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SOUTH AFRICAN QUALIFICATIONS AUTHORITY 
REGISTERED UNIT STANDARD THAT HAS PASSED THE END DATE: 

Determine the properties of air from a psychometric chart and carry out basic calculation involving heat and mass transfer 
SAQA US ID UNIT STANDARD TITLE
9534  Determine the properties of air from a psychometric chart and carry out basic calculation involving heat and mass transfer 
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 3  NQF Level 03  7 
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
116695  Determine the properties of air from a psychometric chart and carry out basic calculation involving heat and mass transfer  Level 3  NQF Level 03  7   

PURPOSE OF THE UNIT STANDARD 
Calculate the amount of heat and water added to or removed from the air or the water flowing in an air-conditioning or refrigeration system. 

LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING 
Carry out simple calculations involving multiplications, divisions. Manipulating of simple formulas. 

UNIT STANDARD RANGE 
Properties of air: Barometric pressure, Dry bulb temperature, wet bulb temperature, dew point temperature, relative humidity, vapour pressure, humidity ratio, enthalpy, density and specific volume.
Charts to be used as supplied by the NMERI or similar.
Properties of water: Density, specific heat capacity and specific latent heat of evaporation. 

Specific Outcomes and Assessment Criteria: 

SPECIFIC OUTCOME 1 
Define and determine the properties of air and give the correct units and symbols. 

ASSESSMENT CRITERIA 

ASSESSMENT CRITERION 1 
1. The psychrometric chart for the correct altitude and temperature range is selected. 

ASSESSMENT CRITERION 2 
2. The state point for the condition given is correctly plotted. 

ASSESSMENT CRITERION 3 
3. The properties of the air are correctly determined and recorded using the correct SI units and symbols. 

SPECIFIC OUTCOME 2 
Calculate the amount of sensible heat added to / removed from the air. 
OUTCOME NOTES 
Calculate the amount of sensible heat (in kilowatt) added to or removed from the air by means of the sensible heat formula and the enthalpy formula. 

ASSESSMENT CRITERIA 

ASSESSMENT CRITERION 1 
1. The correct properties of the air are used. 

ASSESSMENT CRITERION 2 
2. The mass flow of the air is correctly calculated. 

ASSESSMENT CRITERION 3 
3. The amount of sensible heat is calculated correctly. 

SPECIFIC OUTCOME 3 
Calculate the amount of latent heat (in kilowatt) added to or removed from the air. 
OUTCOME NOTES 
Calculate the amount of latent heat (in kilowatt) added to or removed from the air by means of the enthalpy formula as well as the formula using the latent heat of evaporation of water. 

ASSESSMENT CRITERIA 

ASSESSMENT CRITERION 1 
1. The correct properties of the air are used. 

ASSESSMENT CRITERION 2 
2. The mass flow of the air is correctly calculated. 

ASSESSMENT CRITERION 3 
3. The amount of latent heat is calculated correctly by means of the enthalpy formula. 

ASSESSMENT CRITERION 4 
4. The amount of water removed from the air is calculated correctly. 

ASSESSMENT CRITERION 5 
5. The amount of latent heat is calculated correctly using the latent heat of evaporation of water. 

ASSESSMENT CRITERION 6 
6. The results of both calculations agree within 5%. 

SPECIFIC OUTCOME 4 
The amount of total heat added or removed from the air is calculated correctly. 

ASSESSMENT CRITERIA 

ASSESSMENT CRITERION 1 
1. The amount of total heat added to or removed from the air is correctly calculated by using the enthalpy formula. 

ASSESSMENT CRITERION 2 
2. The amount of total heat added to or removed from the air is correctly calculated by adding the sensible and latent heat removed. 

ASSESSMENT CRITERION 3 
3. The values obtained agree within 5%. 

ASSESSMENT CRITERION 4 
4. The amount of chilled water required to remove the load is correctly calculated. 

SPECIFIC OUTCOME 5 
The amount of moisture added to or removed from the air is calculated correctly. 

ASSESSMENT CRITERIA 

ASSESSMENT CRITERION 1 
1. The amount of water added to or removed from the air is calculated correctly in kilograms per second. 

ASSESSMENT CRITERION 2 
2. The amount of water added to or removed from the air is calculated correctly in litres per hour. 

ASSESSMENT CRITERION 3 
3. Whether the moisture is added or removed from the air is correctly stated. 


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 or refrigeration. 

UNIT STANDARD ESSENTIAL EMBEDDED KNOWLEDGE 
Knowledge of the properties of air, water and water vapour
Purpose of psychrometrics as used in air-conditioning and refrigeration 


Critical Cross-field Outcomes (CCFO): 

UNIT STANDARD CCFO IDENTIFYING 
Identify and solve problems
  • Selecting the correct psychrometric chart and determining and using the correct parameters 
    		•

    UNIT STANDARD CCFO COLLECTING 
    Collect, analyse, organise and critically evaluate information
  • Using the correct information and selecting the correct formulas
    Communicate effectively
  • Correctly report on results 
    		•

    UNIT STANDARD CCFO SCIENCE 
    Use science and technology effectively and critically
  • Use of psychrometric chart and psychrometric formulas 
    		•

    UNIT STANDARD CCFO CONTRIBUTING 
    Learner and societal development
  • Understanding the effect of adding or removing heat or moisture to or from the air 
    		•

    UNIT STANDARD NOTES 
    This unit standard has been replaced by unit standard 116695, which is "Determine the properties of air from a psychometric chart and carry out basic calculation involving heat and mass transfer", Level 3, 7 credits.

    One or two conditions of the air, together with the barometric pressure or the altitude to be indicated to the person being assessed
    (e.g. Barometric pressure or altitude plus WB and DB or DB and RH or DB and dew-point
    Accuracy required:
    Dry bulb, wet bulb and dew point temperatures: ? 0,2K
    Relative humidity: ? 3%
    Humidity ratio: ? 0,0003 kg/kg
    Specific volume: ?o,002 m?/kg
    Vapour pressure: ? 25 Pa
    Density: ? 0,1 kg/m?
    Enthalpy: ? 0,2 kJ/kg

    Candidate is to be assessed without being led to the required response. 

    QUALIFICATIONS UTILISING THIS UNIT STANDARD: 
      ID QUALIFICATION TITLE PRE-2009 NQF LEVEL NQF LEVEL STATUS END DATE PRIMARY OR DELEGATED QA FUNCTIONARY
    Elective  20720   National Certificate: Air-Conditioning, Refrigeration and Ventilation  Level 3  NQF Level 03  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.
     
    NONE 


    All qualifications and part qualifications registered on the National Qualifications Framework are public property. Thus the only payment that can be made for them is for service and reproduction. It is illegal to sell this material for profit. If the material is reproduced or quoted, the South African Qualifications Authority (SAQA) should be acknowledged as the source.