A heat exchanger for transferring heat between first and second material streams, said heat exchanger comprising: a body portion comprising a thermally conductive material, said body portion comprising; a plurality of vent channels defined through said body portion with said vent channels configured to pass the first material stream through said body portion, a plurality of feed channels defined through said body portion and configured to pass the second material stream through said body portion with said feed channels spaced from and in thermal communication with said vent channels such that at least one of the first and second material streams transfer heat with another one of the first and second material streams within said body portion, wherein each of said feed channels has a feed inlet for allowing the second material stream to enter said feed channels with said feed inlet having a cross-sectional area and with said cross-sectional area of said feed inlet of at least one of said feed channels different than said cross-sectional area of said feed inlet of another one of said feed channels for normalizing a flow rate of the second material stream through said feed channels of said body portion, wherein each of said feed channels has a feed outlet opposite said feed inlet of said feed channels for allowing the second material stream to exit the feed channels with said feed outlet of each of said feed channels having a cross-sectional area and with said cross-sectional area of said feed outlet of at least one of said feed channels different than said cross-sectional area of said feed outlet of another one of said feed channels, characterized in that said feed channels have a main feed portion between said feed inlet and said feed outlet of said feed channels with said main feed portion of said feed channels having a cross-sectional area and with said cross-sectional area of said main feed portion of at least one of said feed channels larger than said cross-sectional areas of said feed inlet of said feed channels. a body portion comprising a thermally conductive material, said body portion comprising; a plurality of vent channels defined through said body portion with said vent channels configured to pass the first material stream through said body portion, a plurality of feed channels defined through said body portion and configured to pass the second material stream through said body portion with said feed channels spaced from and in thermal communication with said vent channels such that at least one of the first and second material streams transfer heat with another one of the first and second material streams within said body portion, wherein each of said feed channels has a feed inlet for allowing the second material stream to enter said feed channels with said feed inlet having a cross-sectional area and with said cross-sectional area of said feed inlet of at least one of said feed channels different than said cross-sectional area of said feed inlet of another one of said feed channels for normalizing a flow rate of the second material stream through said feed channels of said body portion, wherein each of said feed channels has a feed outlet opposite said feed inlet of said feed channels for allowing the second material stream to exit the feed channels with said feed outlet of each of said feed channels having a cross-sectional area and with said cross-sectional area of said feed outlet of at least one of said feed channels different than said cross-sectional area of said feed outlet of another one of said feed channels, characterized in that said feed channels have a main feed portion between said feed inlet and said feed outlet of said feed channels with said main feed portion of said feed channels having a cross-sectional area and with said cross-sectional area of said main feed portion of at least one of said feed channels larger than said cross-sectional areas of said feed inlet of said feed channels.