How to Detect Leaks in Absorption Refrigerator Systems

Overview of Technical Issues:

The sealed containment structures in the absorption refrigerator system exhibit insufficient blocking function, allowing refrigerant-absorbent solution to escape through defects, while the measuring devices provide insufficient detection of these leaks, resulting in undetected refrigerant loss that progressively degrades cooling performance and creates potential safety hazards; the goal is to establish reliable leak detection capability that identifies leaks early before significant system performance degradation occurs.

Solution directions generated for this problem

Problem Direction 1 :

ImproveLeak detection sensitivity
VS
ConstraintMeasurement device complexity

Inspiration 1 : Cross-domain reference

Application Principle: #2 Taking out (Extraction)
Cross-domain applicability Assess applicability
Road paver having layer thickness detecting device and method
Innovative Solution Refine solution

Dual-chamber differential pressure leak detection system with isolated monitoring zone

Isolate essential detection function using pressure differential
How to solve :
  • Install a secondary low-pressure monitoring chamber (0.1–0.5 bar) surrounding all critical sealed joints and welds, separated from the primary refrigerant circuit by the existing containment structure
  • any refrigerant escaping through micro-cracks enters this chamber, creating immediate detectable pressure rise
  • Use a single differential pressure transducer (sensitivity ±0.01 mbar) connected between monitoring chamber and ambient atmosphere, with mechanical threshold alarm set at 0.05 mbar rise indicating leak detection
  • Evacuate monitoring chamber to 0.2 bar absolute during installation using standard vacuum pump, seal with simple O-ring compression fittings (no precision machining required), and verify baseline pressure stability over 24 hours before system commissioning
Expected Effect : Detects leaks at <1% refrigerant loss within 2–6 hours; uses single pressure sensor vs. multi-sensor arrays; 60% cost reduction vs. electronic chemical sensors
Risk Control :
  • monitoring chamber seal integrity over time
  • false alarms from thermal expansion
  • differential sensor drift calibration

Problem Direction 2 :

ImproveLeak detection sensitivity
VS
ConstraintManufacturing precision requirement

Inspiration 1 : Cross-domain reference

Application Principle: #10 Preliminary action
Cross-domain applicability Assess applicability
Device and method for monitoring the state of the sub-structure of fixed tracks
Innovative Solution Refine solution

Embedded fiber-optic leak detection network in standard-tolerance sealing joints

Embed fiber-optic sensors during assembly
How to solve :
  • Integrate single-mode optical fiber loops (125μm diameter) directly into sealing gaskets during standard assembly process — fibers positioned 0.5–1.0mm from sealing interface using pre-formed grooves in gasket material
  • Connect fibers to optical time-domain reflectometer (OTDR) operating at 1550nm wavelength with 1m spatial resolution — refrigerant vapor exposure causes refractive index change ≥0.002, triggering detectable backscatter signal shift within 2 hours
  • Manufacture gaskets to standard industrial tolerance (±0.2mm) using compression-molded EPDM or Viton with fiber channels — no precision machining of metal sealing surfaces required, fibers self-report any leak path formation
Expected Effect : Detects leaks <1% refrigerant loss; standard tolerance ±0.2mm maintained; response time <2 hours
Risk Control :
  • fiber breakage during installation
  • refrigerant compatibility with fiber coating
  • OTDR calibration drift over time

Problem Direction 3 :

ImproveContainment structure blocking effectiveness
VS
ConstraintManufacturing precision requirement

Inspiration 1 : Cross-domain reference

Application Principle: #40 Composite materials
Cross-domain applicability Assess applicability
Bit holder and base part for receiving a bit holder
Innovative Solution Refine solution

Layered compliant barrier seal for absorption refrigerator joints

Use a layered adaptive seal
How to solve :
  • Add metal carrier plus FKM skin gasket, 0.15-0.30 mm elastomer each side, 70-80 Shore A, carrier 304SS 0.20-0.35 mm
  • Form joint with micro-embossed sealing beads 0.08-0.15 mm high, bolt stress 18-28 MPa or brazed compression, so soft layers fill waviness up to 40 microns
  • Apply barrier topcoat and proof test using FEP or PFA film 25-50 microns, helium leak test below 1x10^-6 mbar L/s, compression set under 20% after 1000 h at 120 C
Expected Effect : Leak rate cut >90%, surface finish need only Ra 1.6-3.2 microns, joint tolerance relaxed to ±0.10 mm, service life +2-3x vs flat metal seal
Risk Control :
  • elastomer ammonia compatibility
  • creep from overcompression
  • film delamination at edges

Problem Direction 4 :

ImproveEarly warning response time
VS
ConstraintMeasurement device complexity

Inspiration 1 : Cross-domain reference

Application Principle: #19 Periodic action
Cross-domain applicability Assess applicability
Sand separator interface detection
Innovative Solution Refine solution

Scheduled micro-sampling leak detection with automated vapor capture

Automated sampling every 2 hours detects leaks early without continuous monitoring
How to solve :
  • Install mechanical timer-actuated sampling valve at refrigerant chamber apex that captures 5mL vapor samples every 2 hours into pre-evacuated collection vials
  • timer mechanism uses simple spring-driven escapement requiring no electronics
  • Deploy colorimetric indicator strips inside each vial containing bromothymol blue solution (pH 6.0-7.6) that changes from blue to yellow when exposed to ammonia refrigerant concentration ≥50 ppm, providing visual leak confirmation
  • Implement daily visual inspection protocol where technician checks vial color under standard lighting (≥500 lux)
  • any yellow indication within 2-hour sampling window confirms
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