Cooling method of co2 screw compressor unit

The cooling method of CO ˇ screw compressor units needs to be based on themHigh pressure and high temperature operating characteristicsSpecially designed, common cooling solutions can be divided into four categories, each with its technical characteristics and application scenarios:

1. Indirect cooling (water/air cooling)

1. water cooling system
   • principle: Cooling water indirectly exchanges heat with CO ˇ gas through plate heat exchangers
   • advantages：
     • High heat exchange efficiency (temperature difference can be controlled to <5℃)
     • Suitable for large-scale units (>100kW)
   • key components：
     • Corrosion resistant heat exchanger (titanium or dual phase steel)
     • Closed circulation cooling tower (to avoid water pollution)
2. air cooling system
   • principle: Forced ventilation dissipates heat through finned tube heat exchangers
   • applicable scenarios：
     • Small unit (<50kW)
     • Water scarce areas or mobile applications
   • enhancements：
     • Use nano-coated fins (improves heat dissipation efficiency by 20%)
     • Variable frequency fan (adjust air volume on demand)

2. Direct evaporative cooling

• principle: Liquid CO ˇ absorbs heat and gasifies in the evaporator, directly cooling the compressed gas
• technical advantages：
  • No intermediate media is needed, the system is more compact
  • Utilize the latent heat of phase change of CO ˇ (1kg of CO ˇ evaporation and heat absorption ≈574kJ)
• challenges：
  • Evaporation pressure needs to be accurately controlled (to avoid liquid CO ˇ entering the compressor)
  • Evaporator requires special design (anti-corrosion, high-pressure resistance)

3. Combination of interstage cooling + post-cooling

• Multi-stage compression process：
  • Set up an intercooler after each stage of compression (reduce intake air temperature)
  • The final exhaust gas is secondarily cooled by an aftercooler
• benefits：
  • Compression power consumption reduced by 15%-20%
  • Reduce the risk of lubricating oil carbonization (exhaust temperature <120℃)

4. Heat recovery cooling system

• principle: Use compression heat to drive the absorption chiller to achieve simultaneous cooling and heating
• application scenarios：
  • Industrial park cold, heat and power triple power supply
  • Data center waste heat utilization
• economy：
  • System COP can reach 1.3-1.5
  • Payback period is approximately 3-5 years (depending on energy prices)

Selection suggestions

note: The cooling system of CO ˇ compressor needs to consider supercritical conditions (when the pressure is>7.38MPa, the physical properties of CO ˇ suddenly change). It is recommended to configure a dynamic simulation system to optimize cooling parameters.