HVAC 1

Question 0

Air conditioners use refrigeration to chill indoor air, taking advantage of a remarkable physical law:

Answer 0

When a liquid converts to a gas (in a process called phase conversion), it absorbs heat.

Question 1

What are the components of an HVAC system?

Answer 1

Hot coils
Compressor
Cold coils
Expansion valve

Question 2

Air conditioners exploit this feature of phase conversion by forcing special chemical compounds to:

Answer 2

evaporate and condense over and over again in a closed system of coils.

Question 3

The compounds involved in refrigeration are refrigerants that have properties enabling them to:

Answer 3

change at relatively low temperatures. Air conditioners also contain fans that move warm interior air over these cold, refrigerant-filled coils. In fact, central air conditioners have a whole system of ducts designed to funnel air to and from these serpentine, air-chilling coils.

Question 4

When hot air flows over the cold, low-pressure evaporator coils, the refrigerant inside absorbs heat as it changes from:

Answer 4

a liquid to a gaseous state. To keep cooling efficiently, the air conditioner has to convert the refrigerant gas back to a liquid again.

Question 5

For the air conditioner to convert the refrigerant gas back to a liquid again, a compressor puts the gas under high pressure, a process that creates;

Answer 5

unwanted heat. All the extra heat created by compressing the gas is then evacuated to the outdoors with the help of a second set of coils called condenser coils, and a second fan.

Question 6

As the refrigerant gas is compressed and it cools, it changes:

Answer 6

back to a liquid, and the process starts all over again. Think of it as an endless, elegant cycle: liquid refrigerant, phase conversion to a gas/ heat absorption, compression and phase transition back to a liquid again.

Question 7

Air conditioners not only cool air, they also function as:

Answer 7

dehumidifiers. Because temperature is a key component of relative humidity, reducing the temperature of a volume of humid air causes it to release a portion of its moisture.

Question 8

The major parts of an air conditioner

are:

Answer 8

Evaporator - Receives the liquid refrigerant
Condenser - Facilitates heat transfer
Expansion valve - regulates refrigerant flow into the evaporator
Compressor - A pump that pressurizes refrigerant