Basic refrigeration 4th year

Question 1

What are the three methods of heat transfer and give an example of each?

Answer 1

1. Conduction:

• The transfer of heat through a metal rod when one end is heated and the other end becomes hot

2. Convection:
   - A pot of water on a stove where the hot water rises to the top, and the cold water sinks to the bottom, creating a convection current

3.Radiation:

• The transfer of heat from the sun to the Earth through space

Question 2

Define Latent heat

Answer 2

the amount of heat required to change the state of a substance without changing its temperature.

Question 3

Define sensible heat

Answer 3

the amount of heat required to change temperature in a substance without changing the state of the object.

Question 4

How many BTU’s are required to increase the temperature of 1 pound of water 1 degree F?

Answer 4

1 degree Fahrenheit is known as its specific heat. The specific heat of water is approximately 1 BTU per pound per degree Fahrenheit.

Question 5

How many BTU’s are required to increase the temperature of 55 cu.ft of air 1 degree F?

Answer 5

Assuming that the air is dry, to increase the temperature of 55 cubic feet of air by 1 degree Fahrenheit, we would need to add approximately 13.2 BTUs of heat energy (55 cubic feet times 0.24 BTU per cubic foot per degree Fahrenheit).

Question 6

How many BTU’s are required to change the state of 1 pound of solid water (ice) to liquid?

Answer 6

This means that 1 pound of solid water (ice) at 32°F would require 144 BTU of heat energy to change its state to liquid water at the same temperature, without any change in temperature..

Question 7

How many BTU’s are required to change the state of 1 pound of liquid water to vapor?

Answer 7

This means that 1 pound of liquid water at 212°F would require approximately 970.4 BTU of heat energy to convert it to water vapor at the same temperature, without any change in temperature.

Question 8

What are the four main components of a mechanical Refrigeration system?

Answer 8

The four main components of a mechanical refrigeration system are:

1. Compressor:
2. Condenser:
3. Expansion Valve:
4. Evaporator:

Question 9

Complete the diagram below. Connect all four components for the Split System and identify which component is high pressure and low pressure

Question 10

Which component of the cooling system absorbs heat from the medium to be cooled?

Answer 10

The component of the cooling system that absorbs heat from the medium to be cooled is called the evaporator.

Question 11

Which component removes heat from the refrigeration system?

Answer 11

The component that removes heat from the refrigeration system is called the condenser.

Question 12

What are the three basic types of condensers?

Answer 12

air- cooled
water-cooled
evaporative

Question 13

What is the purpose of the water flowing through the condenser unit?

Answer 13

The purpose of the water flowing through the condenser unit is to remove the heat from the refrigerant that is being circulated through the system.

Question 14

When using a thermostatic Expansion Valve, where is the sensing bulb located?

Answer 14

The sensing bulb is typically located at the evaporator outlet.

Question 15

The TXV automatically regulates the amount of liquid by what two things?

Answer 15

: the refrigerant pressure and the refrigerant temperature.

Question 16

Where is the thermal bulb located in the system?

Answer 16

The thermal bulb of a thermostatic expansion valve (TXV) is typically located near the evaporator outlet.

Question 17

Can the capillary tube system be modified?

Answer 17

no

Question 18

What do filter dryers do to a cooling system?

Answer 18

Filter dryers play an important role in maintaining the proper functioning of a cooling system. They are designed to remove moisture, acids, and solid contaminants from the refrigerant, which can cause damage to the compressor and other components of the system.

Question 19

Define the following:

Compressor:
Cooling: 
Dehydration: 
Evaporative cooling: 
Heat: 
Micron:
Refrigerant: 
Sub-cooling: 
Super heat

Answer 19

Compressor: A compressor is a device that pressurizes and moves a gas or vapor, such as refrigerant, through a refrigeration cycle.

Cooling: Cooling refers to the removal of heat from an object, substance, or space. In refrigeration and air conditioning systems, cooling is achieved by circulating refrigerant through a system of evaporators, compressors, condensers, and expansion valves.

Dehydration: Dehydration is the process of removing moisture from a substance or material, such as refrigerant in a refrigeration system. This is often accomplished using a filter dryer, which removes moisture and other contaminants from the refrigerant.

Evaporative cooling: Evaporative cooling refers to the process of cooling air by evaporating moisture. In air conditioning systems, evaporative cooling may be used in the form of evaporator coils that remove heat and moisture from the air being circulated through the system.

Heat: Heat is a form of energy associated with the motion of atoms and molecules in a substance. In refrigeration and air conditioning systems, heat is transferred from warmer objects or spaces to cooler ones in order to achieve cooling.

Micron: A micron is a unit of measurement equal to one millionth of a meter. In refrigeration and air conditioning systems, the micron is often used to measure the size of particles or contaminants in the refrigerant system.

Refrigerant: A refrigerant is a substance that is used in refrigeration and air conditioning systems to transfer heat from one area to another. Common refrigerants include R-22, R-404A, and R-410A.

Sub-cooling: Sub-cooling refers to the process of cooling a liquid refrigerant below its saturation point in order to improve its efficiency and effectiveness in the refrigeration cycle.

Superheat: Superheat refers to the amount of heat added to a vapor refrigerant beyond the point at which it condenses. In air conditioning systems, superheat helps to ensure that the refrigerant evaporates fully before it reaches the compressor.

Question 20

What are the limits that a Sheet Metal worker is able to install and service a cooling system?

Answer 20

Sheet metal workers and apprentices in Alberta are allowed to install and service split systems up to and including 5 tons or 60 000 Btuh.

Question 21

How many BTU’s per day are required to change the state of one ton of ice to a liquid?

Answer 21

to change the state of one ton of ice to a liquid, we need to add heat energy equal to:
(2000 pounds) x (144 BTUs per pound) = 288,000 BTUs

So we need 288,000 BTUs to melt one ton of ice.

Question 22

What does ODP stand for?

Answer 22

ODP stands for Ozone Depletion Potential. It is a measure of a su

Question 23

List the refrigerant that is the worst to least when comparing the ODP levels. CFC-12, HFC-410A, and HCFC-22

Question 24

Are refrigerants allowed to be released into the atmosphere?

Question 25

If a refrigerant is spilled on your skin, what will happen?

Answer 25

cause frostbite

Question 26

What is the max. capacity a refrigerant container can be filled to?

Answer 26

no more than 80% full container.