Systems and methods for integrating photovoltaic energy into water heater systems

Patent metadata

Field	Value
Publication number	US-11859869-B2
Application number	US-202016908814-A
Country	US
Kind code	B2
Filing date	Jun 23, 2020
Priority date	Jun 23, 2020
Publication date	Jan 2, 2024
Grant date	Jan 2, 2024

Abstract

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.

First claim

What is claimed is:

1. A method comprising:
receiving, by at least one processor of a control system of a water heater, a current water temperature from the water heater;
determining, by the at least one processor, that the current water temperature is less than a first PV heat point that is greater than a normal lower threshold heat point;
in response to the current water temperature being less than the first PV heat point, calculating, by the at least one processor, a required amount of energy to increase a temperature of the water from the current water temperature to a set point temperature greater than the first PV heat point;
determining, by the at least one processor, that the required amount of the energy is greater than an amount of available PV energy in a PV system at a first time;
in response to the required amount of the energy being greater than the amount of the available PV energy at the first time, determining, by the at least one processor, that the current water temperature is less than or equal to the normal lower threshold heat point;
in response to the current water temperature being less than or equal to the normal lower threshold heat point, determining, by the at least one processor, that the amount of the available PV energy is greater than or equal to the required amount of the energy at a second time; and
in response to the amount of the available PV energy being greater than or equal to the required amount of the energy at the second time, setting, by the at least one processor, a switch of the control system to transfer PV energy from the PV system to a heating device of the water heater, until the current water temperature is greater than or equal to the set point temperature, and to not transfer energy from a utility system to the heating device.

2. The method of claim 1 , further comprising setting, by the at least one processor, the switch to stop the transfer of the PV energy from the PV system to the heating device and from the utility system to the heating device based on detecting that the current water temperature equals the set point temperature.

3. The method of claim 1 further comprising:
receiving, from an energy meter, an indication of the amount of the available PV energy.

4. The method of claim 1 further comprising:
in response to the required amount of the energy being greater than the amount of the available PV energy and subsequent to expiration of a predetermined period of time, determining, by the at least one processor, whether the required amount of the energy is less than or equal to an updated amount of the available PV energy in the PV system.

5. The method of claim 1 further comprising:
in response to determining that the current water temperature is less than the normal lower threshold heat point, determining, by the at least one processor, whether the required amount of the energy is less than or equal to an updated amount of the available PV energy in the PV system; and
in response to the required amount of the energy being greater than the updated amount of the available PV energy, setting, by the at least one processor, the switch to not transfer the updated amount of the available PV energy to the heating device.

6. The method of claim 5 , further comprising:
in response to determining that the current water temperature is less than a second PV heat point lower than the normal lower threshold heat point, determining, by the at least one processor, at a third time, whether the required amount of the energy is less than or equal to a new updated amount of the available PV energy at the third time in the PV system; and
in response to the required amount of the energy being less than or equal to the new updated amount of the available PV energy at the third time, setting, by the at least one processor, the switch to transfer the PV energy from the PV system to the heating device.

7. The method of claim 6 further comprising:
setting, by the at least one processor, the switch to stop the transfer of the PV energy from the PV system to the heating device based on detecting that the current water temperature equals the set point temperature.

8. The method of claim 1 further comprising:
setting, by the at least one processor, the switch to not transfer the energy from the utility system to the heating device based on detecting that the current water temperature equals the set point temperature.

9. A controller for controlling operation of a water heater, the controller comprising:
one or more processors;
a switch; and
a non-transitory computer-readable medium having instructions stored thereon that, when executed by the one or more processors, cause the controller to:
receive a current water temperature from the water heater;
determine that the current water temperature is less than a first PV heat point that is greater than a normal lower threshold heat point;
in response to the current water temperature being less than the first PV heat point, calculate a required amount of energy to increase a temperature of the water from the current water temperature to a set point temperature greater than the first PV heat point;
determine whether that the required amount of the energy is greater than an amount of available PV energy in a PV system at a first time;
in response to the required amount of the energy being greater than the amount of available PV energy at the first time, determine that the current water temperature is less than or equal to the normal lower threshold heat point;
in response to the current water temperature being less than or equal to the normal lower threshold heat point, determine that the amount of the available PV energy at a second time is greater than or equal to the required amount of the energy; and
in response to the amount of the available PV energy being greater than or equal to the required amount of the energy at the second time, set the switch to transfer PV energy from the PV system to a heating device of the water heater, until the current water temperature is greater than or equal to the set point temperature, and to not transfer energy from a utility system to the heating device.

10. The controller of claim 9 , wherein the instructions, when executed by the one or more processors, further cause the controller to set the switch to stop the transfer of the PV energy from the PV system to the heating device based on detecting that the current water temperature equals the set point temperature.

11. The controller of claim 9 , wherein the instructions, when executed by the one or more processors, further cause the controller to:
receive, from an energy meter, an indication of the amount of the available PV energy.

12. The controller of claim 9 , wherein the instructions, when executed by the one or more processors, further cause the controller to:
in response to the required amount of the energy being greater than the amount of the available PV energy and subsequent to expiration of a predetermined period of time, determine whether the required amount of the energy is less than or equal to an updated amount of the available PV energy in the PV system.

13. The controller of claim 9 , wherein the instructions, when executed by the one or more processors, further cause the controller to:
in response to determining that the current water temperature is less than the normal lower threshold heat point, determine whether the required amount of the energy is less than or equal to an updated amount of the available PV energy in the PV system; and
in response to the required amount of the energy being greater than the updated amount of the avai

Assignees

• Rheem Mfg Co

Inventors

• Chaudhry Raheel A
• Reagin James Michael

Classifications

• H02J2101/24

  Photovoltaics · CPC title

• F24H7/002 Primary

  using electrical energy supply · CPC title

• F24D17/0068

  with accumulation of the heated water · CPC title

• F24H9/2021 Primary

  Storage heaters · CPC title

• G05B19/042

  using digital processors (G05B19/05 takes precedence) · CPC title