Dishwasher Water Inlet Switching for Peak Demand Energy Reduction
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Solution Overview
Problem
Conventional dishwashers contribute significantly to energy consumption due to their reliance on hot water from high energy consumption sources, even in systems that attempt to reduce energy use by using both hot and cold water, as they still indirectly consume energy from external hot water heaters.
Innovation Solution
A dishwasher with a controller that selectively switches to using only cold water from a building's hot and cold water supply during periods of high electricity demand, either based on pre-defined times or actual high demand signals, to reduce energy consumption from the external hot water system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the dishwasher uses hot water from the building's hot water system, then the washing effectiveness is improved, but the energy consumption increases during peak electricity demand periods
Solution Approach 1:
The system dynamically switches between hot water and cold water modes based on real-time electricity demand conditions. The controller monitors peak demand periods and automatically adjusts the water supply mode, transitioning from hot water during low-demand periods to cold water during high-demand periods, making the system adaptable to changing energy conditions
Solution Approach 2:
The system changes the temperature parameter of the water supply by switching between hot water and cold water sources. During peak electricity demand, the controller modifies the water temperature parameter from hot to cold, thereby reducing energy consumption while maintaining washing functionality through alternative heating methods or adjusted washing parameters
2Use of energy by moving object
If the dishwasher uses cold water during peak electricity demand, then the energy consumption is reduced, but the washing effectiveness may be compromised
Solution Approach 1:
The system introduces an intermediary heating element within the dishwasher that can heat water locally during the wash cycle even when cold water is supplied during peak demand periods. This intermediary heater ensures that washing effectiveness is maintained by providing heated water only when necessary, decoupling the water supply temperature from the actual washing temperature requirements
3Reliability
If the dishwasher continuously uses hot water, then the washing performance is maintained, but the load on the external hot water system increases
Solution Approach 1:
The system extracts the heating function from the external hot water system and relocates it to the dishwasher's own heating system. By taking out the heating responsibility from the building's hot water system, the dishwasher can use cold water during peak periods without imposing energy demand on the external system, while still maintaining washing performance through its independent heating capability
Data Source
AI summary
A dishwasher and associated control method are provided wherein a water supply manifold supplies a wash chamber with wash liquid. The supply manifold includes a hot water inlet from an external hot water source and a separate cold water inlet, and is configured to be selectively actuated between the hot water inlet or cold water inlet. A controller is in communication with the supply manifold and is configured to act on a signal that is indicative of an actual or pre-defined high electricity demand period on a power supply to the hot water source. The controller is configured to generate an output control signal to the supply manifold to cause the manifold to direct substantially only cold water from the outlet to the wash chamber during the high electricity demand period.