Otago Energy Research Centre (OERC) Seminar 19th June 2018 Assoc Prof MJ (Thinus) Booysen Electrical & Electronic Engineering Department at Stellenbosch University, A founder of Bridgiot, and co-creator of Geasy & Count Dropula (www.bridgiot.co.za) “The Internet of electric water heaters” Household water heaters are ubiquitous, yet mostly hidden from view and tend to be boring and dumb devices we do not think about. However, they are energy hungry, both in terms of load (kW) and energy (kWh). Their capacitive nature allows them to store energy for prolonged periods, making them well suited to scheduled heating control for both reduction in energy (and CO2) converted for heating, and suited for load shifting to reduce the impact on the grid. Although ripple control has been around for decades, the advent of pervasive bi-directional wirelines communications, low-cost controllers, and cloud computing have opened a new chapter on intelligent control of electric water heaters as part of the so-called Internet of Things. Towards exploiting this potential, this talk will explore real-time monitoring and control of a field deployments of water heaters to balance the pulling forces of reduced load on the grid, reduced electrical energy used for water heating, and the oft-neglected user comfort. Some converted water heater controllers have also been used in a water saving campaign at schools, of which some behavioural change results will be presented. Finally, the results will be discussed from a study on the prevalence of Legionella and its potential links to TB. More information: www.schoolswater.co.za, www.bridgiot.co.za,

1. MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 1 / 45
Internet of Water heaters
Energy and Water
E&E Eng. – Stellenbosch University
Thinus (TEA-nis) Booysen
Dunedin, Otago Uni - 19 June 2018 [PG 13]

2. Outline
1 The problem
SA beyond the beauty
Water heating in South Africa
Why geysers matter
2 The solution
Geasy
Thermal model
3 Some Energy Results
4 Load Control
The problem
The solution
5 A few loose ends
6 CFD and analysis and visualisation
7 Legionella
8 Dropula smart water meter
9 Q & A
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 2 / 45

3. Next Section
1 The problem
SA beyond the beauty
Water heating in South Africa
Why geysers matter
2 The solution
Geasy
Thermal model
3 Some Energy Results
4 Load Control
The problem
The solution
5 A few loose ends
6 CFD and analysis and visualisation
7 Legionella
8 Dropula smart water meter
9 Q & A
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 3 / 45

4. Context of SA
• Second highest Gini inequality index (behind Lesotho)
• Prepaid electricity, some top up daily or weekly.
• SA has severe electricity and water constraints
• Cape Town drought
• 34% of potable water does not reach a meter
• rolling blackouts since 2008 (peak loads)
• Electricity generation done by sole parastatal (Eskom)
• beset by corruption
• paralised by unions
• limited investment in infrastructure since 1996
• Heavy on CO2 emissions
• 16th
globally, after Australia
• 67 % is on electrity generation alone
• 77 % of electrircity is coal (NZ = 4 %)
• High burden of TB mortality (top 20 globally – 782 vs. NZ < 10 )
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 4 / 45

5. Background water heating in SA
Water heaters are called “geysers” in SA. Typically:
• almost exclusively mounted horizontally
• made of mild steel
• mostly in the ceiling cavity, life expectancy 3-5 years.
• high pressure (400 to 600kPa)
• 150 L vessel with a 3 kW element
• standing losses of 2.6 kW h d−1 (around double NZ standard)
Images from installers www.geysersonly.co.za and insurance provider www.miway.co.za
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 5 / 45

6. Why geysers matter
Over 5 million electric water heaters in SA, combined annually
• consume NZ$3bn in energy (54 000 kW h d−1)
• 2940 MW peak load
• cost for water heating roughly 18–37% of social grant (Dole)
• pass 500 L bn of water
• cause ca. NZ$1.5bn damages due to “bursts”
Despite ubiquity and consumption impact, various challenges:
• limited and constrained access to control it
• limited and conflicting understanding of factors impacting on
consumption and best control strategy to limit consumption
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 6 / 45

7. Perceptions
• Surveyed 450 users using online poll (self-selection)
• Users
• don’t understand the energy consumption of EWHs
• don’t know how to control EWHs efficiently
• 9% of participants got hypothetical schedule question it right
• 89% of participants use switching for energy management
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 7 / 45

8. Next Section
1 The problem
SA beyond the beauty
Water heating in South Africa
Why geysers matter
2 The solution
Geasy
Thermal model
3 Some Energy Results
4 Load Control
The problem
The solution
5 A few loose ends
6 CFD and analysis and visualisation
7 Legionella
8 Dropula smart water meter
9 Q & A
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 8 / 45

9. Introducing Geasy, the smart geyser controller
Electric
Water
Heater
Relay
Element
Power meter
Outlet
Water meter
Inlet
Internal
Ambient
Temperature
sensors
M2M
Server
Website
and App
GSM
Valve
• Measures and controls water
• Measures and controls electricity
• Measures and controls temperatures
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 9 / 45

10. Geasy Hardware
• About 1 hr to retrofit
• Over 200 already deployed
• Reports in minutely through cellular network
• Manufacturing cost around NZ$ 50, operating cost about NZ$ 1
per month
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 10 / 45

11. Geasy User Interface
• Web site or app interface www.geasy.nz
• Reporting, analysis and control
• Intelligent scheduling and temperature control
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 11 / 45

12. Two-node thermal model
• Models stratification with two separate one-nodes
• Thermocline inbetween with varying surface area (const for vert.)
• Simulate
• scheduled vs. thermostat control
• vertical vs. horizontal orientation
• open-loop and closed-loop simulation
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 12 / 45

13. Two-node thermal model
• Validated with 34 field geysers (coarse)
• Used four field units and two lab units (fine)
6.6
5.1
4.6 4.3
7.6
5.7
4.4
3.9
6.1
4.2
3.9
2.7
7.0
5.7
4.6
4.1
6.9
5.8
4.4
4.0
6.2
4.1 4.1
2.7
Q_elec Q_draw Q_elec Q_draw Q_elec Q_draw Q_elec Q_draw Q_elec Q_draw Q_elec Q_draw
Thermostat Scheduled Thermostat Scheduled Thermostat Scheduled
Lab horizontal Lab vertical Field aggregate
Energy/volume(kWh/100L)
Measured Simulated (closed-loop) Simulated (open-loop)
• Open loop: Energy out measured vs simulated over 1 month.
• 4 % accurate for horizontal, 12 % for vertical
• Closed loop: Energy in measured vs simulated over 1 month.
• 6 % accurate for horizontal, 9 % for vertical
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 13 / 45

14. Next Section
1 The problem
SA beyond the beauty
Water heating in South Africa
Why geysers matter
2 The solution
Geasy
Thermal model
3 Some Energy Results
4 Load Control
The problem
The solution
5 A few loose ends
6 CFD and analysis and visualisation
7 Legionella
8 Dropula smart water meter
9 Q & A
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 14 / 45

15. Case Study: Launchlab bathroom geyser
• Element almost never turned off
• 40kWh to 5kWh per day (87.5% reduction)
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 15 / 45

16. Natural experiment with four field geysers
What is the actual impact of knowing and of switching? Firstly,
provide daily information, then intelligent control
• Two lab units
• Four field units in households (two control + two treatment)
• One month only observing (control period)
• One month only information & compare daily email (behavioural)
• One month with optimised heating schedule
Collaboration with UCT Economics Dept (Prof Martine Visser)
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 16 / 45

17. Natural experiment results
• Behavioural results were inconclusive due to ...
• Saving ranges between 29% and 42%
• Ethalpy controlled saving 6% to 8%
• Energy measured in Watt/litre to control for seasonal and
behavioural variation.
5.1
4.3
5.7
3.9
3.4
2.3
3.1 2.9 2.5
1.5
0.3
1.9
0.5 1.3
0.9
1.6 1.7
0.8
6.6
4.6
7.6
4.4
4.7
3.2
4.7 4.6
3.3
Thermostat Scheduled Thermostat Scheduled Thermostat Scheduled Thermostat
(normalised)
Thermostat
(normalised)
Difference in
diifference
Lab horizontal Lab vertical Field treatment Field control Field impact
Energy/volume(kWh/100L)
Q_draw (Energy used) Thermal losses Q_elec (Energy input)
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 17 / 45

18. WRC - Mpumalanga, baptism of fire
• Installed 200 Geasies in Mpumalanga (rural Northern SA)
• Challenges
• Technically unaware and incapacitated users
• Non-compliant geyser installations
• Municipal collaboration
• Residents distrust municipality
• Ownership
• Environmental exposure
Mkhondo
Stellenbosch
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 18 / 45

19. Aggregate results and savings
Daily (In February 2017)
• 214 geysers online
• 27,000 litres of water through our system
• 1.071 MWh measured (would have been 1.383 MWh)
Savings Energy Water (approx.) Total
kWh Rand value Litres Rand value Rand value
Per user per day 2.1 R 4.80 39 R 0.80 R 5.60
Project per day 310.8 R 710.00 5772 R 118.40 R 1120
Project per year 113,442.00 R 259,150.00 2,106,780.00 R 43,216.00 R 302,366.00
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 19 / 45

20. Cape Town vs. Piet Retief (weekdays)
• Cape Town: 170L and 8.5kWh vs. Piet Retief: 140L and 8.0kWh
• Cape Town 20% more water, but 70% efficiency vs. 46% in Piet Retief
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 20 / 45

21. Cape Town vs. Piet Retief (weekends)
• Cape Town: 148L and 7.9kWh vs. Piet Retief: 87L and 6.0kWh.
• Working class and migrant week labourers?
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 21 / 45

22. Next Section
1 The problem
SA beyond the beauty
Water heating in South Africa
Why geysers matter
2 The solution
Geasy
Thermal model
3 Some Energy Results
4 Load Control
The problem
The solution
5 A few loose ends
6 CFD and analysis and visualisation
7 Legionella
8 Dropula smart water meter
9 Q & A
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 22 / 45

23. Peak loads and ripple control
Always on (default) Load control (ripple control)
User-scheduled heating Proposed PDM
User comfort
Managed load Low energy
EWH GridGrid load
HWC
EWH
Ein
Eout
ELossHWC
EWH
Ein
Eout
ELossHWC
EWH
Ein
Eout
ELossHWC
EWH
Ein
Eout
ELossHWC
EWH
Ein
Eout
ELoss
-20-10
0
102030405060
00:00
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22:30
23:00
23:30
Water (L/min) Thermostat (kW) Ripple control (kW)
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 23 / 45

24. Centralised peak load management - Oracle
Proposed PDM EWH Grid
Metadata
Individual hot water consumption (Vu)
Power limit (Plimit)
Usage DB
HWC
EWH
HWC
EWH
HWC
EWH
HWC
Smart EWH
Real-time internal temperatures (Tint)
HWC
Smart EWH
HWC
Smart EWH
User input
Time
until
hot
Time
until
use
Priority-
based
limiting
heating
control
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 24 / 45

25. Centralised peak load management - Oracle
• Wireless comms strategy to ’compete’ for grid access
• 34 consumption profiles used with model-validated field units
• Plim = [20,30,40,50]kW Tset = [50,60,70]◦C
• Only 2% increase in cold events (only 2 heavy consumers)
-20-10
0
102030405060
00:00
00:30
01:00
01:30
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23:00
23:30
Water (L/min) Thermostat (kW) Ripple control (kW)
-20-10
0
102030405060
00:00
00:30
01:00
01:30
02:00
02:30
03:00
03:30
04:00
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11:3012:0012:3013:00
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23:00
23:30
Water (L/min) PDM-20 (kW) PDM-30 (kW) PDM-40 (kW) PDM-50 (kW)
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 25 / 45

26. Next Section
1 The problem
SA beyond the beauty
Water heating in South Africa
Why geysers matter
2 The solution
Geasy
Thermal model
3 Some Energy Results
4 Load Control
The problem
The solution
5 A few loose ends
6 CFD and analysis and visualisation
7 Legionella
8 Dropula smart water meter
9 Q & A
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 26 / 45

27. Some consumption patterns
Event detection rate
Hit Miss False Accuracy
Positives (%)
Small 48 6 ? 88
Medium 44 0 ? 100
Large 34 1 ? 97
Total 126 7 5 91
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 27 / 45

28. What is the best way to save?
0
5
10
15
20
25
1 2 3 4 5 6 7 8 Average
ReductionintotalenergyusageofEWH(%)
Profile number
Usage Reduction Set Temp Pipe Insulation + Thermal Blanket Schedule Control Schedule, Thermal Blanket and Pipe Insulation
# Sh Bth
1 0 1
2 0 2
3 1 1
4 1 2
5 1 0
6 2 0
7 2 1
8 2 2
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 28 / 45

29. Before you build, consider this
0
2
4
6
8
10
12
14
16
18
1 2 3 4 5 6 7 8 Average
ChangeinTotalEnergyUsage(%)
Profile Number
Inlet
Ambient
# Sh Bth
1 0 1
2 0 2
3 1 1
4 1 2
5 1 0
6 2 0
7 2 1
8 2 2
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 29 / 45

30. Online calculation tool
• www.geyserpleaser.co.za
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 30 / 45

31. Next Section
1 The problem
SA beyond the beauty
Water heating in South Africa
Why geysers matter
2 The solution
Geasy
Thermal model
3 Some Energy Results
4 Load Control
The problem
The solution
5 A few loose ends
6 CFD and analysis and visualisation
7 Legionella
8 Dropula smart water meter
9 Q & A
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 31 / 45

32. Computational fluid dynamics
CFD visualisations on youtube: https://goo.gl/dGGgYF
Important observation - the bottom part of the geyser never goes
above 45, which is perfect Legionella
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 32 / 45

33. Next Section
1 The problem
SA beyond the beauty
Water heating in South Africa
Why geysers matter
2 The solution
Geasy
Thermal model
3 Some Energy Results
4 Load Control
The problem
The solution
5 A few loose ends
6 CFD and analysis and visualisation
7 Legionella
8 Dropula smart water meter
9 Q & A
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 33 / 45

34. Legionella Pneumophila
Took three samples from each of five geysers, and cut eight open
EWH Heating schedule Sample PCR (Qualitative) qRT-PC (Quantitative)
no. temp (◦
C) Legionella spp. Leg. pneum.
(cells/ml)
CT HT1 HT2 CT HT1 HT2
1 03:00 - 05:00;15:00 - 17:00 47 - + + 0 6 5
2 On (Thermostat) 42 + + + 0 7 0
3 04:00 - 07:00;16:00 - 19:00 45 + + + 0 7 0
4 02:00 - 06:00;15:00 - 20:00 46 - - + 0 0 2
5 18:00 - 21:00 44 + + + 0 10 0
Prob. of immunocompromised contracting Leg. pneum. in 10 yrs is 88%.
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 34 / 45

35. Next Section
1 The problem
SA beyond the beauty
Water heating in South Africa
Why geysers matter
2 The solution
Geasy
Thermal model
3 Some Energy Results
4 Load Control
The problem
The solution
5 A few loose ends
6 CFD and analysis and visualisation
7 Legionella
8 Dropula smart water meter
9 Q & A
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 35 / 45

36. Dipping Geasy’s toes in the water
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 36 / 45

37. Case Study: Coffee shop’s Damascus moment
• Owner made aware of consumption after 1 week of monitoring
• Brought down from 1.8kL/day to 0.45kL/day (67.5% reduction).
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 37 / 45

38. Case Study: John Maytham watered down
• Brought down monthly bill from 20kL to 6.5kL (67.5% reduction)
• Obviously I am ignoring externalities
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 38 / 45

39. Irate about irrigation and alerts
Irrigation for 30 minutes Pool company visits
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 39 / 45

40. Count Dropula at schools
Behavioural intervention at schools – www.schoolswater.co.za
• 93 orporates funders, 358 schools Dropula
• NZ$2000 goes to maintenance , NZ$1000 goes to smart service
• Saving just under 1 million litres per day
WEEKLY WATER USAGE REPORT
Rhenish Primary
Start: 2018-06-11
End: 2018-06-17
Weekly Usage Volume and Cost for the Week
Volume Total:
Cost Total:
Highest Usage Days:
46.87 kL
R 4687.00
Wednesday
Thursday
Average Hourly Weekday Usage Volume
Average Daily Volume:
Average Daily Cost:
Highest Usage Hours:
6486 L
R 648.60
14:00
11:00
10:00
Tel 021 201 6989 • Email schools@bridgiot.co.za • URL https://schools.bridgiot.co.za
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 40 / 45

41. Count Dropula at schools
Maintenance impact at schools – www.schoolswater.co.za
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 41 / 45

42. Count Dropula at schools
Behavioural impact at schools – www.schoolswater.co.za
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 42 / 45

43. Municipal water leakage detection
• Detects and classifies leaks in municipal pipes
• Apply leak theory by Van Zyl at UCT to
• Mobile and remote reporting
• Low skilled workers with centralised analysis
• Jasco commercialising
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 43 / 45

44. Next Section
1 The problem
SA beyond the beauty
Water heating in South Africa
Why geysers matter
2 The solution
Geasy
Thermal model
3 Some Energy Results
4 Load Control
The problem
The solution
5 A few loose ends
6 CFD and analysis and visualisation
7 Legionella
8 Dropula smart water meter
9 Q & A
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 44 / 45

45. Thank you!
• Thank you for the opportunity !!
• Spin-off: www.geasy.nz and www.bridgiot.co.za/blog
• Contact: ee.sun.ac.za/staff/mjbooysen and
mjbooysen@sun.ac.za
MJ Booysen (Stellenbosch) Closing the loop iwith IoT Otago Uni, June ’18 45 / 45