Refrigerator Compressor Operation Profile for Transitional Efficiency
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Solution Overview
Problem
Conventional refrigerator appliances experience low operating efficiency during transitional phases of compressor operation, such as when the refrigerant regulating valve switches or the compressor starts up, as power is used to build pressure and temperature gradients rather than cooling.
Innovation Solution
Implementing a controller that identifies changes in the sealed system state and determines a variable compressor operation profile as a function of time, using profiles such as linear ramps, exponential functions, or polynomials to optimize compressor speed and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the compressor operates during transitional phases (starting up, valve switching, speed changing), then the compressor can adapt to different system states, but the operating efficiency decreases significantly
Solution Approach 1:
The controller pre-determines compressor operation profiles for anticipated transitional phases. When a transition is detected ( valve switching, startup, speed change), the controller has already prepared the appropriate speed profile, enabling the compressor to immediately execute the optimized speed curve without delay, thus maintaining efficiency during adaptability transitions
2Speed
If the compressor uses high power during transitional phases to build pressure and temperature gradients quickly, then the system reaches desired states faster, but energy is wasted without effective cooling
Solution Approach 1:
The compressor speed is dynamically adjusted according to the detected system state and predetermined profiles. Instead of maintaining constant high power, the controller varies the speed in real-time based on the transitional phase requirements, optimizing the balance between reaching desired pressure/temperature gradients quickly and avoiding energy waste
Solution Approach 2:
The controller changes the compressor operating parameters (speed, power) based on the system state and transitional phase. By adjusting these parameters according to predetermined profiles for different transitions (startup, valve switching, etc.), the system achieves fast response while improving power utilization efficiency
3Ease of operation
If the compressor speed is allowed to drift freely during operation, then the compressor can respond to varying load conditions, but efficiency decreases during transitional phases
Solution Approach 1:
The controller continuously monitors the sealed system state (pressure, temperature, valve position) and uses this feedback to determine which predetermined profile to execute. This closed-loop approach ensures the compressor speed is actively controlled rather than drifting freely, maintaining both response flexibility and energy efficiency during transitions
Data Source
AI summary
A refrigerator appliance includes a cabinet defining one or more chilled chambers, a sealed system comprising a compressor and one or more evaporators thermally coupled to the one or more chilled chambers, and a controller operably coupled to the compressor. The controller is configured to identify a change of state of the sealed system, determine a compressor operation profile, the compressor operation profile being variable as a function of time, and operate the compressor in accordance with the compressor operation profile.