Fault detection method for air conditioning system
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Large-scale commercial refrigeration systems with injectors face challenges in determining the cause of backflow problems under partial load conditions, which affects system reliability and efficiency.
Innovation Solution
A fault detection method that automatically learns a monotonically decreasing fault detection characteristic curve using the electrical power consumption of the liquid pump and the high-pressure-side pressure of the injector, allowing for the evaluation of injector faults and backflow causes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple sets of parallel injectors are used to achieve better partial load regulation capability, then the operating efficiency under partial load conditions is improved, but the complexity of coordinating the number of injectors and their opening degrees increases, leading to higher risk of backflow problems
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring the high-pressure-side pressure of the injector and the electrical power consumption of the liquid pump, comparing actual values with expected values from a characteristic curve, and automatically detecting backflow conditions. This feedback loop enables automatic adjustment and coordination of multiple injectors without requiring complex manual control, thus maintaining high operating efficiency while reducing coordination complexity.
2Reliability
If the high-pressure-side pressure of the injector and electrical power consumption of the liquid pump are monitored to detect backflow, then the reliability of system operation is improved, but the difficulty of detecting and measuring fault causes increases due to the need to analyze the relationship between multiple parameters
Solution Approach 1:
The patent transforms the complex multi-parameter fault detection problem into a simpler comparison by establishing a characteristic curve that represents the expected relationship between high-pressure-side pressure and electrical power consumption. Instead of analyzing multiple parameters independently, the system only needs to compare the actual parameter pair against this pre-established curve, significantly reducing the difficulty of fault detection while maintaining high reliability.
3Ease of manufacture
If a fault detection method using existing parameters is used to determine backflow causes, then additional hardware costs are avoided, but the measurement precision of fault detection may be insufficient without dedicated sensors
Solution Approach 1:
The patent makes existing sensors serve multiple functions: the high-pressure-side pressure sensor and electrical power consumption sensor, originally designed for normal operation monitoring, are also used for backflow detection and fault diagnosis. By establishing a characteristic curve that represents normal operation, the system can identify backflow conditions using these existing parameters, achieving cost-effective fault detection with sufficient precision without requiring dedicated backflow sensors.
Data Source
Figure 1
AI summary
A fault detection method for an air conditioning system is provided by the present disclosure. The air conditioning system has a liquid pump and an injector. The fault detection method includes: automatically learning to obtain a monotonically decreasing fault detection characteristic curve Y=K(X-XMAX)+A by using an electrical power consumption of the liquid pump and a high-pressure-side pressure of the injector; wherein when Y and A are 0, X corresponds to a maximum high-pressure-side pressure Xmax of the injector; and when the current pressure of the injector Xcurrent≤Xmax: if the current electrical power consumption Ycurrent<K(Xcurrent-Xmax)+A, then a probability of the injector state of the air conditioning system being normal is greater than a first preset value; and if the current electrical power consumption Ycurrent>K(Xcurrent-Xmax)+A, a probability of the injector of the air conditioning system having a fault is greater than a second preset value. According to the air conditioning system of the present disclosure and the fault detection method therefor, the cause of injector backflow can be determined based on the existing sensors in existing systems and parameters acquired by them so that an appropriate treatment can be performed, and there is no need to increase the cost on hardware.