Three-Element Water Heater Layout for Peak Power Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing domestic hot water heaters face challenges in reducing peak power demand during peak hours without compromising the availability of hot water, as consumers tend to draw hot water in larger volumes during single peak periods, leading to inadequate supply and increased power demand.
Innovation Solution
A high efficiency domestic hot water heater with three spaced-apart resistive heating elements, where the middle element is positioned at a level exceeding the average maximum water consumption volume during peak demand, and the bottom element has a low watt density to maintain a temperature barrier and prevent bacterial propagation, while the top element is designed for high power but only activated when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single high power heating element is used in the top portion of the tank, then hot water can be heated quickly for small volume draws, but the element overheats and fails when large volumes of water are drawn during peak periods
Solution Approach 1:
The single heating element is divided into three separate heating elements positioned at different vertical levels in the tank. This segmentation allows each element to serve a specific zone, distributing the heating load and preventing any single element from overheating while providing sufficient heating capacity for large volume draws during peak periods.
Solution Approach 2:
The heating function is extended from a single-point (top portion) to a three-dimensional distributed arrangement with elements at bottom, middle, and top levels. This spatial distribution enables simultaneous heating of different water zones, increasing overall heating capacity and reliability without requiring a single high-power element.
2Power
If utilities increase electricity cost during peak periods, then consumers are forced to use hot water at different periods, but this causes very high instantaneous demand when units are re-activated
Solution Approach 1:
The multiple heating elements preheat water in different zones of the tank during off-peak periods, storing thermal energy throughout the water volume. When peak demand occurs, this preheated water is immediately available, eliminating the need for consumers to shift usage patterns while avoiding sudden high-power reactivation spikes.
Solution Approach 2:
The system changes the temperature distribution parameter within the tank by maintaining different temperature zones at different heights. This allows the water heater to provide adequate hot water volume during peak periods without requiring all elements to operate at full power simultaneously, thus reducing peak power demand.
3Quantity of substance
If the middle heating element is positioned at standard height, then tank heating is simplified, but hot water volume available during peak demand is insufficient when consumers draw water in larger single-period volumes
Solution Approach 1:
Each heating element is positioned at a specific vertical location optimized for its function: the bottom element for preheating incoming cold water, the middle element for maintaining hot water volume in the peak draw zone, and the top element for final hot water storage. This localized positioning ensures sufficient hot water volume during peak demand without excessive complexity.
4Use of energy by moving object
If the bottom heating element has high watt density for faster heating, then heating efficiency increases, but the element lifespan decreases due to overheating and failure
Solution Approach 1:
The bottom heating element operates at reduced watt density (15-30 W/in²) compared to conventional elements, changing the power density parameter to prevent overheating. This lower power density extends element lifespan while the distributed three-element configuration compensates by providing sufficient total heating capacity through coordinated operation of all elements.
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 solution effectively reduces peak power demand by managing hot water distribution and maintaining a consistent supply, ensuring ample hot water is available during peak periods without overloading the electrical network, while also extending the lifespan of the bottom heating element through optimized design and materials.
Implementation Method 1
Three spaced apart resistive heating elements project substantially horizontally in the tank
Implementation Method 2
The bottom element has a low watt density in the range of from about 15 to 30 W/in2
Data Source
AI summary
A high efficiency, peak-power reducing, domestic hot water heater is described. It comprises a closed tank having a predetermined water holding capacity. A hot water outlet is provided in a top end wall of the tank. A cold water inlet is provided in a side wall of the tank adjacent a bottom wall thereof. Three spaced apart resistive heating elements project substantially horizontally in the tank. A bottom one of the resistive heating elements extends in the tank and spaced slightly above the bottom wall. A middle one of the resistive heating elements extends in the tank at a level close to an average maximum water consumption volume drawn during a peak power demand time period. A top one of the resistive heating elements extends between the middle element and the top end wall of the tank. The bottom element has a low watt density in the range of from about 15 to 30 W/in2.