Counter-flow energy recovery ventilator (ERV) core
A heat and humidity exchanger has example application in exchanging heat and water vapor between fresh air entering a building and air being vented from the building. The heat and humidity exchanger has a self-supporting core formed from layered sheets of a moisture-permeable material. Plenums are arranged to direct fluid streams into and out of the core. The plenums may be on opposing sides of the core to permit counterflow exchange of heat and water vapor.
1. A method of making a heat and humidity exchanger core, the method comprising:
molding each of a plurality of water vapor-permeable membrane sheets, the molding deforming the sheets to form a plurality of out-of-plane features in a central section, and a plurality of out-of-plane features in first and second manifold regions on opposing sides of the central section;
stacking the plurality of membrane sheets, and joining adjacent membrane sheets together, to provide:
a plurality of channels between each adjacent pair of the membrane sheets, the channels defined by the out-of-plane features in the central section of adjacent ones of the membrane sheets, and
first and second plenums between each adjacent pair of the membrane sheets, the first plenum defined at least in part by the first manifold regions of adjacent ones of the membrane sheets, and the second plenum defined at least in part by the second manifold regions of adjacent ones of the membrane sheets, the plurality of channels fluidly connecting the first plenum to the second plenum;
wherein the water vapor-permeable membrane sheets are made from a composite material comprising a formable support layer and a water vapor-permeable coating, and a height of the channels is at least 2 mm.
2. The method of claim 1 wherein molding by deforming each of a plurality of water vapor-permeable membrane sheets comprises thermoforming, compression molding or vacuum forming each of the plurality of water vapor-permeable membrane sheets to form the plurality of out-of-plane features in the central section, and the plurality of out-of-plane features in the first and second manifold regions.
3. The method of claim 1 wherein molding by deforming each of a plurality of water vapor-permeable membrane sheets to form a plurality of out-of-plane features in a central section comprises: molding a plurality of water vapor-permeable membrane sheets to form a plurality of parallel pleats or grooves in the central section of each membrane sheet.
4. A method of making a heat and humidity exchanger core, the method comprising:
making molded membrane sheets by molding each of a plurality of water vapor-permeable membrane sheets, the molding deforming the sheets to form a plurality of out-of-plane features in a central section, and a plurality of out-of-plane features in first and second manifold regions of each membrane sheet,
stacking the molded vapor-permeable membrane sheets alternately with co-extensive flat vapor-permeable membrane sheets, and joining adjacent membrane sheets together, to provide:
a plurality of channels between each adjacent pair of the membrane sheets, the channels defined by the out-of-plane features in the central section of a molded membrane sheet and the adjacent flat membrane sheet of each adjacent pair of the membrane sheets; and
first and second plenums between each adjacent pair of the membrane sheets, the first plenum defined at least in part by the first manifold region of a molded membrane sheet and the adjacent flat membrane sheet of each adjacent pair of the membrane sheets, and the second plenum defined at least in part by the second manifold region of the molded membrane sheet and the adjacent flat membrane sheet of each adjacent pair of the membrane sheets, the plurality of channels fluidly connecting the first plenum to the second plenum;
wherein the molded water vapor-permeable membrane sheets are made from a composite material comprising a formable support layer and a water vapor permeable coating, and a height of the channels is at least 2 mm.
5. The method of claim 4 wherein molding by deforming each of a plurality of water vapor-permeable membrane sheets to form a plurality of out-of-plane features in first and second manifold regions comprises: molding a plurality of water vapor-permeable membrane sheets to form a plurality of ribs in said first and second manifold regions of each membrane sheet and wherein the flat water vapor-permeable membrane sheets are supported between ribs of adjacent molded membrane sheets in the first and second manifold regions.