Sensor coupling verification in tandem compressor units
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Solution Overview
Problem
In HVAC systems with tandem compressors, shared refrigerant piping complicates monitoring individual compressor operations, making it difficult to identify specific compressor failures and ensuring accurate temperature sensing, as discharge pressure switches cannot discern which compressor is causing an over-pressure condition due to merged refrigerant flow.
Innovation Solution
A method and apparatus that verify the coupling of sensors with compressors by using a controller to switch compressors between energized and de-energized states, causing a temperature increase in the discharge pipe leg, and determining if the sensor signal indicates temperatures above or below a threshold, thereby generating pairing signals to correctly associate sensor data with the appropriate compressor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If tandem compressors share common refrigerant piping to improve system capacity and partial load efficiency, then overall system capacity and load matching ability are improved, but the ability to monitor and identify specific compressor failures deteriorates
Solution Approach 1:
The patent segments the common refrigerant piping into individual compressor-specific piping sections by installing isolation valves and separate temperature sensors on each compressor's discharge line. This allows independent monitoring of each compressor's refrigerant temperature and pressure, enabling failure identification even within a tandem configuration.
Solution Approach 2:
The patent introduces intermediary components including individual temperature sensors, isolation valves, and control logic that act as mediators between the compressors and the monitoring system. These intermediaries enable the detection system to distinguish which compressor is causing abnormal conditions despite the merged discharge piping.
2Measurement precision
If temperature sensors are placed near compressor discharge ports to accurately sense refrigerant temperature, then temperature sensing accuracy is improved, but the risk of incorrect sensor-compressor pairing increases
Solution Approach 1:
The patent implements a feedback mechanism where the controller monitors temperature sensor readings and compares them against expected temperature ranges for each compressor. The system can detect when a sensor is paired with the wrong compressor based on temperature patterns and provide feedback for correction, ensuring reliable sensor-compressor pairing.
Solution Approach 2:
The control system performs self-verification by analyzing temperature data patterns to automatically identify and correct sensor-compressor pairing errors. The system uses the temperature readings themselves to verify correct pairing, eliminating the need for manual verification and reducing installation errors.
3Device complexity
If discharge pressure switches monitor combined pressure from all tandem compressors to simplify pressure monitoring, then monitoring complexity is reduced, but the ability to identify specific failing compressors deteriorates
Solution Approach 1:
The patent segments the pressure monitoring function by installing individual pressure sensors or using isolation valves to create separate monitoring zones for each compressor. This allows the pressure switch to monitor pressure for each compressor independently, enabling identification of which specific compressor is causing over-pressure conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents incorrect association of sensor data with compressors, ensuring effective monitoring and diagnostic functions to identify inoperative or improperly coupled components, thus safeguarding compressor operations.
Implementation Method 1
The controller may cause a temperature increase of the refrigerant within the first discharge pipe leg of the first compressor
Data Source
AI summary
Provided are a method and apparatus for verifying or correcting the temperature sensor and compressor pairings within the HVAC system control logic, indicating that a sensor is logically paired with the specific compressor, from amongst a tandem compressor group, to which the sensor is coupled.