Enthalpy exchanger
A heat and humidity exchanger comprises panels made up of membrane sheets attached on either side of a separator. Channels extend across each panel between the separator and the membrane sheets. The panels are much stiffer than the membrane sheets. Panels are stacked in a spaced apart relationship to provide an ERV core. Spacing between adjacent panels may be smaller than a thickness of the panels.
1. A heat and moisture exchanger comprising:
a plurality of panels, each of the panels comprising
a flexible separator formed to provide projections to either side of a plane of the separator; and
first and second thin water-vapor-permeable membrane sheets attached to the projections on opposing faces of the flexible separator, the flexible separator holding the first and second water-vapor-permeable membrane sheets in a spaced-apart parallel relationship, the panel stiffened by attachment of the membrane sheets to the flexible separator, the projections formed to provide first channels operable for carrying a first flow between the flexible separator and the first and second water-vapor-permeable membrane sheets in a first direction across each of the panels; and
elongated spacers between the adjacent ones of the panels, the elongated spacers spaced apart from one another in the first direction such that the second channels comprise openings having widths 20 times or more a thickness of the panels;
the panels stacked in a parallel spaced-apart relationship to provide open second channels between adjacent ones of the panels, the second channels extending to carry a second flow through the heat and moisture exchanger in a second direction transverse to the first direction;
wherein adjacent ones of the panels are spaced apart from one another by distances that are less than a thickness of the panels, and the flexible separator of each of the plurality of panels has a depth that is at least 110% of a height of the second channels.
2. The heat and moisture exchanger according to claim 1 wherein the flexible separator of each of the plurality of panels has a depth that is in the range of 110% to 150% of a height of the second channels.
3. The heat and moisture exchanger according to claim 1 wherein the flexible separator comprises a corrugated sheet.
4. The heat and moisture exchanger according to claim wherein the flexible separator is perforated.
5. The heat and moisture exchanger according to claim 1 wherein each of the panels has a thickness in the range of 1.5 mm to 4 mm.
6. The heat and moisture exchanger according to claim 1 wherein the flexible separator comprises a formed aluminum sheet.
7. The heat and moisture exchanger according to claim 1 comprising a plurality of vortex-generating features in at least the first channels or the second channels, the vortex-generating features comprising features selected from: projections from and indentations into one or more surfaces bounding the first channels or the second channels.
8. The heat and moisture exchanger according to claim 1 comprising a plurality of vortex-generating features in at least the first channels or the second channels, the vortex-generating features formed on one or both of the first and second water-vapor-permeable membrane sheets.
9. The heat and moisture exchanger according to claim 8 wherein the plurality of vortex-generating features comprises an array of projections formed in a surface of at least one of the first or second water-vapor-permeable membrane sheets, the projections having heights not exceeding the greater of: 2 mm and 40% of a thickness of the flexible separator.
10. The heat and moisture exchanger according to claim 1 wherein the first and second water-vapor-permeable membrane sheets are asymmetrical and comprise a substrate having an air-impermeable, water-vapor permeable coating on one face of the substrate, wherein the first and second water-vapor-permeable membrane sheets are oriented such that the coatings face into the second channels.
11. A panel according to claim 3 wherein the flexible separator comprises a formed aluminum sheet.