NOVELTY - The method involves forming a membrane seal by intermittently joining unsealed edges (120a) of a sheet portion to adjacent edges (120b) of another sheet portion to form manifold portions along the edges. Another membrane seal is formed by intermittently joining other unsealed edges of the former sheet portion to the adjacent edges of the latter sheet portion to form other manifold portions along other edges. The formation of membrane seals is repeated to form a continuous-pleated membrane exchanger with a stacked array of passageways between membrane layers.    USE - Method for making multiple opening, counter-flow plate-type exchanger e.g. heat and water vapor exchanger such as humidifier and enthalpy exchanger or energy recovery wheel, utilized for energy recovery ventilators (ERVs) applications and heat or moisture applications in a building. Can also be used for air filter applications, gas dryer or separation applications, flue gas energy recovery applications, sequestering applications, gas/liquid separator applications, automobile outside air treatment applications, airplane outside air treatment applications, fuel cell applications, medical and respiratory applications and for humidification of fuel cell reactants for electrical power generation.    ADVANTAGE - The method enables providing an improved counter-flow exchanger that is resistant to all forms of corrosion and an improved separator material that allows airflow to pass bidirectionally without obstruction, thus minimizing pressure drop and allowing for a broader array of geometric configurations. The method enables providing the counter-flow exchanger without the need for any potting resin. The method enables providing a modular and stackable manifold that can be readily integrated into a counter-flow exchanger allowing larger airflow quantities. The method enables providing the plate exchanger with integrated manifold that exhibits a smaller depth profile, comparable to that of an energy recovery wheel. The method enables providing the plate exchanger that is light in weight and utilizes less material, thus reducing overall manufacturing costs and construction time. The method enables providing the plate exchanger that can be easily scaled for large airflow quantities without necessary adjustment to exchanger depth, membrane width, performance efficiency, pressure drop or membrane spacer height. The method enables allowing drop-in replacement for the energy recovery wheels for matching frontal surface dimensions, matching depth dimensions, and matching straight-through airflow arrangement. The method enables providing the exchanger manifold that acts as a drain pan allowing certain condensate holding capacity and allowing longer operation in sub-freezing condensing operation. The method enables providing the exchanger manifold that allows a wide variety of flow path configurations including straight-through, cross-over, and back-to-back configurations, thus structurally attaching and fluidly sealing the manifold plate exchanger to another manifold plate exchanger in a simple manner.    DETAILED DESCRIPTION - The method enables allowing a peripheral sealing unit comprising a silicone foam rubber. The method enables allowing a membrane sheet provided with a water-permeable material selected from a group of corrugated mesh material, corrugated sheet material, mesh material and molded plastic insert. INDEPENDENT CLAIMS are also included for the following:    (1) a core for multiple opening, counter-flow plate-type exchanger for transferring thermal energy and moisture between fluid streams    (2) an opening, counter-flow plate-type exchanger for transferring thermal energy and moisture between fluid streams.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of a starting position for a membrane and a membrane separator that is utilized to make a multiple opening, counter-flow plate exchanger.    Opening counter-flow cores (100)    Reel of membrane (110)    Start of membrane (110a)    Edges of the sheet portion (120a, 120b)    Platform (190)