24534 version 2
Page 1 of 5
Demonstrate and apply knowledge of commercial and light industrial
RAC system design
Level
6
Credits
15
Purpose
This unit standard is intended for use in diploma courses in mechanical
engineering, and covers knowledge and design of refrigeration and air
conditioning (RAC) systems for commercial and light industrial applications.
People credited with this unit standard are able to: demonstrate knowledge
of, design, select components for, and prepare design documents for
commercial and light industrial refrigeration and air conditioning systems.
Subfield
Mechanical Engineering
Domain
Applied Principles of Mechanical Engineering
Status
Registered
Status date
14 December 2007
Date version published
19 March 2010
Planned review date
31 December 2015
Entry information
Recommended: Unit 11385, Demonstrate and apply
knowledge of fluid mechanics in mechanical
engineering; and Unit 21781, Explain and apply laws of
thermodynamics in mechanical engineering; or
demonstrate equivalent knowledge and skills.
Replacement information
This unit standard replaced unit standard 3826.
Accreditation
Evaluation of documentation and visit by NZQA and
industry.
Standard setting body (SSB)
Competenz
Accreditation and Moderation Action Plan (AMAP) reference
0013
This AMAP can be accessed at http://www.nzqa.govt.nz/framework/search/index.do.
 New Zealand Qualifications Authority 2016
24534 version 2
Page 2 of 5
Special notes
1
References
Building Act 2004.
Building Code. Available from http://www.dbh.govt.nz/bcl-get-a-copy-of-buildingcode.
Department of Building and Housing compliance documents for the New Zealand
Building Code (compliance documents). Available at
http://www.dbh.govt.nz/building-code-compliance-documents.
2
Definitions
Commercial and light industrial refrigeration and air conditioning systems – systems
serving facilities such as supermarkets, trucks, fishing boats, shipping containers,
commercial cool rooms, commercial freezer rooms, commercial and light industrial
food processing.
Industry practice – the application of relevant legislation, regulations, standards,
codes, and safe and sound practices, generally accepted by competent practitioners
within the RAC industry.
VRF – Variable Refrigerant Flow rate.
3
Range
a The performance of elements 2, 3, and 4 must reflect compliance with relevant
legislation, regulations, standards, and codes of practice.
b Refrigeration and air conditioning systems – heat pumps, VRF air conditioning
systems, split air conditioning systems, chillers for chilled water and glycol
systems.
Elements and performance criteria
Element 1
Demonstrate knowledge of commercial and light industrial refrigeration and air
conditioning systems.
Range
evidence of three different systems is required.
Performance criteria
1.1
The principles of commercial and light industrial refrigeration and air
conditioning systems are explained with reference to operational processes,
parameters, and components.
Range
operational processes and parameters – heat transfer, refrigerant
circulation, pressures, temperatures and phase changes, type of
refrigerant, compressor protection, oil management, capacity
control, pressure control, temperature control, insulation, energy
use, corrosion control, health and safety.
 New Zealand Qualifications Authority 2016
24534 version 2
Page 3 of 5
1.2
Components used in commercial and light industrial refrigeration and air
conditioning systems are described with reference to operation, construction,
and capacity.
Range
components may include – refrigerants, compressors, condensers,
evaporators, receivers, oil separators, suction accumulators, pipes
and associated fittings, insulation, pressure control valves,
capacity control devices, defrosting devices, protective devices,
temperature controlled enclosures such as coolrooms and freezer
rooms, proprietary components for split air conditioning units and
VRF systems.
Element 2
Design commercial and light industrial refrigeration and air conditioning systems.
Range
evidence of design of two different types of systems is required.
Performance criteria
2.1
Design provides a viable solution to the given requirements in accordance with
industry practice.
2.2
Relevant parameters are determined in accordance with industry practice.
Range
2.3
parameters – load estimation, operating temperatures, refrigerant
flow rate, refrigerant pressure, heat rejection rate, refrigerant
charge, control authority, system protection, energy use.
Design demonstrates sound methodology of analysis and use of relevant
source data, in accordance with industry practice.
Range
source data – building data; refrigerated product data; thermophysical data for refrigerants, air, and water; performance data for
system components; units of measurement; regulations;
standards; codes of practice.
Element 3
Select components for commercial and light industrial refrigeration and air conditioning
systems.
Range
components may include – refrigerants, compressors, condensers, evaporators,
receivers, oil separators, suction accumulators, pipes and associated fittings,
insulation, pressure control valves, capacity control devices, defrosting devices,
protective devices, temperature controlled enclosures such as coolrooms and
freezer rooms, proprietary components for split air conditioning units and VRF
systems;
selection of components for two different types of systems is required.
 New Zealand Qualifications Authority 2016
24534 version 2
Page 4 of 5
Performance criteria
3.1
Component ratings are appropriate for the loads imposed on them in
accordance with industry practice.
Range
3.2
ratings – refrigerant flow rate, working pressures, working
temperatures, heat transfer capacity, maximum pressure,
maximum temperature.
Selected components are suitable for the applications in accordance with
industry practice.
Range
suitability may include consideration of – function, durability, noise
level, reliability, efficiency, ability to fit within available space,
ability to be maintained.
Element 4
Prepare design documents for commercial and light industrial refrigeration and air
conditioning systems.
Range
documentation for two different types of systems is required.
Performance criteria
4.1
Documentation includes sketch plans showing the physical location of all
components within the building in accordance with industry practice.
4.2
Documentation includes schematic drawings showing the interconnection of all
components in accordance with industry practice.
4.3
Documentation includes specifications of all components in accordance with
industry practice.
4.4
Documentation includes operating description of the overall system and its
components, includes a pressure/enthalpy diagram and prediction of energy
use, and indicates key parameters and how they are measured in accordance
with industry practice.
Please note
Providers must be accredited by NZQA, or an inter-institutional body with delegated
authority for quality assurance, before they can report credits from assessment against
unit standards or deliver courses of study leading to that assessment.
Industry Training Organisations must be accredited by NZQA before they can register
credits from assessment against unit standards.
Accredited providers and Industry Training Organisations assessing against unit standards
must engage with the moderation system that applies to those standards.
 New Zealand Qualifications Authority 2016
24534 version 2
Page 5 of 5
Accreditation requirements and an outline of the moderation system that applies to this
standard are outlined in the Accreditation and Moderation Action Plan (AMAP). The
AMAP also includes useful information about special requirements for organisations
wishing to develop education and training programmes, such as minimum qualifications for
tutors and assessors, and special resource requirements.
Comments on this unit standard
Please contact Competenz info@competenz.org.nz if you wish to suggest changes to the
content of this unit standard.
 New Zealand Qualifications Authority 2016