Absorption Refrigerator for Hospital Sterilization Cooling

Overview of Technical Issues:

The evaporator's heat-absorbing function is insufficient under peak sterilization loads and elevated ambient temperatures, causing inadequate cooling of sterilized instruments and extended cooling cycles that delay hospital sterilization throughput; the goal is to optimize the absorption refrigeration system to maintain stable cooling performance across variable operating conditions while meeting strict medical equipment temperature requirements.

Solution directions generated for this problem

Problem Direction 1 :

ImproveEvaporator heat transfer capacity
VS
ConstraintSystem energy consumption

Inspiration 1 : Cross-domain reference

Application Principle: #19 Periodic action
Cross-domain applicability Assess applicability
DC-DC Converters
Innovative Solution Refine solution

Pulsed refrigerant flow modulation with thermal load sensing

Modulate refrigerant flow in synchronized pulses with real-time sterilization load
How to solve :
  • Install variable-frequency pump (10-60Hz) with thermal load sensor at evaporator inlet, pulsing refrigerant flow at 120-180 cycles/hour during peak load (35°C ambient, 100% sterilization), throttling to 40-80 cycles/hour at partial load
  • Implement duty cycle control: high-flow pulse delivers 12kW instantaneous capacity for 15-25 seconds, followed by 35-45 second low-flow recovery phase, achieving 8-10kW time-averaged capacity while maintaining 3.6-3.9kW average power draw
  • Deploy phase-change thermal buffer (paraffin wax PCM, melting point 8-12°C, latent heat ≥200 kJ/kg) in 15-liter reservoir adjacent to evaporator, absorbing excess cooling during pulse peaks and releasing during recovery phases to smooth temperature fluctuations within ±1.5°C
Expected Effect : Heat capacity 8-10kW sustained, energy 3.6-3.9kW average, throughput +35%
Risk Control :
  • pump frequency control precision drift
  • PCM thermal cycling degradation after 5000 cycles
  • sensor response lag causing phase mismatch

Problem Direction 2 :

ImproveEvaporator heat transfer capacity
VS
ConstraintEquipment volume

Inspiration 1 : Cross-domain reference

Application Principle: #7 Nested doll
Cross-domain applicability Assess applicability
Multi-phase heat dissipating device embedded in an electronic device
Innovative Solution Refine solution

Nested multi-tube evaporator with concentric refrigerant channels

Nested tube-in-tube evaporator design with concentric refrigerant channels
How to solve :
  • Design concentric triple-tube evaporator with refrigerant in inner tube (Ø12mm), secondary coolant in middle annulus (Ø18mm outer), and air gap insulation in outer shell (Ø22mm), achieving 2.8× surface area within 0.85m³
  • Use copper inner tubes with internal microgrooves (0.3mm depth, 0.5mm pitch) to enhance nucleate boiling, paired with aluminum outer fins (spacing 2.2mm, thickness 0.15mm) for air-side heat transfer
  • Implement counter-flow arrangement with refrigerant entering bottom at -5°C and exiting top at 5°C, maintaining 8-10kW capacity across 20-35°C ambient through optimized flow distribution (refrigerant velocity 0.8-1.2 m/s, coolant velocity 0.4-0.6 m/s)
Expected Effect : Heat transfer capacity 8.5kW at 35°C ambient, volume 0.85m³, energy consumption 3.6kW
Risk Control :
  • tube concentricity tolerance exceeding ±0.1mm causing uneven flow
  • microgroove manufacturing consistency below 95%
  • thermal expansion mismatch between copper and aluminum causing joint failure

Problem Direction 3 :

ImproveRefrigerant evaporation rate
VS
ConstraintSystem energy consumption

Inspiration 1 : Cross-domain reference

Application Principle: #28 Mechanics substitution
Cross-domain applicability Assess applicability
Latent two-component polyurethane adhesive cured by infrared radiation
Innovative Solution Refine solution

Infrared-activated phase-change refrigerant acceleration system

Replace mechanical pump acceleration with infrared radiation heating
How to solve :
  • Install selective infrared emitters (wavelength 2.5–4.0 μm matched to refrigerant absorption spectrum) targeting evaporator inlet zone, activating refrigerant molecules on-demand during peak load without continuous pump
Patsnap Eureka Solution