CO2 Refrigeration and Phase Behavior

The video explores the unique properties of CO2 as a refrigerant, comparing it to other refrigerants like R134a and R717. It discusses the phase changes of CO2, focusing on the triple point and critical point, and explains the significance of these phases in refrigeration. The video also highlights the revival of CO2 refrigeration technology and its applications. Additionally, it covers the supercritical phase of CO2, noting its properties and potential uses as a solvent, particularly in food products.

What is one of the unique characteristics of CO2 compared to R134a and R717?

• It operates at a lower pressure.

• It has a wider temperature range.

• It operates at a much higher pressure.

• It is less efficient as a refrigerant.

When was CO2 refrigeration technology first introduced?

• 1993

• 1850

• 1950

• 1920

What does the phase diagram of CO2 illustrate?

• The temperature and pressure limits for different phases

• The cost of CO2 refrigeration systems

• The chemical composition of CO2

• The historical usage of CO2

At what pressure and temperature does the triple point of CO2 occur?

• 5.2 bar and -56.6°C

• 73.6 bar and 31°C

• 1 bar and 0°C

• 140 bar and 20°C

What is the significance of the triple point in the CO2 phase diagram?

• It is where solid, liquid, and vapor phases coexist.

• It is where CO2 is only in the vapor phase.

• It is where CO2 is only in the solid phase.

• It is where CO2 is only in the liquid phase.

What happens to CO2 at the critical point?

• The distinction between liquid and vapor phases disappears.

• It becomes a liquid.

• It becomes a solid.

• It becomes a gas.

What is one application of supercritical CO2?

• As a refrigerant in household refrigerators

• As a solvent for extracting materials

• As a fuel for engines

• As a coolant in nuclear reactors

Why is supercritical CO2 considered user-friendly?

• It is non-toxic and has a high density.

• It is highly flammable.

• It is difficult to handle.

• It is very expensive.

What happens to CO2 when the pressure is reduced below the critical point?

• It evaporates completely.

• It remains in the supercritical phase.

• The distinction between liquid and vapor phases becomes evident.

• It becomes a solid.

What should viewers do for more information about CO2 refrigeration?

• Visit a local library

• Contact a refrigeration technician

• Contact their local Danos sales organization

• Search online for CO2 refrigeration