in order to increase heat exchange from the flue gas to the water to be heated. Ribs at the two outer sides of the horizontal row of ribs have a larger height than ribs in the middle of the row of ribs. With height of the rib is meant the dimension of the rib in the vertical direction of the sectional heat exchanger. The more than one intermediate segment(s) each comprise a plurality of rows of pins extending in the flue gas channel to increase heat transfer.