Plate heat exchanger with dual flow path

A plate heat exchanger comprising:

• a plurality of main plates stacked to define a first cavity to direct a first fluid therethrough and a second cavity to direct a second fluid therethrough, the second fluid different from and kept separated from the first fluid, each main plate of the plurality of main plates including a plurality of ridges and troughs, defining at least one main plate peak and at least one main plate valley;
• and
• an intermediate plate located in the second cavity between adjacent main plates, the intermediate plate including a plurality of ridges and troughs, defining at least one intermediate plate peak and at least one intermediate plate valley;
• wherein one or more of a pitch between adjacent intermediate plate peaks differs from a pitch between adjacent main plate peaks or an amplitude between adjacent intermediate plate peaks and intermediate plate valleys differs from an amplitude between adjacent main plate peaks and main plate valleys.