Abstract: The present invention relates to heat exchange elements and heat exchange assemblies and water heaters containing such heat exchange elements. The inventive heat exchange elements include an elongated support member or spine, from which extends either a single vane which is the length of the support member of a series of vanes. The heat exchange element is able of be positioned parallel to the longitudinal axis of a flue. The heat exchange element may impart helical motion to the flue gases in one embodiment, but in another embodiment no helical motion is imparted to the flue gases. The embodiment of the invention includes several methods of manufacture of the heat exchange elements. The embodiments of the water heater and heat exchange assembly also disclose the use of a baffle for use in association with the elements, to improve the efficiency of the elements at the upstream end of the water heater.

Abstract: A flat plate solar collector (10) of the header/riser type housed in a glazed collector enclosure (14) and having liquid conduits comprising risers (24) intercommunicating with headers (22, 26) at both ends of the risers. The risers are tapered and the headers are surrounded by full heat insulation (28, 30) as defined. The tapering of the risers is effective to prevent bursting of any riser occasioned by freezing of a working liquid especially for example potable water contained therein, by promotion of initial freezing in a localized region of the riser around its minimum cross-sectional area (32) followed by progressive travel of the freezing of the working liquid in the riser in a direction away from the localized region. The full heat insulation is effective to substantially delay total freezing of all the liquid in the headers.