Ben Girod Project 2

Freezer Example

Almost everyone uses a refrigerator or a freezer every day; without them food would spoil, and we would be forced to drink warm beverages, but do you know how it works and how a refrigeration cycle comes into play with freezers and refrigerators?

This is a typical freezer; It seems simple, you put in food or liquid

and it freezes, which in turn allows you keep food longer.

Freezers are well insulated and are closed systems, to prevent the

cold environment inside the freezer from allowing the freezers

warmer surroundings to enter thermal equilibrium with the cold

environment within the freezer.

Thermodynamics and Freezers: How They Work

A freezer is based on the refrigeration cycle, more specifically the vapor-compression refrigeration cycle. The refrigerant gas, most commonly used is Freon. The refrigeration cycle is made up of four steps that repeats and makes a cycle.

What are the four processes typically associated with the refrigeration cycle, and what components are associated with these processes?

Ben Girod Project 2

1. Condensation: The Freon is pumped through tubes that radiate heat on the back of the

freezer; this is the condenser, where the Freon vapor changes to liquid Freon, the

condenser releases heat to the surrounding environment. The condenser has a higher

pressure as it leads up to the throttling valve. The condenser I responsible for the

Q out .

2. Expansion: The Freon high pressure liquid then enters the throttling valve, where as you

know controls the volumetric flow-rate and creates a drop in pressure which in turn

creates a significant drop in temperature of the Freon. The throttling valve is responsible

for the P low .

3. Evaporation: As the Freon enters the evaporator, the Freon absorbs heat from the

surroundings, with its low boiling point the Freon becomes a superheated vapor. This

process creates a drop in temperature inside the freezer. The evaporator is responsible for

the P high and the Q in .

How does the law of thermodynamics explain why the Freon absorbs the heat while in the evaporator?

The Freon and environment wants to be in thermal equilibrium, as a result of that the much warmer environment of the evaporator transfers heat to the Freon, which becomes a superheated vapor and is pumped out along with the heat.

4. Compression: The compressor or pump is responsible for making the four processes

repeat and therefore making it a cycle. The compressor converts electrical energy to

mechanical work compressing the vapor Freon. The Freon is then pumped into the

condenser starting the condensation process and beginning the cycle all over again. Ben Girod Project 2

This diagram I created shows all the different components and where they are physically located on and in the freezer and refrigeration cycle.

Ben Girod Project 2

How does the refrigeration cycle effect you in daily life and is it what makes modern living possible? Would you be able to live without saving food, having no cold beverages, or without air-conditioning? As you go throughout the rest of your day think about what it would be like without the different thermodynamic cycles and why it is important to continue the development in the study of thermodynamics.