Abstract: A water heater which includes a tank (60) with a water inlet (64) and outlet (26). At least one divider (18) for dividing the tank into a plurality of chambers (12), (14) with adjacent chambers being arterial (28). A first chamber (14) is connected to the outlet and another one of the chambers (12) is connected to the inlet. Heating means (20) may be located in some or all of the chambers. The dividers may be oriented vertically or horizontally (18). They may be movable and of specific construction including apertures (28) therein for arterial connection to adjacent chambers which apertures may contain flow control thermostats. They may be insulated to reduce heat transfer between compartments. Where displacement is via density/temperature changes in a compartment, stops may be provided to limit the travel of the dividers/partitions. Sacrificial protection (74) may be provided for the tank.

Abstract: A retrofit unit for heating and cooling liquid stored in a recipient, the retrofit unit comprising: a housing defining a cavity and allowing the retrofit unit to be external to the recipient; a thermoelectric device in the cavity, comprising at least one thermoelectric module having a heat radiation side and a heat absorption side; a control unit in the cavity, for controlling the energy to be applied to the thermoelectric module; and a connecting element on the housing, the connecting element allowing the thermoelectric device one of direct contact and indirect contact with the liquid stored in the recipient to selectively heat and cool the liquid by emitting and absorbing heat, respectively.