SAQA

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SOUTH AFRICAN QUALIFICATIONS AUTHORITY

REGISTERED UNIT STANDARD THAT HAS PASSED THE END DATE:

Explain the operation of basic vapour compression refrigeration systems, and identify and explain the function of its components and accessories as well as their retrieval and storage procedures

SAQA US ID	UNIT STANDARD TITLE
9411	Explain the operation of basic vapour compression refrigeration systems, and identify and explain the function of its components and accessories as well as their retrieval and storage procedures
ORIGINATOR
SGB Air-conditioning Refrigeration and Ventilation
PRIMARY OR DELEGATED QUALITY ASSURANCE FUNCTIONARY
-
FIELD			SUBFIELD
Field 06 - Manufacturing, Engineering and Technology			Engineering and Related Design
ABET BAND	UNIT STANDARD TYPE	PRE-2009 NQF LEVEL	NQF LEVEL	CREDITS
Undefined	Regular	Level 2	NQF Level 02	14
REGISTRATION STATUS		REGISTRATION START DATE	REGISTRATION END DATE	SAQA DECISION NUMBER
Passed the End Date - Status was "Registered"		2001-06-13	2004-06-13	SAQA 0836/01
LAST DATE FOR ENROLMENT		LAST DATE FOR ACHIEVEMENT
2005-06-13		2008-06-13

In all of the tables in this document, both the pre-2009 NQF Level and the NQF Level is shown. In the text (purpose statements, qualification rules, etc), any references to NQF Levels are to the pre-2009 levels unless specifically stated otherwise.

This unit standard is replaced by:

US ID	Unit Standard Title	Pre-2009 NQF Level	NQF Level	Credits	Replacement Status
116224	Explain the operation of basic vapour compression refrigeration systems, and identify and explain the function of the components and accessories as well as their retrieval and storage procedures	Level 2	NQF Level 02	8

PURPOSE OF THE UNIT STANDARD

Describe and explain how a refrigeration system transfers heat from air to a liquid or from a liquid to air and identify and explain the function of its components and accessories.

LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING

Ability to read and write. A basic knowledge of physics relating to heat and temperature.

UNIT STANDARD RANGE

Refrigeration systems:

System cooling air or water and rejecting heat via an air-cooled condenser, a water-cooled condenser and a cooling tower or an evaporative condenser.

Components:

The compressor, the expansion valve, evaporators cooling liquid or air and water and air-cooled condensers, the cooling tower and the evaporative condenser.

Accessories:

Compressor, condenser, evaporator, metering device, interconnecting piping, cooling tower, fan, pump, receiver, surge drum, suction accumulator, vibration eliminator, crankcase heater, sight glass, moisture indicator, service valves, shut-off valves, safety valves fusible plugs, charging valves, filter driers, refrigerant strainer, muffler, suction-liquid line heat exchanger, oil separator.

Specific Outcomes and Assessment Criteria:

SPECIFIC OUTCOME 1

Explain, with aid of a block diagram, the operation of the vapour compression refrigeration system

OUTCOME NOTES

Explain, with the aid of a block diagram, the operation of the vapour compression refrigeration system.

ASSESSMENT CRITERIA

ASSESSMENT CRITERION 1

1. A correct block diagram of the vapour compression refrigeration system is drawn.

ASSESSMENT CRITERION 2

2. The operation of a vapour compression system explained.

SPECIFIC OUTCOME 2

Name the components and pipes in the block diagrams drawn and indicate direction of flow

OUTCOME NOTES

Name the components and pipes in the block diagrams drawn and indicate direction of flow of refrigerant and water.

ASSESSMENT CRITERIA

ASSESSMENT CRITERION 1

1. Each component is named correctly.

ASSESSMENT CRITERION 2

2. Each pipe run is named correctly.

ASSESSMENT CRITERION 3

3. The direction of the flow of refrigerant, air and water is correctly indicated.

SPECIFIC OUTCOME 3

Explain the process-taking place in each component

ASSESSMENT CRITERIA

ASSESSMENT CRITERION 1

1. The processes taking place in the components are explained correctly.

ASSESSMENT CRITERION 2

2. The purpose of the condenser water and the spray water pumps in the system is explained correctly.

ASSESSMENT CRITERION 3

3. The state of the refrigerant at the inlet and outlet of all components is stated correctly.

ASSESSMENT CRITERION 4

4. The temperature of the refrigerant and the water at the inlet and outlet of all the components is stated correctly.

SPECIFIC OUTCOME 4

Discuss the relationship between the pressure and the temperature of a refrigerant

ASSESSMENT CRITERIA

ASSESSMENT CRITERION 1

1. The relationship between the pressure and the temperature of the refrigerant is correctly stated.

ASSESSMENT CRITERION 2

2. The fact that the gas increases in temperature when being compressed is stated.

ASSESSMENT CRITERION 3

3. The fact that evaporation and condensation of the refrigerant occur at constant temperature is stated and explained.

SPECIFIC OUTCOME 5

Identify and explain the function of components and accessories of a refrigeration system

ASSESSMENT CRITERIA

ASSESSMENT CRITERION 1

1. The various components and accessories of a refrigeration system are correctly identified and their position located on a refrigeration plant.

ASSESSMENT CRITERION 2

2. The purpose of each component and accessory in the refrigeration system is explained.

ASSESSMENT CRITERION 3

3. The various types of components and accessories are listed.

ASSESSMENT CRITERION 4

4. The different makes and models of components and accessories are identified.

SPECIFIC OUTCOME 6

Handle and store refrigeration system components and accessories

ASSESSMENT CRITERIA

ASSESSMENT CRITERION 1

1. The handling and storage of refrigeration components and accessories in accordance with manufacturer's requirements is demonstrated.

ASSESSMENT CRITERION 2

2. The procedure for issuing components and accessories from and returning to stores is explained.

UNIT STANDARD ACCREDITATION AND MODERATION OPTIONS

Any person wishing to be assessed against this unit standard may apply to an assessment agency, assessor or provider institution accredited by the relevant ETQA, who may appoint a moderator to be present at the assessment.

The assessor must have knowledge and experience of air-conditioning and refrigeration.

UNIT STANDARD ESSENTIAL EMBEDDED KNOWLEDGE

The basic processes involved in the vapour compression refrigeration cycle.

The various systems used and the role and application of refrigeration in daily life.

The function and operation of refrigeration components and accessories.

The handling, retrieval and storage of refrigeration system components and accessories.

Interpreting manufacturer`s and/or work instructions or company guidelines regarding handling, retrieval and storage of refrigeration system components and accessories.

Critical Cross-field Outcomes (CCFO):

UNIT STANDARD CCFO IDENTIFYING

Identify and solve problems:

Identify refrigeration components and accessories

UNIT STANDARD CCFO WORKING

Work effectively with others:

Assisting Level 3 Trade hand (Mechanic) by supplying correct accessory

UNIT STANDARD CCFO ORGANISING

Organize and manage my activities and myself responsibly and effectively:

Selecting required component and accessory and retrieve from stores

UNIT STANDARD CCFO COMMUNICATING

Communicate effectively:

By oral or written stores` order for component or accessory. Communicating with Level 3 Trade hand (Mechanic)

UNIT STANDARD CCFO SCIENCE

Use science and technology effectively and critically:

By understanding the processes involved

UNIT STANDARD CCFO DEMONSTRATING

Demonstrate an understanding of the world as a set of related systems:

Be aware of the effect of leakage of refrigerants on the environment

UNIT STANDARD CCFO CONTRIBUTING

Learner and societal development:

By learning how a refrigeration system operates

UNIT STANDARD NOTES

This unit standard has been replaced by unit standard 116224, which is "Explain the operation of basic vapour compression refrigeration systems, and identify and explain the function of the components and accessories as well as their retrieval and storage procedures", Level 2, 8 credits.

Supplementary information:

The learner must show a basic understanding of the processes involved, for this he must be able to explain the processes in simple terms, the temperatures in terms of cold, warm or hot and the state in terms of liquid, vapour or a moisture.

Specific requirements are contained in one or more of the following documents:

Manufacturer`s instructions regarding the handling of components and accessories.

Company procedures and guidelines regarding retrieval of components and accessories from stores.

QUALIFICATIONS UTILISING THIS UNIT STANDARD:

	ID	QUALIFICATION TITLE	PRE-2009 NQF LEVEL	NQF LEVEL	STATUS	END DATE	PRIMARY OR DELEGATED QA FUNCTIONARY
Core	20719	National Certificate: Air Conditioning, Refrigeration and Ventilation	Level 2	NQF Level 02	Passed the End Date - Status was "Registered"	2004-06-13	Was MERSETA until Last Date for Achievement

PROVIDERS CURRENTLY ACCREDITED TO OFFER THIS UNIT STANDARD:

This information shows the current accreditations (i.e. those not past their accreditation end dates), and is the most complete record available to SAQA as of today. Some Primary or Delegated Quality Assurance Functionaries have a lag in their recording systems for provider accreditation, in turn leading to a lag in notifying SAQA of all the providers that they have accredited to offer qualifications and unit standards, as well as any extensions to accreditation end dates. The relevant Primary or Delegated Quality Assurance Functionary should be notified if a record appears to be missing from here.

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