Water Heater Load Shifting With Feedback-Based Peak Demand Control
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Solution Overview
Problem
Current water heater load management systems are limited in accuracy, reliability, and detail, often requiring significant capital investment and offering only small economic incentives to customers, leading to slow adoption rates and inefficient peak load management.
Innovation Solution
A system that uses a controller at the end-user's establishment to shift energy demand from on-peak to off-peak times by monitoring and controlling water heater temperatures, communicating with a central control server to manage load shifting while maintaining service quality, and utilizing existing WAN networks for data collection and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If unidirectional control systems are used to shed load during peak demand periods, then load management capability is provided, but system reliability and verification accuracy deteriorate because there is no upstream communication to verify command execution
Solution Approach 1:
The patent implements bidirectional communication between water heaters and utility servers, enabling feedback loops where execution status and operational data are transmitted upstream. This allows the utility to verify whether load shedding commands were properly executed and to monitor actual load reduction effectiveness, thereby resolving the reliability verification problem of unidirectional systems.
Solution Approach 2:
The patent introduces communication modules and protocols as intermediaries between water heaters and utility servers. These intermediaries facilitate reliable data exchange and command verification, enabling the utility to accurately track and verify load management execution without requiring direct complex integration with water heater control systems.
2Extent of automation
If substantial capital investment is made to build RF infrastructure for water heater control, then load management capability is improved, but system cost increases significantly
Solution Approach 1:
The patent leverages existing wide area network infrastructure (telephone lines, power lines, wireless networks) that water heaters and utilities already possess or can access. By making these existing networks serve the additional function of load management communication, the system avoids requiring dedicated RF towers and backhaul infrastructure, thereby significantly reducing capital investment while maintaining load management capabilities.
Solution Approach 2:
The patent enables water heaters to utilize existing communication infrastructure already present in the building or accessible to the premises. The system self-configures to use available networks (power line communication, telephone lines, or wireless) without requiring utility-deployed dedicated infrastructure, thereby eliminating the need for substantial capital investment in RF towers and backhaul.
3Productivity
If peak load shedding is implemented through water heater control, then energy demand during peak periods is reduced, but customer service quality may deteriorate due to lack of hot water
Solution Approach 1:
The patent pre-cools water storage tanks before anticipated peak demand periods by storing cold water in insulated tanks. When peak demand occurs and water heaters are curtailed, the pre-stored cold water can be used or gradually warmed, ensuring continuous hot water supply to customers without requiring active heating during peak periods. This preliminary preparation maintains service quality while enabling peak load reduction.
Solution Approach 2:
The patent dynamically adjusts water heater operating parameters (temperature setpoints, heating element cycling) based on real-time utility signals and predicted customer usage patterns. By optimizing these parameters to maintain minimum acceptable hot water temperatures and availability during load shedding, the system achieves peak demand reduction while preserving customer service quality within acceptable ranges.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively reduces peak energy demand, delays or eliminates the need for new power generation facilities, and reduces carbon emissions by shifting 12%-18% of domestic water heating load to off-peak times without causing undue inconvenience to customers, enabling utilities to offer incentives and qualify for energy efficiency programs.
Implementation Method 1
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
Data Source
AI summary
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.