Performance degradation diagnosis system for refrigeration cycle device
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Solution Overview
Problem
Existing refrigeration cycle apparatus diagnosis systems fail to accurately identify the cause of performance degradation among various factors, including compressor degradation, soiling, and refrigerant leakage, leading to inefficient maintenance and potential operational interruptions.
Innovation Solution
A performance degradation diagnosis system that includes a determining unit and a control unit, which adjusts the operation condition of the refrigeration cycle apparatus to suitable settings for each performance degradation factor, allowing for accurate identification of the cause of degradation by controlling parameters such as compressor rotation, fan speed, and expansion valve opening based on subcooling and superheating values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the refrigeration cycle apparatus operates under normal operating conditions, then the apparatus maintains efficient cooling performance, but the determining unit cannot accurately identify performance degradation causes
Solution Approach 1:
The system dynamically adjusts operating conditions based on the type of performance degradation being diagnosed. For refrigerant leakage diagnosis, it sets the expansion valve to a fully open state and operates the compressor at high capacity. For soiling diagnosis, it operates at low capacity. This dynamic adaptation allows accurate diagnosis under different operating conditions without permanently reducing system efficiency.
Solution Approach 2:
The system changes key operating parameters (expansion valve opening degree, compressor capacity) to create distinct operating conditions suitable for different types of performance degradation diagnosis. By controlling these parameters, the determining unit can accurately measure temperature differences and identify degradation causes that would be indistinguishable under normal operating conditions.
2Measurement precision
If the operation condition is adjusted to diagnose performance degradation, then accurate identification of degradation causes is achieved, but operational time is lost
Solution Approach 1:
The system performs performance degradation diagnosis during regular operation without requiring separate maintenance shutdowns. The control unit automatically adjusts operating conditions and initiates diagnosis procedures while the apparatus is running, allowing degradation detection to be integrated into normal operational cycles rather than requiring dedicated maintenance time.
Solution Approach 2:
The determining unit automatically identifies performance degradation causes by analyzing temperature differences under controlled operating conditions, eliminating the need for manual inspection or external diagnostic equipment. The system self-diagnoses issues like refrigerant leakage and heat exchanger soiling, reducing maintenance time and labor requirements.
3Adaptability or versatility
If multiple performance degradation factors are monitored simultaneously, then comprehensive diagnosis is achieved, but system complexity increases
Solution Approach 1:
The system segments the diagnosis process into distinct modes for different types of performance degradation (refrigerant leakage, heat source side soiling, use side soiling). Each degradation type has a specific operating condition and diagnostic approach. This segmentation allows the system to handle multiple degradation factors comprehensively while maintaining a relatively simple control structure by treating each case separately rather than simultaneously.
Data Source
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AI summary
Provided is a performance degradation diagnosis system for a refrigeration cycle apparatus, capable of accurately identifying a cause of performance degradation. A performance degradation diagnosis system (200) is a performance degradation diagnosis system for an air conditioning apparatus (100) that includes a refrigerant circuit including a compressor, a heat-source-side heat exchanger, and a use-side heat exchanger. The performance degradation diagnosis system includes a determining unit (216) and an air-conditioning control unit (214). The determining unit determines, based on an index indicating an operation state of the air conditioning apparatus, performance degradation of the air conditioning apparatus with respect to each of a plurality of performance degradation factors of the air conditioning apparatus. In a case where the determining unit determines performance degradation of the air conditioning apparatus with respect to each of the performance degradation factors, the air-conditioning control unit grasps an operation condition of the air conditioning apparatus which is operating, and in a case where the operation condition of the air conditioning apparatus is not suitable for determining performance degradation of the air conditioning apparatus with respect to a performance degradation factor of a determination target, controls the operation condition of the air conditioning apparatus so that the operation condition of the air conditioning apparatus becomes an appropriate operation condition.