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Contents
Page 3 – Executive Summary
Page 4 – HVAC Report
Page 5 - 6 – Solar Power
Page 7 - 8 – HVAC Systems
Page 9 - 11 - Passive Systems
Page 12 - HVAC Algorithm
Page 13 - Final Questions/Conclusion
Page 14 - References Page
Total Pages: 14 Pages
Work Experience 2014, De La Salle Malvern
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Executive Summary
Due to the rising electricity costs, we have
suggested many implementations to the HVAC
(Heating, Ventilation, Air conditioning) system
to reduce energy use and in turn cost. Installing
solar panels on the roof of the NHP building will
supply an office room of the building with
enough power to keep the HVAC systems
running, without having to use power from the
main power supply.
We plan to use Breezair evaporative air
conditioners because they have use up to 90%
less electricity than traditional air conditioning
units. An evaporative air conditioner draws the
hot air from outside and into water moisten
pads. The water then evaporates and the
evaporative air absorbs the heat and cools the
hot air. Heat recovery ventilation is a system
that replaces the stale air in the room with
fresh air. This system uses the heat from the
stale air and brings it back into the room
warming the fresh air. These two systems don’t
use much energy but remain efficient.
We also use many passive systems such as
Insulpaint. This paint is used as insulator and it
is used to keep the heat in the room and
maintain room temperature. PCM (Phase
Change Material) is another passive material
that can be implemented to prevent the rapid
change in temperature. It stores and releases
heat and cold as the temperature changes.
Reflective blinds are a passive system controlled
by temperature sensors to control the room
temperature. One side of the blinds is reflective
and the other side is absorbent. The reflective
side reflects heat into or away from the building
depending on the results of the temperature
sensors. The report also addresses: What other
sensors could be used in our system, if our
system could be used in refrigerator and what
would happen if it rains.
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HVAC REPORT:
Project brief:
The rapidly rising cost of electricity makes passive heating and cooling systems for buildings more
important. Assuming that there are temperature sensors in the roof, indoors, outdoors and under the
building, design a logic algorithm to open and close vents to reduce active heating and cooling costs.
What other sensors would be
a good idea? What happens if
it’s raining? Could a
refrigerator use a similar
system?
What is the problem?
The problem is that the cost
of electricity is rapidly rising.
This means that the demand
for passive heating and
cooling systems will rise. How
can we assist in reducing the
cost of electricity and power?
Possible solutions:
-Solar
-Full wall of windows
-Reflective Blinds
-Water Tanks which store water for cooling usage
-Evaporative system
-Phase change material (PCM)
-InsulPaint.
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This graph from the Parliament
of Australia’s website confirms
that the price of electricity in
Australia is indeed rising,
meaning that more people will
start to turn to passive heating
and cooling systems, or active
systems that use less energy.
-Heat recovery ventilation
Solutions to the Problem:
Solar:
By putting solar panels on the roof of the NHP building, we can capture sunlight and transform it into
energy that can power the HVAC systems in a room of the building that we are basing our project on.
This will reduce the amount of power the building is using, because the power will be coming from the
sun.
If we assume that the roof is on an angle, Solar panels can be positioned to receive the maximum
amount of sunlight per day. Solar panels that are placed on the roof capture energy from the sun and
transform it into DC (Direct Current) electricity. In the power box of the solar energy system, there is an
inverter that turns the DC energy into AC (alternating current) energy which can be used by homes or
businesses. This electricity that is produced can be used to power the HVAC system in a room of the
building.
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This diagram shows how Solar panels capture the sun, and how the sun’s energy is
transformed into electricity.
This image shows that rooftop solar energy only accounts for 1% of Australia’s energy generation, but
this amount will probably rise in the next few years as people are now turning towards renewable
resources to power their homes and businesses because it saves you money.
This diagram shows how a HVAC venting system works. The solar energy would power the fan and
heating coils in the HVAC system.
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HVAC Systems:
We have picked two active HVAC systems that will greatly reduce the cost of electricity because the
systems implemented use renewable energy efficiently. Without these systems, the electricity cost of
the HVAC in an average office building accounts for 28% of the electricity use, according figure 1 graph
below. Different systems such as Motion sensing or Heat sensing systems will save energy by detecting
turning the system on and off when HVAC is needed.
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An evaporative air conditioner draws the hot air from outside and into water moisten pads. The water
then evaporates and the evaporative air absorbs the heat and cools the air. The remaining air is then
blown outside the window hence cooling the room. The evaporative air conditioner will continue to cool
the room until it is at a temperature set by the thermostat connected. Breezair evaporative air
conditioners have exceptionally low running costs and uses up to 90% less electricity than traditional air
conditioning units.
Water tank: A container that costs at an estimate of $199.99 that will use the rainwater to give the
evaporative air conditioner an endless supply of water.
Heat recovery ventilation: The heat recovery ventilation has a fan that blows all the stale air from the
room and replaces it with fresh air from outside. The stale air is filtered expelling the impurities and
recovering the heat and putting it back into the room with the fresh air heating the room. Little to no
energy is used to power the fan and by implementing the Heat Recovery Ventilation you will save
money.
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Passive Systems:
Reflective Blinds
Double sided reflective blinds reflect heat inside or outside of buildings. One side of the blind is
reflective, while the other is absorbent. The temperature sensors in the roof, indoors and outdoors
decide whether the reflective side faces the sun or inside the building. When the temperature is warmer
outside than it is inside, the reflective side of the blind should face outside to reflect heat from the sun
away from the office building to keep the building at a cool temperature. When the temperature is
warmer inside than it is outside, the reflective side will face the building to keep heat from active
heating inside of the building.
Diagram: Reflective
blind reflecting heat
from the sun away
from building.
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Phase-Change Material (PCM)
Phase change material is another method that our team believes can assist NHP and many other
buildings and homes in the struggle of rising electricity costs and methods to reduce the amount of
power that is consumed by HVAC systems such as heaters and air-conditioners. This is because PCM’s
have the ability to reduce mechanical heating and cooling needs. It also moderates indoor temperature
to keep it at a constant and comfortable temperature.
These materials are currently under research and development. With the information already know we
can see that they can smooth daily temperature changes, resulting in a more comfortable environment.
PCM’s reduce home heating and cooling loads which will greatly assist the need for energy for heating
and cooling, which saves money for the consumer.
PCM’s are solid at room temperature; they then liquefy (melt) as the temperature rises. This cools the
surrounding environment because when the PCM liquefy they absorb heat and store it. Contrariwise,
when the temperature falls, the material will solidify, thus releasing heat which warms the area.
With this information, it is quite obvious to see that by incorporating PCM’s into building envelopes,
they will absorb heat during the day, cooling the house during the day, and then releasing that heat at
night when it is cooler.
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InsulPaint
We plan to use an Australian product called InsulPaint.
InsulPaint is a paint, which designed with a chemical called
Acrad 8, which acts as an insulator. Because the HVAC
system runs on a thermostat the insulating paint keeps the
heat in the room reducing the required use of the HVAC
system. The insulated coating of paint acts as a thermal
barrier.
Where normal paint allows most heat through, or with a
light colour reflects some light, the InsulPaint coating
absorbs the heat minimizing the amount of heat leaving
the room. You also have the advantage of a light
coloured paint reflecting additional heat if a light colour
is chosen.
Glass
We would also change the main
east facing wall to a glass wall
with reflective blinds to capture
the rising sunlight and heat in the
morning and retain later in the
day.
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HVAC Algorithm:
The algorithm first takes into
consideration whether there is any sun to
power the solar panels. If the panels are
not receiving power, the system takes
power from the reserve solar energy
supply or, if unavailable, takes from the
main power supply. The HVAC systems act
on a thermostat so the temperature can
be set to a person’s liking. The system
allows 3°C either above or below the set
temperature before turning on the
cooling (Evaporative System) or heating
(Heat Recovery System). Once returning
to x°C the system shuts down. All passive
systems are implemented to keep the
temperature at the set room
temperature.
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Conclusion/Final Questions:
What other sensors would be a good idea?
We have chosen a temperature sensor however a movement sensor could also be effective. A
movement sensor can be used to turn the system on or off by detecting whether or not people are in
the room. However turning the system on and off can actually waste power and the movement sensor
would become frustrating e.g. System will shut off when people are sitting down at their desk and not
moving much.
What happens if it’s raining?
If it rains the solar energy that was generated from when the power was available will be stored and be
used for times like that. If the solar energy runs out, we will take energy from the grid. If it rains the
passive systems will not be affected by the rain. So energy can still be saved and produced from some of
these systems.
Could a refrigerator use a similar system?
The fundamentals of refrigeration are also at work in the air conditioner. The principle behind most
refrigeration is simple. When a liquid evaporates, it absorbs heat in the process. If you want to get rid of
heat, you need to coax a liquid to convert to its gaseous state. The exact same process is use in the
Evaporative System we plan to use in our project.
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Bibliography/Sources:
Solar Energy:
http://www.westservicesmemphis.com/content/images/picture2.jpg
http://www.originenergy.com.au/energyfromthesun
http://www.totalsolarsolutions.com.au/wp-content/uploads/2013/02/solar-panel-diagram1.png
Reflective Blinds:
http://www.ehow.com/info_8270431_can-energy-turning-blinds-down.html
http://dev.reflectiveblinds.com.au/wp-content/uploads/2012/11/diag.gif
HVAC
http://www.totalinsulation.ie/heat-recovery-ventilation.htm
http://www.breezair.com/eu/why-evaporative/how-evaporative-works
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