Kevin O'Malley Eddy Kettle Technical Report copy

Eddy Kettle
Technical Report
Kevin O’Malley - 2080753o
Product Design Engineering MEng
Technical Supervisor: Dr John Shackleton
April 2018

Executive Summary
The electric kettle is considered to be one of the most “disposable” and environmentally
damaging kitchen appliances. Many design issues that lead to a high environmental impact are
associated with this product, that is found in over 95% of UK households.
This technical report outlines the engineering decisions made during the design process of the
Eddy Kettle to ensure a lower environmental impact compared to conventional electric kettles. A
Life Cycle Assessment is then carried out on the final design of the Eddy Kettle and two other
electric kettles to evaluate and assess the effectiveness of the design decisions.
Firstly, the current issues with electric kettles leading to a substantial environmental impact are
investigated. With the main issues highlighted, the selection of induction heating as the heating
method was explored as a solution to increase the durability of the product. Various switch-off
mechanisms are then assessed before selecting the Whistle Stop as a boiling point detection
method. Finally, the materials of the Eddy Kettle are selected to ensure minimal environmental
impact over its extended lifetime.
The Life Cycle Assessment (LCA) conducted following ISO 14040 in this report shows that the
Eddy Kettle has the potential to significantly reduce the carbon footprint of kettles by up to 30%
compared to others currently on the market. It was determined that all the engineering
considerations investigated in this report contribute to a total carbon footprint saving of 2%. The
investigated topics primarily affect the carbon footprint of the Eddy Kettle during the Material
Manufacture, Product Manufacture, Disposal and End of Life Potential stages in the LCA.
However, the most significant saving in carbon footprint is down to the unique location of the
water level indicators on the inside of the vessel (see Appendix A). By allowing the user to see
how much water they are filling into the vessel, as they fill it, the Eddy Kettle can save up to 40%
of the water consumed during the In Use phase of life. This saving in water consumption
corresponds to a saving of 28% of CO2 emissions during the lifecycle of the product.
The Eddy Kettle shows excellent potential to significantly reduce the carbon footprint of the
conventional electric kettle, warranting further development of the physical product for the
consumer market.

Contents
1. Kettles In Use 1
1.1 Heating Efficiency 1
1.2 Points of failure 3
1.3 Controlled Filling of the Chamber 3
2. Induction Heating 4
2.1 Why Induction Heating? 4
2.2 Experimental Modelling 5
2.3 Simulation Modelling 8
3. Switch-off Mechanism 10
3.1 Investigation 10
3.2 Whistle-Stop Technology 13
4. Material Selection 17
4.1 The “Dumb” Jug 17
4.2 The “Smart” Base 23
5. Overview of Eddy Kettle Operation 24
5.1 Schematic Flow Diagram 24
6. Life Cycle Assessment 25
6.1 Goal & Scope Definition 25
6.2 LCA Modelling 28
6.3 Life Cycle Impact Assessment 30
7. Discussion and Conclusion 33
8. References 34
9. Appendix 36

List of Tables & Figures
Name Description Page no.
Fig. 1.1.1 - Horseshoe heating element in a premium range kettle 1
Fig. 1.1.2 - Submerged heating element in a budget range kettle 1
Fig. 1.1.3 - Results from the electric kettle efficiency experiment 2
Table 1.2.1 - Short-Term Key Failure Points 3
Table 1.2.2 - Long-Term Key Failure Points 3
Fig. 2 - Cross-section of the Eddy Kettle induction heating components 4
Fig. 2.2.1 - Labeled experiment apparatus 6
Fig. 2.2.2 - Cross-section of experiment apparatus 6
Fig. 2.2.3 - The resulting graph from the induction heating experiment 7
Table 2.2.4 - table from the induction heating experiment 7
Fig. 2.3.1 - Cross-section trimetric and elevation views of CAD model 8
Fig. 2.3.2 - Graph showing the relationship between the number of turns and maximum temperature 9
Table 2.3.3 - The number of turns and corresponding wire diamete 9
Fig. 2.3.4 - Cross-section of simulation results with water in the vessel. 9
Fig. 2.3.5 - Cross-section of the simulation results with the jug isolated 10
Fig. 3.1.1 - Flow Chart of the infrared detection system 11
Fig. 3.1.2 - Flow Chart of the inductive detection system where “Z” is impedance 11
Fig. 3.1.3 - Flow Chart of the piezoelectric detection system where “V” is Volage 11
Fig. 3.1.4 - Piezoelectric experiment apparatus 12
Fig. 3.1.5 - Results from the piezoelectric experiment 12
Fig. 3.1.6 - Flow Chart of the whistle-stop detection system where “f” is frequency 13
Fig. 3.2.1 - Cross-section of a typical kettle whistle (Henrywood and Agarwal, 2013) 13
Fig. 3.2.2 - Sample sound spectra, taken from a whistle 14
Fig. 3.2.3 - A labelled cross-section of the whistles geometry 14
Table 3.2.4 - Data used in calculations 14
Fig. 3.2.5 - Cross-section view of CAD model 16
Fig. 3.2.6 - 3D printed whistle 16
Fig. 3.2.7 - A 3-second clip of the audio frequency spectrograph produced by the whistle 16
Fig. 4.1.1 - CES graph showing the range of material categories suitable for Option 1 18
Fig. 4.1.2 - CES graph showing the range of materials suitable for Option 1 19
Fig.4.1.3 - CES graph with new axes, note the underlined material - Porcelain 19
Fig. 4.1.4 - CES graph showing all suitable plastics 20
Fig. 4.1.5 - CES graph showing a range of PP compositions. 20
Table 4.1.6 - A comparison between Option 1 and Option 2 21
Fig. 4.1.7 - CES graph showing a range of suitable stainless steels 22
Fig. 4.1.8 - CES graph showing the thermal & electrical properties of AISI 429 22
Fig. 5.1 - Schematic flow diagram of the Eddy Kettle operation 24
Fig. 6 - The process in which this LCA will follow 25
Fig. 6.2.1 - System framework and boundary 29
Table 6.2.5 - The cradle to grave transport of all kettle 29
Table 6.2.6 - Electrical energy consumption data for the In Use stage 30
Fig. 6.3.1 - Comparison of the carbon footprint produced by each kettle over 12 years 30

1. Kettles In Use
It has been highlighted by numerous studies that the “In Use” stage of an electric kettle’s life
produces the most substantial environmental impact. Many studies quote from 80-92% of the
total environmental impact occur during this stage (Marcinkowski and Zych, 2017, WRAP 2009,
Gallego-Schmid et al., 2018). It is widely believed that the significant environmental impact
caused by this stage in life could be reduced by:
1. Increasing the heating efficiency of the electric kettle.
2. Increasing the durability by reducing points of failure.
3. Preventing users from filling unnecessary water into the vessel.
1.1 Heating Efficiency
Since the 1950’s, the heating method of an electric kettle has remained predominantly
unchanged. Nearly all electric kettles on the market utilise Joule heating (Ohmic Heating), but the
location of the heating element varies. In many “premium” range kettles, the horseshoe-like
heating element is welded to the base of the heating vessel (Figure 1.1). The majority of the heat is
then transferred through the conductive steel base and into the volume of water. This layout of
components is presumably to allow for easy cleaning of the vessel and eradicate the need for a
minimum fill line by covering a submerged element. In many “budget” range kettles, the heating
element is located within the heating chamber (Figure 1.2).
Fig. 1.1.1 - Horseshoe heating element in a Fig. 1.1.2 - Submerged heating element in a
premium range kettle
budget range kettle
Joule heating is an extremely efficient process, with virtually 100% of the electrical energy
transferred into heat energy. However, the location of the heating element in current electric kettle
design does not utilise this heating method to its full potential.
In the “premium” range of kettles, the location of the horseshoe element means that heat loss
occurs through convection to the air body around the base of the kettle and conduction to other
kettle components. In the “budget” range of kettles, the element is protruding from the wall on the
inside of the heating vessel. This location does not make optimum use of the convective currents
in the body of water.
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With this in mind, experiments were carried out on a range of kettles to determine their heating
efficiency. Each kettle was filled with 1 litre of water and boiled. A power meter was used to read
the power consumption of each kettle, and a stopwatch was used to record the heating period.
The body of water was at room temperature before each experiment, and the kettles were
assumed to reach 100°c at switch-off. The specific heat capacity of water was taken as 4185.5 J
kg-1 K-1.
Q Ou t = cΔT
(1)
Q in = pt
ϵ = Q Ou t
(2)
(3)
Q in
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By merely using the specific heat (1), power (2) and coefficient of performance (3) equations, the
efficiency of each kettle was calculated. The results of these experiments are shown in Figure 1.3
and Appendix B of this report.
Fig. 1.1.3 - Results from the electric kettle efficiency experiment
The results from this experiment show that the “budget” range kettle with a submerged element
was the most efficient at heating water to 100°c despite the fact it has the lowest power rating
(220kW compared to 280kW for every other kettle). Generally, the higher the power rating, the less
time it takes to transfer the heat to the water. This means that there are fewer losses in efficiency
through conduction to other kettle components and convection to air. As the element is
submerged in the volume of water, the efficiency of direct heat transfer is higher. Losses occur
due to the longer heating time; heat energy can dissipate through the body of the kettle.
This experiment outlined the importance of the location of the heating element when it comes to
designing for efficiency.
2 36

1.2 Points of failure
Poor design of multiple kettle components leads to a premature end of life. The average lifespan
of the electric kettle has been highlighted in multiple studies to be only between 3-5 years
(Marcinkowski and Zych, 2017, Gallego-Schmid et al., 2018, AEA Technology, 2008, WRAP, 2012).
It has been shown that by increasing the durability of a kettle and therefore increasing its lifespan
from 4 to 7 years can reduce the environmental impact by up to 5% (Marcinkowski and Zych,
2017).
WRAP 2013 gathered statistics from 7,904 kettles over a range of 19 brands to highlight the short
term and long term key failure points of electric kettles. This data has been formatted in Table
1.2.1 and Table 1.2.2.
Failure Point
Leaks from water level
window or at base.
Leaking spout
Will not switch off
Lid not closing or not
open-able
Table 1.2.1
Short-Term Key Failure Points
Driver
Design and method of connections
Plastic kettles that have separate
poorly attached spouts to bodies.
Failure to switch off at correct time
can be due to a variety of design
flaws
Poor design unsuitable choice of
materials voids in mouldings etc.
Failure Point
Elements failing
Plastic failures
On/off switch failure
Base and plug
electrical connection
Table 1.2.2
Long-Term Key Failure Points
Driver
Damage due to impact, oxidation/
corrosion, production faults causing
hotspots, deterioration of electrical
connection, scale build-up
Poor design and material choice.
Switch mechanism
Arcing occurs when kettle lifted
before power shuts off.
Too noisy
The noise level is affected by many
factors; power rating, scale build-up,
shape and surface of hotplate, etc.
It was noted that leaks from the vessel, failure of the lid mechanism and failure of the heating
system (both switch and heating element) were areas that required focus during the design
process. Increasing the durability of a kettle does, however, leave the product subject to other
reasons for disposal. With ever-changing fashion trends in the home, over a long time-period
aesthetic obsolescence of operational products is a notable contributor to a premature end of life.
Section 3 and 4 of this report highlight the reduced points of failure in the Eddy Kettle by replacing
the current heating system in a kettle with induction heating and “whistle-stop” technology.
1.3 Controlled Filling of the Chamber
The UK Energy Saving Trust published a report stating that if everyone in the UK only filled the
correct amount of water every time they filled the kettle, in one year, we would save enough
energy to power all the streetlights in the UK for 2 months (Energy Saving Trust, 2012). Other
studies have stated that by using an eco-kettle that ensures the correct amount of water needed
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is filled into the kettle every time, a 30% reduction in environmental impact can be made over its
entire life (Marcinkowski and Zych, 2017).
The 10 Page Summary in Appendix A highlights the primary design considerations to ensure
accurate filling.
2. Induction Heating
The Eddy Kettle gets its name from the novel application of induction heating included in the final
design. Induction heating is defined as the process of heating a ferromagnetic material by
electromagnetic induction. Induction heating is very efficient in the application of domestic
cooktops where efficiency can range from 0.84 to 0.94 (EPRI, 2014, Semiconductor Components
Industries, 2014, ). This is competitive with the average efficiency in electric kettles which was
investigated in Section 1.1 and determined to be approximately 0.84.
Fig. 2 - Cross-section of the Eddy Kettle induction heating components
The heating element of the Eddy Kettle is located inside of the PP container, held in place by an
insulating silicon composite. This position was chosen to maximise the heat transfer to the
volume of water and reduce inefficiencies caused by conduction and convection to the kettle's
environment.
2.1 Why Induction Heating?
The proposed operational design for the Eddy Kettle is shown in Figure 2.
Induction technology has been incorporated into the Eddy Kettle with the aim to:
1. Increase durability and therefore lifespan.
2. Promote circular economy and reduce aesthetic obsolescence.
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Increased Durability
A Preparatory Working Plan for establishing the next European Union eco-design regulation has
suggested that increasing the durability of electric kettles should be a focus for future eco-design
regulations (Fischer et al., 2014). Many induction cooktop manufacturers claim a lifespan of over
2,500 hours (Falcon, 2018). If an induction heated kettle is also granted the same lifespan and
was boiled for 10 minutes every day, the product could potentially last 41 years. However, it is
assumed that as the product is subject to high thermal and electrical cycling, the electronic
lifespan of the “smart” base is significantly lower. The defined lifespan is ultimately dependent on
the point which is most likely to fail. The design for disassembly highlighted in the 10 Page
Summary (Appendix A) ensures that the induction base is easily repaired should any failure of
electrical components occur.
By coupling induction heating with “whistle-stop” technology (discussed in Section 3.2), the
mechanical break point of the switch is removed. The switch is noted to be one of the most
common points of failure in electric kettles. WRAP 2013 reporting that 39% of product failure was
down to the switch or heating element (WRAP, 2013).
The Eddy Kettle vessel is designed to be manufactured from one piece of injection moulded
Polypropylene (PP), meaning that there are no seals that can fail and become points of leakage. It
was reported in WRAP 2013 that leaking through seals accounted for 22% of premature end of
life (WRAP, 2013).
Creating a Circular Economy
WRAP 2018 defines circular economy as “an alternative to linear economy (make, use, dispose) in
which we keep resources in use for as long as possible, extract the maximum value from them
whilst in use, then recover and regenerate products and materials at the end of each service
life” (Wrap.org.uk, 2018).
The inclusion of induction heating and whistle-stop technology in the Eddy Kettle design has
allowed for no electronic components in the jug assembly. Furthermore, the jug assembly is
primarily manufactured from recyclable materials (see Section 4.1), meaning the jug can be
replaced with minimal environmental impact. As the jug is designed for disassembly, as well as
having no electronic components, the ease of recycling is significantly increased compared to that
of a regular electric kettle.
2.2 Experimental Modelling
Physical proof of concept for the proposed induction heating method needed to be investigated.
An induction hob was disassembled and used to investigate the efficiency of the proposed Eddy
Kettle design.
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An experimental model was assembled based on the proposed heating method shown in Figure
2. The apparatus for this experiment can be seen in Figure 2.2.1. A power meter was used to
record the power input to the induction hob. The power input is considered to be directly related
to the inductance of the ferromagnetic heating element during the heating process.
Fig. 2.2.1 - Labeled experiment apparatus
An illustrated cross-section of the experiment set up is also visible in Figure 2.3.2. Note the
significant distance between the induction coil and the base of the ferromagnetic heating element.
Fig. 2.2.2 - Cross-section of experiment apparatus
The experiment was conducted using a similar method to that of the previous kettle efficiency
experiments in Section 1.1. The time, temperature change and power input were recorded (see
Table 2.2.4). The starting temperature was equal to that of the ambient temperature of the room at
the beginning of the experiment. The induction hob was set to maximum power and the
temperature recorded on the thermometer was noted every 20 seconds to produce the graph
shown in Figure 2.2.3. The experiment was brought to an end before the water reached boiling
point and the induction hob entered a state of intermittent heating. It is assumed that the
cooktop’s contact thermal readings on the base of the container prevented any further heating.
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The results from this experiment were exported to an Excel file where equations (1), (2) and (3)
were used to calculate the heating efficiency over a range of 19.8°c to 73.7°c. The efficiency
rating was calculated to be 0.76. Comparing this efficiency to that of the electric kettle
experiments in Section 1.1 (averaging at 0.84), there is an 8% difference.
90
80
70
Measurement
Table 2.2.4
Value
Temperature (c°)
60
50
40
30
20
10
Power (W) 1235
TStart (°c) 19.8
TEnd (°c) 73.7
Spicific Heat Capacity of
Water Jkg -1 K-1
4185.5
Time (s) 240
Ein (J) 296,400
Eout (J) 225,598
0
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320
Time (s)
Fig. 2.2.3 - The resulting graph from the induction heating experiment
This experiment outlined some interesting findings:
1. A (relatively) straight line graph indicates the losses from radiation to the surrounding were
negligible, even over the significant time period of heating.
2. Although the power rating of the hob is 22kW, the power input for the experiment was only
1.235kW. This was a result of the distance between the coil and conducting disk. The power
input from induction heating is directly related to the coil inductance. In this case, it is
assumed that the disk was outside the reach of many of the eddy currents generated by the
induction coil.
The efficiency rating of this experiment is not competitive with that of an electric kettle; however,
many uncontrollable factors are used in this “unrefined” experiment apparatus. More than
anything, this efficiency experiment shows “proof of concept”. Refinement in the component
layout should increase boiling efficiency significantly.
Should the Eddy Kettle concept be taken further, the refinement of the heating method is an
essential area needing to be addressed with more physical testing under laboratory conditions.
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2.3 Simulation Modelling
Methodology
A trial of the EMS add-in for Solidworks was obtained to simulate the steady-state and transient
temperature in the kettle. The main areas that were investigated using this finite element software
were;
1. Variance in steady state temperature with a fixed inner and outer coil diameter
2. The maximum temperature of the jug during the boiling process
First, the proposed heating system from Figure 2 was modelled in Solidworks (see Figure 2.2.3).
The EMS add-in was then opened, and the suitable material properties were applied to each
component. The material properties in this simulation were taken from Cambridge Engineering
Selector (CES). Table 2 in Appendix G shows the defined parameters of the simulation.
Fig. 2.3.1 - Cross-section trimetric and elevation views of CAD model
It was decided that simulating the system without a water body would not give an accurate
distribution of temperature in the Eddy Kettle. Although the convection current of water could not
be accurately simulated using the EMS software, a “water” body with the volume of 1 litre was
added to the inside of the vessel. This body was given properties that are considered to be similar
to that of water (see Appendix G, Table 3). The function of this mass was to absorb the heat
produced by the heating element to give a reasonably accurate indication of the system when
filled with water.
Results - Number of Turns in the Coil
The graph in Figure 3.3.2 was produced by varying the number of turns in the coil but keeping the
external and inner diameter constant throughout steady-state simulations (see Figure 1, Appendix
G). This experiment aimed to show that the output power of the induction heating can be adjusted
by varying the number of turns in the coil.
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An inner diameter of 30mm was used as this is a commonly found parameter in induction hobs
(Qiu et al., 2015). An outer diameter of 140mm was assigned to ensure the eddy currents
penetrated the entire heating element. The wire diameter relating to the number of turns in the coil
was then calculated.
Max Temperature of Kettle (°C)
250
230
210
190
170
150
24 25 26 27 28 29 30
Number of Turns in the Coil
Table 2.3.3 - The number of turns
and corresponding wire diameter
Number of turns
Approximate Wire
Diameter (mm)
24 2.29
25 2.20
26 2.12
27 2.05
28 1.96
29 1.90
30 1.83
Fig. 2.3.2 - Graph showing the relationship between
the number of turns and maximum temperature
As expected, the increase in inductance that is associated with a higher number of turns also
translates to a rise in maximum temperature in steady state. This result confirms that the diameter
of the coil and therefore “smart” base unit can remain fixed throughout laboratory testing.
Experimentation with the number of turns in the coil can be conducted to determine the optimum
heating system.
Maximum Temperature of the Jug During Heating
The experiment was run in a transient set up with the selected coil to inspect the temperature of
the PP jug at an approximate boiling point. Figure 2.3.4 and Figure 2.3.5 were produced at a time
step of 160s when a large quantity of the water body was noted to be over 100°C. It was
assumed that if the software could accurately simulate the convective currents produced in water;
this would be the approximate boiling point.
Fig. 2.3.4 - Cross-section of simulation results with water in the vessel.
Note a maximum temperature of 109.6°C obtained by the heating element.
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Fig. 2.3.5 - Cross-section of the simulation results with the jug isolated.
Note a max temperature of 93.75°C obtained on the base of the container.
The results in Figure 2.3.4 and Figure 2.3.5 show the silicon component was effective in insulating
the PP container from the heat generated by the stainless steel heating element. The maximum
temperature of the jug is 93.75°C which is within the working temperature of PP (102-120°C)
outlined in Section 4.1 of this report. Given that this is the boiling point of the water, the system
will switch off and the PP container will not be subjected to any further heating. Further physical
lab testing and analysis on the final Eddy Kettle design is needed to determine the accuracy of
these results.
3. Switch-off Mechanism
The challenge associated with the stopping mechanism was to identify when the water inside the
vessel reaches boiling point without including electronic components in the jug. Rapid detection
of the water boiling point has been highlighted as a pivotal area to reduce the environmental
impact of the In-Use stage in a kettles’ life (Marcinkowski and Zych, 2017).
3.1 Investigation
Many solutions were investigated for the switch-off mechanism of the boiling process. This
section contains a brief overview of the investigation into the following methods of detection:
1. Infrared Detection
2. Inductive Sensor Temperature Measurement
3. Piezoelectric Vibration Sensor
Infrared Detection
Many induction cooktops use infrared sensors located under the ceramic glass to detect the
temperature of the underside of the pot. Utilising this detection method, the temperature of the
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ase of the jug could be detected. It could then be assumed that when the bottom of the jug
reaches 100°c, the water inside the chamber is at boiling point.
Induction
heating
Read infrared
sensor
TJug ≥100°c
Fig. 3.1.1 - Flow Chart of the infrared detection system
No
Yes
End heating
process
This method was rejected as it did not allow for accurate detection of the water temperature and
therefore would decrease efficiency. However, an infrared sensor is included in the final design to
act as a boil-dry safety switch (see Section 5).
Inductive Sensor Temperature Measurement
A recent study on the application of inductive heat sensors in induction cooktops has suggested
that the temperature of the ferromagnetic material could be detected by measuring the
impedance variation in the material (Franco et al., 2012). This sensing method is based on the
dependence of the electrical conductivity of the ferromagnetic disk with respect to its
temperature.
Induction
heating
Read
impedance
ZDisk ≥ ZThreshold
Fig. 3.1.2 - Flow Chart of the inductive detection system where “Z” is impedance
No
Yes
End heating
process
This method of boil detection was rejected, as the temperature detected from the ferromagnetic
disk does not necessarily correspond to the bulk temperature of the water. There are also issues
with the accuracy of the sensor. This method of temperature sensing has proven to be accurate
within a range of 20-220°c with an error lower than 6°c. Should a 6% overshoot of boiling
temperature occur (106°c), the efficiency of the kettle is significantly reduced. Should a 6%
undershoot of the boiling temperature occur (94°c), the kettle has not fulfilled its primary function
of boiling water.
Piezoelectric Vibration Sensor
During the boiling cycle, the element of the kettle rises to extremely high temperatures and a film
of vapour is formed on the element’s surface. Eventually, this layer detaches to rise through the
cooler water as vapour bubbles. These vapour bubbles collapse before reaching the surface due
to temperature differences in the water. As these bubbles implode, they create shockwaves of
sound. This process is called cavitation (Caupin and Herbert, 2006). As the entire volume of water
increases in temperature, the vapour bubbles rise higher and produce more aggressive
implosions.
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Induction
heating
Read
Piezo Voltage
VPiezo ≥ VThreshold
Fig. 3.1.3 - Flow Chart of the piezoelectric detection system where “V” is Voltage
No
Yes
End heating
process
A piezoelectric vibration sensor could be installed in the base of the kettle to detect these
“aggressive” implosions at boiling point. This sensor would have to be calibrated to determine the
expected vibration of different water volumes. A prototype of this boil detection method was
programmed on an Arduino Uno board and tests were conducted on the Phillips HD4644 electric
kettle (Figure 3.1.4). The force of the vibration was indirectly measured by the potential across the
piezoelectric. The resulting graph in Figure 3.1.5 was produced from this experiment.
Fig. 3.1.4 - Piezoelectric experiment apparatus
Fig. 3.1.5 - Results from the piezoelectric experiment
Although Figure 3.1.5 shows that a significant increase in potential difference was detected
around the electric kettles “switch-off point”, there were a range of concerns surrounding the
accuracy of boil detection;
1. Spikes in the graph, as labelled in Figure 3.1.5, before reaching boiling point may cause early
switch-off; therefore, the kettle will not complete its primary function of boiling water.
2. Implementation of a weight sensor may be needed in the base of the Eddy Kettle to couple
with the piezoelectric for increased accuracy in boil detection. This way the volume of the
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water is known and the calibrated piezoelectric has predetermined voltage “peaks” to detect
for switch off.
3. The largest concern is switch-off cause by vibrations outside the Eddy Kettle system. For
example, if a washing machine was on and the Eddy Kettle was sitting on the counter above
it, vibrations from the environment may effect the Eddy Kettle operation.
3.2 Whistle-Stop Technology
Audio detection of the frequency produced by a whistle at boiling point was selected as the ideal
solution for the final design of the Eddy Kettle. The classic stove-top kettle has used a whistle to
notify users when water is boiling for over 100 years. It has already proven to work well at
identifying the boiling point of water.
A frequency detecting microphone is integrated into in the “smart” base of the Eddy Kettle. The
microphone becomes active as the heating process is initiated. The microphone is listening to
detect the predetermined frequency which is emitted from the whistle at boiling point. Once
detected, the heating process is terminated.
Induction
heating
Read
microphone
frequency
fDetected ≈ fSwitchOff
Fig. 3.1.6 - Flow Chart of the whistle-stop detection system where “f” is frequency
No
Yes
End heating
process
Theory
A study conducted in 2013 on the aeroacoustics of steam kettles concludes that whistle kettles
produce up to 3 distinct frequencies as the water reaches boiling point (Henrywood and Agarwal,
2013).
The basic geometry of a kettle whistle consists of two offset stainless steel plates creating a
cavity. Each disk has a hole in the centre for the flow of steam to pass through. The whistling
sound is generated from the vortices radiating at the frequency of sound as the steam leaves the
spout. Resonance within the spout can also produce a distinct frequency depending on the length
and diameter. Figure 3.2.1 illustrates how these frequencies are produced in the whistle and
spout.
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Fig. 3.2.1 - Cross-section of a typical kettle whistle (Henrywood and Agarwal, 2013)
Figure 3.2.2 shows sample sound spectra detected as the kettle whistles. The pure whistle tone
can be identified at 1716Hz with a smaller harmonic occurring at 3434Hz. The whistle for the Eddy
Kettle should be designed to give off a similar distinct tone to be detected by the microphone in
the base.
Fig. 3.2.2 - Sample sound spectra, taken from a whistle.
The peak frequency is f=1716Hz, the frequency of the 1st harmonic is 3434 Hz.
(Henrywood and Agarwal, 2013)
Defining the Whistle Geometry
The approach used in Henrywood and Agarwal, 2013, where the whistle tone was calculated
analytically to an error of 1.2%, was used to determine the geometry of the Eddy Kettle whistle.
Initially, some constraints need to be defined to ensure enough constants for accurate
calculations. As we are not concerned with generating resonance within the kettles spout, the
diameter of this feature is fixed at 25mm. The final spout design was chosen through user testing
the pouring stream from the jug. The orifice diameter ( δ ) is fixed at 3mm, and the flow has an
assumed Reynolds Number (Re) of ~2400. All relevant data used in the calculations can be seen
in Table 3.2.4. As the Mach number of the flow is assumed to be negligible, the effective neck
length of 1.5mm was used.
f
The target frequency ( ) for detection was determined to be 1,568Hz. This specific frequency was
selected as it is outside the range of human speech and many musical instruments (including a
Page 14 of 36

Table 3.2.4 Data used in calculations
Property Symbol Value
Diameter of Chamber
Orifice Diameter
Speed of Sound
Traget Frequency
Effective Neck Length
D
δ
c 0
f
l
25mm
3mm
340m/s
1,568Hz
1.5mm
Fig. 3.2.3 - A labelled cross-section of the
whistles geometry
piano), yet the note produced is a “G” on the musical scale (Home.tir.com, 2018 ). By using the
equation;
ω o = 2π f
(4)
the required Helmholtz angular frequency of the system can be defined as;
ω o = 3136π
.
As shown in Henrywood and Agarwal, 2013, the whistle can be modelled by a Helmholtz
resonator mechanism. The resonant frequency for a Helmholtz resonator is defined by the
equation;
ω o = C 0
A
Vl
.
(5)
Where the A is the cross-sectional area of the neck opening;
A = πδ2
4
(6)
and V is the volume of the whistle cavity;
V = πD2 h
4
.
(7)
We can then substitute equations (4), (6) and (7) into equation (5) and rearrange to solve for h;
Page 15 of 36

h =
1 C o δ
D 2 l * ( 2π f )
2
.
(8)
Using the data provided in Table 3.2.4, the height of the chamber was calculated as;
h = 11.4mm
.
Physical Testing
The defined whistle geometry was prototyped by generating a CAD model and 3D printing using
Polylactic Acid (PLA) filament (Figure 3.2.5 and Figure 3.2.6).
Fig. 3.2.5 - Cross-section view of CAD model
Fig. 3.2.6 - 3D printed whistle
The whistle was then tested by attaching it the end of a stove-top kettle and boiling the water
inside the chamber. The audio frequency produced at boiling point was recorded using the
microphone on a mobile phone. An audio frequency spectrograph was then generated to show
the distribution of frequency with respect to time (Figure 3.2.7).
Fig. 3.2.7 - A 3-second clip of the audio frequency spectrograph produced by the whistle.
Note the resonant frequency at ~ 1,568Hz and the weaker harmonics detected at around 2.3kHz
(~5π*1,568Hz) and 4.4kHz (~π*1,568Hz).
Figure 3.2.7 shows a distinct frequency was detected between 1.4Hz and 1.6kHz. Inaccuracies in
the whistle 3D printing, assembly and deformation when, exposed to steam, are considered to be
the primary sources of error in the results.
Page 16 of 36

The results of this experiment indicate that one primary and 2 secondary whistle frequencies
could be detected by the microphone to terminate the system. For example, If the whistle that
produced the spectrum in Figure 3.2.7 was used in the final design, the microphone would initially
search for a frequency between 1.4-1.5kHz and then confirm the signal is, in fact, the kettle's
whistle by detecting a matching harmonic of ~2.3kHz or ~4.4kHz before switch-off.
Notes for Further Testing
The frequency produced by the whistle is dependent on the Mach number of the flow at the
whistles exit (
). The Mach number determines the effective neck length in the model. The
effective neck length of 1.5mm was used as it was in line with the calculations used in Henrywood
and Agarwal, 2013. However, the flow rate and therefore Mach number will depend on the
geometry of the boiling chamber. Therefore further testing on a physical model of the Eddy Kettle
is needed to determine the exact whistle geometry.
M e
Page of
4. Material Selection
Material choice is crucial when it comes to designing a more sustainable kettle. The choice of
materials will determine the environmental impact during every stage of the product’s lifecycle.
Some properties that significantly affect the environmental impact of each stage are highlighted
below.
• Manufacture - Embodied energy, manufacturing process, joining processes etc.
• Transport - Density and volume
• In Use - Thermal properties (conductivity of heating & insulating components) and durability
• Disposal - Recyclability / downcycle-ability, toxicity
These properties have been considered in the design of essential structural and operational
components in the Eddy Kettle. Cambridge Engineering Selector (CES) was utilised in the
selection process of all components in this section. CES data sheets of all materials investigated
are available to view in Appendix D of this report.
4.1 The “Dumb” Jug
This section will outline the material selection process for the jug assembly of the Eddy Kettle;
1. The vessel
2. The heating element/disk
3. The handle
17 36

The whistle and lid were excluded from this investigation as they are relatively small components
and their materials depend on the selected material of the vessel component.
The Vessel
The function of the vessel is to store and insulate the body of water during the boiling process. It
will therefore also have to withstand high temperatures and thermal loading from the heating
element. The ideal properties of the vessel, in order of importance, are:
1. Food safe
2. Corrosion resistance - Freshwater
3. BPA free
4. Low cost
5. Young’s modulus - High
6. Specific heat capacity - High
7. Recyclable
8. CO2 emissions in primary production - Low
9. Ease of manufacture
10. Embodied energy - Low
With all these properties considered, a CES file was generated to limit the material properties. It
became apparent that there was a significant trade-off between recyclable materials and materials
which could stand high thermal loading. A decision had to be made between two material
options:
Option 1 - use a material with properties that allow for high thermal loading.
Option 2 - use a recyclable plastic for the vessel and add an extra component to insulate the
thermal loading from the heating element.
Option 1 was initially investigated to determine the optimum plastic for the given application. By
plotting the results from CES, “CO2 footprint in primary production” vs “Thermal conductivity”,
Figure 4.1.1 was produced to highlight the suitable material categories. Many of the Non-technical
Ceramics were excluded from the results as they were traditionally used as building materials, for
example; brick and cement. The remaining materials are shown in Figure 4.1.2.
Page 18 of 36

Fig. 4.1.1 - CES graph showing the range of material categories suitable for Option 1
Fig. 4.1.2 - CES graph showing the range of materials suitable for Option 1
From this graph, the manufacture methods of some glass materials such as Borosilicate and
Glass Ceramic 9608 were investigated to determine their “formability” and suitability for batch
production. The materials from this graph were then exported into another CES graph (Figure
4.1.3) showing the “CO2 footprint in primary production” vs “Price”.
Fig.4.1.3 - CES graph with new axes, note the underlined material - Porcelain
Page 19 of 36

From the results shown in Figure 4.1.2 and Figure 4 .1.3, porcelain was considered a suitable
material based on ease of manufacturing and the use of the material in similar applications such
as teapots. In many cases, porcelain can be injection moulded, making it a suitable material for
batch production (Santacruz et al., 2003). Although porcelain is not recyclable, it can be
downcycled and ground up for use in the construction industry. However, a “send-back” scheme
would need to be implemented as this form of downcycling is not common in recycling plants. An
argument could be made that if the container was manufactured from high-quality porcelain, the
user might inherently treat the jug as a "more valuable" item, prolonging the life of the jug.
Selecting porcelain also lends the jug to a secondary function as a teapot when the water is
boiled.
Option 2 was then investigated in CES. The maximum operating temperature in the CES study
was reduced, and thermoplastic polymers were selected. This produced the graph shown in
Figure 4.1.4.
Fig. 4.1.4 - CES graph showing all suitable plastics.
Note how the suitable plastics compare to the highlight material; porcelain
As shown in Figure 4.1.4, a wide range of plastics with similar properties and could be applied in
the vessel design. However, recyclable thermoplastics have been utilised in the design of kettles
for many years. These include:
• Polypropylene (PP)
• Polyoxymethylene (POM)
Out of the two materials, PP has the lower recycling code (PP-5 vs POM-7) and embodied energy.
Therefore PP is the plastic of choice to achieve a more sustainable product. PP (homopolymer,
flame retarded HB) was selected at the most suitable PP composition for its high maximum
working temperature, low thermal conductivity and fire retardant properties (Figure 4.1.5).
Page 20 of 36

Fig. 4.1.5 - CES graph showing a range of PP compositions.
note the highlighted material of choice
A suitable material for the insulating the heating element in option 2 also had to be determined.
This component must have a high specific heat capacity (be thermally insulating), food safe and
have a high working temperature. Based on these properties, Silicon (VMQ, heat cured,10-30%
fumed silica) was selected as it is widely available for manufacture and used in thermal insulating
and food save environments (see Appendix D).
Option 1 and Option 2 were then compared in Table 4.1.6.
Table 4.1.6 - A comparison between Option 1 and Option 2,
Property Option 1 - Porcelain Option 2 - Polypropylene
Recyclable at End of Life No Yes
Max service temperature 680°c 120°c
Specific heat capacity 365J/kg.°c 1500J/kg.°c
Embodied energy (primary production) 40MJ/kg 50MJ/kg
Need for additional components Possibly Yes
Suitability for batch manufacture Not Ideal Yes
Density (effecting transport stage of life) 2300kg/m^3 1240kg/m^3
The values highlighted in Table 5.1.6 are determined the more desirable for the given application.
Option 2 was selected as the ideal material as PP is better suited to large batch manufacture and
the material is expected to have an overall lower environmental impact.
The Heating Element/Disk
A suitable material for the heating element also had to be selected. This component must be
ferromagnetic to conduct the eddy currents produced by the induction coil. The ideal properties
of this component are:
• High thermal conductivity
Page 21 of 36

• High electrical conductivity (Qiu et al., 2015)
• Corrosion resistant - freshwater
• Low cost
• Recyclable
The following CES graphs were produced to investigate the best balance of properties.
Fig. 4.1.7 - CES graph showing a range of suitable stainless steels
and the selected AISI 429 highlighted
Fig. 4.1.8 - CES graph showing the thermal & electrical properties of AISI 429
in comparison to other stainless steels
From these graphs, Stainless Steel AISI 429 Annealed was selected as it proved to have the best
balance of all necessary properties combined with a relatively low environmental impact. AISI 429
is currently used in the processing of potentially corrosive liquids, such as beverages and
chemicals.
The Handle
A wooden handle was incorporated into the design after some very positive user testing. As one
of the main touch points of the kettle, the material choice is based more on the aesthetics,
Page 22 of 36

durability and user ergonomics rather than environmental impact. The wooden handle is
removable; therefore its life could surpass the life of the PP jug container and be attached to
future jug designs.
Bamboo was initially investigated for the manufacture of the jugs handle as it is considered to be
a sustainable fast-growing plant. Although it is not technically wood, bamboo is extremely
lightweight and robust substitute. However, increased transport emissions and processing to
produce bamboo board suitable for manufacture makes the material less than ideal.
Typically, hardwoods are more suited to applications that require durability as they have a tighter
grain. Although processing hardwoods is considered to have a higher environmental impact than
softwoods, by including a hardwood timber the handle is guaranteed to have a prolonged
lifecycle. Native hardwood timbers to where the Eddy Kettle is manufactured are ideal to prevent
emissions in the transport of timber. Should the kettle be produced in the UK, maple and ash are
determined to be suitable timbers based on their strength and “neutral” light-coloured aesthetic.
Ideally, to minimise environmental impact, the material should be sourced from naturally fallen and
air-seasoned timber. However is this unlikely to source for large-scale batch production.
4.2 The “Smart” Base
The lifecycle of the induction base is considerably longer than that of the jug; therefore durability,
ease of manufacture and disassembly are the primary considerations for this component.
Structural Components
The structural components are intended to be manufactured from the same polypropylene
composition (PP homopolymer, fire retarded HB) as that found in the jug design for the following
reasons:
1. The colour & surface finish of both the jug and base components is easier to match.
2. PP is widely used in snap-fit components, which is ideal in design for disassembly.
3. The PP composition could be purchased in greater quantity, potentially reducing the
manufacturing cost.
Other Components
All other components in the smart base assembly are scaled versions of existing operational
induction cooktop components. Therefore the material choice should remain the same;
1. Ceramic/Glass surface - Fused silica/quartz
2. Induction pancake coil - Copper
3. Flux concentrators - Iron
Page 23 of 36

5. Overview of Eddy Kettle Operation
5.1 Schematic Flow Diagram
Fig. 5.1 - Schematic flow diagram of the Eddy Kettle operation
with numbered switch-off mechanisms
A schematic flow diagram of the kettle operation can be seen in Figure 5.1. The diagram has two
main operational subsystems; Jug Detection and Heating Process. After interaction with the
button, four mechanisms can cause the system to terminate. These mechanisms have been
divided into their relative subsystem and highlighted below.
Jug Detection
1. To prevent switch-on of the smart base when the jug is not docked, an inductance sensor has
been incorporated into the base design. This inductance sensor detects when current is
drawn from the coil to excite the ferromagnetic disk. Induction cooktops utilise this technology
as a safety feature, even in the most basic models.
Heating Process
2. Once the heating process has begun, the inductance sensor is used to detect when the jug
has been removed from the base before the water reaches boiling point.
Page 24 of 36

3. An infrared sensor is used to detect the temperature of the underside of the jug during the
heating process. This feature is commonly found in domestic induction hobs where it is used
for temperature control with an error of less than 5°C (Lasobras et al., 2014). The function of
this sensor is to prevent overheating of the PP jug during the heating process. The given
maximum working temperature for the PP jug is assumed to be 120°C; the maximum
achievable working temperature for the selected PP. Should the infrared sensor detect a
temperature of 105°C (within an error range of 100-110°c); the heating process is terminated
to prevent degradation of the PP component. This feature is considered a “boil-dry” safety
feature that switches off the kettle when whistle-stop fails. For example, whistle-stop cannot
work as a detection method where there is no water in the vessel or the whistle has been
removed.
4. As discussed in Section 3.2, whistle-stop is the boil detection and switch-off method in the
Eddy Kettle.
6. Life Cycle Assessment
It is the role of a designer to consider the life cycle and potential environmental impact of
consumer products before production. The designer determines the raw materials, manufacturing
process, how the product is intended to be used and considerations for end of life disposal. With
the development of new European legislation and eco-friendly consumer trends, the responsibility
of a designer has become the most important from a sustainability standpoint.
The following life cycle assessment (LCA) of the Eddy Kettle has been conducted in accordance
with ISO 14040/44 guidelines (ISO, 2006a, 2006b). Although lifecycle consideration has
significantly influenced the design of the Eddy Kettle, this report will be conducted as a linear
process, highlighted in Figure. 6.1.
Goal & Scope Definition
Inventory Analysis
Impact Assessment
Interpretation
Fig. 6 - The process in which this LCA will follow
6.1 Goal & Scope Definition
The primary objective of this LCA is to evaluate the effectiveness of the Eddy Kettle in reducing
the environmental impact of an electric kettle. For this reason, two other electric kettles are
included in this LCA to compare environmental impact during each stage of the product’s life.
Page 25 of 36

All stages in the kettles life, excluding the In Use phase, uses information gathered from the Eco-
Audit tool in Cambridge Engineering Selector (CES). This feature in CES is limited in its
assessment scope as it does not take into account solid, waterborne or raw emissions. However,
this software is designed to give accurate CO2 footprint and energy consumption data. Production
of CO2 is considered to have the most significant environmental impact during the life of a kettle
(Gallego-Schmid et al., 2018). This CO2 footprint is used as an overall environmental impact
indicator for the given kettles.
Through using the Eco-Audit tool and hand calculations, the following activities and processes
have been assessed:
1. Raw material production - production processes of metals, alloys, plastics, ceramics, etc.
2. Primary production manufacturing processes - impact of the product manufacture.
3. Lifetime Transport - transport of materials to manufacturing facilities, the product to retailers
and waste disposal at the end of life.
4. Product in use energy consumption
5. Waste disposal
6. End of life potential - end of life savings that can be realised in future life cycles by recovered
materials or components.
As all the kettles are assumed to come in similar packaging, the production and disposal of all
packaging has been excluded from this report. The volume of all kettle packaging is also
considered to be similar; therefore the carbon footprint produced by the transport stage of the
kettles life is directly proportional to the products mass.
Functional Unit
The functional unit of this LCA is defined as:
“Use of a kettle to boil 540 litres of water annually over a period of 12 years in a UK
household.”
A breakdown of the functional unit is given below.
“Use of a kettle”
All products compared in this LCA are kettles. However, they are recognised to have considerably
different expected lifespans. It is assumed that the user replaces their kettle every time it reaches
its expected end of life; 4 years for electric kettles and 12 for the Eddy Kettle.
Page 26 of 36

“to boil”
The primary function of domestic kettles is to boil water. However, there are some digital kettles
on the market that allow users to heat water to temperatures from 70-100°c. For this LCA study,
only kettles that boil water are considered.
“598 litres of water annually”
The defined water volume in the functional unit is based on the specification provided in Gallego-
Schmid et al., 2018. In this study, a sensitivity analysis was conducted on a volume of 1028L
boiled annually used in a range of European studies (Fischer et al., 2014, AEA tech., 2008, Carbon
Footprint, 2016). This number was adjusted to include only UK households. The user of the Eddy
kettle is assumed to fill the correct amount of water into the jug every time; whereas, a 40%
overfilling of both electric kettles is included to produce the figure of 837L/yr (598L plus 239L, for
the 40% extra water). A figure of 50% overfilling is most commonly assumed in kettle LCA studies
(Fischer et al., 2014, AEA tech., 2008, Carbon Footprint, 2016). However, a study in the
Netherlands, based on data gathered from 2,454 users showed that the figure was closer to 40%
(Foekema et al., 2008).
From conducting an experiment where users were asked to fill a given amount of cups into both
the prototyped Eddy Kettle jug and a standard electric kettle, it was found that users overfilled by
up to 33% (filling 4 cups when asked to fill 3) into the electric kettle. Although, it must be noted
that users were asked to fill a certain quantity of water. When these users fill the kettle
subconsciously, they may not be considering the level of water. From the upright standing
position, the location of water level indicators on electric kettles is not immediately visible. For the
Eddy Kettle, it is assumed that the location of the water level indicators raises awareness of the
volume of water filling into the vessel as it is being filled (see Appendix A).
“over a period of 12 years”
Many studies conducted on the electric kettle use estimated lifetimes between three and five
years (AEA tech., 2008, Cox et al., 2013, Defra, 2009, Gallego-Schmid et al., 2018, Marcinkowski
and Zych, 2017). In this LCA, an expected lifetime of 4 years has been used for both electric
kettles. Therefore, over the 12 year period, a user must replace their kettle twice, leading to a
significantly higher impact in the manufacture and disposal stages of the products life.
As commercial induction hobs have a lifespan of over 2,500 hours (Falcon, 2018), it is assumed
that the induction technology in the “smart” base has a functional life of over 12 years
(approximately 730hours of use if used daily for 10minutes).
“in UK households”
Over 95% of the 28.1 million households in the UK have an electric kettle, making it a suitable
geographical location for the potential user (AEA Technology, 2008).
Page 27 of 36

6.2 LCA Modelling
Assumptions
As the Eddy Kettle is not currently in production, some assumptions must be used for the basis of
this report.
Although the efficiency used in this LCA will affect the result of the model significantly, the defined
efficiency of the fully developed Eddy Kettle is difficult to determine without continuous
development and lab testing. Multiple studies conclude that induction cooktops are between
0.84-0.90 efficient when coupled with a ferromagnetic pot (EPRI, 2014, Semiconductor
Components Industries, 2014). An “unrefined” experiment in section 2.2 was also carried out to
determine an efficiency rating of 0.76. It is assumed that with further design refinement, the
efficiency of the Eddy Kettle will match the average efficiency of electric kettles on the market.
Therefore, the efficiency of all kettles compared in this LCA is 0.84.
All materials and components are assumed to be sourced and manufactured within a 150km
range of Shanghai, China. This location was selected as many consumer electronic products sold
in the UK are manufactured and exported through the Port of Shanghai. In reality, this may not be
the chosen location for the manufacture of the Eddy Kettle. However, to accurately compare the
impact of the Eddy Kettle to the other selected kettles, it is assumed they are all manufactured in
the same facility.
It is assumed that because stainless steel and polypropylene are widely recycled; 50% of
stainless steel and polypropylene components in each kettles inventory is manufactured using
virgin materials.
As the Eco-Audit tool in CES has a limited range of materials and only considers primary
manufacturing methods, in some cases component materials & manufacturing methods have
been approximated. The manufacturing stage of the LCA is expected to have a much lower
impact in comparison to the use stage; therefore, these approximations should not make a
significant change to the results.
Page 28 of 36

System Framework
Inputs
Raw Materials
Energy
System Boundary
Manufacture
Transport
Use
Waste Disposal
End of Life Potential
Co 2 Emissions
Outputs
Fig. 6.2.1 - System framework and boundary
Materials & Manufacture
Appendix E of this report contains the full LCA inventory of the selected kettles. The mass of each
part was calculated using the material density in CES and the volume of the CAD part in
Fusion360. The mass of the electronic subassembly components (resistors, diodes, capacitors,
transformers, LED) were estimated based on a previously published study focusing on the LCA of
a domestic induction hob electronic board (Pina et al., 2015).
The LCA inventories of the two other electric kettles (K1 and K2) were taken from previously
published papers; Marcinkowski and Zych, 2017, Gallego-Schmid et al., 2018, where the
environmental impact of plastic electric kettles was investigated. As the Eddy Kettle jug is
considered to be replaceable at a low cost, the selected kettles are considered to be market
competitors.
Transport
The “cradle to grave” transport of all kettles is outlined in Table 6.2.5. Any user transport is
excluded from this report as there is much uncertainty related to consumer behaviour and
allocation of impacts to the kettle in relation to other products purchased at the same time. This
method is in line with the approach found in PAS 2050 standard (BSI, 2011).
Table 6.2.5 - The cradle to grave transport of all kettle
From To Method of Transport Distance (km)
Raw material source Shanghai Manufacturing Centre 32 tonne truck 150
Shanghai Manufacturing Centre Port of Shanghai 32 tonne truck 150
Port of Shanghai Felixstowe Port Sea freight 22,051
Felixstowe Port London Distribution Centre 32 tonne truck 150
London Distribution Centre Retailer 14 tonne truck 200
End of Life Disposal Facility 14 tonne truck 100
Total 22,801
Page 29 of 36

In Use
The data from Table 6.2.6 was used to calculate the annual energy consumption of the kettles.
Table 6.2.6 - Electrical energy consumption data for the In Use stage
Model
Change in
Specific Heat
1/ Kettle
Temperature Volume Boiled
of Water
Efficiency
of Water (L/yr)
(J/(kg⋅K))
(1/Ɛ)
(°c)
Eddy Kettle 4185.5 80 598 1.19047619
Electric Kettles 4185.5 80 837 1.19047619
Equation 9 was then used to calculate the annual energy consumption in Joules;
E annu al = qm(δT )
ϵ
.
(9)
The mass of CO2 released into the atmosphere per Joule of national grid energy in the UK is
1.07E-07 kg/J (Carbon Footprint Ltd, 2018). This figure is represented by the constant; , in
Equation 10. The mass of CO2 released annually was then calculated by the equation;
f
m CO2 = f E Annu al
.
(10)
6.3 Life Cycle Impact Assessment
The carbon footprint of all kettles over a 12 year period is shown in Figure 6.3.1. The CES
datasheets produced along with further tables and graphs can be found in Appendix D and
Appendix F.
Eddy K1 K2
440.00
410.00
380.00
350.00
320.00
290.00
CO2 Footprint (kg)
260.00
230.00
200.00
170.00
140.00
110.00
80.00
50.00
20.00
-10.00
Materials Manufacture Transport In Use Waste Disposal End of Life Potential
Fig. 6.3.1 - Comparison of the carbon footprint produced by each kettle over 12 years
Page 30 of 36

Result Validation
As expected, the majority of the environmental impact of each kettle occurs during the In Use
stage of its life. The impact percentages calculated for the 4-year lifecycle were compared to the
source study of the LCA inventory for K2. The study concluded that 92% of the environmental
impact in a kettles life is during the In Use stage, whereas a value of 95% was concluded in this
LCA (Marcinkowski and Zych, 2017). The percentage impact of both K1 (96.4%) and K2 (95%) are
slightly higher than other LCA studies conducted over 4-5 years that quote an impact of 84-93%
(AEA tech., 2008, Cox et al., 2013, Defra, 2009, Gallego-Schmid et al., 2018). However, the
environmental impact of the listed studies also consider solid and waterborne emissions which
play a significant part in the production of materials and manufacture.
4 Years
Over the expected lifespan of an electric kettle, the Eddy Kettle proves to reduce the total CO2
footprint by 25% in comparison to K1 and K2 (Appendix F; Figure 1). Although the Materials,
Manufacturing and Transport stages of the Eddy Kettle life are significantly higher, they are shown
to only account for 10.6kg compared to the 102kg of CO2 produced during the In Use stage (less
than 10% of the total carbon footprint). This is due to the high usage of the kettle throughout the
four years and the relatively high amount of energy needed to boil water. In the, near impossible
scenario, that the Eddy Kettle was to achieve 100% efficiency, the In Use energy consumption
would still be a substantial 88% of the total carbon footprint.
12 Years
As both K1 and K2 are expected to be replaced twice over the 12 year period, the CO2 footprint in
the Materials, Manufacture and Transport has increased threefold, significantly surpassing the
same stage impact of the Eddy Kettle. The Eddy Kettle to electric kettle ratio of In-Use carbon
footprint remains unchanged over the 12 years as there is assumed to be no change in efficiency.
The End of Life Potential (EoLP) for the Eddy kettle is still competitive with that of K1 and K2, even
though both electric kettles have been replaced twice (1.71kg in CO2 saved vs 0.79kg and 3.16kg
for K1 and K2 respectively). This shows that the circular economy design of the Eddy Kettle is
effective in significantly increasing the EoLP. However, over a 12-year lifecycle, the EoLP is
negligible compared to the total carbon footprint produced (0.5%).
Over 12 years, the Eddy Kettle has a 30% lower CO2 footprint compared to K2. To put this saving
into context, if 10,000 homes were to use the Eddy Kettle rather than an electric kettle for 12
years, they would save 1,187tonnes of CO2 released into the atmosphere
(135kg_in_savings*10,000). This is the equivalent to taking 289 passenger vehicles off the road for
a year (US EPA, 2018).
Page 31 of 36

Sensitivity Analysis
A sensitivity analysis was carried out to assess the carbon footprint of the kettles if different
parameters were used in the LCA.
If a yearly consumption of 365 litres of water was used in the LCA (1 litre per day for 12 years),
there is a carbon saving of over 31.3% in using the Eddy Kettle compared to K2 (see Appendix F;
Figure 2). This showed that the volume of water boiled doesn't significantly change the savings in
CO2 produced. A 61% reduction in water volume only results in a 3% increase in carbon savings.
The increase in savings indicates that the materials, manufacture and transport are more effective
in reducing the carbon emissions with lower volumes of water.
If the “unrefined” experiment conducted in section 2.2 of this report was accurate in determining
the efficiency of the Eddy Kettle; 0.76, the carbon footprint savings are reduced from 28% to
22.5% (see Appendix F; Figure 3). This shows that increasing the efficiency of the kettle design is
not nearly as effective as filling the correct amount of water into the kettle every time it’s boiled.
Lastly, if the overfilling percentage used (40%) was reduced to 30%, the savings in carbon
footprint are significantly reduced to 17.6% (see Appendix F; Figure 4). This result highlights the
importance of filling the correct amount of water into the kettle every time it is boiled.
A carbon footprint pay-off time in years by using an Eddy Kettle is approximately 347 days or 569
litres of boiled water. From this point on, the Eddy kettle is saving CO2 emissions compared to K1.
Page 32 of 36

7. Discussion and Conclusion
The LCA conducted in this report shows that the Eddy Kettle is a more sustainable solution to the
conventional electric kettle. Over a 12 year period, the Eddy Kettle has the potential to save 30%
of carbon emissions produced in comparison to other kettles on the market.
The engineering design decisions made in this report, excluding the In Use phase, result in a total
carbon footprint saving of 45% and 60% compared to the same stages in the life of K1 and K2
respectively. Although these savings are significant for the Manufacture, Transport, Disposal and
End of Life Potential stages of the kettle’s life, they account for less than 2% of the total savings
made by using the Eddy Kettle. The primary design feature that leads to a more sustainable
product is the location of the water level indicators (shown in Appendix A). The simple
repositioning of the indicators draws attention to the water level being filled as the user fills the
kettle, reducing water consumption by up to 40%. The saving in water consumption accounts for
28% of the total carbon savings of the Eddy Kettle.
As the carbon footprint of the kettle is considered to have the most significant environmental
impact, the LAC conducted in this report gives a good eco-indicator of the environmental impact
of each kettle. In reality other side products such as solid, waterborne or raw emissions
associated with the lifecycle of each kettle will effect the overall impact. Should the Eddy Kettle
be developed for manufacture, a second LCA study should be conducted taking into account
these side products to give a more comprehensive measure of environmental impact.
As for product development, the primary focus should be on the refinement of the induction
heating method. Controlled laboratory testing is necessary to ensure that the Eddy Kettle has a
competitive efficiency with other electric kettles on the market. Although the sensitivity study in
this LCA concluded that there is still a significant saving in emissions when the Eddy Kettle
efficiency is as low as 0.74, the product must compete with the boil time of other kettles and get
recognised as an energy efficient device should EU energy efficiency class ratings be introduced.
Overall, the Eddy Kettle shows a successful application of lifecycle consideration with substantial
savings in carbon emissions during every stage of the products life.
Page 33 of 36

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[Accessed 31 Mar. 2018]
Page 35 of 36

9. Appendix
Appendix A: 10 Page Summary
Page 36 of 36

Eddy Kettle
10 Page Summary
Kevin O’Malley - PDE5
1

Appendix B: Efficiency Calculations
Electric Kettle Calculation Data
Kettle Phillips HD4644 Tesco Stainless Steel Asda Basic
Russell Hobbs Mode
Kettle
Power rating (W) 2500-3000 2500-3000 1850-2000 2500-3000
Spicific Heat Capacity of
Water (J kg-1 K-1)
4185.50 4185.50 4185.50 4186.50
Experiment No. 1 2 1 2 1 2 1 2
Power input (W) 2834.00 2854.00 2881.00 2948.00 2150.00 2200.00 2773.00 2715.00
Room temperature (c°) 19.10 18.90 21.30 22.50 21.20 20.20 20.80 20.50
Time taken to boil (s) 147.00 142.00 134.00 131.00 178.00 178.00 142.00 150.00
Boiling Temperature (c°) 100.00 100.00 100.00 100.00
EIn (W) 416598.00 405268.00 386054.00 386188.00 382700.00 391600.00 393766.00 407250.00
EOut (W) 338606.95 339444.05 329398.85 324376.25 329817.40 334002.90 331570.80 332826.75
Efficiency Raating 0.81 0.84 0.85 0.84 0.86 0.85 0.84 0.82
Aveage Efficiency Raating 0.83 0.85 0.86 0.83
Appendix B

Table of Material Properties
Appendix C: CES Material Properties
Appendix C

Appendix D: CES Eco-Audit Output Data
Kettle 1 (K1)
Appendix D

Kettle 2 (K2)
Appendix D

Eddy Kettle
Appendix D

Appendix E: LCA Inventories
LCA Inventory of The Eddy Kettle
Labelled “smart” induction base of the Eddy
Kettle
Labelled “dumb” jug of the Eddy Kettle
Part Key Component Sub Assembly Material Process
Mass
(kg)
1 Ceramic Silica - quartz Glass moulding 0.101
2 Cover Polypropylene Polymer moulding 0.138
3 Induction Coil Copper Wire drawing 0.157
4 Iron Core (x7) Iron Rough rolling 0.129
5 Support Polypropylene Polymer moulding 0.033
PCB PCB assembly Incl. 0.015
Heat Sink Aluminium Extrusion 0.038
"Smart" Base
Resistors Resistor Incl. 0.003
6 Electronics* Diodes Diodes and LEDs Incl. 0.005
Capacitors Capacitor Incl. 0.005
Transformers Transformer Incl. 0.020
LED Diodes and LEDs Incl. 0.001
7 Base Polypropylene Polymer moulding 0.103
8 Screws (x3) Stainless steel Rough rolling 0.001
Other Cable & Plug
Cable Cable Incl. 0.050
Plug Plug Incl. 0.040
9 Lid Polypropylene Polymer moulding 0.045
10 Heating Disk Stainless steel Rough rolling 0.285
11 Insulated Insert Silicone Polymer moulding 0.049
"Dumb" Jug 12 Whistle
Body Polypropylene Polymer moulding 0.006
S. Steel Plates Stainless steel Rough rolling 0.006
13 Container Polypropylene Polymer moulding 0.359
14 Allen Screw Stainless steel Rough rolling 0.003
15 Handle Oak* Laser machining** 0.039
Total 1.631
Appendix E

*As CES has a limited range of timbers available for the eco-audit tool, oak was chosen as an
approximation of the selected handle material.
**Laser machining was selected ad an approximation for CNC milling
LCA Inventory of Kettle 1 (K1)
Material Process Weight (kg)
Polypropylene (PP) Polymer molding 0.467
Polyamides (Nylons, PA) Polymer molding 0.066
Polyvinylchloride (tpPVC) Polymer molding 0.058
Polyoxymethylene (Acetal, POM) Polymer molding 0.013
Polycarbonate (PC) Polymer molding 0.009
Silicone elastomers (SI, Q) Polymer molding 0.016
Cable Incl. in material value 0.040
Plugs, inlet and outlet Incl. in material value 0.050
Stainless steel Rough rolling 0.248
Brass Rough rolling 0.027
Copper Rough rolling 0.02
Semiconductor diodes, LEDs Incl. in material value 0.0005
Total 1.0145
LCA Inventory of Kettle 2 (K2)
Material Process Weight (kg)
Stainless steel Rough rolling 0.546
Medium carbon steel Rough rolling 0.0015
Copper Wire drawing 0.017
Brass Rough rolling 0.01
Nickel Rough rolling 0.07
Nickel-chromium alloys Rough rolling 0.017
Polypropylene (PP) Polymer molding 0.758
Polyethylene (PE) Polymer molding 0.0013
Polyvinylchloride (tpPVC) Polymer molding 0.08
Silicone elastomers (SI, Q) Polymer molding 0.026
Total 1.5268
Appendix E

Appendix F: Additional LCA Tables & Charts
Table 1
12 Year Lifespan 4 Year Lifespan
Eddy Kettle K1 K2 Eddy Kettle K1 K2
CO2
(kg)
impact
%
CO2
(kg)
impact
%
CO2
(kg)
impact
%
Materials 8.34 2.65 12.44 2.80 17.71 3.93 8.34 7.52 4.15 2.80 5.90 3.93
Manufacture 1.72 0.55 3.37 0.76 5.08 1.13 1.72 1.55 1.12 0.76 1.69 1.13
Transport 0.45 0.14 0.87 0.20 2.37 0.53 0.45 0.41 0.29 0.20 0.79 0.53
In Use 306.07 97.21 428.00 96.39 428.00 95.07 102.02 92.07 142.80 96.40 142.80 95.07
Waste
Disposal
0.07 0.02 0.12 0.03 0.22 0.05 0.07 0.06 0.04 0.03 0.07 0.05
EoLP -1.79 -0.57 -0.79 -0.18 -3.16 -0.70 -1.79 -1.61 -0.26 -0.18 -1.05 -0.70
CO2
(kg)
impact
%
CO2
(kg)
impact
%
CO2
(kg)
impact
%
Total: 314.86 444.01 450.22 110.82 148.14 150.21
CO2 released and the percentage contribution to the total carbon footprint
of each kettle over a 12 and 4 year period
Figure 1
Figure 2
Materials Manufacture Transport In Use
Waste Disposal
300
262.5
150.00
140.00
130.00
Eddy Kettle Kettle I Kettle II
225
187.5
Co2 Footprint (kg)
120.00
110.00
100.00
90.00
80.00
70.00
60.00
50.00
40.00
CO2 Footprint (kg)
150
112.5
75
30.00
20.00
10.00
0.00
37.5
-10.00
Materials Manufacture Transport In Use Waste Disposal End of Life Potential
0
Eddy Kettle Kettle I Kettle II
Comparison of the total carbon footprint produced by each kettle
over 4 years.
Comparison of the total carbon footprint of each kettle if 365 litres
a year are boiled rather than 540 litres.
(12 years)
Appendix F

Figure 3 Figure 4
Materials Manufacture Transport In Use Waste Disposal
Materials Manufacture Transport In Use
Waste Disposal
500
500
450
450
400
400
350
350
300
300
CO2 Footprint (kg)
250
CO2 Footprint (kg)
250
200
200
150
150
100
100
50
50
0
Eddy Kettle Kettle I Kettle II
Comparison of the total carbon footprint of each kettle if the
Eddy Kettle has an efficiency of 0.76 rather than 0.84.
(12 years)
0
Eddy Kettle Kettle I Kettle II
Comparison of the total carbon footprint of each kettle if a 30%
overfill was applied to the LCA.
(12 years)
Appendix F

Appendix G: EMS FEA Parameters
Figure 1
Di
De
Cross-section of induction coil with the labelled diameters.
Di - Inner Diamater
De - External Diameter
Table 2
Simulation Parameters Unit Value
Frequency Hz 24000
Room Temperature K 300
Time Duration s 180
Number of Turns in Coil 28
RMS Current per Turn A 12
Table 3
Properties of Water Body Unit
Value
Thermal Conductivity W/(m*K) 0.591
Mass Density kg/m^3 997
Specific Heat J/(kg*K) 4185.5
Convection Properties W/(m^2.K) 2000
Temperature at Time=0 K 300
Appendix G