Waste water heat recovery unit

摘要

The heat exchanger comprises a primary tube arranged to receive a first fluid and a plurality of secondary tubes arranged to receive a second fluid. The primary tube is fluted. The secondary tubes are received in respective flute channels of the primary tube to facilitate conductive thermal transfer of energy between the first and second fluids. The heat exchanger is particularly suitable for use in recovery of thermal energy from waste water of a shower, whereby the waste water can be passed through the primary tube and mains cold water passed through the secondary tubes before being sent to a mixer valve of the shower, thereby requiring less hot water to be mixed to provide a shower of the same temperature. The secondary tubes may be provided on a manifold (figure 2A) that fits onto the primary tube (figure 1A). When arranged vertically, the primary tube may be helical (figure 1B) to slow the descent of warm waste water to ensure sufficient time for heat transfer. The primary tube fluting may also be helical (figure 1C) to promote turbulent flow of waste water, enhancing heat transfer. A thermally insulated jacket (figure 3A) can be provided around the heat exchanger.