Electric Hot Water Heater Responsive to Grid Frequency

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Technology Description


This technology utilizes residential water heaters to provide a low cost method of stabilizing the electric grid. Electric water heaters can be used as a demand response resource to control the amount of power consumed in response to instantaneous availability of renewable generation. Standard electric hot water heater control relies on chained operation of upper tank and lower tank relays, dependent solely on temperature. The upper tank thermostat/relay has priority, as the hot water is drawn from the upper tank. In the proposed control approach, the upper thermostat/relay operation is unchanged. The lower thermostat/relay is replaced with a “smart" component comprised of a temperature sensor, a micro-controller, and a power-converter that controls the amount of power applied to the lower element. The power applied to the lower element is applied based on two considerations: temperature and grid frequency.


Features & Benefits


  • Retrofits existing technology to provide massive grid inertia at a low cost
  • Water heater is responsive to grid
  • No change to water heater performance
  • Secure, Not part of the Internet of Things




  • Improve load response to dynamic generation
  • Electrical grid stability control


Background of Invention


Renewable energy sources such as wind, solar, and marine energy provide many benefits and are quickly gaining use across the world. One of the key limitations to large-scale integration of these renewable energy sources is the variability that comes with their use. The fluctuations in power generation caused by environmental factors make electrical grid stability an issue. Electrical grid stability can be controlled through fast acting reserve generation but the variability of large scale integration of renewable power sources can exceed the system limits. Another method of managing variability in energy generation is energy storage, which is currently significantly more expensive than generation. A much more cost effective solution is to use demand response; adjusting load dynamically in response to available generation.





US Provisional Patent Application No. 62/239,765; Available for licensing


Patent Information:
For Information, Contact:
David Dickson
IP & Licensing Manager
Oregon State University
Ted Brekken
Energy Storage
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