Absorption Refrigerator Noise and Vibration Reduction

Overview of Technical Issues:

The absorption refrigerator's circulation pump generates harmful vibration during operation, and the refrigerant flow creates turbulent noise in the piping system, while the mounting structure provides insufficient vibration isolation, allowing these disturbances to transmit to the installation foundation and amplify throughout the system; the goal is to reduce overall noise and vibration levels to improve user comfort and system operational stability.

Solution directions generated for this problem

Problem Direction 1 :

ImproveMounting structure damping capacity
VS
ConstraintMounting structure weight and complexity

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
Methods for manufacturing vapor deposition masks and methods for manufacturing organic semiconductor devices
Innovative Solution Refine solution

Modular zoned damping mount with targeted vibration path isolation

Divide damping into independent modules at vibration sources
How to solve :
  • Partition the mounting structure into three independent damping zones: pump feet module, pipe support module, and electrical entry module, each with optimized damping coefficients (0.15-0.25) targeting specific frequency ranges (pump: 50-120Hz, pipe: 200-500Hz, electrical: 100-300Hz)
  • each zone uses thin-layer constrained-layer damping (0.8-1.2mm viscoelastic core between 0.5mm aluminum facesheets) providing loss factor ≥0.3 at 40% weight of monolithic rubber pads
  • install localized isolation only at three primary transmission paths — pump mounting feet receive 15×15mm damping pads, refrigerant pipe connections receive 8mm diameter damping grommets, electrical conduit entry receives 10mm damping bushing, total added mass <150g versus 600-800g for full-chassis damping treatment
Expected Effect : Vibration transmission -28dB, weight +18% only, damping efficiency 3.2× per gram
Risk Control :
  • viscoelastic material aging under thermal cycling
  • interface bonding failure between damping layers
  • frequency mismatch if pump speed varies

Problem Direction 2 :

ImprovePump rotor dynamic balance quality
VS
ConstraintPump rotor manufacturing precision requirement

Inspiration 1 : Cross-domain reference

Application Principle: #2 Taking out
Cross-domain applicability Assess applicability
Silicone emulsions, and methods for the production thereof
Innovative Solution Refine solution

Post-assembly field balancing with removable correction weights

Extract balance correction from rotor body manufacturing
How to solve :
  • Design rotor with pre-drilled radial correction pockets at 8 evenly-spaced positions (45° intervals) on non-critical rotor sections, depth 3–5mm, diameter 6mm, allowing post-assembly balance adjustment without sub-micron machining precision on rotor body
  • Perform dynamic balancing test after rotor assembly using standard balancing machine (ISO 21940 Grade G6.3), measure residual unbalance vector, then insert calibrated tungsten or brass correction weights (0.5–5g increments) into calculated pocket positions and secure with thread-locking adhesive
  • Establish quality control protocol: initial rotor machining tolerance relaxed to ±0.05mm (vs. ±0.01mm conventional), final residual unbalance ≤6.3 g·mm/kg after field correction, vibration velocity ≤2.8 mm/s at pump mounting feet measured per ISO 10816-3, acceptance criteria verified on every unit before shipment
Expected Effect : Manufacturing cost −35%, residual unbalance ≤6.3 g·mm/kg, vibration ≤2.8 mm/s
Risk Control :
  • correction weight retention failure under vibration
  • pocket position calculation error
  • adhesive curing inconsistency

Problem Direction 3 :

ImproveRefrigerant flow velocity stability
VS
ConstraintMounting structure weight and complexity

Inspiration 1 : Cross-domain reference

Application Principle: #2 Taking out
Cross-domain applicability Assess applicability
rack and drones using the rack
Innovative Solution Refine solution

Geometry-optimized piping layout for laminar flow stabilization

Eliminate turbulence sources by redesigning piping geometry without adding components
How to solve :
  • Replace existing sharp 90° bends with gradual radius bends (R≥3D, where D=pipe diameter) and eliminate sudden diameter changes by using tapered transition sections with 7–12° included angle to naturally stabilize flow patterns
  • Reconfigure refrigerant circuit to utilize vertical gravity-assisted flow sections for 40–60% of total pipe length, positioning pump discharge vertically upward and condenser return vertically downward to leverage density stratification for flow stabilization
  • Install ultra-thin perforated flow straightener screens (0.3–0.5mm thickness, 55–65% open area ratio) at 2–3 strategic locations immediately downstream of unavoidable disturbances, using laser-cut stainless steel mesh weighing <15g per unit to break turbulent eddies
Expected Effect : Flow velocity fluctuation reduced by 60–75%; turbulent noise decreased by 8–12 dB(A); total added weight <50g for entire piping system; pressure drop increase <3%
Risk Control :
  • bend radius tolerance exceeding ±0.5mm causing residual turbulence
  • screen perforation clogging by refrigerant contaminants
  • vertical section air pocket formation during startup

Problem Direction 4 :

ImproveOverall vibration isolation effectiveness
VS
ConstraintMounting structure weight and complexity

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
Pressure relief system for footwear
Innovative Solution Refine solution

Modular zoned vibration isolation architecture for absorption refrigerators

Deploy independent isolation modules at critical transmission points only
How to solve :
  • Install three independent isolation zones at pump mounting feet, refrigerant pipe connections, and electrical conduit entries rather than isolating entire chassis — each zone uses fiber-reinforced composite isolators (carbon fiber/viscoelastic matrix) providing damping coefficient ≥0.15 at 40% weight of conventional rubber-metal mounts
  • Configure each zone with tuned stiffness properties — pump feet zone: 8–12 kN/m vertical stiffness for 25–50 Hz isolation, pipe connection zone: 5–8 kN/m radial stiffness for flow-induced vibration, conduit zone: 3–5 kN/m for electrical noise decoupling
  • Quality control: measure transmissibility ratio at each zone (acceptance ≤0.25 at operating frequency), verify composite isolator Shore hardness 60–70A, inspect fiber orientation alignment within ±5°, conduct sweep frequency test 10–200 Hz confirming >15 dB attenuation at pump fundamental frequency
Expected Effect : Vibration transmission reduced 65%, weight added <1.2 kg, installation time unchanged
Risk Control :
  • composite isolator manufacturing consistency
  • zone-specific stiffness calibration accuracy
  • long-term viscoelastic creep under thermal cycling
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