The invention concerns devices for water storage heating and delivery. A storage water heater of the invention provides an amount of unmixed recently heated water from an internal small volume during a draw along with water from a main volume. When water is drawn from the storage water heater an amount of recently heated water substantially unmixed with the remaining volume of the tank is drawn along with heated water from the remaining volume. Substantial performance increases in the hot water that may be delivered over a period such as an hour may be achieved compared to an otherwise identical storage water heater that lacks the invention. Non-confidential Abstract of Invention: The invention provides a significant increase in the performance of storage-based water heating systems both in terms of short-term discharge characteristics and long-term energy efficiency through controlled energy addition. The control of the energy addition process is achieved primarily through passive means which assure both manufacturability and reliability. The invention is applicable to all storage-based water heating systems in which the heating of the stored volume is primarily internal to the device (across a material interface) and in which the heated water is drawn directly from the stored volume. Applications: Since this type of configuration is essentially universal the scope of the invention includes devices for which the material interface is in the form of either an electrical resistance element or a heat exchange surface separating the stored volume from a higher temperature fluid such as in combustion-fired systems heat-pump systems heat recovery systems and steam-based systems.
Better performance in terms of short-term discharge characteristics and long-term energy efficiency.