What is the difference between energy conservation and energy efficiency?
Energy conservation is anything that saves energy, that simply uses less energy.
Energy efficiency is specifically using
less energy to provide the same services
What might be a “structural” change to the economy that may make Australia’s energy usage do down, but not reduce global energy use?
Exportation of energy intensive production, such as manufacturing.
Manufacture, and heavy industry (like mining) require more energy than other
industries, such as tourism, and retail. If these activities leave Australia due to rising
costs, and move to somewhere that is cheaper (eg a developing country), then
Australia might use less energy, but this energy is still being consumed somewhere.
People often talk about the “non-energy” benefits of energy efficiency
programs, what is meant by this? Name 3 non-energy gains that could come
from energy efficiency programs.
- SAVE MONEY
- Less maintenance (smaller systems)
- Noise
- Less GHG emissions
- Longer battery life
What other benefits arise by using CFLs that have not been considered (Ie economic)?
- Reduced electricity demand and need for T&D ( Transmission and Distribution) upgrades, reduced need for new power generation plants.
- Reduced GHG emissions particularly CO2
- Reduced HVAC loads in summer due to reduced incandescent heating.
- Reduced product transportation and distribution costs due to fewer number required over time.
- Reduced packaging and storage requirements for similar reasons.
- Reduced maintenance and repair costs
- Drawbacks include higher embodied energy in CFL and disposal
issues (mercury content).
What is the IRR
The Internal Rate of Return (IRR) is defined as the discount rate that would result in a
zero NPV over the period. It is where the future discounted savings match the initial
investment and describes the rate of return (in present dollars) on the initial
investment to pay it back.
Name 2 potential additional benefits of installing power factor correction system excluding economic.
- You could significantly reduce the size of the generator needed (usually rated
in kVA, not kW), therefore less total capital cost - You could possibly reduce the size of cable needed, as less current is being
carried, therefore less capital cost - Less power required in kVA, therefore less dependence on diesel being
brought in
Draw a picture of a thermosiphon solar hot water system and explain how
thermosiphoning transfers the fluid around the system without requiring any energy
input.
Basically uses the difference in density of the water to move hot water into the storage tank above the collector and lets the more dense cold water run to the collector.
Name 2 advantages and disadvantages of EV and ICE drivetrains. Discuss how they
come together in hybrid powertrains.
Electric Good:
- Easily Fuel switchable (as in the fuel that produces the electricity)
- Energy is cheap (ish)
- Motors are simple and lightweight - High power density.
- Good at stop/start - no need to idle
- Torque and power across a broad RPM range -> limits need for a gearbox
- Regenerative braking.
Electric Bad:
- Batteries are heavy - long range a challenge.
- Batteries are expensive - long range a challenge.
ICE Good:
- Lot’s of experience with the technology.
- Extremely energy dense fuel.
ICE Bad:
- Difficult to find renewable fuel
- Relatively complex mechanical systems.
- Relatively narrow power and efficiency band, needs a gearbox, and generally stays on at idle.
How many different Australian Standards specifically address Energy
Audits? What do they cover?
3 separate standards AS/NZS3598.1.2014, 3598.2.2014, 3598.3.2014. AS3598.1.2014
is the standard referred to in your first assignment. These cover commercial, industrial, and transport efficiency audits.
What are the differences between Type 1,2 and 3 Audits?
Type 1 Audits are very broad, and give a quick overview of energy usage.
Type 2 audits are more detailed and involve taking actual measurements over some
time period. Most common but expensive
Type 3 Audits go into great detail of a particular subsystem
When completing a Type 1 Audit on a building, do you need to make
recommendations about improvements?
Yes
Which of the building rating schemes have a design rating? (This is
they are rated pre construction)
LEED, NatHERS, Green Star and BASIX.
Which of the building rating schemes have a performance rating?
(That is looking at how the building actually performs - not just what
they think will happen)
LEED, NABERS, Green Star, BASIX
Transport is a category in which standards? What does this category
refer to specifically?
LEED and Green Star.
Transport of occupants that use the building after it is constructed (eg. work there). It looks at the ways that the buildings has incentives or facilities that encourage occupants to use greener modes of transport - eg bike racks, showers, accessibility to public transport etc.
What rating scheme is it compulsory to have on advertisements
when selling or leasing large commercial spaces greater than
1,000m
2?
NABERS
What does the Community rating scheme encompass? Use either the
LEED or Green Star rating scheme
Green star: Liveability, the promotion of active lifestyles, health and
inclusive spaces, mixed use space (residential and commercial together),
leadership and transparency of building practices, training and community
skill development through the construction process. Local environmental
impacts as well as reducing overall ecological footprint.
Which rating scheme(s) would you use for a large renovation on your own home in NSW
BASIX/NatHERS - is compulsory. LEED could also be used if
desired.
Which rating scheme(s) would you use for showcasing the benefits of a building that wasn’t rated before construction, but is a very green building at a university?
LEED, Green Star, NABERS (NABERS being the main one
recognised as a performance only rating).
Which rating scheme(s) would you use for your current home for which you have made no changes to?
NatHERS
You have a highly water efficient existing building, but don’t
care about energy?
In NABERS each category is rated separately - you can chose to
have all of water, energy, waste rated - but each is given a
separate star rating
What are MEPS? How are they different to Star Ratings?
Minimum Energy Performance Standards.- They specify the poorest energy efficiency of number of products (fridges, motors etc)
that anyone is allowed to sell (new) in Australia. They are an important safeguard
against really terrible appliances being sold.
Star ratings describe the energy efficiency of a particular appliance compared with other
appliances of the same type and similar size. These provide consumers with easy to
understand information about the energy usage of their appliances.
In what situation(s) would you consider installing power factor correction?
How could this save money?
Most commonly Power Factor correction would be installed by commercial and industrial
electricity users with a demand charge. Peak demand charges are generally in KVA or
total/apparent power. This means that improving power factor can reduce the peak demand
charge. Peak demand charges are paid over a period (for example month, quarter, year) based
on the peak demand during that period. Something like $/KVA (peak)/day.
If you ran your own generator and transmission line (such as in a microgrid) there may also be
efficiency and capacity savings of installing power factor correction. Or if you had electrical switchboards/wires/components that are reaching maximum capacity,
improving power factor could give you better utilisation of these components.
Why there is a difference in COP for heating and coolling?
The Coefficient of Performance (COP) is defined as the ratio of the useful work out to the work in. Heat pumps transfer heat energy from a low temperature to a higher temperature and so the input of work is
required (this is the opposite of natural heat transfer). If used for heating, the useful work is the energy transferred to the higher temperature. If used for cooling, the useful work is the energy removed from the
lower temperature. For a given amount of work (energy) in, the energy transferred to the higher temperature is greater than the energy removed from the lower temperature.
- Basically its easier to add heat then remove it due to the first law of thermodynamics
Saturated vapour pressure and boiling point
A liquid boils when its saturated vapour pressure becomes equal to the external pressure on the liquid. When that happens, it enables bubbles of vapour to form throughout the liquid. If the external pressure is higher than the saturated vapour pressure, these bubbles are prevented from forming, and you just get evaporation
at the surface of the liquid.
