Water Heater Demand Shifting With Bidirectional Load Verification
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Solution Overview
Problem
Current water heater demand 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 inefficiencies in peak load management.
Innovation Solution
A system that uses a controller at the end-user's establishment to shift energy demand from 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 receipt or load avoidance
Solution Approach 1:
The patent implements a bidirectional communication system where the water heater controller sends upstream messages to the utility controller to verify command receipt and report load avoidance status. This feedback mechanism ensures that control actions are confirmed and their effects are verified, resolving the reliability issue of unidirectional systems.
Solution Approach 2:
The patent introduces a communication interface as an intermediary between the utility controller and water heater controller. This intermediary manages the bidirectional communication protocol, ensuring reliable message exchange and verification while maintaining system automation.
2Ease of operation
If RF infrastructure (radio towers and backhaul) is built to enable water heater control, then communication capability is provided, but capital investment cost increases substantially
Solution Approach 1:
The patent utilizes existing WAN networks (digital cellular RF networks, fiber to the home, DSL, broadband over cable) that serve multiple purposes for utility customers. By leveraging these existing multi-functional networks, the system avoids the need to build dedicated RF infrastructure, significantly reducing capital investment while maintaining communication capability.
3Productivity
If peak load is reduced through water heater control, then new power generation facility construction is delayed or eliminated, but customer service quality may deteriorate due to hot water unavailability
Solution Approach 1:
The patent pre-heats water in the water heater tank before peak demand periods occur. By storing thermal energy in advance, the system can reduce or eliminate heating during peak periods without affecting customer hot water availability, thus maintaining service quality while achieving peak load reduction.
Solution Approach 2:
The patent dynamically adjusts water heater operating parameters (heating power, temperature setpoints, timing) based on predicted peak demand periods and customer usage patterns. This allows optimization of both peak load reduction and customer service quality by controlling when and how much heating occurs.
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
controls upper and/or lower water heater heating elements in accordance with a demand shift process
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.