A hot water supply system that can reduce energy consumption is provided. The hot water supply system includes a liquid heater for heating a liquid, a liquid-water heat exchanger, a water-heating circuit in which the liquid is circulated between the liquid heater and the liquid-water heat exchanger, a lower outward path for leading water from a lower part of a hot water storage tank to the liquid-water heat exchanger, the upper return path for leading the water from the liquid-water heat exchanger to an upper part of the hot water storage tank, a middle outward path for leading the water from a middle part of the hot water storage tank to the liquid-water heat exchanger, a middle return path for leading the water from the liquid-water heat exchanger to a middle part of the hot water storage tank.

A method of heating water in a water storage tank. The method includes: selecting an outlet port and an inlet port from at least three ports located in the tank at different heights along a vertical direction. The outlet port is below the inlet port. The method further includes extracting water from the outlet port, supplying the extracted water to an external heat exchanger configured for heating the extracted water, and delivering heated water from the heat exchanger to the selected inlet port.

A piping system for recovery heat energy from an exhaust gas in a heat recovery furnace, the piping system comprising a piping inlet, where the piping inlet transects a wall of a stack zone of the heat recovery furnace, a piping run, the piping run fluidly connected to the piping inlet, and a piping outlet, the piping outlet fluidly connected to the piping run, where the piping outlet transects the wall of the stack zone of the heat recovery furnace, where the piping system is positioned in a stack zone of the heat recovery furnace between a stack inlet and a stack outlet.

A piping system for recovery heat energy from an exhaust gas in a heat recovery furnace, the piping system comprising a piping inlet, where the piping inlet transects a wall of a stack zone of the heat recovery furnace, a piping run, the piping run fluidly connected to the piping inlet, and a piping outlet, the piping outlet fluidly connected to the piping run, where the piping outlet transects the wall of the stack zone of the heat recovery furnace, where the piping system is positioned in a stack zone of the heat recovery furnace between a stack inlet and a stack outlet.

A system for heating water to improve safety and efficiency. The system may have normal operation measured in time. After a time of normal operation, a water temperature setpoint may be checked. If the setpoint is not at a certain level, normal operation may continue. If the setpoint is within the certain level, water temperature may be measured. If the water temperature is less than a desired level, one or more draws of water may be measured for a preset temperature drop. If the draws do not meet the temperature drop, a return to check the setpoint may be made. If the draws meet the temperature drop, the setpoint may be reduced and a time of normal operation may be measured to determine whether a burn cycle occurs within the time. If not, normal operation may continue; but if so, a return to check the setpoint may be made.

A water heating system can include 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 a plurality of algorithms and measurements made by the first and second temperature sensors. The plurality of algorithms solves for at least one calculated temperature for at least one point between a first location of the first temperature sensor and a second location of the second temperature sensor, where the at least one calculated temperature is used to determine the amount of heated water in the tank.

The disclosed technology includes a liquid storage tank having a heating element, an inlet for receiving unheated liquid, an outlet for outputting heated liquid, and a partition configured to divide the tank into a first portion and a second portion. The partition can have an aperture such that the first portion and the second portion are in fluid communication. The liquid storage tank can include an actuator in mechanical communication with the partition and configured to linearly move at least a portion of the partition based at least in part on the temperature of liquid within the tank.

A system for heating water to improve safety and efficiency. The system may have normal operation measured in time. After a time of normal operation, a water temperature setpoint may be checked. If the setpoint is not at a certain level, normal operation may continue. If the setpoint is within the certain level, water temperature may be measured. If the water temperature is less than a desired level, one or more draws of water may be measured for a preset temperature drop. If the draws do not meet the temperature drop, a return to check the setpoint may be made. If the draws meet the temperature drop, the setpoint may be reduced and a time of normal operation may be measured to determine whether a burn cycle occurs within the time. If not, normal operation may continue; but if so, a return to check the setpoint may be made.

A water heating system is described. The water heating system comprises a vessel for holding water and for receiving heat from one or more heat sources for heating water in the vessel. The water heating system comprises a sensor comprising a plurality of temperature sensing elements for sensing a distribution of temperatures in the vessel. The water heating system comprises a connector for connecting the sensor to a retrofittable tank controller. The water heating system is configured to provide one or more characteristics of the water heating system to a retrofittable tank controller such that a retrofittable tank controller connected to the sensor and in receipt of the characteristics of the water heating system can determine from the distribution of temperatures in the vessel a quantity of useable heat stored in the vessel. A retrofittable tank controller for controlling a water heating system is also described. A sensor for measuring a temperature distribution of fluid within a vessel is also described.

A smart energy-saving compartmentalized storage boiler for heating liquid with low energy consumption comprising a housing, at least one separator disposed within the housing to form a plurality of compartments, each of the at least one separator having flow passage means for liquid communication with adjacent compartment(s), a liquid inlet in a compartment disposed within the housing, a liquid outlet in a compartment disposed within the housing, a heater disposed in one of said compartments and means for moving liquid.

Wherein while hot liquid is flowing out through said liquid outlet at a compartment, fresh liquid is flowing in through said liquid inlet at a compartment to replace said hot liquid.

Wherein the liquid is movable from one compartment to another compartment, thus, changing the size/capacity of each of said compartments.

Thereby, the at least one separator preventing mixing of liquid in one compartment with liquid of adjacent compartments, and thus, saves energy.