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# HVAC 121 - Fundamentals of Refrigeration & A/C

Credits: 3

Examines the physical, gas, and chemical laws of refrigeration. Develops an understanding of the theory of heat, temperatures, pressures of gases and thermodynamics. Analyzes basic refrigeration cycle and components such as vacuum pumps, gauges, and (PT) Pressure Temperature Charts. Develops an understanding of units on safety and EPA Refrigerant Certification. Credit may be earned in only one of the following: HVAC 121, RHA 121 or SKPT 121 .

Prerequisite(s): None
Corequisite(s): None
Lecture Hours: 35 Lab Hours: 10
Meets MTA Requirement: None
Pass/NoCredit: Yes

Outcomes and Objectives 1.     Demonstrate knowledge of Thermodynamics and heat transfer.

A.          Define matter and heat.

B.          Define heat transfer direction and rates.

C.          Define three methods of heat transfer.

1.    Conduction

2.    Convection

D.         Identify the four reference points for temperature.

1.    Boiling point

2.    Freezing point

3.    Critical temperature

4.    Absolute zero

E.          Explain the difference between heat and temperature.

F.          Identify the types of heat.

1.    Latent heat

2.    Latent heat of fusion

3.    Latent heat of condensation

4.    Sensible heat

5.    Specific heat

6.    Super heat

G.         Define the difference between heat and temperature.

H.         Define the difference between latent heat and sensible heat

I.           Explain the change of state of matter.

J.          Define specific heat.

K.          Define sensible heat.

L.          Define latent heat of fusion.

M.         Define latent heat of vaporization

N.         Define enthalpy.

O.         Define saturation temperature (dew point temperature).

P.          Define water vapor pressure.

Q.         Explain the direction and rate of moisture transfer.

R.         Calculate total heat (in BTU's) a pound of any substance contains.

S.          Define the BTU.

T.          Identify gas laws used in refrigeration applications.

U.         Define density, specific gravity, and specific volume.

V.          Explain Boyle’s law.

W.         Explain Charles’ law.

X.          Explain Dalton’s law.

2:    Demonstrate knowledge of pressures in fluids and in gases.

A.          Explain the relationship of pressures and explain the relationship of fluids at saturation temperatures.

B.          Explain the difference between temperature and pressure using the PT chart.

C.          Define pressure.

D.          Explain atmospheric pressure.

E.          Explain compound gauges.

F.           Explain Bourdon tubes.

G.          Explain barometric pressure.

H.          Explain absolute pressure.

I.            Explain gauge pressures.

J.           Explain inches of mercury absolute.

K.          Explain micron

L.          Calculate absolute and gauge pressures.

M.         Measure absolute and gauge pressures.

N.          Relate pressure and temperature using the PT chart.

O.          Measure a vacuum using a micron gauge.

P.           Identify vacuums on gauges.

Q.          Calculate Boyle’s law of gases.

R.          Calculate Charles’ law of gases.

S.          Calculate Dalton’s law of gases.

3.    Demonstrate knowledge of the vapor compression refrigeration cycle.

A.          Identify the four major components of the vapor compression refrigeration system.

B.          Describe the state and conditions of the refrigerant during the cycle.

C.          Explain the effects of

1.    Superheating the suction gases

2.    Increasing the condensing pressure

3.    Sub cooling the liquid

D.          Explain the importance of sub cooling and superheat.

E.          Define refrigeration.

F.           Explain the functions of the four major components of a refrigeration system.

1.    Compressor

2.    Condenser

3.    Metering device

4.    Evaporator

G.         List the components which separate the high side from the low side of the system.

H.         Describe the Temperature/Enthalpy (T-H) diagram.

4.    Identify and draw a refrigerator cycle on a pressure enthalpy chart.

A.          Draw a refrigeration cycle on a pressure enthalpy chart:

1.    Diagram a simple refrigeration cycle.

2.    State the unit of measurement for heat (BTU/H).

3.    Define entropy and enthalpy.

4.    Show arrows for directions of cycle flow.

5.    Place accumulator, receiver, and oil separator correctly on refrigeration cycle drawing.

B.          Draw a simple refrigerant cycle diagram and label each of the basic components as well as the refrigerant lines. Place arrows on the
diagram to show the direction of refrigerant flow.

C.          Calculate problems using Temperature/Enthalpy (T-H) diagram.

D.          Label the line, which represents each of the four basic components on a pressure/enthalpy diagram.

E.          Define the BTU.

5.    Demonstrate knowledge of units of heat, power, velocity, mass, and length in US units, and S.I. units.

A.          Convert from US to metric units for the following:

1.    Length

2.    Area

3.    Volume

4.    Mass

5.    Force

6.    Velocity

7.    Density

8.    Temperature

9.    Energy

10.  Power

11.  Specific heat

12.  Volume flow rate

13.  Capacity

B.          Convert pounds to ounces.

6.    Demonstrate safety in handling of pressurized fluids.

A.          List safety requirements.

B.          Explain application of pressure relief valves.

C.          Explain proper storage and handling of refrigerants.

D.          Explain the effect of temperature and hydraulic expansion.

E.          Explain proper storage and handling of oxygen, nitrogen, and acetylene bottles.

F.           Explain the effects of mixing oxygen and oil.

G.          Follow procedures specified in the material safety data sheets (MDDS).

H.          Store and dispose of hazardous material according to EPA specifications.

I.           Explain ASHRAE Refrigerant Safety Classification of refrigerants for toxicity and flammability.

J.           Fill and tag a refrigerant cylinder properly.

K.          Determine if a refrigerant cylinder needs retesting.

L.          Identify EPA Refrigerant Certification regulation.

M.         Identify the safe handling of refrigerants as identified by the EPA.

N.         Explain the use of a Material Safety Data Sheet (MSDS).

O.         Define the difference between hazardous materials, substances, and wastes.

P.          Explain the use of a hazardous use manifest.

Q.         Locate MSDS and identify particular effect.

R.         Demonstrate use of proper clothing and equipment.

S.         Demonstrate first aid procedures.

7.    Demonstrate knowledge of the characteristics of refrigerants.

A.          Define the classes of refrigerants (CFC/HCFC/HFC/HC/Azeotropic Mixtures/Zeotropic mixtures).

B.          Define physical and chemical properties of refrigerants.

1.    Flammability and toxicity

2.    Materials compatibility

3.    Miscibility and oil return

4.    Pressure and temperature data

5.    Refrigerant Temperature Glide, Environmental properties ODP, GWP, TEWT

6.    Bubble point/dew point

C.          Define pure refrigerants and azeotropic mixtures.

D.          Define zeotropic mixtures.

E.          Define zoetrope blends.

F.           Identify the color and classification of the refrigerant by Pantone Matching System (PMS) color number.

G.          Explain fractionization of blends.

H.          Explain the function of lubricants in the system.

I.           Explain the different types of and applications of refrigerant lubricants.

1.    Alkyl benzenes-AB

2.    Mineral Oils

3.    Polyolesters-POE

4.    Polyblycols-PAG

J.          Explain the properties of lubricants.

1.    Materials compatibility

2.    Miscibility and oil return

3.    Pour point and flash point

4.    Viscosity

5.    Water absorption

6.    Rust and oxidation inhibitors.

K.          Describe proper oil disposal.

L.          Demonstrate methods of replacing refrigerant oil.

M.        Demonstrate methods of acid testing the refrigerants

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