A heat exchanger can include a stacked array of interconnected fluid transfer members. The stacked array of interconnected fluid transfer members can include a first fluid transfer member, a second fluid transfer member, a third fluid transfer member, and a fourth fluid transfer member. The first fluid transfer member can include a liquid passageway extending lengthwise though the first fluid transfer member and a set of helical fins extending outwardly from an outer surface of the first fluid transfer member and rotating along a length of the first fluid transfer member. The stacked array of interconnected fluid transfer members can form a jointless structure.