channel inlet and outlet instead of terminating at an edge of a plate 10 pass through each plate 10 the insulating channels can also be positioned to provide thermal separation of neighboring sections of any channels to limit thermal communication the insulating channels can improve the effectiveness of the heat exchange zone between two neighboring channels by thermally isolating sections that fold in a sinuous pattern an example of the further use of insulating channels is shown in fig4 the heat exchanger comprises at least one plate 10 having a first channel 12 defined therein and having an inlet 14 and an outlet 16 the plate 10 can be divided into two sections a heat exchange section 40 and an expansion section 48 where the expansion section 48 is partially thermally insulated from the heat exchange section 40 by an insulating channel or by an insulating region such as a hole 60 through the plate 10 the hole 60 can be filled with a low conductivity gas or an insulating material the first channel 12 follows a sinuous path where there is a first section for carrying a coolant the first channel 12 then passes through a second section that is disposed within the expansion section 48 of the plate 10 the first channel 12 continues back to the heat exchange section 40 where the first channel 12 follows a sinuous path to provide a longer heat exchange path for the coolant the sinuous path of the first channel 12 folds back on itself and is separated by a insulating channel 62 to limit the heat flow between neighboring sections of the first channel 12 the first channel 12 can include an insulating channel 24.