A heat transfer sheet for a rotary regenerative heat exchanger , the heat transfer sheet comprising: a plurality of rows (F,G) of heat transfer surfaces , each of the plurality of rows (F,G) being aligned with a longitudinal axis (L) that extends between a first end and a second end of the heat transfer sheet , parallel to intended flow directions (A,B), the heat transfer surfaces having a first height (H1) relative to a central plane (CP) of the heat transfer sheet ; and at least one notch configuration for spacing the heat transfer sheets apart from one another, the at least one notch configuration being positioned between adjacent ones of the plurality of rows (F,G) of heat transfer surfaces , the notch configuration comprising: at least one first lobe extending away from the central plane (CP) in a first direction; at least one second lobe extending away from the central plane (CP) in a second direction opposite to the first direction; and either one or both of the at least one first lobe and the at least one second lobe having a second height relative to the central plane (CP), the second height being greater than the first height (H1, H2), characterized in that the at least one first lobe and the at least one second lobe are connected to one another and are in a common flow channel (P) in a longitudinal alternating pattern such that the at least one first lobe is longitudinally adjacent to the at least one second lobe . a plurality of rows (F,G) of heat transfer surfaces , each of the plurality of rows (F,G) being aligned with a longitudinal axis (L) that extends between a first end and a second end of the heat transfer sheet , parallel to intended flow directions (A,B), the heat transfer surfaces having a first height (H1) relative to a central plane (CP) of the heat transfer sheet ; and at least one notch configuration for spacing the heat transfer sheets apart from one another, the at least one notch configuration being positioned between adjacent ones of the plurality of rows (F,G) of heat transfer surfaces , the notch configuration comprising: at least one first lobe extending away from the central plane (CP) in a first direction; at least one second lobe extending away from the central plane (CP) in a second direction opposite to the first direction; and either one or both of the at least one first lobe and the at least one second lobe having a second height relative to the central plane (CP), the second height being greater than the first height (H1, H2), at least one first lobe extending away from the central plane (CP) in a first direction; at least one second lobe extending away from the central plane (CP) in a second direction opposite to the first direction; and either one or both of the at least one first lobe and the at least one second lobe having a second height relative to the central plane (CP), the second height being greater than the first height (H1, H2), characterized in that the at least one first lobe and the at least one second lobe are connected to one another and are in a common flow channel (P) in a longitudinal alternating pattern such that the at least one first lobe is longitudinally adjacent to the at least one second lobe . <EOS>