Jakob Schweiger, Joshua Ishimwe
LOW-ENERGY AND COMFORTABLE
BUILDINGS IN RWANDA
JOSHUA ISHIMWE, JAKOB SCHWEIGER
RAPID PLANNING
RAPID PLANNING - LOCATIONS
Project goal: Finding planning solutions for rapidly growing cities
RAPID PLANNING – GREEN BUILDING
RESEARCH ASSISTANTS IN KIGALI
Leonard Byiringiro
Ba. Of Eng. Buildig and construction engineering
Joshua Ishingwe
Ba. Of Eng. Buildig and construction engineering
Remy Ruberambuga
Ba. of Eng. Building and construction engineering
Michel Schmitt
Ba. of Eng. Green Buildings
Jakob Schweiger
Ma. of Sci. Energyefficient and sustainable buildings
OVERVIEW
• Definition of climate
• Climate Engineering
• Climate in Kigali
• Indoor climate comfort
• Residential building 2-storey
• School house
• Office building
• Outlook
Goal: Create curiosity about climat engineering in Kigali
DEFINITION OF CLIMATE
Humidity
Climate - Weather
long term - short term
Temperature Athmospheric pressure
Wind
Percipitation
Athmospheric particle count
CLASSIFICATION OF CLIMATE BY SIZE
Source: Printerest.com
CATHEGORISATION OF THE MACROCLIMATE
Cool
Temperate
Desert
Subtropics
Tropics
Source: Hausladen, Liedl, de Saldanha: Building to Suit the Climate. A Handbook. Basel, 2012
CLIMATE ENGINEERING - COOL
Polar climate: Igloo
Source: Sol Power .The Evolution of Solar Architecture by Sophia Behling, Stefan Behling, Norman Foster
CLIMATE ENGINEERING - TEMPERATE
Mountain climate: Farmhouse in Switzerland
Source: Sol Power .The Evolution of Solar Architecture by Sophia Behling, Stefan Behling, Norman Foster
CLIMATE ENGINEERING - TEMPERATE
Mediterean climate:
Thermal mass and shading in Italy
Source: Sol Power .The Evolution of Solar Architecture by Sophia Behling, Stefan Behling, Norman Foster
CLIMATE ENGINEERING - DESERT
Desert climate:
Thermal mass and wind catcher
in Pakistan
Source: Rudofsky, Bernard: architecture without architects. Doubleday & Company. New York. 1987.
CLIMATE ENGINEERING - SUBTROPIC
Subtropical climate:
Chinese „Roundhouse“ with roof
overhang for shading and light
construction
Source: Sol Power .The Evolution of Solar Architecture by Sophia Behling, Stefan Behling, Norman Foster
CLIMATE ENGINEERING - TROPIC
Tropical climate:
King‘s hut in Rwanda
• Shelter from rain and
insulation against sun
• No windows to prevent solar
radiation and overheating Source: Printerest.com
CLIMATE ENGINEERING
But!
The building usage and their architecture changed
“Vernacular architecture does not go through fashion cycles.
It is nearly immutable, indeed, unimprovable, since it serves its purpose to
perfection.“
Offices Schools More storey
buildings
Shopping
centers Hospitals Hotels
MORE SUSTAINABLITY WITH CLIMATE
ENGINEERING
people
planet profit
Energy-efficiency
Less air pollution Comfortable housings
Energy-efficiency
Resource efficiency
CLIMATE ENGINEERING TODAY
Climate engineering software based on:
- Mathemathical models
- Physical correlations (eg. Thermo-dynamics)
- Research results on comfort of humans (ASHREA 55,...)
Source: IDA ICE
MESOCLIMATE IN KIGALI
15
17
19
21
23
25
Ou
tsid
e t
em
pera
ture
in
°C
Temperature Temperature night Temperature day
Source: Meteonorm 2017
MESOCLIMATE IN KIGALI
50
55
60
65
70
75
80
85
90
95
100
rel. H
um
idit
y i
n %
rel. Humidity rel. Humidity night rel. Humidity daySource: Meteonorm 2017
MESOCLIMATE IN KIGALI
150
170
190
210
230
250
270
Rad
iati
on
in
W/m
²
diffus radiation day direct radiation daySource: Meteonorm 2017
MESOCLIMATE IN KIGALI
10
12
14
16
18
20
22
24
26
28
30
0
100
200
300
400
500
600
700
800
900
1000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Tem
pera
ture
in
°C
Rad
iati
on
in
W/m
²
Typical day in rainy season
direct radiation diffuse radiation TemperatureSource: Meteonorm 2017
MESOCLIMATE IN KIGALI
10
12
14
16
18
20
22
24
26
28
30
0
100
200
300
400
500
600
700
800
900
1000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Tem
pera
ture
in
°C
Rad
iati
on
in
W/m
²
Typical day in dry season
direct radiation diffuse radiation TemperatureSource: Meteonorm 2017
MESOCLIMATE IN KIGALI
0.000
0.002
0.004
0.006
0.008
0.010
0.012
0.014
0.016
0.018
0.020
0 5 10 15 20 25 30 35 40
Ab
so
lute
hu
mid
ity [
kg
H2O
/ kg
air
]
Dry bulb temperature [°C] Source: Meteonorm 2017
INDOOR COMFORT
New requirements to architecture and...
PPD in % (Predicted percentage of dissatisfied) Source: Hausladen, Saldanha, Liedl, Sager: ClimaDesign. München, 2004. p.33.
2-STOREY RESIDENTIAL – BASIC MODEL
Rooms:
Ground floor
• Storage
• Toilet
• Living and cooking
First floor
• Child 1
• Child 2
• Parents
• Bathroom
• Floor
Building part Material U-value
Ground floor slab Concrete 2.4 W / m²K
Exterior wall CSEB 2.3 W / m²K
Interior wall CSEB 2.3 W / m²K
Floor Concrete 2.4 W / m²K
Windows Single glazing 5.9 W / m²K
Roof Corrugated metal 5.9 W / m²K
Usage:
• Residential 4-5 pers.
• Cooking inside – lunch + dinner
• Electrical light
• Ventilation with window
openings and ventilation bricks
2-STOREY RESIDENTIAL – BASIC MODEL
0
500
1000
1500
2000
2500
3000
10
20
30
40
Un
met
ho
urs
in
h
Op
era
tive
tem
pera
ture
in
°C
Min op temp, DegC
Max op temp, DegC
Unmet hours (cooling)
Unmet hours (heating)
8% 7% 7%
17% 17% 17% 20%
17%
0%5%10%15%20%25%30%
0
20
40
60
80
100
Ø P
PD
in
%
Rel. h
um
idit
y i
n %
Min rel hum, %
Max rel hum, %
Ø PPD in %/Pers
Temperature, Humidity, PPD, heating and cooling demand
0
500
1000
1500
2000
2500
3000
10
20
30
40
Un
met
ho
urs
in
h
Op
era
tive
tem
pera
ture
in
°C
Min op temp, DegC
Max op temp, DegC
Unmet hours (cooling)
Unmet hours (heating)
7% 7% 7% 9% 8%
11% 9% 8% 0%5%10%15%20%25%30%
0
20
40
60
80
100
Ø P
PD
in
%
Rel. h
um
idit
y i
n %
Min rel hum, %
Max rel hum, %
Ø PPD in %/Pers
2-STOREY RESIDENTIAL – ROOF INSUALTION
Temperature, Humidity, PPD, heating and cooling demand
+ 6 cm Strawtec panel under the corrugated metal sheet
1-STOREY PRIMARY SCHOOL
Rooms:
Ground floor
• Class room 1
• Class room 2
• Class room 3
Building part Material U-value
Ground floor slab Concrete 2.4 W / m²K
Exterior wall CSEB 2.3 W / m²K
Interior wall CSEB 2.3 W / m²K
Floor Concrete 2.4 W / m²K
Windows Single glazing 5.9 W / m²K
Roof Corrugated metal 5.9 W / m²K
Usage:
• School 1 teacher 35-40
• Start at 7am
• End at 5pm
• 1 hour lunchbreak
• No electrical light
• Ventilation through ventilation
bricks and windows
1-STOREY PRIMARY SCHOOL – BASIC
MODEL
15
17
19
21
23
25
27
29
31
33
35
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10 12 14 16 18 20 22 24O
pera
tive t
em
pera
ture
in
°C
PP
D in
%
Hour in h
PPD, PredictedPercentage ofDissatisfied
Operativetemperature
Typical day in dry season
1-STOREY PRIMARY SCHOOL – ROOF
INSULATION
15
17
19
21
23
25
27
29
31
33
35
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10 12 14 16 18 20 22 24O
pera
tive t
em
pera
ture
in
°C
PP
D in
%
Hour in h
PPD, PredictedPercentage ofDissatisfied
Operativetemperature
Typical day in dry season
+ 6 cm straw board under the corrugated metal sheet
1-STOREY PRIMARY SCHOOL – ROOF
INSULATION DOUBLE
15
17
19
21
23
25
27
29
31
33
35
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10 12 14 16 18 20 22 24O
pera
tive t
em
pera
ture
in
°C
PP
D in
%
Hour in h
PPD, PredictedPercentage ofDissatisfied
Operativetemperature
Typical day in dry season
+ 12 cm straw board under the corrugated metal sheet
1-STOREY PRIMARY SCHOOL – ROOF INSULATION
DOUBLE – REMOVED VENT. BRICKS
15
17
19
21
23
25
27
29
31
33
35
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10 12 14 16 18 20 22 24O
pera
tive t
em
pera
ture
in
°C
PP
D in
%
Hour in h
PPD, PredictedPercentage ofDissatisfied
Operativetemperature
Typical day in dry season
+ 12 cm straw board under the corrugated metal sheet
+ removing of the ventilation bricks
3-STOREY OFFICE BUILDING - BASIC
Rooms:
• Offices 6-8 people
• Floor
• Staircase
Building part Material U-value
Ground floor slab Concrete 2.4 W / m²K
Exterior wall CSEB 2.3 W / m²K
Interior wall CSEB 2.3 W / m²K
Floor Concrete 2.4 W / m²K
Windows Single glazing 5.9 W / m²K
Roof Corrugated metal
+Straw panel
1.2 W / m²K
Usage:
• Offices 6-8 occupants
• Start at 7am
• End at 5pm
• Ideal cooling, heating and
ventilation
• Electrical light
• 1 computer per occupant
Floors:
• Ground: 90% window/wall
• 1st: 40% window/wall
• 2nd: 20% window/wall
Building
• East-West orientation
• Office - building
• Location in Kigali
3-STOREY OFFICE BUILDING - BASIC
0
20
40
60
80
100
120
140
Purchased energy
Heating
Equipment,tenant
HVAC aux
Cooling
Energy-demand:
• 126 kWh/m²*a in total
• With 0.22 $/kWh
27.7 $/m²*a energy demand
For the whole building:
33,600$/a
+ fixed costs
+ maintainance & service
CLIMATE ENGINEERING IN TROPICAL ZONES
Window wall ratio 40%
Solar control glacing g=0.4
Light blades turnable
Overhang with photovoltaik
Solarcontrol glacing g=0.2
Low absorbtion
Source: Hausladen, Liedl, de Saldanha: Building to Suit the Climate. A Handbook. Basel, 2012
3-STOREY OFFICE BUILDING - OPTIMATED
Usage:
• Offices 6-8 occupants
• Start at 7am
• End at 5pm
• Ideal cooling, heating and
ventilation
• Electrical light
• 1 computer per occupant
Rooms:
• Offices 6-8 people
• Floor
• Staircase
Floors:
• Ground: 90% window/wall
• 1st: 40% window/wall
• 2nd: 20% window/wall
Building part Material U-value
Ground floor slab Concrete 2.4 W / m²K
Exterior wall CSEB 2.3 W / m²K
Interior wall CSEB 2.3 W / m²K
Floor Concrete 2.4 W / m²K
Windows Single glazing 5.9 W / m²K
Roof Corrugated metal
+Straw panel
1.2 W / m²K
3-STOREY OFFICE BUILDING - OPTIMATED
Energy-demand:
• 129 kWh/m²*a in total
• With 0.22 $/kWh
28.4 $/m²*a energy demand
For the whole building:
34,500$/a
+ fixed costs
+ maintainance & service
0
20
40
60
80
100
120
140
Purchased energy
Heating
Equipment,tenant
HVAC aux
Cooling
CURRENT STAGE OF CLIMATE ENGINEERING
IN RWANDA
Climate data in Kigali:
• Min. one weather station per district in Rwnada METEO Rwanda
• No mesoclimate date for hill-side, wet-land etc.
• Global warming can change climate for the next years
Comfort of Rwandese inhabitants
• ASHREA claims, that their researches of thermal comfort are international applicable
• Research in Madagascar show that 28°C indoor temperature are comfortable
Climate Engineering
• Many international software products for thermal comfort
• Lack of knowledge for software use in Rwanda
• Some international publications about climate engineering in tropical zones may not be applicable to Rwandan housings due to high location and therefore special climate
OUTLOOK – HEAT ISLAND EFFECT
Source: Photo Foster + P.
OUTLOOK – CLIMAT ENGINEERING IN THE
CITY
Source: LAVA
OUTLOOK – CLIMATE ENGINEERING IN THE
CITY
Source: LAVA
CONTACTS
Green building team in Kigali
Jakob Schweiger [email protected] Remy Ruberambuga [email protected] Michel Schmitt [email protected] Leonard Byiringiro [email protected] Joshua Ishimwe [email protected] Rapid Planning – Kigali coordinator
Sylvie Kayitesi [email protected] Rapid Planning – Kigali focal point coordinator
Bernd Franke [email protected]
TO READ
Energy and Resource Efficiency Building Code for Tropical Countries: Guidelines (Final Draft) • Link: http://eebea.org/?q=doc-2.3.4 • Special guidelines for buildings in tropical highlands
The Rapid Planning project • Link: http://rapid-planning.net/ • Research in the sectors food, waste, waste water, fresh water and energy • Comming: Scenarios in the differnet sectors and synergies
Software for climate engineering • IDA ICE by equa https://www.equa.se/de/ from Sweden • Trnsys by Thermal Energy System Specialists http://www.trnsys.com/ from
the US
CONTACTS
Murakoze!
Danke!
Merci!
Thank you!
RAPID PLANNING
Murakoze! Thank you!
Merci!
Danke!