Systems and methods for integrating photovoltaic (PV) energy into water heater systems are disclosed. The disclosed technology includes determining whether a current water temperature is less than a first PV heat point that is greater than a normal heat point, and if so, outputting instructions for PV energy to be transferred from a PV system to a heating device of the water heater. If the current water temperature falls below a second PV heat point that is less than the normal heat point, the disclosed technology includes outputting instructions for energy to be transferred from a utility system to the heating device.

An instant hot water delivery system includes a thermal storage bin that receives hot water from a water heater via a hot water supply conduit and stores the hot water therein. The thermal storage bin is disposed adjacent a point of demand to deliver the hot water instantly to the point of demand responsive to a demand. The thermal storage bin is configured to retain a thermal energy of the hot water for a prolonged period using a phase change material. When the hot water stored in the thermal storage bin cools down below a threshold temperature, the cooled down hot water is recirculated to the water heater via a cold water supply conduit using a crossover valve. The recirculation is based on thermosiphon. Fresh hot water from the water heater replaces the cooled down hot water that is displaced from the thermal storage bin.

A recirculation valve for use with a tankless water heater in a system that includes hot and cold water fixtures and a cold water supply. The recirculation valve includes a valve body having an inlet connection, a pair of outlet connections and an internal chamber; a thermostatic element that is disposed in a first portion of the internal chamber of the valve body and includes an actuation body that is responsive to water temperature; wherein the valve body further has a port opening that is disposed between the thermostatic element and a second portion of the internal chamber; wherein the thermostatic element further includes a piston constructed and arranged to operatively extend from said actuation body when the actuation body is heated, and a plunger that is carried by and is moveably responsive to the actuation body; and whereby, when the actuation body is heated, the valve transitions from an open position to a closed position by the piston moving the actuation body and plunger so that the plunger moves to seal against the port opening of the valve body.

A dual fluid heat exchange system is presented that provides a stable output temperature for a heated fluid while minimizing the output temperature of a cooled fluid. The heated and cooled fluids are brought into thermal contact with each other within a tank. The output temperature of the warmed fluid is maintained at a stable temperature by a re-circulation loop that connects directly to the mid portion of the tank such that the re-circulated fluid flow primarily warms only a re-circulation section of the tank. The other, lower flow rate, section of the tank may be positioned so that it has a cooler temperature and thus serves to increase the efficiency of the heat exchange by extracting extra heat energy out of the cooled fluid before it leaves the tank. Alternatively, the low flow rate section of the tank may be warmer than the re-circulated section, and thus allow the re-circulated section to be cooler than the output temperature of the warmed fluid.

A heating and hot-water supply apparatus includes a combustion means, a heat exchanger, a circulation passage, a circulation means, a bypass passage, a distribution means, a hot-water supply heat exchanger, a water entry passage, a hot-water supply passage, and a control means. The circulation passage connects an external heating terminal and the heat exchanger. The water entry passage supplies water of an external hot-water supply pipe and an external water supply pipe to the hot-water supply heat exchanger. The control means controls the distribution means to be adaptable to each of a heating operation and a hot-water supply operation. The control means prioritizes the hot-water supply operation when there is a hot-water supply request for warm water use in addition to a heating request, and prioritizes the heating operation when there is a temperature-maintaining request for maintaining a temperature of the hot-water supply pipe in addition to the heating request.

A heating and hot-water supply apparatus includes a combustion means, a heat exchanger, a circulation passage, a circulation means, a bypass passage, a distribution means, a hot-water supply heat exchanger, a water entry passage, a hot-water supply passage, and a control means. The circulation passage connects an external heating terminal and the heat exchanger. The water entry passage supplies water of an external hot-water supply pipe and an external water supply pipe to the hot-water supply heat exchanger. The control means controls the distribution means to be adaptable to each of a heating operation and a hot-water supply operation. The control means prioritizes the hot-water supply operation when there is a hot-water supply request for warm water use in addition to a heating request, and prioritizes the heating operation when there is a temperature-maintaining request for maintaining a temperature of the hot-water supply pipe in addition to the heating request.

The invention relates to a method for operating a circulation system (10) comprising a heating device having an inlet port and an outlet port for controlling the temperature of water, and comprising a pipe system having a plurality of strings which include one or more sections of a given thermal coupling to the surroundings and are connected by means of nodes, one or more of the pipes of the pipe system being designed as a supply pipe (4, 5, 6), at least one individual delivery pipe (7) connected to a removal point (9) and at least one pipe designed as a circulation pipe (10a) being connected to the supply pipe(s) (4, 5, 6), said method comprising the steps: —setting a water temperature at the outlet port to a value Ta by means of the heating device; —setting a volumetric flow rate at the inlet port to a value Vz, and comprising the following steps: —determining, in particular calculating, a temperature change of the water between the start region and the end region according to a model of the axial temperature change for the first section connected to the outlet port, starting from a temperature start value TMA* and a volumetric flow rate start value Vz*; —determining, in particular calculating, a temperature change of the water between the start region and the end region for each further given section according to the model of the temperature change, subject to the boundary condition that the water temperature in the start region of the given section is the same as the water temperature in the end region of the section to which the given section is connected; and —selecting the value Ta of the water temperature and the value Vz of the volumetric flow rate at the outlet port in such a way that in the end region of each section the water temperature TME is in a specified temperature range around Tsoll, in particular at the inlet port (12a, 14b) the water temperature Tb<Tsoll is set with Tsoll−Tb<Θ, where Θ>0 is a specified value. Furthermore, the invention also relates to a circulation system for carrying out the method.

A water dispensing apparatus includes a hot water module configured to heat supplied water using an induction heating method, a water supply pipe configured to supply water to the hot water module, a flow rate control valve provided on the water supply pipe to control a flow rate of water supplied to the hot water module, a flow rate sensing device provided on the water supply pipe to sense the flow rate of water supplied to the hot water module, and a controller configured to increase an opening speed of the flow rate control valve when the flow rate of supplied water sensed through the flow rate sensing device is equal to or less than a set flow rate.

A hot water temperature sensing cut-off system and method for use with electric water heaters to preclude the flow of unsafe water from the water heater into the hot water distribution conduit to prevent the risk of bacteria transfer in the hot water distribution conduit. One simple solution is to mount a temperature responsive shut-off valve between the hot water supply outlet conduit of the tank of the water heater and the hot water distribution conduit and wherein the valve will shut-off water flow upon detection of an unsafe water temperature below 125 degrees Fahrenheit. Another solution is to use a controller to operate a shut-off valve. A temperature sensor is located to sense the water temperature at the intake of the hot water conduit and feeds a signal to the controller to operate a closure component of the valve to shut-off the hot water supply upon detecting a predetermined low water temperature fed to an inlet end of the control shut-off valve. When the water heats up to a predetermined safe temperature, the controller opens the valve and continues supplying hot water.

A water heating and treatment system includes a water heater, a hot water outflow line from the water heater, and a cold water supply line to supply water to the water heater. The cold water supply line includes at least one of an anti-scale device, and a UV sanitation lamp. A mixing station supplies a temperature regulated heated water to one or multiple temperature zones. A mixing station supplies heated water to at least a first temperature zone at a first hot water temperature. The water heater, the anti-scale device, the UV sanitation lamp and the mixing station are contained in a single enclosure having at least one sliding transparent wall through which components can be viewed. A plurality of pipe connections passing through a rear panel of said single enclosure are also described.