In one aspect, the present invention is directed to boiler heating system, comprising: a hollowed-walls cylinder, for storing therein water to be heated; a partition in a form of a cylinder, disposed inside the hollowed-walls cylinder, distantly from its vertical walls; the partition having an upper water passage and a lower water passage, for allowing water transition between the inner side of the partition and the outer side of the partition; a heating element disposed inside the inner space of the hollowed-walls cylinder; a water inlet, disposed in the lower side of the hollowed-walls cylinder; and a water outlet, disposed in an upper side of the hollowed-walls cylinder, thereby (a) allowing heating the water without being in direct contact between the heating element and the water, resulting with no scale accumulation, and (b) separation between ascending water and descending water, thereby accelerating the water warming.

A settings data storage stores unique serial numbers and information regarding a plurality of patterns for alternately switching between normal operation for operating at high capacity and suppressed operation for operating at low capacity each unit time. A pattern specifier determines information for a pattern set in accordance with even and odd serial numbers. A water-heating heat amount determiner determines a heat amount necessary for water heating. A water heating scheduler establishes a water heating plan based on information regarding the pattern determined by the pattern determiner and the water-heating heat amount as determined by the water-heating heat amount determiner. A water heating controller alternately switches between normal operating and suppressed operation to heat water in accordance with the water heating plan established by the water heating scheduler.

The present invention relates to a hot water storage tank (202, 302, 402, 502, 602, 702), defining a primly storage volume (204, 304, 404, 504, 604, 704), with at least one heat source (212, 312, 412, 512, 612, 712) positioned in and operable to directly heat water in the upper portion (207, 307, 407, 507, 607, 707) of the primary storage volume (204, 304, 404, 04, 604, 704), and a pump or other means (237, 337, 437, 537, 637) that draws water, from the lower portion (209, 309, 409, 509, 609, 709) of the tank into a heat transfer device (216, 316, 416, 516, 616, 716), situated in said upper portion (207, 307, 407, 507, 607, 707). The heat transfer device (216, 316, 416, 516, 616, 716) is configured to enable the transfer of heat from heated water in the upper portion (207, 307, 407, 507, 607, 707) to the drawn water prior to discharge into the water in the upper portion (207, 307, 407, 507, 607, 707).

In one aspect, the present invention is directed to boiler heating system, comprising: a hollowed-walls cylinder, for storing therein water to be heated; a partition in a form of a cylinder, disposed inside the hollowed-walls cylinder, distantly from its vertical walls; the partition having an upper water passage and a lower water passage, for allowing water transition between the inner side of the partition and the outer side of the partition; a heating element disposed inside the inner space of the hollowed-walls cylinder; a water inlet, disposed in the lower side of the hollowed-walls cylinder; and a water outlet, disposed in an upper side of the hollowed-walls cylinder, thereby (a) allowing heating the water without being in direct contact between the heating element and the water, resulting with no scale accumulation, and (b) separation between ascending water and descending water, thereby accelerating the water warming.

A washer tank according to an embodiment includes: a first container which stores a washer fluid and retains a temperature of the washer fluid; an inflow pipe through which the washer fluid flows into a storage space in the first container; an outflow pipe through which the washer fluid flows out of the first container from the storage space; and a heating portion which heats the washer fluid, in which all the inflow pipe, the outflow pipe, and the heating portion are disposed in a lower portion of the first container.

A water heater appliance, including methods of operation, is provided herein. The water heater appliance may include a casing, a tank, an inlet conduit, an electric heating system, and a controller coupled to an auxiliary power generator. The tank may be disposed within the casing and define an inlet and an outlet. The inlet conduit may be mounted to the tank at the inlet of the tank. The controller may be operably coupled to the electric heating system and configured to initiate a heating cycle. The heating cycle may include identifying a daily peak auxiliary power period, determining a contemporary voltage reading at the water heater appliance, predicting an occurrence of the daily peak auxiliary power period from the auxiliary power generator, and heating water within the water heater at the predicted occurrence of the daily peak auxiliary power period.

A thermosiphon system for hot water heaters. In an embodiment, the thermosiphon includes a multi-tubular structure which in an embodiment is insertable through the cold water connection in a hot water tank in order to provide for a thermosiphon action in the hot water heater, to keep water circulating and prevent temperature stratification of water in the tank. In another embodiment, a thermosiphon design is fabricated within a water heater tank at the factory.

A water holding tank for electric water heaters is described and particularly an improvement to the bottom end construction of the tank to prevent bacteria proliferation and the elimination of the cavitated circumferential area where sediments deposit to form a culture bed for bacteria to proliferate. Instead of modifying the shape of the bottom wall the improvement is a simple solution in that a filler material is set in at least a lowermost portion, and preferably a major portion, of the cavitated circumferential area to isolate that area from the interior of the water holding tank and form smooth flat surface areas which are planar to cause sediments to disperse and not form beds for bacteria to proliferate.

A variable power water heater is disclosed. In embodiments, the variable power water heater includes a water tank, a heating element, a power supply circuit, a switch, and a controller. The heating element may be disposed within or coupled to the water tank. The power supply circuit may be configured to generate a power signal for the heating element. The switch may be configured to couple the power supply circuit to the heating element, and the controller may be configured to toggle the switch according to a pulse width modulation (PWM) scheme to control a duty cycle of the power signal transmitted from the power supply circuit to the heating element.