Condensers: Water-Cooled Condensers

 Tube and Tube Condensers:

• Design: Water flows in the inner tube while refrigerant flows around it in the outer tube, transferring heat from the refrigerant to the water (desuperheating, condensing, and subcooling the refrigerant).
• Types:
  1. Flange Type:
     • Two straight tubes (one inside the other) running horizontally.
     • End flanges can be unbolted and removed for easy cleaning using brushes.
  2. Coil Type (Coaxial Type):
     • Two coiled tubes (one inside the other).
     • Often used in low-temperature refrigeration systems, sometimes incorporating motor cooling by wrapping the water coil around the compressor before entering the condenser.

Examples:

• Flange Type:
  • Water enters at the bottom, flows counter to the refrigerant, and exits at the top.
  • Discharge vapor enters at the top and condenses as it moves downward, leaving as subcooled liquid refrigerant.
• Coil Type:
  • Water enters through a water regulating valve and exits after passing through the condenser, cooling the discharge vapor in a counterflow arrangement.

Water-Cooled Condenser with No Regulator:

• Example:
  • Water Temperature: 85°F entering, 95°F leaving.
  • Condensing Temperature: 105°F.
  • A difference of more than 10°F between the leaving water temperature and condensing temperature may indicate mineral buildup or insufficient water supply.

Water Regulating Valve:

• Purpose: To maintain proper head pressure and condensing temperature by regulating water flow based on incoming water temperature.
• Operation:
  • The valve senses discharge pressure and adjusts to maintain a set head pressure.
  • Example: Colder water (e.g., 55°F) will require less flow through the condenser, so the valve reduces water flow to maintain proper head pressure.
  • The valve can be adjusted using a screwdriver or valve wrench.

Installation and Adjustment:

• Directional Flow: Ensure correct installation by following the arrow stamped on the valve.
• Adjustment: A pressure bell on the bottom of the valve responds to head pressure, while a spring on top controls the valve opening based on pressure changes.