Disclosed herein is a water heating system including a water heater having a tank, and a first temperature sensor disposed toward a top end of the tank to measure a first temperature and a second temperature sensor disposed toward a bottom end of the tank to measure a second temperature. The water heating system can further include a controller communicably coupled to the first temperature sensor and the second temperature sensor, where the controller determines an amount of heated water in the tank based on one or more algorithms and measurements made by the first and second temperature sensors.

Disclosed are a water heating device, and a method for manufacturing a smoke tube for a water heating device. The water heating device includes a body having an interior space that accommodates water, a combustion chamber provided in the interior space of the body and that provides a space for a combustion reaction, a smoke tube connected to the combustion chamber, that guides a combustion gas generated during the combustion reaction from the combustion chamber to an outside of the body, and wound in a spiral shape in at least a partial section, and a turbulator provided in at least a partial section of an interior of the smoke tube to make the combustion gas flowing in the interior of the smoke tube turbulent, and wound in a spiral shape to correspond to the spiral shape of the smoke tube.

The disclosed technology includes systems and methods for operating a fluid heating device comprising an electric heating element and a gas burner. The disclosed technology can include a system and method that can receive flow data from a flow sensor that is indicative of a flow rate of a fluid in a fluid heating system, determine if the flow rate is less than or equal to a threshold flow rate, and output a control signal to heat the fluid with the electric heating element, the gas burner, or both based on the flow rate data.

The purpose of the present invention is to provide a hot water supplying apparatus which enables supply of hot water by utilizing waste heat of a pipe and a boiler as a heat source if there is a small quantity of residual hot water to use therefor, the residual hot water being required when using hot water of an instantaneous boiler, and a method for utilizing waste heat of a hot water supplying apparatus. The hot water supplying apparatus of the present invention for achieving said purpose comprises: a sensible heat exchanger for heating a heating fluid by means of combustion heat from a burner; a hot water supply heat exchanger for generating hot water by means of a heat exchange between the heating fluid heated by the sensible heat exchanger and direct water, and supplying the hot water to a faucet; and a pump for circulating the heating fluid via a heating fluid flow path which connects the sensible heat exchanger and the hot water supply heat exchanger, wherein the hot water supplying apparatus comprises: a signal reception unit for receiving a final hot water use signal; and a control unit for stopping the operation of the burner on the basis of the signal received by the signal reception unit and controlling the pump to circulate the heating fluid.

A solar power system has a photovoltaic module that supplies electrical current derived from sunlight to a heater system of a hot water tank. The heater system uses the electrical energy from the photovoltaic module, and optionally also from a local power grid, to heat water up to a selected maximum stored hot water temperature. Control circuitry senses when the level of electrical power is below a threshold solar-power level, and in response sets the stored hot water temperature for the heater system to a first lower temperature value. The control circuitry also senses when the level of electrical power is above the threshold solar-power level, an in response sets the stored hot water temperature for the heater system to a second elevated temperature value higher than the lower temperature, making advantageous use of solar power when available. A mixing unit adds cold water to set the dispensed water temperature.

A heating system including a water conductor, a valve configured to cooperate with a fluid moving device which together operable to selectively circulate a heat transfer fluid in at least one of a first fluid circuit and a second fluid circuit, a heat exchanger and a blower operable to supply a stream of fluid over the heat exchanger, wherein the heat exchanger is fluidly connected to the first fluid circuit, wherein the heat exchanger being disposed to transfer heat between the heat transfer fluid and the heat exchanger, a coil fluidly connected to the second fluid circuit, wherein the coil is configured to be disposed on a drainage tube to transfer heat between the heat transfer fluid and the coil, a final heat exchanger configured for thermally coupling the first fluid circuit and the water conductor and the second fluid circuit and the water conductor.

A hot water returning system according to the present disclosure includes a hot water generator that generates hot water, a hot water line that supplies the hot water to a source of demand, a water returning line that returns the hot water to the hot water generator for preheating the hot water in the hot water line, a pump which pumps the hot water for returning of the hot water, and a processor electrically connected to the pump, and the processor is configured to determine a need for preheating corresponding to whether it is necessary to preheat the hot water and a status for use of hot water corresponding to whether the hot water is supplied to a source of demand, and control the pump based on the need for preheating and the status for use of hot water.

The invention is based on a method, particularly a locally fixed method, for measuring a contamination of drinking water by microorganisms (16) in a drinking water conduit (12).

It is proposed that a contamination of drinking water is predicted in at least one prediction procedure (88) by means of at least one contamination risk parameter, and an actual contamination of drinking water is measured in at least one measuring procedure (90).

When a hot water supply operation is started, a single mode is used in which hot water is output only from a second hot water supply circuit of a water heater, by cut-off of a flow path in a first hot water supply circuit of a space-heating water heater by a cut-off mechanism. When a load imposed by hot water supply by the second hot water supply circuit increases during the hot water supply operation in the single mode, the cut-off mechanism is opened to start hot water output from the first hot water supply circuit and a hot water supply operation in a parallel mode is performed in which hot water is output from both of the first hot water supply circuit and the second hot water supply circuit.

A recirculation valve includes a housing including a hot water fluid passage which is used to allow the hot water to flow through, a cold water fluid passage to allow the cold water to flow through, and a recirculation fluid passage to allow the hot water in the hot water fluid passage to flow into the cold water fluid passage, a water pressure plate provided to close the recirculation fluid passage when the cold water or the hot water is used, and to open the recirculation fluid passage when the cold and hot waters are not used, and a bimetal plate configured to open the recirculation fluid passage as the bimetal plate is spaced apart from a recirculation opening and to close the recirculation fluid passage by making contact with the recirculation opening, and positioned downstream of the recirculation opening in a direction in which the hot water flows.