Abstract: A concentric receiver tube for passing water to be disinfected twice before the aperture path of a concentric solar reflector. The novel receiver tube uses the water that is heated by the reflector to additionally pre-heat fresh incoming water to maximize the heat transfer exchange rate. The novel concentric tube receiver to preheat and disinfect water when the source of heat are combustion gases or catalyst beds. The maximum disinfecting temperature needs only be 90 C in order to create an instantaneous disinfection condition.

Abstract: Profiling the temperatures in the regeneration airstream for a desiccant bed yields higher thermal efficiency. In staged regeneration, distinct heating elements are thermostatically controlled to attain progressively higher temperatures toward the hotter end of the bed. Stratified heat recovery can be used to transfer heat from process air from zones on the process side to regeneration airstreams headed for thermally corresponding zones on the regeneration side of the desiccant bed. A recirculation system diverts process air from the hottest process zone or zones directly to the hottest corresponding zone or zones on the regeneration side.