Heat-Pump Refrigerant Charge Diagnostics Using Air Temperature Sensors

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Solution Overview

Problem

Existing heat-pump systems face challenges in accurately diagnosing and maintaining optimal refrigerant charge levels, leading to inefficient operation and potential faults such as undercharge, overcharge, or flow restrictions, which are not effectively addressed by current monitoring systems.

Innovation Solution

A cloud-based processing system that communicates with various sensors to determine the working-fluid charge condition, generating alerts and providing guidance for technicians to adjust the refrigerant levels, using a method that involves calculating temperature differences from multiple sensors to diagnose faults and optimize the charge level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual troubleshooting and refrigerant charge monitoring are performed using conventional methods, then technicians can identify charge issues, but the process is time-consuming and lacks real-time diagnostic capability

Engineering Contradiction:
Improverefrigerant charge level detection accuracyVSAvoidtime for manual troubleshooting
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system continuously monitors temperature data from multiple sensors and provides real-time feedback about refrigerant charge conditions. The processor compares actual temperature differentials against expected values and generates alerts when charge issues are detected, enabling continuous monitoring without manual intervention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-diagnosis by automatically analyzing temperature data from sensors to determine refrigerant charge conditions. The processor independently evaluates charge status and generates notifications without requiring technician intervention, allowing the system to monitor itself continuously.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If multiple sensors and cloud-based processing are implemented to improve diagnostic accuracy, then refrigerant charge conditions can be precisely determined, but system complexity increases

Engineering Contradiction:
Improvefault diagnosis accuracyVSAvoidmonitoring system structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The processor serves multiple functions: it collects data from sensors, analyzes temperature differentials, determines refrigerant charge conditions, generates alerts, and provides diagnostic information. This multi-functionality reduces the need for separate dedicated components for each task.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cloud-based processing system acts as an intermediary between the physical sensors and the diagnostic output. It receives raw temperature data, performs complex analysis to determine charge conditions, and translates this into actionable diagnostic information and alerts.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If real-time temperature monitoring and analysis are performed to diagnose refrigerant charge issues, then accurate fault identification is achieved, but energy consumption increases

Engineering Contradiction:
Improvesystem operation reliabilityVSAvoidenergy for continuous monitoring
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs temperature monitoring and analysis at periodic intervals rather than continuously. The processor evaluates temperature differentials and determines charge conditions at scheduled times, reducing energy consumption while maintaining reliable diagnostic capability.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system monitors changes in temperature parameters over time to detect refrigerant charge issues. By analyzing temperature differentials and their changes rather than maintaining constant high-power monitoring, the system achieves reliable detection with reduced energy consumption.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2981772B1Heat-pump system with refrigerant charge diagnostics
Publication Date: 2022.01.12 EMERSON CLIMATE TECHNOLOGIES INC
  • EP2981772B1 patent drawingFigure 1~2
  • EP2981772B1 patent drawingFigure 3

AI summary

A heat-pump circuit may include an indoor heat exchanger, an outdoor heat exchanger, a compressor adapted to circulate a working fluid between the indoor and outdoor heat exchangers, and an expansion device disposed between the indoor and outdoor heat exchangers. A monitor for the heat-pump system may include a return-air temperature sensor, a supply-air temperature sensor, and a processor. The return-air temperature sensor may be adapted to measure a first air temperature of air upstream of the indoor heat exchanger. The supply-air temperature sensor may be adapted to measure a second air temperature of air downstream of the indoor heat exchanger. The processor may be in communication with the return-air temperature sensor and the supply- air temperature sensor. The processor may be programmed to determine a working-fluid-charge condition of the heat-pump system based on the first and second air temperatures.