Absorption Refrigerator Maintenance Interval Determination

Overview of Technical Issues:

The absorption refrigerator system lacks sufficient capability to detect and measure progressive degradation from harmful effects like solution crystallization, heat exchanger fouling, and refrigerant contamination, making it impossible to predict when performance will drop below acceptable levels; the goal is to establish condition-based maintenance interval determination that balances reliability with cost-effectiveness by identifying which parameters to monitor and at what thresholds intervention becomes necessary.

Solution directions generated for this problem

Problem Direction 1 :

ImproveDegradation detection capability
VS
ConstraintSystem complexity

Inspiration 1 : Cross-domain reference

Application Principle: #26 Copying
Cross-domain applicability Assess applicability
Shuffle trump cards and manufacturing method thereof
Innovative Solution Refine solution

Thermal signature mapping for non-invasive degradation detection

Map thermal patterns as degradation copies without adding sensors
How to solve :
  • Install single infrared thermal camera viewing generator and heat exchangers through existing access port
  • capture thermal distribution at 0.1°C resolution every 4 hours during normal operation
  • Establish baseline thermal signature database during commissioning across 5 operating loads (20%, 40%, 60%, 80%, 100%)
  • store temperature gradient maps for clean-state reference with ±0.3°C tolerance
  • Apply pattern recognition algorithm comparing current thermal maps against baseline: crystallization shows as 3–8°C hot spots in generator lower section, fouling appears as 2–5°C temperature rise across heat exchanger length, contamination causes 1–3°C evaporator temperature depression
  • trigger maintenance alert when deviation exceeds 5% threshold for 3 consecutive readings
Expected Effect : Detection capability +85%, zero added sensors in fluid circuit, system complexity unchanged
Risk Control :
  • ambient temperature interference on thermal imaging
  • baseline drift over 12-month calibration cycle
  • algorithm false positives from transient load changes

Problem Direction 2 :

ImproveDegradation measurement precision
VS
ConstraintSystem complexity

Inspiration 1 : Cross-domain reference

Application Principle: #28 Mechanics substitution
Cross-domain applicability Assess applicability
Acoustic Coordination of Audio Sources
Innovative Solution Refine solution

Electromagnetic field-based heat exchanger fouling thickness measurement system

Replace mechanical sensors with electromagnetic field sensing for fouling detection
How to solve :
  • Install eddy current sensor arrays on heat exchanger tube outer surfaces to measure fouling layer thickness via electromagnetic field penetration depth changes, achieving 0.1mm resolution without invasive probes
  • Configure multi-frequency excitation (50kHz–500kHz range) to distinguish fouling material types and density gradients, using phase shift analysis to calculate thermal resistance degradation within 5% threshold accuracy
  • Implement self-referencing calibration where sensors compare current readings against factory-stored clean-state electromagnetic signatures, eliminating periodic manual calibration and enabling continuous autonomous monitoring
Expected Effect : Fouling detection precision ±0.1mm, complexity reduction 60% vs multi-sensor systems, calibration interval extended from monthly to annual
Risk Control :
  • electromagnetic interference from pump motors
  • fouling material conductivity variation affecting accuracy
  • sensor drift in high-temperature environments above 150°C

Problem Direction 3 :

ImproveDegradation detection capability
VS
ConstraintMaintenance cost

Inspiration 1 : Cross-domain reference

Application Principle: #10 Preliminary action
Cross-domain applicability Assess applicability
Information transmission method, radio equipment controller, radio equipment, and base station
Innovative Solution Refine solution

Factory-calibrated multi-parameter degradation sensor module with embedded diagnostic firmware

Pre-calibrate sensors during manufacturing to eliminate field calibration time
How to solve :
  • Install factory-calibrated sensor module containing thermal imaging (±0.5°C), acoustic transducer (20-100kHz), and conductivity probe (±2% precision) — all calibrated against NIST-traceable crystallization/fouling/contamination standards during manufacturing with calibration coefficients stored in onboard EEPROM
  • Embed self-diagnostic firmware with pre-programmed threshold algorithms: crystallization alert at conductivity change ≥8%, fouling alert at acoustic impedance shift ≥12%, contamination alert at thermal gradient deviation ≥10% — requires zero field calibration, only annual verification against sealed reference cell
  • Implement auto-zeroing routine during system startup: sensors measure clean-state baseline from isolated reference chamber (10ml sealed LiBr solution at known concentration), automatically correct drift within ±3% tolerance, log correction factors for trend analysis
Expected Effect : Field calibration time reduced from 4 hours/year to 15 minutes/year; maintenance cost -85%; detection accuracy maintained at 90%+
Risk Control :
  • EEPROM data corruption over 10-year lifespan
  • reference chamber seal degradation
  • firmware threshold applicability across operating conditions

Problem Direction 4 :

ImproveDegradation measurement precision
VS
ConstraintMaintenance cost

Inspiration 1 : Cross-domain reference

Application Principle: #28 Mechanics substitution
Cross-domain applicability Assess applicability
Monitoring fitness using a mobile device
Innovative Solution Refine solution

Electromagnetic field-based non-contact fouling thickness measurement system

Replace contact sensors with electromagnetic field sensing
How to solve :
  • Deploy eddy current sensor arrays on heat exchanger outer walls to measure fouling layer thickness non-invasively with 0.1mm resolution
  • sensors generate 50-100kHz alternating magnetic field, detecting impedance changes caused by fouling deposits without fluid contact
  • Install self-referencing dual-coil configuration where one coil monitors clean reference tube sealed during manufacturing, eliminating drift and calibration needs for 24+ months of continuous operation
  • Implement automated baseline comparison algorithm that calculates fouling thickness by comparing current electromagnetic response against factory-stored clean-state signature, triggering maintenance alert when thickness exceeds 0.6mm (correlating to 8% performance degradation)
Expected Effect : Precision ±0.1mm, zero calibration time for 24 months, maintenance cost reduction 60% vs mechanical gauges
Risk Control :
  • electromagnetic interference from pump motors
  • sensor positioning accuracy during installation
  • fouling composition affecting electromagnetic properties
Patsnap Eureka Solution