Refrigeration - Refrigerant Properties

SKU: C-844Duration: 16 Minutes

Pay-per-view (PPV) format perfect for individual users.

Get immediate access to this interactive eLearning course online. Must be used within 30 days, expires 48 hours after launch.

Language:  English

\$19

Ideal for corporate licensing and high volume users.

Course Details

Specs

Training Time: 16 minutes

Compatibility: Desktop, Tablet, Phone

Based on: Industry Standards and Best Practices

Languages: English

In the vapor-compression refrigeration cycle, it is the refrigerant that circulates through the equipment, transporting heat from the cooled (or refrigerated) space to an outside fluid (air or water). The transfer of heat to and from the refrigerant is accomplished by the refrigerant changing phase from liquid to gas and from gas to liquid. The refrigerant used in a system must be able to evaporate at a temperature below the desired temperature in the refrigerated space, and condense at a temperature above the temperature of the outside fluid.

Learning Objectives

• Describe the four states of matter
• Define the terms: convection, boiling point, superheated, subcooled, evaporation, and condensation
• Explain how the boiling point-pressure relationship affects refrigerant selection
• Discuss how phase change affects heat transfer in the refrigeration cycle
• Describe the relationship between gas temperature, pressure, and volume

Key Questions

The following key questions are answered in this module:

Does "evaporation" occur on the low pressure side or high pressure side of the refrigeration cycle?
The low pressure evaporator side is where the refrigerant evaporates from a liquid to a gas.

Does "condensation" occur on the low pressure side or high pressure side of the refrigeration cycle?
The high pressure condenser side is where the refrigerant condenses from a gas to a liquid.

What is a vapor pressure curve?
It is a curve that shows the relationship between pressure and boiling point temperature for a particular substance.

What should you consider when selecting a refrigerant?
The pressures in the system, desired temperature in the refrigerated space, and temperature range of the outside fluid (air or water) must all be considered.

Why is it desirable for the refrigerant in the line going to the compressor to contain some superheat?
This prevents liquid refrigerant from reaching the compressor, which can damage it, and it also increases the total amount of heat removed from the refrigerated space.

Sample Video Transcript

Below is a transcript of the video sample provided for this module:

For a fixed number of gas molecules (n), the relationship between pressure (P), volume (V), and temperature (T) can be described by the Ideal Gas Law. This law states that if the number of molecules (n) doesn't change, an increase in the temperature (T) of a gas will cause its pressure (P) and/or volume (V) to increase. (In this equation, R is equal to the gas constant, a value that doesn't change.) Likewise, a decrease in gas temperature will cause its pressure and/or volume to decrease. So, if a gas is contained in a vessel with a fixed volume (V), a change in temperature (T) will cause a corresponding change in pressure (P). This is why the increase in pressure that is accomplished by the compressor is accompanied by an increase in temperature.