Mingledorff’s, Inc.

Basic Refrigeration, Its Components, and Its Cycle

Introduction to Refrigeration

Refrigeration: Cooling to preserve products and provide comfort.

Types of Refrigeration Processes•High Temperature - Air conditioning (comfort cooling)•Medium Temperature - Food preservation (keeping product cool)•Low Temperature - Food preservation (freezing of the product)

What is Refrigeration?

The process of transferring heat from a place where it is not wanted to a place where it

makes little or no difference.

Remember: Heat flows from warm to cold.

How Do We Rate Air Conditioning Equipment?

One ton of Air Conditioning = The removal of 12,000 Btu per

hour.

Four Major Refrigeration System Components

•The evaporator•The compressor•The condenser•The metering device

The Four Major Components

The Evaporator

•A heat exchanger to absorb heat•Evaporator coil - used to absorb heat from the conditioned space or product•Located on the low side of the sealed system between the metering device and low side of the compressor

The Evaporator

•Operates at temperatures colder than the medium passing across the coil•Absorbs heat by boiling a low temperature liquid to a low temperature vapor•Metering device feeds liquid refrigerant into the evaporator. Under standard conditions, the mixture coming into the evaporator is 75% liquid and 25% vapor

The Evaporator•Superheat - the heating of a vapor above the refrigerant saturation temperature•Superheat ensures that no liquid returns to the compressor •Design evaporator superheat ranges from 8 to 12 degrees F•Superheat is determined by subtracting the evaporator's saturation temperature from the temperature of the outlet of the evaporator

The Evaporator

The Compressor

•Pumps heat laden vapor from the evaporator to the condenser•The compressor reduces the pressure on the low side of the system•The compressor increases the pressure on the high side of the system

The Compressor

•Most common types of compressors used are the reciprocating, the rotary, and the scroll

•Positive displacement compressors require that the compressed gas be moved into the condenser or damage will occur

The Compressor

The Compressor

The Condenser

•Rejects sensible and latent heat from the system that was absorbed by the evaporator and the compressor•Located on the high side of system

The Condenser•The heat is released from the refrigerant in the condenser causing it to change state from a high-temperature, high-pressure vapor to a high-pressure high-temperature liquid•Condensing temperature is determined by the system's head pressure

The Condenser•The condenser normally subcools the liquid at the end of the condenser •Subcooling is lowering the temperature of a liquid below saturation•Standard air cooled condensers are designed to subcool the liquid by a minimum of 10 degrees F below the saturation temperature •Amount of subcooling is determined by subtracting the outlet temperature of the condenser from the condenser saturation temperature

The Condenser

The Refrigerant Metering Device

•Controls the flow of subcooled liquid refrigerant into the evaporator•Orifice Metering Device-Creates a pressure drop between the high side and low side of the sealed system•25% of the liquid leaving the metering device turns to vapor called flash gas

The Refrigerant Metering Device

The Refrigerant Metering Device

Low Side/High Side

The Refrigeration System

COMPRESSOR

LOW PRESSURE VAPORLOW PRESSURE LIQUIDHIGH PRESSURE LIQUIDHIGH PRESSURE VAPOR

LIQUID REFRIGERANT

RECEIVER

EVAPORATOR

CONDENSER

TX VALVE

ACCUMULATOR OIL SEPARATOR

DRIER

SOLENOID

SIGHT GLASS

Now, Lets Play

Lets Put What We Have Learned and Apply It To The Refrigeration

Trainer