Electric Water Heater Systems for Power Grids with Distributed Generation

Patent metadata

Field	Value
Publication number	US-2016010879-A1
Application number	US-201514795394-A
Country	US
Kind code	A1
Filing date	Jul 9, 2015
Priority date	Jul 10, 2014
Publication date	Jan 14, 2016
Grant date	—

Abstract

Systems and methods for storing power from distributed generation systems or other loads and sources that affect line voltage are disclosed. In embodiments, a water heater can be powered in a way that absorbs excess power from the grid by heating water when a controller senses excess power generation in the grid. Excess power generation can be sensed by either an increase in line voltage amplitude above a predetermined standard, or an increase in line voltage frequency above a predetermined standard.

First claim

1 . An energy storage system for thermal storage of excess power from distributed-generation sources on a power line comprising:
a water heater tank having a lower portion and an upper portion; an upper heating package having:
an upper thermostat configured to sense an upper portion temperature; and
an upper resistive heating element configured to provide heat at the upper portion;
a lower heating package having:
a lower thermostat configured to sense a lower portion temperature; and
a lower resistive heating element configured to provide heat at the lower portion;
a controller operably coupled to the power line and the water heater tank and run the upper heating package and the lower heating package based on a voltage at the power line as well as the upper portion temperature and the lower portion temperature.

2 . The energy storage system of claim 1 , wherein the controller is configured to:
(a) provide power to the upper resistive heating element when the upper portion temperature is below a first selected temperature; (b) provide power to the lower resistive heating element when the controller senses that an amplitude of the voltage exceeds a predetermined amplitude and the lower portion temperature is below a second selected temperature; (c) provide power to the lower resistive heating element when the controller senses the amplitude is less than the predetermined amplitude and the lower portion temperature is below a third selected temperature; and (d) turn off power to both the lower resistive heating element and the upper resistive heating element when none of the conditions (a)-(c) are met.

3 . The energy storage system of claim 1 , wherein the controller is configured to:
(a) provide power to the upper resistive heating element when the upper portion temperature is below a first selected temperature; (b) provide power to the lower resistive heating element when the controller senses that a frequency of the voltage exceeds a predetermined frequency and the lower portion temperature is below a second selected temperature; (c) provide power to the lower resistive heating element when the controller senses the frequency is less than the predetermined frequency and the lower portion temperature is below a third selected temperature; and (d) turn off power to both the lower resistive heating element and the upper resistive heating element when none of the conditions (a)-(c) are met.

4 . The energy storage system of claim 1 , wherein the upper portion and the lower portion are in fluid communication with one another.

5 . The energy storage system of claim 4 , further comprising a hot water output in fluid communication with the upper portion.

6 . The energy storage system of claim 5 , further comprising a cold water input in fluid communication with the lower portion.

7 . The energy storage system of claim 6 , wherein the cold water input is configured to deliver cold water to the lower portion at substantially the same rate as hot water is taken from the upper portion via the hot water output.

8 . A controller comprising:
means for communicating with both an upper heating package having an upper resistive heating element and a lower heating package having a lower resistive heating element; means for receiving a first sensed temperature at the upper heating package and a second sensed temperature at the lower heating package; means for operating an upper heating element and a lower heating element, wherein the upper heating element is disposed at the upper heating package and the lower heating element is disposed at the lower heating element, based on the first sensed temperature and the second sensed temperature.

9 . The controller of claim 8 , wherein each of the upper heating package and the lower heating package are configured to send and receive communications with the controller to activate their respective resistive heating elements.

10 . The controller of claim 8 , wherein the controller is electrically coupled to a power line having a line distribution voltage having a line amplitude and a line frequency.

11 . The controller of claim 10 , wherein the controller is configured to:
(a) provide power to the upper resistive heating element when the upper portion temperature is below a first selected temperature; (b) provide power to the lower resistive heating element when the controller senses that the line amplitude exceeds a predetermined amplitude and the lower portion temperature is below a second selected temperature; (c) provide power to the lower resistive heating element when the controller senses that the line amplitude is less than the predetermined amplitude and the lower portion temperature is below a third selected temperature; and (d) turn off power to both the lower resistive heating element and the upper resistive heating element when none of the conditions (a)-(c) are met.

12 . The controller of claim 10 , wherein the controller is configured to:
(a) provide power to the upper resistive heating element when the upper portion temperature is below a first selected temperature; (b) provide power to the lower resistive heating element when the controller senses that the line frequency exceeds a predetermined frequency and the lower portion temperature is below a second selected temperature; (c) provide power to the lower resistive heating element when the controller senses that the line frequency is less than the predetermined frequency and the lower portion temperature is below a third selected temperature; and (d) turn off power to both the lower resistive heating element and the upper resistive heating element when none of the conditions (a)-(c) are met.

13 . A power grid control system configured to utilize thermal storage of excess power from distributed-generation sources on the power grid comprising:
a power distribution bus having a line amplitude and a line frequency;
a plurality of transformers, each configured to provide power to an attached load from the distribution bus, wherein at least one of the attached loads includes a distributed-generation power source; and
a controller configured to activate a resistive heating element that is electrically connected to the distribution bus and positioned in a water tank, wherein the controller is configured to activate the resistive heating element when:
the line voltage exceeds a predetermined voltage; and
a temperature in the water tank is below a predefined temperature.

14 . The power grid control system of claim 13 , wherein the distribution bus is coupled to the controller, an upper resistive heating element at an upper portion of the water tank, and a lower resistive heating element at a lower portion of the water tank.

15 . The power grid control system of claim 14 , wherein the controller is configured to receive a sensed temperature at the upper portion and a sensed temperature at the lower portion.

16 . The power grid control system of claim 15 , wherein the controller is configured to:
(a) provide power to the upper resistive heating element when the upper portion temperature is below a first selected temperature; (b) provide power to the lower resistive heating element when the controller senses that the line amplitude exceeds a predetermined amplitude and the lower portion temperature is below a second selected temperature; (c) provide power to the lower resistive heating element when the controller senses that the line amplitude is less than the predetermined amplitude and the lower portion temperature is below a third selected temperature; and

Assignees

• Cooper Technologies Co

Inventors

• Rognli Roger W
• Allmaras Kevin
• Oong Matthew

Classifications

• F24H1/202

  with resistances · CPC title

• G05B15/02

  electric · CPC title

• F24D19/1063 Primary

  counting of energy consumption · CPC title

• F24H9/2021

  Storage heaters · CPC title

• Y02E60/14

  Thermal energy storage · CPC title