PROJECT REPORT 3
THE WOND-AIR
Michal Kovacs
David Phibbs
Katharine Dong
Yiqing He
April 28, 2010
Team 8
Abstract
When charged with the task to create a system that utilizes low voltage direct current, our group
came up with the idea of an air purification system which uses the properties of electricity to
purify the air, instead of the inefficient replaceable air filters that are commonly used now-adays. Our design uses a simple device called a negative ion generator which can convert either
an AC or DC power supply into negative ions. With this product in mind we decided to disperse
the charge onto aluminum plates with a large surface area to attract particles in the air. This is
beneficial in three ways, it cleans the air without filters, it’s silent, and it naturally circulates the
air based on the properties of attraction. Once we had this concept in mind we performed some
calculations and discovered that not only was it possible to clean the air in a large room without
traditional filters, but it was actually cheaper and more environmentally friendly.
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1.0 Introduction
Our team needed to design a system that runs on DC power without needing any
conversions. At first, we wanted to design a search system in a library helping
people find books more easily and conveniently, but this design was not acceptable
because it was not practical and had little sales marketing. It took us a long time to
come up with a new design topic. Through searching for information about air
purifiers, our team decided to update the common air purifiers with the technology
of negative ionic generators. In general, air purifiers contain filters that need to be
replaced very frequently, which brings people a lot of troubles. We aim to make
our product extremely user and environmentally friendly. Our team first did lots of
external research about the negative ionic generators, for the reason that none of us
were familiar with this technology before. We got to know the principals and
functions of this technology through looking into some ionic breeze air purifiers.
However, the size of metal plates in the ionic breeze air purifiers is too small, so
we added seven metal plates in parallel and enlarged the area of the aluminium
plates.
As a result, our system, composed of negative ionic generators, is very useful in
large rooms such as office buildings, hospitals and restaurants, because it is very
energy efficient. In addition, the only energy consuming device in this system is a
small duct fan. Thus, the cost of energy, especially the electricity is so little that
customers only need to pay pennies every day.
1.1 Initial Problem Statement
We were issued the task of coming up with innovative ways for using 24 volts of DC current
run through the ceiling. Ideally we wanted to create a system or appliance that would be more
efficient and environmentally friendly when run on DC rather than AC.
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2.0 Customer Needs Assessment
2.1 Weighting of Customer Needs
Table 1. Initial Customer Needs List Obtained from Focus Group and Individual
Interviews
User Friendly
Low Noise
Easy to clean
Discrete
Safe
Durability
Long lasting
Low maintenance
Easy maintenance
Environmentally friendly
Energy efficient
Low waste
Minimum carbon footprint
Table 2. Hierarchal Customer Needs List Obtained from Focus Group and Individual
Interviews
1. User Friendly
1.1 Low Noise
1.2 Easy to clean
1.3 Discrete
1.4 Safe
2. Durability
2.1 Long lasting
2.2 Low maintenance
2.3 Easy maintenance
3. Environmentally friendly
3.1 Energy efficient
3.2 Low waste
3.3 Minimum carbon footprint
3
Pairwise Comparison
User Friendly
Durable
Environmentally
friendly
Total
Weighting
3.00
6.00
0.53
User Friendly
1.00
Durable
0.50
1.00
2.00
3.50
0.31
Environmentally
friendly
0.33
0.50
1.00
1.83
0.16
Figure 1. AHP Pairwise Comparison Chart to Determine Weighting for Main Objective
Categories
User Friendly
Low Noise
Easy to Clean
Discrete
Safe
Total
Weighting
Low Noise
1.00
2.00
3.00
0.50
6.50
0.29
Easy to Clean
0.50
1.00
2.00
0.33
3.83
0.17
Discrete
0.33
0.50
1.00
0.25
2.08
0.09
Safe
2.00
3.00
4.00
1.00
10.00
0.45
Figure 2. AHP Pairwise Comparision Chart to Determine Weighting of User
Friendly Sub-Objectives
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Durable
Long Lasting
Low
Maintenance
Easy Maintenance
Total
Weighting
Long Lasting
1.00
2.00
3.00
6.00
0.53
Low Maintenance
0.50
1.00
2.00
3.50
0.31
Easy Maintenance
0.33
0.50
1.00
1.83
0.16
Figure 3. AHP Pairwise Comparison Chart to Determine Weighting for Main Objective
Categories
Environmentally Friendly
Energy
Efficient
Low Waste
Min. Carbon
Footprint
Total
Weighting
Energy Efficient
1.00
3.00
4.00
8.00
0.61
Low Waste
0.33
1.00
0.50
1.83
0.14
Min. Carbon
Footprint
0.25
2.00
1.00
3.25
0.25
Figure 4. AHP Pairwise Comparison Chart to Determine Weighting of
Environmentally Friendly Sub-Objective
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Table 3. Weighted Hierarchal Customer Needs List Obtained from Focus Group and
Individual Interviews
1. User Friendly (0.53, 0.53)
1.1 Low Noise (0.29, 0.15)
1.2 Easy to clean (0.17, 0.09)
1.3 Discrete (0.09, 0.05)
1.4 Safe (0.45, 0.24)
2. Durability (0.31, 0.31)
2.1 Long lasting (0.53, 0.16)
2.2 Low maintenance (0.31, 0.10)
2.3 Easy maintenance (0.16, 0.05)
3. Environmentally friendly (0.16, 0.16)
3.1 Energy efficient (0.61, 0.10)
3.2 Low waste (0.14, 0.02)
3.3 Minimum carbon footprint (0.25, 0.04)
3.0 Revised Problem Statement
To create an air purification system that is simple, effective, and environmentally friendly that
will be able to run on nothing but DC power supplied from the ceiling.
4.0 External Search
In order to come up with our design, we needed to look as different resources in order to figure
out what already exists. Once we did this, we were able to manipulate the previous designs to
suit the needs for our creation.
4.1 Literature Review
The idea of the design is from the combination of the ionic breeze and the air blower.
Traditionally, the air purification contained a filter, which needs to be changed a couple times
since a dirty filter slow the airflow (Department of Energy). Ionic plates are able to work much
longer than filter and need not to be changed over time. The user only needs to clean them to
allow the ionic plates to continue functioning. However, from the research, we found a huge
limitation about an ionic purification. As the crossed field created by the ionized plates is
extremely small, it can only affect the dirt and dust 1/80 inch away (Air Purification Review).
The weak suction makes the purification work inefficiently. In order to improve the efficiency,
we add an air blower for the ionic breeze to suck faster.
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4.2 Experimentation
Alternating Current (or AC) is current that travels in a back and forth motion. This type
of current is more commonly used because of its ability to be easily transported over long
distances; however, it has some distinct disadvantages. Although some devices can run on AC
current (like a light bulb) most devices use DC current and therefore the AC must be converted
into DC in the appliance. Because of this conversion, some of the electrical energy can be lost do
to heat, thus making the appliance less energy efficient.
Direct Current (or DC), unlike AC, only flows in one direction. This makes it harder to
transport and that’s why AC is the electricity of choice in the United States. However, because
appliances run on DC power, it is often less efficient to convert the AC current to DC. In short,
DC is most efficient, but not applicable while traveling long distances.
Since this project only requires the use and not the transportation of the DC current, we
only focused on its positive attributes. To test that DC is a better power supply we looked at a
laptop. Laptops run on DC power, but they are supplied by AC power. To change the AC to DC
there is a converter on the power cable for all laptops. These converters get warm while plugged
in, so therefore some electrical energy is lost to heat. If the laptop was plugged into a current of
DC power, there would be no conversion of AC to DC and thus no loss due to heat. Essentially
by looking at a laptop our group was clearly able to see that when using AC for some appliances,
energy can be lost.
To prove this experimentally we tried to run a light bulb on both AC and DC power and
see which required less voltage to make the bulb light up. In theory we believed that because DC
is more efficient it would require less voltage than AC to light up the bulb. However, our group
failed to note that light bulbs do not require a conversion of AC to DC in order to work and
therefore our experiment was a total waste of time. But, we did light up the light bulb.
By looking at the laptop we could see the detriments of using AC power for some
appliances. We tried to prove this in an experiment, but it wasn’t properly designed. Although
we couldn’t show a percentage of energy lost, or something like that, we were still able to learn
vital information for our project. By our failed experiment we know that there is practically no
benefit for running regular lights on DC power because they don’t require conversion from AC
to DC. The only real benefit for doing this would be that DC usually comes from a “greener”
source and is better for the environment.
4.3 Patent Search
Table 4. Art-Function Matrix
Item
Air purification
Low Noise air
Blower
Electrolysis
apparatus
Negative Ion
Generator
Patent
No.
5476536
######
Description
A Process of removing unwanted adulterant and
gas
5567127
######
Deliver air-Circulation of air
4056452
1-Nov-77 Create electric field
2499320
Issue Date
23-June-47 Create negative ions from electricity.
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4.4 Benchmarking
Feature
IQair Health Pro Plus
Austin Air HealthMate
Noise
Environmental
Friendliness
Price
Effectiveness
4
3
Honywell
Enviracaire 50250-N
2
4
4
3
2
5
4
4
5
4
The IQair Health Pro Plus is an incredible effective air purifier, unfortunately it
is extremely expensive and like all filter based systems it has some amount of waste and noise
due to fans.
The Austin Air HealthMate is a more midrange priced unit. It sells for less than
$500, however it’s louder and less effective than the better systems.
The Honywell Enviracaire 50250-N is cheap air purifying system that retails for
less than $200 and because of that it has some major drawbacks such as its loud noise and its
rather large impact on the environment.
Images courtesy of consumersearch.com
4.5 Design Target
After doing our external research we learned that the majority of previous air purification
systems are not only extremely noisy, but are rather expensive. They also all run with some sort
of filter that needs to be replaced every so often. Our team decided that we needed to make a
product that was the best in these three fields. We need to make it quiet, rather inexpensive, and
without a filter. If we achieve these, we will be able to have the most user friendly, durable, and
energy efficient system.
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5.0 Concept Generation
5.1 Problem Clarification
Figure 5. EMS Model for the Wond-Air
The whole point of our design is for it to run off DC power. As you can see on our EMS model,
there are two parts of the system that run off of the DC power. It powers both the fan as well as
the negative ion generators. The fan pulls dirty air from the room through the system while the
negative ion generators generate ions onto the aluminium plates. The dirt is then pulled from the
air and onto the aluminium plates. The fan then pushes the now clean air back into the room.
5.2 Concept Generation
The first function we had was how to circulate the air through the system. We decided that
we could have multiple fans, one pulling and the other pushing the air through the system, on
fan, which pulled and pushed the air, or just use the attraction of ions to pull the air through the
system. Our second function was how to purify the air further than just pulling dirt out. We
came up with an ultraviolet light to kill bacteria, an ozone purification, which uses ozone to kill
bacteria, or a carbon filter, which filters the bacteria out of the air. Our final function was how to
clean the dirt that gets stuck to the aluminium plates. Our ideas included: a detachable cover,
where we would remove the bottom and reach up with a feather duster to clean, make the entire
unit detachable, so the until could be taken down and then cleaned, or an auto cleaning system,
which would automatically wipe the dirt off of the aluminium plates.
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Combination:
One fan, UV light, and auto cleaning
This system although extremely convenient for the user, it is the noisiest and least energy
efficient combination. For the previous reasons it was not chosen for the final design.
Attraction, none, auto cleaning
This system is the most user friendly because it requires no cleaning and has no moving parts.
However it uses the most energy so it does not solve our problem of making an energy efficient
system.
Multiple fans, carbon filtration, and detachable unit
This system is the most efficient in the circulation of air and the carbon filter offers an energy
free way to filter out bacteria. On the other hand, this is the least user friendly combination
because it requires the most work on the part of the user. The fan that pulls in the dirty air will
need to be cleaned, the filter will have to be replaced every so often, and the user would have to
lift the entire thirty-two inch unit in and out of the system every time they needed to clean it
(which is about every two weeks).
One fan, none, and detachable cover
This is the best combination because it provides moderate air circulation while using a minimum
amount of moving parts while remaining nearly silent. It also requires a low amount of cleaning
and no parts will ever need to be replaced.
Methods of Concept Generation
Brainstorming:
Used for problem clarification and concept generation. We chose it because it is a good
method for developing a lot of ideas on a single topic. We would use it by each member of our
group simply writing down any idea that comes to mind for a set time interval (5 minutes). After
doing it once we didn’t all agree on one concept to base our project on. So we assigned ourselves
a homework assignment: each team member must come up with at least 5 new ideas. From this
second attempt we came up with our initial design concept of a new air purification system.
Synectics:
This method was again be used for problem clarification and concept generation. We chose
Synectics because it provided unique or unexpected results because it’s such an interesting way
of thinking. We’d implement it by following the 4 steps of Synectics, thinking of potential
problems and solutions for each of the steps. We used Synectics after we had our initial idea, but
wasn’t sure how we were going to use the DC power effectively. We also wanted to come up
with a more environmentally friendly way to purify air in a commercial setting. With the use of
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Synectics we came up with an air purification system that would use charged metal plates to pull
dirt out of the air.
Morphological Charts:
Used during conception generation, this method was used to come up with different functions
we wanted our air purification system to perform. We also wanted to think of certain ways our
system would perform these functions. To do the morphological charts each member of our
group made a chart with different functions and solutions. Some functions were cut out and some
solutions were added once we all shared ideas. We finally came up with the three main functions
that can be seen in our final morphological chart in our project.
Gallery Method:
The gallery method was used during concept selection. We feel this was a good fit because
the gallery method brings together each team member’s ideas and sketches and then the team
collectively looked at the sketches. By doing this we were be able to make the best selection for
our final concept. When we used the gallery method it was basically just a check. Everyone
looked at everyone else’s ideas after we had already picked our concept. We just wanted to make
sure that we had the best idea possible. The gallery method was great because we were able to
just lay out all our previous brainstorming attempts and make sure we chose our best idea. We
used all the brainstorming techniques just on concept generation and selection because we felt
having a sound concept for using the DC power was the most important part of the project.
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Figure 6. Morphological chart
6.0 Preliminary Concept Selection
Air Circulation
Air Sanitation
How to Clean
Multiple Fans
Ultraviolet Light
Detachable Cover
One fan
None
Detachable Unit
Attraction
Ozone Purification
Auto Cleaning
Carbon Filtration
12
Air Circulation
User Friendly
Durability
Environmental
Friendliness
Weighting
0.53
0.31
0.16
Total
Multiple Fans
Rank
2
One Fan
1
1
1
1
1
Attraction
1
1
1
1
1
Air Circulation
User Friendly
Durability
Environmental
Friendliness
Total
Rank
Weighting
0.53
0.31
0.16
Multiple Fans
-1
-1
-1
0
3
One Fan
Attraction
1
-1
1
1
13
-0.06
2
Air Circulation
User Friendly
Durability
Environmental
Friendliness
Weighting
0.53
0.31
0.16
Multiple Fans
-1
-1
One Fan
1
-1
Total
Rank
-1
0
3
-1
0.06
1
Attraction
2
Air Sanitation
User Friendly
Durability
Environmental
Friendliness
Weighting
0.53
0.31
0.16
Total
Ultraviolet Light
Rank
2
None
1
1
1
1
1
Ozone Purification
-1
1
1
-0.06
3
Carbon Filtration
-1
-1
-1
-1
4
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Air Sanitation
User Friendly
Durability
Environmental
Friendliness
Weighting
0.53
0.31
0.16
Ultraviolet Light
-1
-1
-1
Total
Rank
-1
2
None
1
Ozone Purification
-1
-1
-1
-1
2
Carbon Filtration
-1
-1
-1
-1
2
Air Sanitation
User Friendly
Durability
Environmental
Friendliness
Total
Rank
Weighting
0.53
0.31
0.16
Ultraviolet Light
1
-1
-1
0.06
2
None
1
1
1
1
1
Ozone Purification
Carbon Filtration
3
-1
-1
-1
15
-1
4
Air Sanitation
User Friendly
Durability
Environmental
Friendliness
Weighting
0.53
0.31
0.16
Ultraviolet Light
1
1
None
1
Ozone Purification
1
Total
Rank
1
1
1
1
1
1
1
1
1
1
1
Carbon Filtration
2
How to Clean
User Friendly
Durability
Environmental
Friendliness
Weighting
0.53
0.31
0.16
Total
Detachable Cover
Rank
2
Detachable Unit
-1
-1
0
-0.84
3
Auto Cleaning
-1
-1
-1
-1
1
16
How to Clean
User Friendly
Durability
Environmental
Friendliness
Weighting
0.53
0.31
0.16
Detachable Cover
1
1
0
Total
Rank
0.84
1
Detachable Unit
3
Auto Cleaning
1
-1
-1
0.06
2
How to Clean
User Friendly
Durability
Environmental
Friendliness
Total
Rank
Weighting
0.53
0.31
0.16
Detachable Cover
1
1
1
1
1
Detachable Unit
-1
1
1
-0.06
3
Auto Cleaning
2
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7.0 Concept Refinement with TRIZ
The two contradictions we used for our TRIZ assessment were that we wanted to improve the
continence of the use of our system and the undesirable result was a waste of energy. Under
these parameters, we ended up with the following principles: separation or extraction (2),
periodic action (19), and the other way around (13). We then used these to make our system
more convenient for the user. For separation and extraction we removed any unnecessary parts
from the system. For example, we initially had to fans in our system; one to pull the air in and
the other to push the air out. To simplify this we decided to take one of the fans out so that we
just had the one fan pulling and pushing the air. The main benefit of this is that there is now no
fan touching the “dirty” air so that eliminates the cleaning of any fans. For the periodic action,
we contemplated running the ion generators on a periodically changing system so that sometimes
they were off and sometimes they were on. We thought that this would save energy. However,
we discovered that with this in place, the air was not cleaned as efficiently as we wanted it to be.
Figure 7. EMS Model for the Wond-Air
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8.0Final Design
8.1 Materials and material selection
We researched what materials would be best for our product and decided on a high strength, light
weight aluminium, which has excellent conductive properties to use for the metal plates. We
housed the plates in a strong insulating fibreglass box which is lightweight, low cost, and used
for ventilation. We used simple negative ion generators that are able to be connected to the
aluminium plates. They use low energy and are able to be directly run on DC. We then chose
standard 8” diameter plastic tubing which is commonly used for air conditioning and ventilation.
A small fan is placed in the tubing to increasing circulation of air. Lastly the system is connected
to the room using ceiling diffusers which bring up the air on one end and disperse it throughout
the room on the other end.
8.2 List of Materials
Table 6. List of required materials and components
Qty
1
1
7
1
1
2
Description
Catalog Number
¼” fiberglass sheet, 1512 sq. in.
1/8” high strength aluminum alloy, 2688 sq. in.
120 VAC Negative Ion Generator
8” Duct Fan
8” diameter air duct, 25 ft
Standard Ceiling diffuser, 12in. diameter
8537K15
8973K36
G1783
185010
56355K38
2559K9
Vendor
McMaster Carr
McMaster Carr
The Electronic Goldmine
Lowe’s
McMaster Carr
McMaster Carr
Total Cost
Total Cost
$91.19
$198.51
$48.65
$29.93
$97.75
$55.06
$521.09
The above cost projection is based on the price for the supplies to make one unit. Prices would be expected to drop
significantly once supplies are bought in bulk.
Table 7. Contact information for suppliers of required Materials
McMaster Carr Supply Co.
473 Ridge Rd.
Dayton, NJ 08810
(732) 329-3200
Lowe’s
104 Valley Vista Drive
State College, PA 16803
(814) 321-9130
The Electronic Goldmine
9322 N. 94th Way
Suite 104
Scottsdale, AZ 85258
(800) 445-0697
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8.3 Assembly instructions
The main unit (the plastic box) will be installed flush with the ceiling so that the bottom of the
unit will be exposed for easy removal and cleaning. The negative ion generators are wired to the
DC power supply and attached to the aluminium plates. The generators themselves will be
housed outside the box with only the wires coming through. Air ducts are then attached to the
box and go approximately 12.5 feet in either direction. The small duct fan is placed at the end in
which the air is desired to come out of. Finally the ceiling diffusers are placed in the ceiling and
connected to the ducts.
Cross section of unit from above
Aluminum Plates
Whole Wond-Air system
Cross section from front
Plastic unit housing aluminum plates
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9. Design Calculations
Fan and Negative ion generators run on 12 volts DC
When wired in parallel we have 3 equal paths that all supply power to 2 generators and 1 path
the supplies power to one generator and the fan.
2 watts per ion generator*7 generator=14 watts
Fan= 30 watts
Total Watts=44watts
Total kilowatt hours /month=31.68
Cost of Kilowatt hour ($0.12) *31.68 kilowatt hours
=$3.80 per month
10.0 Conclusions
Our team was able to design a system that successfully purifies air with out the use of filters that
need replacing or loud energy consuming fans. Our system can successfully run on 24 volts of
direct current and as shown from the calculations above the whole system only requires 44 watts.
Because of its low energy cost and its permanent fixture, once the product is installed it will run
for pennies a day without and pieces needing to be replaced.
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References
Consumer Search. Air Purification Review. January 2010. Web. 28 April. 2010.
United States. Department of Energy. Heat & Cool Efficiently. Web. 28 April. 2010
22