Refrigerator Defrost Heater Control During Peak Energy Demand
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Solution Overview
Problem
Existing defrost systems in refrigerators consume significant energy during peak demand periods, and premature termination of defrost cycles can lead to ice buildup, which is difficult to remove and may block airflow, causing cooling issues.
Innovation Solution
A control system that detects high energy demand periods and switches the defrost heater from standard to reduced power consumption mode, ensuring the defrost cycle is not prematurely terminated by adjusting the power supply to the defrost heater, using a power switching unit and controller to manage energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the defrost heater operates at standard power consumption during high demand periods, then the defrost cycle can be completed quickly and reliably, but the energy consumption exceeds the DSM limit of 50% of peak usage
Solution Approach 1:
The defrost heater's power consumption is made dynamic by switching between standard and reduced power modes based on real-time demand period detection. The controller adjusts the heater's operation from full power during low-demand periods to reduced power during high-demand periods, allowing the system to adapt to changing energy constraints while maintaining defrost functionality.
Solution Approach 2:
The system changes the operational parameters of the defrost heater by modifying its power consumption level. During high demand periods, the heater operates at a reduced power parameter (approximately 50% of peak usage) compared to standard operation, enabling DSM compliance while still achieving defrost objectives through extended operation time.
2Use of energy by moving object
If the defrost cycle is delayed until low demand periods, then energy consumption during high demand periods is reduced, but the evaporator remains frosted longer and cooling performance deteriorates
Solution Approach 1:
The defrost cycle is initiated during low demand periods in advance, before high demand periods occur. This preliminary action allows the defrost process to begin when energy constraints are not active, and continues through the high demand period at reduced power, ensuring the evaporator is cleared before the next cooling cycle begins, thus maintaining cooling performance while managing energy consumption.
3Use of energy by moving object
If the defrost cycle is prematurely terminated to reduce energy consumption during high demand periods, then DSM requirements are met, but ice buildup refreezes and blocks airflow
Solution Approach 1:
The defrost heater's useful action continues uninterrupted through the high demand period, though at a reduced power level. By maintaining continuous heating action rather than terminating the cycle, the system ensures that the frost-melt-water mixture has sufficient time to fully evaporate and the evaporator surface remains clear, preventing refreezing and maintaining airflow reliability while still meeting DSM energy constraints.
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
This solution reduces energy consumption during peak demand periods while ensuring complete defrosting, preventing ice buildup and maintaining appliance performance by extending the defrost cycle as needed.
Implementation Method 1
Typical defrost systems utilize defrost heaters to melt the ice build up. The defrost heater may be similar to the heating elements on an electric stove
Implementation Method 2
a radiant heater is often positioned inside a housing and below the evaporator to warm the evaporator by both convection and radiant heating
Implementation Method 3
a radiant heater is often positioned inside a housing and below the evaporator to warm the evaporator by both convection and radiant heating
Data Source
AI summary
A method includes providing a standard supply of electrical power to a defrost heater during a standard defrost cycle for a refrigeration system of an appliance, detecting a high energy demand period during the standard defrost cycle, and enabling a reduced consumption of electrical power by the defrost heater in a low power defrost cycle.