System and method for identifying causes of HVAC system faults
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Solution Overview
Problem
Conventional HVAC systems lack effective methods for early detection and identification of faults, leading to delayed recognition of system failures, potential damage, and costly repairs, as users typically notice performance issues only after significant problems have arisen, without information on the specific malfunctioning component.
Innovation Solution
The implementation of suction-side and liquid-side sensors in HVAC systems to monitor refrigerant properties and trends, allowing a controller to detect potential faults such as fan malfunctions, refrigerant conduit blockages, and blower malfunctions by analyzing changes in suction-side and liquid-side properties over time, and triggering alerts or system shutdowns to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional HVAC systems are used without advanced sensing and monitoring, then the system structure remains simple, but fault detection is delayed and system reliability deteriorates
Solution Approach 1:
The suction-side and liquid-side sensors are installed to monitor refrigerant properties before faults occur. The controller continuously analyzes trends in suction pressure, liquid pressure, and temperature to detect early signs of fan malfunctions, blockages, or blower failures, enabling proactive maintenance before system failure
Solution Approach 2:
The controller acts as an intermediary that processes sensor data from both suction-side and liquid-side of the refrigerant cycle. By analyzing the relationship between suction pressure trends, liquid pressure trends, and temperature differentials, the controller identifies fault conditions that would be invisible to conventional single-point monitoring
2Loss of time
If users rely on conventional performance-based fault detection, then the system operation remains simple, but the time to detect faults increases significantly
Solution Approach 1:
The controller implements continuous feedback monitoring by comparing actual sensor readings against expected operational ranges and trends. When deviations are detected in suction-side or liquid-side properties, the system provides immediate feedback alerts to identify fault conditions such as fan failures or refrigerant blockages before they cause system shutdown
Solution Approach 2:
The patent replaces conventional mechanical fault detection methods with electronic sensing and digital signal processing. The controller uses microprocessor-based algorithms to analyze sensor data trends, substitute mechanical diagnostics with electronic monitoring, and automatically identify fault types based on patterns in suction and liquid side property changes
3Measurement precision
If multiple sensors and monitoring systems are added to improve fault detection, then measurement precision improves, but device complexity increases
Solution Approach 1:
The controller is designed as a multi-functional device that performs multiple tasks: it monitors suction-side pressure and temperature, monitors liquid-side pressure and temperature, analyzes trends in all parameters, identifies multiple fault types (fan failure, blockage, blower failure), and provides diagnostic information. This universal controller consolidates what would otherwise require multiple separate monitoring systems
Solution Approach 2:
The patent combines the suction-side monitoring function and liquid-side monitoring function into a single integrated controller system. By merging the data acquisition, analysis, and diagnostic functions into one controller, the system achieves comprehensive monitoring without proportionally increasing complexity, as the controller processes all sensor inputs through unified algorithms
Data Source
AI summary
A controller of an HVAC system is communicatively coupled to a suction-side sensor and a shutoff switch. The controller stores measurements of the suction-side property over an initial period of time. The controller detects that the shutoff switch is tripped at a first time stamp corresponding to an end of the initial period of time. The controller accesses the measurements of the suction-side property. The controller determines, based on the measurements of the suction-side property, whether the suction-side property has an increasing or decreasing trend. In response to determining that the suction-side property has the increasing trend, the controller determines that a malfunction of a fan caused the shutoff switch to trip. In response to determining that the suction-side property has the decreasing trend, the controller determines that a blockage of the refrigerant conduit subsystem caused the shutoff switch to trip.