Refrigeration System Practices

Chapter 1: Liquid Overfeed Systems

Chapter 2: System Practices for Halocarbon Refrigerants

Chapter 3: System Practices for Ammonia and Carbon Dioxide Refrigerants

Chapter 4: Secondary Coolants in Refrigeration Systems

Chapter 5: Refrigerant System Chemistry

Chapter 6: Control of Moisture and Other Contaminants in Refrigerant Systems

Chapter 7: Lubricants in Refrigerant Systems

Chapter 8: Refrigerant Containment, Recovery, Recycling, and Reclamation

Terminology

Low-pressure receiver Sometimes referred to as an accumulator, this vessel acts as the separator for the mixture of vapor and liquid returning from the evaporators. A constant refrigerant level is usually maintained by conventional control devices.

Pumping unit One or more mechanical pumps or gas-operated liquid circulators are arranged to pump overfeed liquid to the evaporators. The pumping unit is located below the low-pressure receiver.

Wet returns These are connections between the evaporator outlets and low-pressure receiver through which the mixture of vapor and overfeed liquid is drawn.

Liquid feeds These are connections between the pumping unit outlet and evaporator inlets.

Flow control regulators These devices regulate overfeed flow into the evaporators. They may be needle valves, fixed orifices, calibrated manual regulating valves, or automatic valves designed to provide a fixed liquid rate.

Advantages and Disadvantages

The main advantages of liquid overfeed systems are high system efficiency and reduced operating expenses. These systems have lower energy...