Defrost control method and heat pump system
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Solution Overview
Problem
Conventional defrosting control methods for heat pump systems are inefficient, leading to either excessive defrosting causing energy waste or inadequate defrosting affecting device performance and user comfort due to fixed time intervals that do not account for varying environmental conditions.
Innovation Solution
A defrosting control method that adjusts the defrosting interval based on a preset indicatrix, adjusting default parameters to match actual frost formation conditions, using parameters TMn and TNn to determine when defrosting is necessary, and adjusting these parameters based on actual defrosting time deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a preset fixed time interval is used for defrosting control, then the control method is simple to implement, but the defrosting interval cannot adapt to varying environmental conditions leading to either excessive defrosting causing energy waste or inadequate defrosting affecting device performance
Solution Approach 1:
The patent transforms the static fixed time interval into a dynamic adaptive interval by introducing an indicatrix X=T1/TMn+T2/TNn that continuously adjusts the defrosting timing based on accumulated running hours T1 and T2, outdoor temperature, and humidity conditions. This allows the system to automatically adapt to varying environmental conditions while maintaining straightforward control logic.
Solution Approach 2:
The patent changes the control parameter from a fixed time interval to a variable interval determined by the indicatrix X, which incorporates multiple parameters including running hours T1/T2, temperature thresholds, and humidity levels. By modifying these parameters based on actual operating conditions, the system optimizes defrosting timing to prevent both excessive defrosting and inadequate defrosting.
2Reliability
If frequent defrosting is performed to ensure adequate frost removal, then device performance is maintained, but energy is wasted and user experience deteriorates due to prolonged heating mode interruptions
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors the indicatrix X value, which accumulates running hours T1 and T2 under different temperature conditions. When X reaches the threshold indicating sufficient frost accumulation, defrosting is triggered. This feedback loop ensures defrosting occurs only when necessary, maintaining device performance while avoiding unnecessary energy consumption from frequent defrosting cycles.
3Loss of energy
If defrosting is delayed until the preset time interval expires, then energy is conserved by reducing defrosting frequency, but thick frost accumulates affecting device performance and extending subsequent defrosting duration
Solution Approach 1:
The feedback mechanism through indicatrix X prevents excessive frost accumulation by continuously tracking accumulated running hours T1 and T2. When the threshold is reached, defrosting is promptly initiated, preventing thick frost formation that would degrade device performance and extend defrosting duration, while still minimizing unnecessary defrosting cycles for energy conservation.
4Reliability
If defrosting is performed urgently when frost becomes serious, then device performance is maintained, but user experience deteriorates due to long heating mode interruption during extended defrosting process
Solution Approach 1:
The system performs preliminary monitoring of the indicatrix X, accumulating running hours T1 and T2 before frost becomes problematic. By detecting frost accumulation trends in advance and triggering defrosting when X reaches the threshold, the system prevents severe frost formation that would require extended defrosting periods, thus maintaining device performance while minimizing heating mode interruptions and preserving user comfort.
Data Source
AI summary
A defrosting control method comprises: initializing a first default parameter TMn and a second default parameter TNn in a preset defrosting interval indicatrix X when a heat pump system runs, wherein the preset defrosting interval indicatrix X=T1/TMn+T2/TNn; executing the defrosting cycle when the preset defrosting interval indicatrix X is greater than or equal to a preset constant value, and terminating the defrosting cycle after a defrosting cycle exit condition is met; obtaining an actual time spent on the defrosting cycle; comparing the actual time spent on the defrosting cycle with an expected defrosting time, and adjusting the first default parameter and the second default parameter when the actual defrosting time deviates from the expected defrosting time.