Water Heater Demand Side Management System
First Claim
1. A water heater controller for controlling a water heater to alter electrical demand while providing hot water for normal use, said water heater comprising an upper heater for heating an upper volume of water and a lower heater for heating a lower volume of water;
- said water heater controller comprising;
a power control means for varying the power supplied to said upper heater and for separately varying the power supplied to said lower heater;
a processor having a memory, said memory storing a load shift algorithm comprising instructions for varying power applied by said power control, said load shift algorithm specifying a reserve volume capacity for said water heater,a lower temperature sensor measuring a temperature of said lower volume of water and providing a resulting lower volume temperature measurement to said processor;
means for determining a remaining volume capacity of hot water in said hot water heater;
wherein said processor operates said power control device to control a temperature of said lower volume of said water heater in accordance with said load shift algorithm when said remaining capacity exceeds said reserve capacity.
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Accused Products
Abstract
A system for shifting energy demand from on-peak time windows to off-peak time windows by using hot water heater load shifting, while providing the end user with the level of service (i.e., availability of hot water) according to the user'"'"'s customary use described by service quality criteria. The shift is accomplished by a controller located at the end user establishment and in communication with a central control server. The controller monitors local water heater upper and/or lower temperature and controls upper and/or lower water heater heating elements in accordance with a demand shift process commanded by the central control server. The controller may determine usage and remaining capacity for reporting back to the central control server. A volumetric capacity and usage determination is disclosed. The control server may select water heaters according to use patterns and/or measured capacity. One embodiment is adapted for use with existing water heaters without disrupting safety features of the existing water heater.
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Citations
30 Claims
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1. A water heater controller for controlling a water heater to alter electrical demand while providing hot water for normal use, said water heater comprising an upper heater for heating an upper volume of water and a lower heater for heating a lower volume of water;
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said water heater controller comprising; a power control means for varying the power supplied to said upper heater and for separately varying the power supplied to said lower heater; a processor having a memory, said memory storing a load shift algorithm comprising instructions for varying power applied by said power control, said load shift algorithm specifying a reserve volume capacity for said water heater, a lower temperature sensor measuring a temperature of said lower volume of water and providing a resulting lower volume temperature measurement to said processor; means for determining a remaining volume capacity of hot water in said hot water heater; wherein said processor operates said power control device to control a temperature of said lower volume of said water heater in accordance with said load shift algorithm when said remaining capacity exceeds said reserve capacity. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for controlling a plurality of water heaters to reduce peak loading on a power grid comprising the steps of:
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receiving temperature data at a water heater control server from a plurality of water heaters connected to said power grid at separate customer locations, generating usage pattern information for each water heater based on said temperature data; receiving load demand information at said water heater control server from a power grid monitoring system monitoring said power grid; said water heater control server commanding a control strategy comprising a temperature limit over time for each water heater of said plurality of water heaters based on said received temperature data, said load demand data, predicted load demand information; wherein each water heater of said plurality of water heaters is controlled in accordance with hot water delivery quality criteria applied to said usage pattern information specific to each said water heater. - View Dependent Claims (9, 10, 11)
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12. A method for shifting a load of a power grid comprising the steps of:
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providing a control server in network communication with a plurality of water heater controllers controlling a respective plurality of water heaters; determining historical water heater usage patterns for said plurality of water heaters; said historical usage patterns comprising an expected usage as a function of time over at least one daily interval; receiving a load shift goal at said control server from a power grid controller for said power grid; selecting a first set of water heaters of said plurality of water heaters based on said historical water heater usage patterns; receiving contemporaneous hot water remaining capacity measurements by said control server for each water heater of said first set of water heaters; selecting a second set of water heaters based on said contemporaneous hot water remaining capacity measurements, said second set of water heaters being a subset of said first set of water heaters; commanding said respective water heater controllers for said second set of water heaters to reduce a temperature associated with a lower heating element of each water heater of said second set of water heaters. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A water heater controller for controlling a water heater to alter electrical demand, said water heater comprising an upper heater for heating an upper volume of water in accordance with an upper thermostat and a lower heater for heating a lower volume of water in accordance with a lower thermostat, said upper thermostat switching from said upper heater to said lower thermostat when said upper volume of water is above an upper thermostat set point;
- said water heater controller comprising;
a power input for receiving power from a power source; a power output for connecting to said water heater and supplying power to said water heater; a power control device connected between said power input and said power output for varying the power supplied to said water heater; a processor having a memory, said memory storing a load shift algorithm for varying power applied to said water heater to alter the electrical demand by said water heater, said processor controlling said water heater by controlling said power control device; a lower temperature sensor measuring a temperature of said lower volume of water and providing a resulting lower volume temperature measurement to said processor; a thermostat state sensor determining a switch state of said upper thermostat and communicating said switch state to said processor; wherein said processor operates said power control device to control a temperature of said lower volume of water when said upper thermostat is switched to deliver power to said lower thermostat, said temperature of said lower volume of water controlled in accordance with said load shift algorithm, said lower volume temperature measurement, and said switch state of said upper thermostat. - View Dependent Claims (26, 27, 28, 29, 30)
- said water heater controller comprising;
Specification