Refrigerant & Oils

Question 1

A _________ is any fluid that picks up heat by evaporating at a low temperature and pressure and gives up heat by condensing at a higher temp and press (volatile fluid)

Answer 1

refrigerant

Question 2

Main categories;

1. CFC - Chloroflurocarbons

R-12, R-11 : Today these refrigerants are used very _______, in normal refrigeration systems

Answer 2

rarely

Question 3

Main categories;

2. HCFC - Hyrdochloroflurocarbons

R-22, MP39, R-123: Today these refrigerants are being phased out due to the _______ depletion potential of the chlorine atoms in the mixture

Answer 3

ozone

Question 4

Main categories;

3. HFC - Hydroflurocarbons:

R-134a, AZ-50 (R-507): This family of refrigerants are the long term replacements for the CFCs and _____

Answer 4

HCFC’s

Question 5

Main categories;

4. HC - Hydrocarbons

R-12a, R-22a : These refrigerants are either pure or mixtures of hydrocarbon molecule such as _______

Answer 5

propane

Question 6

Main categories;

5. HFO - Hydro fluro olefin

R-1234uf (solstace of honeywell): Being developed for the __________ market

Answer 6

automotive

Question 7

Main categories;

6. Ammonia

R-717: Naturally occurring refrigerant that is normally used in _________ applications

Answer 7

industrial

Question 8

Name the three refrigerant properties?

Answer 8

Chemical, Physical, Thermal

Question 9

Environmental Impacts of Refrigerants:

Ozone Layer-Depletion: Resulting in increases in ultra violet radiation;

1. increased skin _______
2. eye _______
3. Food production ________
4. Effects human _______ system

Answer 9

1. cancer
2. problems
3. decreases
4. immune system

Question 10

Refrigerant classification: Ashrae Standard adopted by the B-52 Refrigeration code refrigerants classified as to their toxicity and flammability;

Group A1: Low toxicity, ___ flammability

Group A3: Low toxicity, ______ flammability

Group B1: Higher toxicity, ___ flammability

Group B2: Higher toxicity, _______ flammability

Answer 10

A1. Low

A3. higher

B1. Low

B2. higher

Question 11

Definitions: Pure fluid

A fluid when used in refrigeration cycle does not change in _________ composition. Or saturation temperature as they evaporate or condense at a constant temp

R-12 , R-134A

Answer 11

volumetric

Question 12

Definitions:

Blend: Refrigerants consisting of mixtures or ____ or more different chemical compounds

Azeotrope: A refrigerant blend when used in refrigeration cycle does not change volumetric composition or saturation temperature appreciably as they evaporate or condense at a _______ temperature
-R-507 , R508B

Answer 12

constant

Question 13

Definitions:

Zeotrope: Blends, when used in refrigeration cycle, that change volumetric composition and saturation temperature to varying extent as they evaporate or condense at a _______ temperature

R-401A (MP39)

Answer 13

constant

Question 14

Definitions:

Glide: The difference between the starting and ________ temperature of a phase change process by a refrigerant at a constant temperature

Answer 14

ending

Question 15

Definitions:

Fractionalization: A change in the composition of a blend by preferential evaporation of the more ________ component or condensation of the less volatile component

Answer 15

volatile

Question 16

Definitions:

Critical Temperature:

1. The highest temperature at which a refrigerant can exist as a liquid. When a refrigerant reaches its critical temperature it can no longer be condensed into a ________
2. Critical pressure: The vapour pressure at the _______ temperature

Answer 16

1. liquid

2. critical

Question 17

Refrigerants;

1. Storage temp not to exceed ___C( 130F)
2. Working temp not to exceed ___C (120F)

Answer 17

1. 54C

2. 49C

Question 18

Refrigerant Oils: Purpose of oil in a system;

1. Lubrication; The separation of moving parts by a thin film of ___
2. ________ friction
3. Prevent _____
4. Create a ______ seal
5. Act as a coolant in _______
6. Dampens noise in compressor ________

Answer 18

1. oil
2. minimize
3. wear
4. fluid
5. compressor
6. crankcase

Question 19

Types of Oils:

1. Animal
2. Vegetable
3. Mineral
4. ______

Answer 19

4. Synthetic

Question 20

Synthetic oils must be stored in ______ containers

Answer 20

metal

Question 21

Polyol Ester Oil;

1. Pour point _________
2. Floc point _________
3. _______ index improves
4. Thermal stability _______

Answer 21

1. depressants
2. depressants
3. viscosity
4. Improves

Question 22

Oil Properties:

1. Viscosity:
2. Floc point: The point at which the wax will separate from the ____ (temp rating)
3. Pour point: Temp at which it ceases to _____
4. Dialectic Strength: A measure of an oils resistance to _______ current

Answer 22

1. how thick or thin oil is
2. oil
3. flow
4. electric

Question 23

Oil Properties: (Cont’d)

1. Oxidation Resistance: Resistance to ______ and O2
2. Moisture content: ______ of oil
3. Flash point: The temperature at which the oil vapour _____ burns

Answer 23

1. water
2. dryness
3. flash

Question 24

Oil Properties: Viscosity;

1. Quality of how _____ the oil is
2. Measured in ____: Saybolt Seconds Universal
3. Higher the number means _______ the oil
4. Viscosity decreases as refrigerant mixes with the ____
5. Viscosity decreases with an ________ in temp

Answer 24

1. Thick
2. SSU
3. thicker
4. oil
5. increases

Question 25

Viscosity:

1. A refrigerant oil must maintain a ______ enough viscosity to properly function at the highest normal temp in the system

At the same time

2. The oil must remain ______ enough to flow back to the compressor through the lowest temperature of the system

Answer 25

1. high

2. liquid

Question 26

Vacuum Pump Oil:

1. Lubricates and seals at the operating temperatures usually found in a ______ pump.
2. Very low vapour pressure so that the oil does not vaporize at low levels of ________
3. High viscosity index assures proper _______ at high and low pressures

Answer 26

1. vacuum
2. pressure
3. lubrication