2 ENERGY ANALYSIS FOR RESOURCE EFFICIENT BRICKS (REB)
2.1
Quantifying Energy savings
2.1.1


2.1.2






Objectives
To quantify the operational energy performance of Resource efficient bricks using
building simulations.
To draw a comparative energy performance of buildings between resource efficient
bricks and other conventional building materials such as normal bricks, perforated
bricks, fly ash bricks and hollow concrete blocks.
Assumptions
A single floor, hypothetical building model is considered for simulations, as a generic
test case irrespective of the type and function of the building.
All the thermal properties of walling materials, considered in the simulations are
derived from the Design builder software. The simulation considers only assembly U
– values irrespective of perforations in the hollow blocks. Hence, the U – value (1.1
W/m2K) of REB is referred directly from Wienerberger. Other materials U – values
are as per defined (default values) in Design builder software.
The outputs from the simulations for varying walling materials are also based on the
net assembly U – value and hence percentage of perforations cannot be modelled.
The simulations are done only to analyse the energy performance in varying wall
materials hence the floor and roof properties remains same for all the simulation
cases.
REB and normal bricks considered for simulations do not include plaster; this is
mainly intended to understand its level of efficiency with exposed masonry when
compared to other walling materials like concrete blocks that necessarily needs to be
plastered.
All the simulations and results are analyzed annually. However, monthly and hourly
energy consumption also follows the same pattern as annual simulations.
2.1.3 Methodology
A simulation model with floor area of 100 m² with 1:1 Square aspect ratio is analysed for
different climatic zones that is Bangalore for moderate, Delhi for composite, Ahmedabad for
Hot-dry and Chennai for warm and humid climates are analysed for walling materials such
as:
a)
b)
c)
d)
e)
Normal bricks
Perforated bricks
Fly ash bricks
Hollow concrete blocks
Resource efficient bricks.
This model is analysed for 30% window wall ratios as per (figure1). U – values of the walling
assembly are as per table 2.
5
A base model is configured with constant construction roof and floor material. The wall
materials are varied and results for those are analyzed. Other systems like HVAC, lighting
and occupancy schedules remain same for all the models.
Table 1: Roof and floor properties
Constant Roof and Floor properties
Layers
Thickness
Ceramic / porcelain
0.01 m
Roof screed
0.025 m
Concrete roofing slab
0.15 m
Plaster
0.012 m
Thermal properties
Conductivity (W/m-K)
Specific heat (J/kg-K)
Density (kg/m3)
1.300
840
2300
U – valuie (W/m2-K)
0.860
Figure 1: Flow chart showing Simulation methodology.
Note: As mentioned earlier, the percentage of perforations for simulations in the blocks are
not considered. However, the material property has been mentioned for reference purpose
only. The percentage of perforations in perforated brick is 19% 1 (source – Jay Jalaram
bricks, Godhra), in hollow concrete block is 48% 2 (source – Kesarjan Building centre,
Ahmedabad) and in REB is 52.5% 3 (source – Weinerberger).
1
Sharda, keyur. Personal interview. 22 April 2011.
2
Hemrajani Tarun. Personal interview.1 Dec. 2010.
3
Weinerberger, www.weinerberger.in
6
2.1.4 Base Model Description
Firstly a base model of 100 m², with 30% window wall ratio for Ahmedabad is analyzed with
varying wall materials and their U values are as per (graph1). Brief model description is
mentioned in (table1).
Table 2: Brief of Base Model description for Simulations
Characteristics
Description(For Base Model)
Location
Ahmedabad
Area
100 m²
Floor Dimensions
10m x 10 m
Occupancy Type
Generic Building
Plan Shape
1:1 (Square)
No. of floor
Intermediate floor (roof and floor are adiabatic)
Zones
1 core zone
Window wall ratio
30%
Type of Glass
Single Clear 6mm
Shading
No
Roof
150 mm Concrete slab with plaster
Floor
Ceramic floor ,with 100 mm Cast concrete and
70 mm Screed
lighting
T8 - (25mm-dia Flourescent-triphospher)
lighting schedule
As per occupancy Schedule
HVAC type
Constant Volume DX -using unitary multi zone
Cooling system Cop
1.19
HVAC Schedule
As per occupancy Schedule
Figure 2: Showing hypothetical for simulation.
7
Materials
Comparative U - value considered for simulations
REB - 400 X 200 X 200 mm
Hollow concrete block - 400 X 200 X200 mm
Flyash brick - 230 X 110 X 75 mm
Perforated brick - 235 X 110 X 72 mm
Normal brick - 229 X 100 X 70 mm
1.079
2.251
1.929
1.716
2.187
0
0.5
1
1.5
2
2.5
U-value
Graph 1: U values of alternative wall assemblies from design builder software.
Figure 3: Showing walling assemblies and U-values of different materials.
8
The considered U values are for respective wall materials with 18mm plaster outside and 12
mm plaster inside. The software considers the default values for thermal properties such as:
Conductivity, Specific heat and Density. Other U – values considered here area as per
referred / calculated U values. 4
Occupancy schedule and activity patterns are defined for a typical energy intensive building
that operates from 0930-1830 and for 6 days a week. The occupancy is assumed to be full
throughout the scheduled time. The HVAC and lighting also operates in the same duration.
2.1.5 Simulation analysis and results
As mentioned earlier the base model of 100 m2 with 30% window wall ratio is simulated for 5
wall materials and 4 climate zones. These combinations of 20 cases are simulated using
Design builder – that is a graphic user interface for Energy Plus. The total annual energy
consumption and chiller energy consumption are analyzed from the simulation outputs.
All the results analyzed are normalized for one meter square area that is the consumption
values presented here are annual energy used per square meter area. As per (graph 2) it is
seen that annual chiller energy consumption for REB and perforated bricks are
comparatively lower than other materials in Ahmedabad. Graph 3 shows percentage
increase, where as graph 2 shows the actual values. Similar order is followed in all the
analysis and graphs mentioned below. Hence, in comparing the results with REB (A) normal
bricks consume 0.49% higher than REB, (C) fly-ash bricks are 0.14% higher than REB and
(D) hollow concrete blocks consume highest of 0.93% in chiller energy consumption. It is
seen that REB consumes the least amount of chiller energy compared to alternative walling
materials.
Annual chiller energy consumption-Ahmedabad (hot & dry)
REB - 400 X 200 X 200 mm
384.92
Materials
Hollow concrete block - 400 X 200 X200 mm
388.49
Flyash brick - 230 X 110 X 75 mm
385.47
Perforated brick - 235 X 110 X 72 mm
384.92
Normal brick - 229 X 100 X 70 mm
386.81
383
384
385
386
387
388
389
kWh/m2
Graph 2: Chiller Energy Consumption for alternative Walling Materials (Ahmedabad).
4
U-values of Fly-ash and perforated brick are referred from unpublished thesis - Sonagara, Nirav.
“Embodied and operational energy assessment of alternative walling materials for multi-storey
buildings in Ahmedabad.” Diss. Cept University, Ahmedabad, 2011.
9
% increase in Chiller energy - compared to REB (Ahmedabad)
Materials
REB - 400 X 200 X 200 mm
0
Hollow concrete block - 400 X 200 X200 mm
0.93
Flyash brick - 230 X 110 X 75 mm
0.14
Perforated brick - 235 X 110 X 72 mm
0.00
Normal brick - 229 X 100 X 70 mm
0.49
0
0.2
0.4
0.6
0.8
1
Percentage
Graph 3: % Increase in Chiller Energy Consumption for alternative Walling Materials
(Ahmedabad).
Total energy consumption includes energy usage in cooling, heating, lighting, equipments,
miscellaneous activities, etc. All these energy loads contribute to the total energy
consumption of a building. The total energy consumption of a building is the operational
energy required to operate the building. Graph 4 shows the total energy consumption of a
building using alternative walling materials. From the results it is observed that Hollow
concrete block consumes the highest amount of total energy per square meter of the
building, REB and perforated brick consumes the lowest amount of total energy per square
meter of the building.
Annual total energy consumption-Ahmedabad (Hot & dry)
Materiaks
REB - 400 X 200 X 200 mm
509.92
Hollow concrete block - 400 X 200 X200 mm
513.48
Flyash brick - 230 X 110 X 75 mm
510.47
Perforated brick - 235 X 110 X 72 mm
509.92
Normal brick - 229 X 100 X 70 mm
511.81
508
509
510
511
512
513
514
kWh/m2
Graph 4: Total Annual Energy Consumption for alternative walling Materials (Ahmedabad).
Analysing total energy consumption graph 5 shows that REB wall has the lowest energy
consumption compared to alternative walling materials. The next lowest consuming material
is perforated brick wall. The annual energy consumption for (A) normal brick wall is 0.37%
higher to that of REB; (C) Fly-ash brick wall is 0.11% higher than REB; and (D) hollow
concrete block wall is 0.70% higher than REB wall and is found to be the highest consuming
wall material comparatively.
10
% increase in total energy - compared to REB (Ahmedabad)
Materials
REB - 400 X 200 X 200 mm
0
Hollow concrete block - 400 X 200 X200 mm
0.70
Flyash brick - 230 X 110 X 75 mm
0.11
Perforated brick - 235 X 110 X 72 mm
0.00
Normal brick - 229 X 100 X 70 mm
0.37
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Percentage
Graph 5: % increase in Total Annual Energy Consumption for alternative walling Materials
(Ahmedabad).
From the results of graph 4 and graph 5 it is observed that REB consumes less, when
analyzed for annual total energy consumption. Hence, operational energy required for the
REB wall is comparatively efficient when compared to hollow concrete block, fly-ash brick
and normal brick. As a result from the simulated base model for Ahmedabad, it is observed
that REB‟s are comparatively efficient than other walling materials.
Comparative chiller consumption for REB
Cities
Chennai
436.79
Ahmedabad
384.92
Delhi
374.67
Bangalore
279.69
0
50
100
150
200
250
300
350
400
450
500
kWh/m2
Graph 6: Comparative Chiller Energy Consumption for REB- Analyzed for different climate
zones.
Table 3: Comparative Chiller Energy Consumption analyzed for different climate zones
Material
Normal brick - 229 X 100 X 70 mm
Perforated brick - 235 X 110 X 72
mm
Flyash brick - 230 X 110 X 75 mm
Hollow concrete block - 400 X 200
X200 mm
REB - 400 X 200 X 200 mm
% increase or decrease in chiller energy consumption - compared
to REB
Bangalore (decrease)
Delhi
(increase)
Ahmedabad
(increase)
Chennai
(increase)
4.81
0.52
0.49
0.44
3.96
0.21
0
0.31
4.76
0.005
0.14
0.37
3.52
0.93
0.93
0.16
0
0
0
0
11
Table 4: Total Energy for REB - analyzed for different climate zones
% increase or decrease in total energy consumption - compared to REB
Material
Normal brick - 229 X 100 X 70 mm
Perforated brick - 235 X 110 X 72
mm
Flyash brick - 230 X 110 X 75 mm
Hollow concrete block - 400 X 200
X200 mm
REB - 400 X 200 X 200 mm
0.31
Ahmedabad
(increase)
0.37
Chennai
(increase)
0.34
2.61
0.15
0
0.24
3.16
0.00
0.11
0.28
2.32
0.67
0.70
0.12
0
0
0
0
Bangalore (decrease)
Delhi (increase)
3.17
Note: Figures in red colour indicate the decrease in chiller energy consumption and in total
energy consumption. (Refer table 3.1, 3.2 graph 9 and graph 10)
Performance of REB when compared to other materials for different climate zones is
different. In Bangalore – moderate climate, by using REB there is an increase in both the
chiller load and total energy consumption compared to alternative walling materials. The
percentage increase in total energy consumption using REB ranges from 2.3 – 3.17 %.
In Delhi – composite climate and Chennai – warm & humid climate, by using REB there is a
decrease in the both the chiller load and total energy consumption compared to alternative
walling materials. From the table it is observed that, using REB more percentage savings are
obtained in Ahmedabad hot and dry climate compared to other alternative cities such as
Delhi, Chennai and Bangalore having different climates.
% decrease in Chiller energy - compared to REB (Bangalore)
Materials
REB - 400 X 200 X 200 mm
0
Hollow concrete block - 400 X 200 X200 mm
3.52
Flyash brick - 230 X 110 X 75 mm
4.76
Perforated brick - 235 X 110 X 72 mm
3.96
Normal brick - 229 X 100 X 70 mm
0.00
4.81
1.00
2.00
3.00
4.00
5.00
6.00
Percentage
Graph 7: % decrease in Chiller Energy Consumption for alternative Walling Materials
(Bangalore).
12
% decrease in total energy - compared to REB (Bangalore)
REB - 400 X 200 X 200 mm
0
Materials
Hollow concrete block - 400 X 200 X200 mm
2.32
Flyash brick - 230 X 110 X 75 mm
3.16
Perforated brick - 235 X 110 X 72 mm
2.61
Normal brick - 229 X 100 X 70 mm
3.17
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50
Percentage
Graph 8: % decrease in Total Annual Energy Consumption for alternative walling Materials
(Bangalore).
From the simulation results in graphs 7 and 8 it is observed that REB and perforated brick
consumes more chiller energy as well as more total energy compared to other walling
materials. The model considered for simulation is a conditioned building in which naturally
ventilated conditions are not included. In moderate climate model internal load becomes a
cause for higher chiller consumption as compared to hot and dry climate, which is a more
severe climate than temperate climate. As a result REB is not as beneficial as it is in other
climates. Normal bricks and fly-ash bricks shows a decrease of 4.81 – 4.76 % in chiller
energy consumption and also a decrease of 3.17 – 3.16 % in total energy consumption
compared to that of REB.
% increase in Chiller energy - compared to REB (Delhi)
Materials
Hollow concrete block - 400 X 200 X200 mm
Flyash brick - 230 X 110 X 75 mm
Perforated brick - 235 X 110 X 72 mm
Normal brick - 229 X 100 X 70 mm
0.93
0.005
0.21
0.52
0.000.100.200.300.400.500.600.700.800.901.00
Percentage
Graph 9: % Increase in Chiller Energy Consumption for alternative Walling Materials (Delhi).
13
% increase in total energy - compared to REB (Delhi)
Materials
REB - 400 X 200 X 200 mm
0
Hollow concrete block - 400 X 200 X200 mm
Flyash brick - 230 X 110 X 75 mm
0.67
0.00
Perforated brick - 235 X 110 X 72 mm
0.15
Normal brick - 229 X 100 X 70 mm
0.31
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80
Percentage
Graph 10: % increase in Total Annual Energy Consumption for alternative walling Materials
(Delhi).
% increase in Chiller energy - compared to REB (Chennai)
Materials
REB - 400 X 200 X 200 mm
0
Hollow concrete block - 400 X 200 X200 mm
0.16
Flyash brick - 230 X 110 X 75 mm
0.37
Perforated brick - 235 X 110 X 72 mm
0.31
Normal brick - 229 X 100 X 70 mm
0.00
0.44
0.10
0.20
0.30
0.40
0.50
Percentage
Graph 11: % Increase in Chiller Energy Consumption for alternative Walling Materials
(Chennai).
% increase in total energy compared to REB (Chennai)
Materials
REB - 400 X 200 X 200 mm
Hollow concrete block - 400 X 200 X200 mm
Flyash brick - 230 X 110 X 75 mm
Perforated brick - 235 X 110 X 72 mm
Normal brick - 229 X 100 X 70 mm
0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40
Percentage
Graph 12: % increase in Total Annual Energy Consumption for alternative walling Materials
(Chennai).
14
2.1.6 Conclusion
Analyzing the chiller consumption for REB in different climate zones indicates that REB‟s are
more efficient in hot dry climatic zone when compared with other climatic zones. (Refer
graph 7.8.9.10.11 and 12).Comparing the percentage increase in energy consumption using
other walling materials and their assemblies shows that different materials act differently in
different climatic zones based on their thermal and surface properties.
% increase in annual chiller energy consumption compared to REB Ahmedabad
1
0.9
0.8
Percentage
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
REB
Perforated brick
Flyash brick
Normal brick
Hollow concrete
block
Materials
Graph 13: Showing lowest chiller consumption of REB.
% Increase in annual consumption compared to REB - Ahmedabad
0.8
0.7
Percentage
0.6
0.5
0.4
0.3
0.2
0.1
0
REB
Perforated brick
Flyash brick
Normal brick
Hollow concrete
block
Materials
Graph 14: Showing REB‟s lowest annual energy consumption compared to other materials.
15
2.2
Quantifying resource savings
Brick /Wall Types
A.
B.
C.
D.
E.
Normal bricks
+
inside
plaster
Perforated
bricks + both
side plaster
Fly ash wall +
both
side
plaster
Hollow
concrete
Blocks + both
side plaster
Resource
efficient bricks
+
inside
plaster
Dimensions
(mm)
Volume /
brick(m³)
Weight/brick
(Kg)
Density
of
material
3
(kg/m )
1700 1750
229 X 100 X 70
0.0016
2.75
235 X 110 X 72
0.0018
230 X 110 X 72
Source
Jay Jalaram
bricks, Godhra
2.7
1400 1500
Jay Jalaram
bricks, Godhra
0.0018
3.5
1850 1900
Kesarjan,
Ahmedabad
400 X 200 X
200
0.016
20
1350 1400
Kesarjan,
Ahmedabad
400 X 200 X
200
0.016
11
694 783
Wienerberger,
India
Table 4: Comparative Wall types and Dimensions
2.2.1 Comparative carpet areas
Carpet areas vary with respect to the thickness of the material used for walls. Comparing
different wall materials for built up area of 100 m², it is found that maximum of 91.52 m² is
available as usable carpet area by using resource efficient bricks whereas other materials
like normal bricks, fly-ash bricks, perforated bricks and hollow concrete blocks provide lesser
available carpet area comparatively as in (Graph 15).
Fly-ash brick 230 X 110
X 72 mm
Perforated brick 235 X 110
X 75 mm
REB 400 X 200 X 200
mm
Normal brick 229 X 100
X70 mm
Hollow concrete block
400 X 200 X 200 mm
16
Table 5: Comparative carpet area available using different wall types.
Sr. no.
Material
Plaster
Comparative carpet
area available using
different wall types
1
Normal brick - 229 X 100 X 70
mm
inside plaster
90.36
3
Perforated brick - 235 X 110 X 72
mm
Fly-ash brick - 230 X 110 X 75
mm
outside and inside
plaster
outside and inside
plaster
4
Hollow concrete block - 400 X
200 X200 mm
outside and inside
plaster
90.8
5
REB - 400 X 200 X 200 mm
inside plaster
91.52
2
85.08
89.6
Comparative carpet area available using different types of wall
REB - 400 X 200 X 200 mm
91.52
Materials
Hollow concrete block - 400 X 200 X200
mm
90.8
Flyash brick - 230 X 110 X 75 mm
89.6
Perforated brick - 235 X 110 X 72 mm
85.08
Normal brick - 229 X 100 X 70 mm
90.36
80
82
84
86
88
90
92
94
Area m2
Graph 15: Comparative carpet area available using different wall types.
2.2.2 Comparative area of walls
Wall area is the amount of space occupied by walls among built up area. As mentioned
earlier, the carpet area available is higher in REB hence the wall area occupied is also lesser
when compared to other wall materials. For instance, for 100 m² of built up area, the wall
area occupied by REB is 8.48m² which is lesser than other materials, as in (graph 16),
perforated brick wall occupies maximum that is 14.92m²,next Fly ash brick wall and hollow
concrete block wall occupies 10.4m² and 9.2m2 of wall area.
17
Table 6: Comparative area of space occupied by walls.
Sr. no.
Material
Plaster
Comparative area of
space occupied by
walls
inside plaster
9.64
1
Normal brick - 229 X 100 X 70 mm
2
Perforated brick - 235 X 110 X 72
mm
outside and inside plaster
14.92
3
Flyash brick - 230 X 110 X 75 mm
outside and inside plaster
10.4
4
Hollow concrete block - 400 X 200
X200 mm
outside and inside plaster
9.2
5
REB - 400 X 200 X 200 mm
inside plaster
8.48
Comparative area of space occupied by walls
REB - 400 X 200 X 200 mm
8.48
Materials
Hollow concrete block - 400 X 200 X200…
9.2
Flyash brick - 230 X 110 X 75 mm
10.4
Perforated brick - 235 X 110 X 72 mm
14.92
Normal brick - 229 X 100 X 70 mm
9.64
0
2
4
6
8
10
12
14
16
Area m2
Graph 16: Comparative wall area occupied by different wall types.
2.2.3
Comparative Volume of walls
Table 7: Comparative volume of walls occupied by different wall types.
Sr. no.
Material
Comparative volume
of walls occupied by
different walls types
1
Normal brick - 229 X 100 X 70 mm
28.8
2
Perforated brick - 235 X 110 X 72 mm
31.8
3
Fly-ash brick - 230 X 110 X 75 mm
31.2
4
Hollow concrete block - 400 X 200
X200 mm
27.6
5
REB - 400 X 200 X 200 mm
25.44
18
Note: Calculations done to calculate the total volume of the walls for the base case are done
considering English bond masonry for all alternative walling materials. Thickness of the
plaster is also considered in calculating the volume of the walls.
Volume of the wall using REB for the base case building of size 10M X 10M X 3 M is about
25.44 m³ that is comparatively lesser than normal brick and hollow concrete block wall that
results to 28.8 m³ and 27.6 m3. Volume of perforated brick wall is highest that is about
31.8m³ of volume per unit wall. (graph 17)
Comparative volume of walls occupied by different walls
REB - 400 X 200 X 200 mm
25.44
Materials
Hollow concrete block - 400 X 200 X200 mm
27.6
Flyash brick - 230 X 110 X 75 mm
31.2
Perforated brick - 235 X 110 X 72 mm
31.8
Normal brick - 229 X 100 X 70 mm
28.8
0
5
10
15
20
25
30
35
Volume m3
Graph 17: Comparative volume of walls occupied by different wall types.
2.2.4 Usage of material per unit area
Comparing the number of bricks consumed per unit area of a wall, around ± 12 bricks of
REB and hollow concrete blocks are used, whereas for perforated bricks and fly-ash bricks
around ±58 bricks are used, and ± 62 normal bricks are used for every unit m² of wall.
Materials
Comparative no. of bricks / blocks used per m2 area of wall
REB - 400 X 200 X 200 mm
12
Hollow concrete block - 400 X 200 X200 mm
12
Flyash brick - 230 X 110 X 75 mm
58
Perforated brick - 235 X 110 X 72 mm
59
Normal brick - 229 X 100 X 70 mm
62
0
10
20
30
40
50
60
70
no. per m2
Graph 18: Comparative Number of bricks used per m² area of wall.
19
2.2.5 Comparative density for different walling materials
Comparing the density of Fly-ash brick with REB block, REB‟s density is approximately 3
times lesser than fly-ash brick. Density of REB is approximately 2 times lesser compared to
other walling materials.
Comparative densities of alternative walling materials
REB - 400 X 200 X 200 mm
783
Materials
Hollow concrete block - 400 X 200 X200 mm
1400
Flyash brick - 230 X 110 X 75 mm
1900
Perforated brick - 235 X 110 X 72 mm
1500
Normal brick - 229 X 100 X 70 mm
1750
0
400
800
1200
1600
2000
kg/m3
Graph 19: Comparative densities of alternative walling materials.
2.2.6
Comparing carpet area between Square and Rectangle plan forms for different
wall materials
It is seen that the area availability is comparatively lesser in rectangular plan forms than
square plan for REB‟s, hollow concrete block wall, Fly ash wall, and normal brick wall.
Comparing carpet area between square and rectangle plan
forms for different wall materials
Materials
REB- 400 X 200 X 200
Hollow concrete brick
Fly Ash brick
CASE 2 - 100 m2 Area (1:2
Rectangular space)
Perforated bricks
CASE 1 - 100 m2 Area (1:1
sqaure space)
Normal Bricks
87.00 88.00 89.00 90.00 91.00 92.00
Area m2
Graph 20: Comparative carpet area between 1:1 & 1:2 Plan form.
20
2.2.7
Comparing wall areas between Square and Rectangle plan forms for different
wall materials
As seen in the (graph21) it is observed that the rectangle plan (1:2) aspect ratio has
occupies higher wall areas compared to others. Wall area occupied by REB in both the
cases is less compared to wall area of other walling materials.
Comparing area occupied by walls - Between square and
rectangular plan forms
Materials
REB- 400 X 200 X 200
Hollow concrete brick
Fly Ash brick
CASE 2 - 100 m2 Area (1:2
Rectangular space)
Perforated bricks
CASE 1 - 100 m2 Area (1:1
sqaure space)
Normal Bricks
0.00 2.00 4.00 6.00 8.0010.0012.00
Area m2
Graph 21: Comparative wall area between 1:1 & 1:2 Plan form.
2.2.8
Comparing volume of walls between Square and Rectangle plan forms for
different wall materials
From (graph 22) it is observed that volume of all the materials for square plan is less
compared to rectangular plan. REB has the least volume of walls compared to other
materials.
Comparative volume of walls -Between square and
rectangular plan forms
Materials
REB- 400 X 200 X 200
Hollow concrete brick
Fly Ash brick
CASE 2 - 100 m2 Area (1:2
Rectangular space)
Perforated bricks
CASE 1 - 100 m2 Area (1:1
sqaure space)
Normal Bricks
0.00
10.00 20.00 30.00 40.00
Volume m3
Graph 22: Comparative volume of walls between 1:1 & 1:2 Plan form.
21
Six different cases with different floor area and aspect ratio are analysed to compare the
resource savings using different materials. The calculation details are shown in table 7. The
cases are as follows:
Case 1 – 100m2 area (1:1 square space), Case 2 – 100m2 area (1:2 rectangular space),
Case 3 – 500m2 area (1:1 square space), Case 4 – 500m2 area (1:2 rectangular space),
Case 5 – 1000m2 area (1:1 square space), Case 6 – 1000m2 area (1:2 rectangular space).
2.3
Conclusion
Ranking of alternative walling materials:
Note:

Ranking 1-8 shows the efficiency of the materials.

1 - shows material with highest efficiency and 8 - shows material with least efficiency.

One REB is equal to approx. 8-8.5 normal bricks.
Table 8: Ranking of walling materials.
Materials
Normal
Perforated
Fly-ash
Hollow
brick
brick
brick
concrete
REB
block
U-values
4
2
3
5
1
Annual Chiller
4
2
3
5
1
4
2
3
5
1
1
2
3
5
4
Density
4
3
5
2
1
Available
3
4
5
2
1
3
4
5
2
1
4
5
3
2
1
energy
consumption
Total
annual
energy
consumption
Volume
per
brick / block
carpet area
Area occupied
by walls
Volume
occupied
by
walls
22
Blocks
used
5
4
3
2
1
3
5
4
2
1
3
5
4
2
1
2
3
1
4
5
2
/m of wall
Wall area in
square
and
rectangular
plan
Carpet area in
square
and
rectangular
plan
Cost per brick
/ block
Note: REB is considered without outside plaster, hence the carpet area of REB has
increased compared to Hollow concrete block.
Following are the benefits of using REB’s
1. Less weight and volume (less dead load) when compared to equivalent size of
normal brick.
2. Uniform size, shape and better finish.
3. Less mortar and less plaster.
4. Easy construction.
5. Less u-value (heat transfer co-efficient).
6. Less annual chiller energy and total energy consumption.
7. More carpet area and less wall area in both square and rectangular form plans.
8. Less number of blocks per m2.
9. Less cost per unit when compared to equivalent size of normal brick.
23
Table 9: Showing comparative resource savings using different wall materials.
S.No
.
Material
Type
Size of unit block
(mm) (lxbxh) (b
considered as envelop
width with plaster)
Volume
of unit
block
(mm3)
A
Normal
Bricks
240 X 100 X 70
0.0016
B
Perforate
d bricks
265 X 110 X 75
0.0021
Thermal
performance
Weigh
t of
unit
block
(Kg)
Total
no.of
blocks
per
m2
area
K
Value
U Value
(W/m2K
)
0.811
W/mK
2.187
3
1.716
Total Area (m2)
Area of walls (m2)
Carpet Area (m2)
Volume of walls (m3) (taking 3 m floor to ceiling ht.)
Case
1
Case
2
Case
3
Case
4
Case
5
Case
6
Case
1
Case
2
Case
3
Case
4
Case
5
Case
6
Case
1
Case
2
Case 3
Case 4
Case 5
Case 6
Case
1
Case
2
Case
3
Case
4
Case 5
Case 6









21.47
22.77
30.36
32.20
90.36
89.82
478.53
477.23
969.64
967.80
28.80
30.53
64.40
68.30
91.07
96.61
2.7









23.70
25.14
33.52
35.56
89.40
88.76
476.30
474.86
966.48
964.44
31.80
33.71
71.10
75.41
100.55
106.67
1.929
3.5









23.25
24.66
32.88
34.89
89.60
88.98
476.75
475.34
967.12
965.11
31.20
33.07
69.76
73.99
98.65
104.66
C
Fly-Ash
brick
260 X 110 X 72
0.002
0.54
to
0.70
W/mK
D
Hollow
concrete
brick
400 X230X200
1840000
0
0.018
2.251
20









20.57
21.82
29.09
30.86
90.80
90.25
479.43
478.18
970.91
969.14
27.60
29.26
61.71
65.45
87.27
92.58
400 X 212 X 200
1696000
0
0.016
1.1
11.1









18.78
19.92
26.56
28.18
91.52
91.10
481.22
480.08
973.44
971.82
25.44
26.97
56.88
60.33
80.44
85.34
3249000
0.003
2









16.99
18.02
24.03
25.49
92.40
91.94
483.01
481.98
975.97
974.51
22.80
24.17
50.98
54.07
72.09
76.48
2349000
0.002
3









8.05
8.54
11.38
12.08
96.40
96.18
491.95
491.46
988.62
987.92
10.80
11.45
24.15
25.61
34.15
36.23
REB- 400
X 212 X
200
E
190x190x9
0
290x90x90
withou
t
plaster
The analysed results are shown in headings 9.2.6, 9.2.7 and 9.2.8 respectively.
24