GUIDE TO
SCHOOL WALKWALK-THROUGH
AUDITS
FOR TEACHERS & STUDENTS
By Clare Pries
April 2008
© Coolmob trading as Environment Centre Northern Territory, April 2008
WALKWALK-THROUGH ENERGY AUDITS
AUDITS
The aim of a walk-through audit is to collect information about what appliances are using
energy, how much energy is being used, and if this energy use can be reduced.
WHAT ARE THE MAIN ENERGY CONSUMING APPLIANCES AT YOUR SCHOOL?
Cooling & Ventilation
There are generally four main categories of air-conditioning systems that could be installed at
your school:
Centralized cooling plants that service the whole or most of the buildings,
Large packaged (PAC) units that service a single building,
Split system air-conditioners which service single rooms or small buildings, and
Window/wall box air-conditioners which service single rooms only.
Centralized cooling plants
Centralized cooling plants are the most efficient system for cooling large buildings, these have
a energy efficiency rating (EER) of 4 to 6 1, that is, for every unit of electrical energy
consumed they can remove 4 to 6 units of heat energy from the building. The main electrical
energy consuming components of these systems include: motors (to run compressors, pumps,
and fans), valves, controls, and sensors. These systems are normally controlled by a computer
based management programme which is maintained by external contractors. Manual operation
by school staff is usually limited to after hours remote start-stop activation switches. To
undertake the cooling audit within this guide, it will not be necessary (and would be
unrealistic) for students and teachers to identify and assess the centralized cooling system
components at the school. However, there are a number of technical opportunities available to
increase the efficiency of these systems and it is recommended that a professional audit of the
system be obtained if possible.
Components of centralized cooling systems
Compressor
Air Handling Unit
Cooling Towers
Packaged air-conditioners (PAC’s)
PAC’s have EER’s of 2.4 to 4.5 2 so are less efficient than large centralized cooling systems.
These units are generally installed for smaller buildings of 1 to 2 classrooms. Most of the
electrical components are housed in a single external unit positioned near to the room/s being
cooled, though some systems will have heat exchange units (which increase efficiency)
retrofitted into the air circulation circuit within the building. The main controls for these
systems are located within the unit housing and are maintained by external contractors.
Manual operation of these units by school staff can include the programming of timers and the
operation of remote start/stop switches.
1
Sustainable Energy Development Office – Government of Western Australia, Technology Table 9.1, ‘Heating, Ventilation and Air Conditioning
(HVAC)’, Energy Saving Manual – Energy Smart Toolbox, http://energysmart.com.au/sedotoolbox/index.asp
2
PAC EER’s based on 2001 MEPS for three phase refrigerated air-conditioners and highest indicated EER shown on Australian Government Energy
Rating web-based product listings, available at http://energyrating.gov.au/pac1.html.
Examples of packaged air-conditioning units
Split-system & Box air-conditioners
Split-system and box air-conditioners have EER’s of 2.2 – 4.23. These units are available in
much smaller sizes than PAC units and are commonly used in computer server rooms, staff
offices, canteens, and withdrawal rooms, though one or two larger split systems may be used
for classrooms. These units are serviced by external contractors, however staff have total
control (at appliance or through remote control) over their operation.
Fans
Ceiling, floor and wall mounted fans are generally used to provide cooling in non-air
conditioned areas of the school. Exhaust fans are commonly used to provide additional
ventilation in photocopy rooms, store rooms, canteen facilities, and toilets. Fresh air fans are
used to ensure a minimum air exchange within the buildings to remove odours and prevent
carbon dioxide build-up, these are normally located within the roof cavity. The control of
cooling and exhaust fans is usually by manual control of local on/off switches. Fresh air fans
are automatically activated with air conditioning systems. Whilst improvements in the
operation of fresh air fans can provide substantial energy savings, the technical aspects
require that these be assessed by qualified personnel and are not discussed further within this
guide.
Lighting
The main lighting systems at a school consist of classroom and office lighting, external security
lighting, gym lighting, and, exit and emergency lighting. The lighting technologies most
frequently used for these systems include fluorescent, incandescent, low and high voltage
halogen, mercury vapour, low and high pressure sodium, and metal halide. The power needed
to operate each of these lights depends on the size of the lamp (in Watts) and the components
within the fixtures required to run them (i.e. the type of control gear, ballasts/transformers,
used with fluorescent, mercury vapour, sodium, halogen, and halide lamps). In most cases you
will need to ask your maintenance staff for this information.
The most common type of lamp used for school classrooms and
office buildings is the ‘T8’ linear fluorescent tube. These lamps
have a diameter of 26mm and come in 600mm/18W,
1200mm/36W, and 1500mm/58W. Older lighting systems may
still use less efficient 38mm ‘T12’ tubes which come in
600mm/20W, 1200mm/40W, 1500mm/64W. Very new systems
may have 16mm ‘T5’ tubes installed, these come in
550mm/14W, 1150mm/28W, and 1450mm/35W.
T5 (top), T8 (bottom)
3
The type of phosphor coating used in these lamps determines
the overall efficiency of the lamp. Older lighting systems may
have ‘monophosphor’ or ‘halophoshor’ lamps installed where as
EER’s based on 2004 MEPS for single phase refrigerated air-conditioners, available at http://energyrating.gov.au/pac1.html
newer systems should have ‘triphosphor’ lamps installed, ask your maintenance staff what
type are used at your school. The older, less-efficient lamps are no longer allowed to be sold
but some remain operating in buildings.
Hot water systems
The most common form of hot water systems used in top-end schools are electric or solar
powered water storage units, and electric hot water urns. Whilst solar hot water systems and
electric hot water urns can easily be identified through a visual inspection of the school, many
electric hot water storage systems are located in rarely accessed or restricted areas. To
identify where these systems are located a copy of the school building plans should be
obtained from the Infrastructure Sustainability Unit (see contact details on page 49). The
position of hot water systems are usually represented by the letters hws enclosed in a circle
(see figure below).
It is a good idea to also check inside every cupboard and crevice of the school for any hot
water heaters that have not been picked up in the Department of Planning and Infrastructure
Building Asset Management System inspections.
Cold water dispensers
The two most commonly used cold water dispensers are self contained free-standing or wall
mounted drinking fountains, and remote storage bubbler outlets. Drinking fountains and
bubbler outlets are easily identified during a walk-through audit of the school by students.
Remote storage components of bubbler systems are usually located in store or maintenance
rooms and will require the assistance of maintenance personnel to undertake successful cold
water audit.
Drinking Fountains
Bubblers
Bubbler Cold Water Storage Units
School maintenance staff control the operation of these systems.
Refrigeration
Most of the refrigeration units used in schools are typical household appliances, however
specialized products such as glass door display refrigerators, ice slushy makers, ice cream
display freezers, and large cool rooms may also be used and are usually located within canteen
facilities. Teachers, canteen and administration staff, usually control the operation of these,
though large cool rooms are normally controlled by external contractors.
Computers, office equipment & audio/visual appliances
A school can have hundreds of these small appliances located in classrooms and offices
throughout the facility. Most can easily be identified by teachers and students during an audit.
If you are unsure of what something is, ask for assistance from your administration or
maintenance staff. Whilst most appliances are controlled by the staff responsible for the area,
computer servers which can be located at a number of different areas within the school, are
usually controlled by school or contract IT staff.
Examples of components of school computer server
Other
Other energy consuming appliances/equipment that you will most likely find at your school
include:
• cleaning equipment - vacuums (usually kept in cleaning or maintenance store rooms),
dishwashers
• cooking appliances - microwave ovens, stoves, kettles, toasters, convection ovens, pie
warmers (located in classrooms, offices, and canteen)
• pool pumps, located in service sheds near pools
• security and fire protection systems
• workshop and craft tools (wood & metal working tools, air compressors, kilns,…)
• fume hoods
• maintenance vehicles (buses, cars/vans, lawn mowers, tractors,…)
Some schools will also supply the energy needs of caretaker residences located on or near the
school grounds.
What information do you need to collect?
The amount of information that you will be able to collect during an audit will depend on the
time allocated to the task, assistance from other staff members, and student ability. Examples
of checklists and survey questions which are focussed on identifying where energy can be
saved are supplied, however these are only provided as a guide and can be altered to suit your
students. To complete a reasonably accurate analysis of where your energy is going you will
need to collect information on all the appliances at your school. To concentrate on the main
energy efficiency opportunities you will only need to collect the specific data noted in the
sections to follow.
Preparing for a walk-through audit
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Identify and address safety issues.
Obtain an understanding of the energy saving opportunities. Consider getting an expert
to come in and do a talk & answer questions, before conducting audit. Contact details
provided on page 49 of this guide.
Prepare check sheets and survey questions.
Communicate with other staff on what is being done and why.
Find out who is responsible for areas being audited.
Obtain school plans.
Purchase or borrow equipment needed to carry out audit (thermometers, energy
meters, lux meters). Contact the Infrastructure Sustainability Unit to discuss loans of
equipment.