-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
1/23
1
WOOD WOOL CEMENT PANEL (WWCP) AS ALTERNATIVE BUILDING
MATERIAL IN MALAYSIA.
Loo Kok Hoo, Elias Salleh, Parida Bt Md Tahir and Sabarinah Sh AhmadDepartment of Architecture, Faculty of Design and Architecture,University Putra Malaysia
Department of Forestry, Universiti Putra Malaysia,
Department of Architecture, Faculty of Architecture, Planning & Surveying,
Universiti Teknologi MARA, Malaysia.
HP: 012-2835168
Email: [email protected]: 7, Jalan Hujan Batu, Overseas Union garden, Jalan Klang Lama, 58200 Kuala Lumpur,
Malaysia
ABSTRACT
The research investigates the thermal performance of wood wool cement panel (WWCP) as
alternative building material in Malaysia. WWCP is one of the building materials used in
temperate countries but not common in Malaysia.
The research was conducted in two stages. Stage one compared the thermal performance of
WWCP with conventional cement and bricks by field measurement. Two test cells wereconstructed, one in WWCP and the other in conventional cement and bricks in UPM campus
with field measurements carried out over a period of one month to monitor the respective
thermal performance. Stage two is using Tas computer simulation to verify if WWCP a suitable
alternative building materials in tropical Malaysia. Some preliminary results obtained from field
recording of temperatures inside and outside the building are presented and comments made on
their actual performance relative to their expected performance.
Keywords: Thermal Performance, Sustainable Buildings, Wood Wool Cement Panel, Thermal
Monitoring
mailto:[email protected]:[email protected] -
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
2/23
2
1. IntroductionThe objective is to use test cells and simulations to investigate the thermal performance of
WWCP in the hot and humid tropical climates as building wall envelopes in Kuala Lumpurcompare to conventional bricks walls. Two test cells were constructed for both cases, field
measurements were recorded and Tas simulations were carried out in the investigation.
2. MethodologyTwo test cells were constructed in University Putra Malaysia (UPM) campus for fieldmeasurement. Test Cell One (TC1) is the base case using conventional plastered brick wall and
Test Cell Two (TC2) is the test case using 75mm thick Wood Wool Cement Panel. Equipment
used for the field measurements are Hobo meter and mini Deltalog Meters over a selected datesof the years. Results were tabulated and plot into graph for analysis.
Figure 1: Two test cells, base and test cells were installed in UPM.
Figure 2: Hobo Meter was placed on the exterior and interior of the Test Cells, above the window levels.
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
3/23
3
Figure 3: HD32.2 Deltalog Meter for field measurements
3. Sustainable Building MaterialWood Wool Cement Panel (WWCP)Wood Wool Cement Panels (WWCP) is one of the materials made from wood wool, Portland
cement, salt solution and water compressed into a module with various thicknesses. This
material is available in Europe since 1950s and has proven its versatility and durability intemperate climate, with the properties of fire resistance, wet and dry rot resistance, termite and
vermin resistance, thermal insulation and acoustic performance, however it is not common in
Malaysia.
Figure 4: the textures of the wood wool cement panels.
4. Constructions of WWCPThe constructions of the panels are in modular form (600mmx2100mm / 2400mm), the fixing
of the joint can be using C-Channel for every three panels and both sides plastered. There are
two types of WWCP commonly used: 50mm thick and 75mm thick for walls, in roof insulation,normally 50mm or 75mm thick panels can be used. The test cell is using 75mm WWCP.
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
4/23
4
Figure 5: Modular construction methods (Courtey of Duralite Sdn Bhd, Malaysia)
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
5/23
5
5. Properties and specification of Brick wall and WWCPThe thermal properties of woodcement panels and standard values are as follows:
Figure 6: Properties of different materials for construction
6. Field measurementTest Cells One and Two were measured in the equinox month of September 2009 usingHobometers. The days taken were from 21st Sept 2010 to 27th Sept 2010 including the
summer equinox in 23rd
Sept 2010. The reading on 23rd
Sept 2009 was used for
comparison since the Sun is directly above the horizon and nearest to the equator. Themajor components in the Hobo measurement are light intensity, relative humidity, dew
point and temperature. The internal data and performances of Test Cell One (TC1) and
Test Cell Two (TC2)(WWCP) are combined and compared on 23 Sept 2010.
7. Analysis of the dataThe data from the results were analyzed and compared.
Figure 7: Light Intensity.
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
6/23
6
The light intensity
The light intensity of TC1 is lower than TC2 (WWCP). The highest value recorded forTC1 is 540 lux and TC2 (WWCP) is 710Lux. This mean WWCP has permit higher
daylight penetration.
Figure 8: Temperature
TemperatureFor higher daylight penetration, the internal temperatures of both test cells are similar.
The temperatures in TC2 (WWCP) are overlapping with TC1 until 12noon, thereafter,
TC2 (WWCP) indicated a higher value maintained until 1800hrs. at 1500hr, TC1 is35.4C and TC2 (WWCP) 35.6C. After 1500hrs, the temperature in TC1 dropped more
significantly than TC2 (WWCP). This indicated that TC2 (WWCP) is able to absorbedand maintained heat energy more than the TC1.
Figure 9: Raltive Humidity
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
7/23
7
Relative Humidity
The relative humidity (Rh) of TC1 is lowered than TC2 (WWCP) at the night by roughly2%. From 0800hrs to 1300hrs, the Rh drop is similar and TC2(WWCP) has a lightly
higher value (1%), from 1300hrs to 1800hrs, the Rh increases equally, then from 1800hrs
2000hrs, Rh of TC1 had a sudden jump, reason unknown, after 2000hrs, the two graphs
are overlapping with TC2(WWCP) on a slightly higher value. The overall patternindicated TC2 (WWCP) has a generally higher Rh values. This could be due to the
porosity of the materials that are able to keep water vapour. The plastered brick wall in
TC1 has less ability to keep water vapour.
Figure 10: Dew Point
Dew Point
As defined inAtmospheric Science: An Introductory Survey by Wallace & Hobbs, " DewPoint is the temperature at which air must be cooled at constant pressure in order for it to
become saturated with respect to a plane surface of water". Simply put, it is thetemperature where the air becomes saturated. The graph above indicated the overall Dewpoint for TC2 (WWCP) is higher than TC1. At night, the Dew points fluctuated from 24-
26C, during the day, 0900hr to 1700hrs; it fluctuated between 20-26C.
Results interpretation
The above results indicated that
Description TC1 TC2(WWCP)
Light Intensity Lower light intensity by
(710-540) 160lux
WWCP allows higher light
intensity to the interiorTemperature Similar graph. Lower value Similar graph, higher value
Relative Humidity Similar graph. Lower value Similar graph, higher value
Dew Point Similar graph. Lower value Similar graph, higher valueFigure 11: Comparison of field measurement properties
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
8/23
8
The results show that TC2 (WWCP) is able to allow more daylight into the interior, however,
this only slightly increase the internal temperature. The nature of porosity of the materials helps
in maintaining water vapour and this increases the relative humidity and dew point temperatures.
The next section will be using Tas simulation to model the test cells for more comprehensive
analysis of the thermal performance of the materials.
8. Performance Analysis using Tas :The model was constructed using Tas for further comparison and analysis. The Test Cell is
divided into two zones, Zone one is for internal space and Zone two is the canopy at perimeter.
Figure 12: Plan and perspective views of the Tas Model
9. Properties of Materials:The respective properties of the materials are tabulated below:
Base conventiona 215mml Brick wall (External)
Layers M-Code Width Conductivity Convention Vapour Density Specific Description
mm WK1
m1
Coeff ic ient Diffusion Kg/m3 Heat
W/m2C) Factor J/Kg.K
Inner1 am1brick\8 215 0.65 0 9.6 1530 920 Brick Common 1*3
Base conventional 215mm Brick wall (External)
Internal External Internal External Solar Acceptance Emmisivity Conductance Time
Flow Direction U Value U value R value R value Ext surf Int Surf External Internal (W/m.K) Const
W /(mK) W /(mK) (mK/W) (mK/W)
Horizontal 1.693 1.997 0.591 0.501 0.725 0.725 0.93 0.93 3.023
Upward 1.884 2.124 0.531 0.471
Downward 1.491 1.849 0.671 0.541
Figure 13 Basic Properties of External Brick Wall
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
9/23
9
The constructon properties of 75mm WWCP having 10mm plastered on both sides as below:75mm plastered Wood Wool Cement Panel Wall (WWCP)
Layers M-Cod e Width Co nduc tivity Co nvect ion V apou r Density Spec ific Desc ri pt ion
mm WK1
m1
Coeff ic ient D if fusion Kg/m3 Heat
W/m2C) Factor J/Kg.K
Inner1 am1\plast\1 10 0.079 0 11 400 837 Lightweight plaster 1*4
wwcp2 75mm WWCP 75 0.9 0 0.5 390 1000 Wood Wool Cement Panel
Inner3 am1\plast\1 10 0.079 0 11 400 837 Lightweight plaster 1*4
75mm plastered Wood Wool Cement Panel Wall (WWCP)
Internal External Internal External Solar Acceptance Emmisivity Conductance Time
Flow Direction U Value U value R value R value Ext surf Int Surf External Internal (W/m.K) Constant
W /(mK) W /(mK) (mK/W) (mK/W)
Horizontal 0.743 0.796 1.346 1.256 0.4 0.4 0.9 0.9 0.92 1.16
Upward 0.777 0.815 1.286 1.226
Downward 0.701 0.771 1.426 1.296 Figure 14: Construction properties of 75mm thick WWCP
10.Analysis in Kuala Lumpur Context:Based on the data input, the building was simulated in Tas for Base Case (TC1) and
(TC2)WWCP and performance results are below:
na = not applicable.
Figure 15: Performance Summary comparison between Brick wall and WWCP for Kuala Lumpur climate
Discussions:
The discussion is based on data that show differences and assumed that the test cell is meant fornatural ventilation, hence the values of heating, cooling loads and latent energies are zero and
not discussed. Both cases are exposed to the same external temperature and criteria as shown in
items 13-16 of Fig 12.1.
a. Air temperatureThe test case TC1 has lower maximum temperature (40.48C) than base case TC2
(42C) and it happen 17 hours a day for 237 days compared to base case (61 days
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
10/23
10
and 14 hrs/day). This means the test case TC2 has lower temperature than the
base case TC1 inside.
b. HumidityMaximum humidity happened at zone 2 and similar for both cases (TC1: 99.67%,
TC299.89%). However, the test case TC2 has more humid days in a year (test:302 days, base: 288 days) and longer hours per day.
Minimum humidity is lower in base case TC1 (10.28%), has more days (Base
TC1: 61 days, Test TC2:11 days) and less number of hours per day (Base TC1:14
hrs, Test TC2:17 hrs). The above results indicate WWCP is able to retain
moisture and hence more humid.
c. Resultant TemperatureResultant temperature is an average of the dry bulb temperature and the meanradiant temperature in degree Centigrade (C). TC1 and TC2 are having similar
and it occurs in Zone 2, which is the perimeter overhang area and exposed toopen space, hence will not affect the internal space.
d. Mean Radiant Temperature (MRT)Mean radiant temperature (MRT) is a measure of an occupant's perception of the
radiant temperature in the zone. MRT is calculated as a weighted average of thezone's surface temperatures, modified by the effects of radiant gains (plant,
incidental gains and the diffuse component of solar gain). It is displayed in
degrees centigrade (C)i
Both maximum and minimum MRT happened in zone 2 which is exposed to open
space. TC2 has higher Max MRT (59.83) and lower Min MRT (21.55), withwider range for MRT (59.83-21.55= 38.38) compare to Base case TC1 (59.03-
22.9=36.13). The number of days and hours are the same in Max MRT, however,
in Min MRT, the Base case TC1 has 302 days but Test case TC2 only has 8 days.
This means WWCP has very few days to maintain low temperature.
Figure 16: Overall Performance of brick wall (Base TC1) and TC2 (WWCP) walls of 75m
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
11/23
11
In summary, the overall performance patterns of the materials are similar as in above graph. The
general performance of WWCP has larger maximum and minimum range in temperature andhumidity compared to brick wall. Further detailed analysis looks at their overall performance in
the two solstices and equinoxes, instead of select only one day, a range of 6 days was used:
March (days 78-84), June (days 170-176), September (days 263-269) and December (days 353-
359).
11.Analysis of various thermal propertiesThe followings performance criteria were compared in Zone 1, which is the interior zone of thetest cell. The analysis of the thermal properties is on
a. Mean Radiant Temperatureb. Dry Bulb Temperaturec. Resultant Temperatured. Relative Humiditye. Building Heat Transferf. External Conduction Opaque
11.1. Analysis: Zone 1 Mean Radiant Temperature (MRT)
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
12/23
12
Figure 17: Mean Radiant temperatures in two equinoxes and solstices
The MRT of the Test Material (TC2 WWCP) is lower during daytime and similar to Base
material (TC1) at night. The range for TC1 is between 26C to 38C (78 days March 1300 hrs)
and TC2 is 26C to 36C (175 days, June 1300hr). TC2 always has a lower value than TC1.The gradient of the TC2 is lower; it means it takes longer time to increase in temperature than
TC1.
11.2 Analysis: Zone 1 Dry Bulb Temperature (DBT)
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
13/23
13
Figure 18: Dry Bulb Temperatures in two equinoxes and solstices
The Dry Bulb Temperature (DBT) appears to be similar pattern as in MRT.
TC2 always has a lower temperature than TC1.
TC1 has temperature range 25C to 39C (78 days, March 1300hr)
TC2 has temperature range 25C to 37C (78 days, March 1700hr)
The time taken to achieve the highest temperature by TC2 is lagged by 5 hours (1300hrs to1700hrs) on the same days. This is shown by the lower gradient of the TC2 graph. This means
TC2 (wwcp) can maintain lower temperature and the rise of temperature is slower than TC1.
11.3 Analysis: Zone 1 Resultant Temperatures (RT)Resultant temperature is an average of the dry bulb temperature and the mean radiant
temperature in degree Centigrade (C). From the previous readings, the results of RT shows
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
14/23
14
TC2 always has a lower temperature than TC1.
TC1 has temperature range 26C to 39C (78 days, March 1300hr)TC2 has temperature range 25C to 37C (78 days, March 1700hr)
The time taken to achieve the highest temperature by TC2 is lagged by one hour (1300hr to
1400hr) on the same days. TC2 (wwcp) with lower gradient, can maintain lower temperature and
the rise of temperature is slower than TC1.
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
15/23
15
Figure 19: Resultant Temperature in two equinoxes and solstices
11.4 Analysis: Zone 1 Relative Humidity RH
Relative humidity (RH) is expressed as a percentage. TC1 always has a lower humidity thanTC2:
TC1 has humidity range 13%C to 32%C (357 days, Dec 0900hr)
TC2 has humidity range 14%C to 32%C (357 days, Dec 0900hr)From 0900hrs to 1700hrs, TC2 is more humid than TC1 and from 1700hrs to 0900hrs; humidity
is similar with TC1 slightly higher than TC2. The time taken to reach the peak humidity every
day is similar as shown by the graph.
This means the overall range of humidity for TC1 and TC2 are from 13% to 32%, however,from 0900 to 1700hrs, TC2 has higher humidity percentage. This could be due to the fact that
during the night, the material TC2 is porous, it absorbs moisture and keep within the pores while
the surface while TC1 brick wall keeps most of the water vapour on the surface, hence humiditylevel is similar but slightly higher in TC1, During day time, water vapour from TC1 evaporates
faster than TC2 and TC2 takes longer time to evalporate due to vapour trapped within the pores,
this explains why TC2 has higher humidity percentage than TC1. This property is conducive to
reduce the internal space temperature in the day.
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
16/23
16
Figure 20: Relative humidity in two equinoxes and solstices
11.5 Analysis: Zone 1 Building Heat Transfer (BHT)
Building Heat Transfer represents the sum of heat gains from 2 sources: (1) heat entering thezone from a Link, Null Link or Internal building component, and (2) heat released into the zone
which had been temporarily stored in the air (this quantity is positive when the air temperature is
falling and negative when it is rising). It is measured in Wattsii
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
17/23
17
Figure 21: Building Heat Transfer (BHT) in two equinoxes and solstices
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
18/23
18
The Base Material TC1 has a much higher positive (+) and negative (-) values than the Test
Material TC2. TC1 Ranges from -700W to 300W (175 days June 2100hrs) (difference: 1000W).TC2 Ranges from -40W to 120W (difference: 160W). TC1 is about 6.25 times more than TC2
(1000/160=6.25)
Day time from 0900hrs to 1800hrs, TC1 temperature increased tremendously in negative values,
(more than -400 W) while TC2 increase in positive value but below +100W, much less in
magnitude than TC1. Negative values indicate air temperature increase and positive valuesindicate air temperature falling. This means the sum of heat gain by TC1 is about 500W more
and in faster rate than TC2.
At night, from 1800hrs to 0900hrs, TC1 positive values can increase up to 300W, and TC2
remains more or less constant at -40W. Temperature fall in TC1 is fast and comparatively more,
while TC2 remains constant, with minimum and constant heat transfer.
The large fluctuation range for TC1 shows heat (energy) transfer during the day and night. TC1is difficult to keep heat with the internal space, while TC2 with a relatively constant and narrow
range is able to maintain the energy within. For example, if air-condition is used, the energy willdissipate faster through the walls in TC1 than TC2.
11.6. Analysis: Zone 1 External Conduction Opaque (ECO)
ECO is the heat gained (or if negative lost) through the inside surfaces of opaque componentsexposed to the outside or touching the ground measured in Watts (W). Similarly TC1 has much
higher fluctuation range than TC2 in ECO.
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
19/23
19
Figure 22: External Conduction Opaque in two equinoxes and solstices
Heat gained for TC1 ranges from -200W to 780W, with a magnitude of 980WHeat gained for TC2 ranges from -100W to 180W, magnitude 280W, about 3.5 times less.
In daytime, TC1 increases to peak from 1300hrs to 1700hrs, with values all above 400W and
even peak at 780W in March. For the same period, TC2 decreases to trough (lowest) to only -
50W average. This means in the day, TC1 is absorbing a lot of energy (positive value),especially heat energy and TC2 is losing energy (negative value). The difference is at least
450W.
At night, 1700hrs to 0700hrs, TC1 is losing heat energy (negative value from -200W to -300W)
and TC2 gain heat energy (positive values from 50W to 70W). This means TC1 loses energy
about 4 times faster than TC2 at night.
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
20/23
20
The rate of heat transfer (gain or lose) is worked out based on information in Sept, days 263-364
in next section.
11.7 The rate of heat transfer for TC1 and TC2
Figure 23: Rate of Heat Transfer comparison.
Day Time Night time
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
21/23
21
Daytime
To find out the rate of heat transfer, taking readings from Sept days 263.
Daytime Part A 0800-1200hrs
For TC1, Taking gradients: Y=640W and X=3 hrs. Y/X=640/3=213.3W/hr (heat gain)
For TC2, Y=-90 and X=3hrs, Y/X=-90/3=-30W/hr (heat loss)
TC1 is absorbing heat (gain) at 213W/hr and TC2 is releasing heat (loss) at 30W/hr
Daytime Part B 1300-1700hrs
TC1: Y=-640W, X=4 Y/X=-640/4= -160W/hrs (heat loss at lower rate)
TC2:Y=-4W, X=-4hrs Y/X=4/4=1W/hrs (heat gain at lower rate)
TC1 start to reduce the rate of energy absorption (heat gain) 160W/hr
TC2 is increasing the rate of releasing heat (heat loss) at 1W/hr
While TC1 absorbs energy (heat gain) from the Sun when the day is hot, TC2 releases
energy in the day (heat loss). This is possible due to the fact the water vapor and air trapped
in TC2. Water has a high specific heat index. This means that water can absorb a lot of heat
before it begins to get hot and the air can its latent heat can carry the heat away fast. Water
vapour trapped in the previous night takes a longer time before the heat of the sun reaches
the interior, hence energy still releasing into the interior at rate of 30W/hr (heat loss),
eventually when the heat from the sun slowly built up, the rate of releasing (heat loss) goes
down to 1W/hr.
Night Time
TC1 had two rates for heat loss
a. Y=-200W X=2hrs, Y/X=-100W/hrb. Y=-210-(-60)=150W,X=9hr,
Y/X=16.7W/hrAverage rate 116W/11hrs=10.54W/hr (heat loss)
TC2 indicated various rates in the night to heat gain
a. Y=20W/X=2hrs=10W/hrb. Constant for 3 hrsc. Y=20W/X=3hrs=6.67W/hrd. Y=-20W/X=5.5hrs=-3.64W/hre. Y=-40W/X=2hrs=-20W/hr
Average rate=40.31/15.5hr=2.6W/hr (heat gain)
Similarly, due to the latent heat of water vapour and air, the heat gain at night is slow forTC2. TC1 on the other hand, stored abundance heat in day time; the heat is dissipating out
at night (heat loss)
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
22/23
22
12.A summary of the properties:The comparison of properties is summarized as below:
Base Material
(TC1)
ConventionalBrick walls.(Tas)
Test material TC2
(WWCP) 75mm
thick plastered
(Tas)
Comment based on TAS
simulations results
Field Measurements Results
Mean RadiantTemperature (MRT)
26C to 38C 26C to 36C Slightly lower in WWCP Na
Dry BulbTemperatures (DBT)
25C to 39C 25C to 37C Slightly lower in WWCP Na
Resultant
Temperatures (RT)
26C to 39C 25C to 37C Slightly lower in WWCP Slightly lower in WWCP
Relative Humidity 13%C to
32%C
14%C to 32%C TC2 has higher humidity in
the day and similar at night
with WWCP has slightlylower values at night.
TC2 has slightly higher value
in the days and night. The
graphs are similar and almostoverlapping.
Building HeatTransfer (BHT)
-700W to300W, about 64
times more thanWWCP
-40W to 120W Temperature fall in TC1 isfast and comparatively
more, and TC2 remainsconstant, with minimumand constant heat transfer.
Na
External ConductionOpaque (ECO)
-200W to 780W -100W to 180W TC1 absorbed energy atmuch faster rate than TC2in the day and loses energyfaster in the night.
Na
Light Intensity 540 Lux 720 Lux Na WWCP has much higher lightintensity.
Dew Points na Na Na Similar with WWCP has
higher values
Fig 9.1.A summary of thermal performance of Base and Test Materials..
13.Discussions and recommendationsTwo types of materials are used for testing 1) Base Case - 215mm thick conventional brick. 2)
Test case-75mm thick WWCP with plaster on both sides. Combining the data from field
measurements and Tas simulations, we observed the following performances:
TC2 (WWCP) always has a lower temperature range than TC1 (Base) by 1to 2 C. It happens inMRT, always 2C lower on the upper temperature, and RT, 1C lower on the lower temperature.
This means TC2 (WWCP) provides a lower temperature internal environment.
Relative humidity are having similar range in TC1 (13%-32%) and TC2 (14% -32%), however,
TC2 has a higher humidity values in day and night from Field measurement, but in Tassimulation, TC2 has slightly lower values. But the overall graphs are similar and show
overlapping.
In Building Heat Transfer (BHT), the difference is significant. TC1 has a larger range (-700W-
300W) than TC2 (-40W-120W), this means, the heat gain and lost in TC1 varies a lot in the day
than TC2. The significantly lower heat transfer range in TC2 can resist the external heat from
penetrating into the internal space better and with minimum fluctuations in temperature.
-
7/30/2019 Alam Cipta Conference Write Up Sept 2010 Revised to 23 Pages
23/23
23
Similar situation happens in External Conduction Opaque (ECO), TC1 ranges from -200W to
780W while TC2 ranges from -100W to 180W. TC2 conducts much mess heat into the internal
space.
Field measurement also indicated TC2 allow more lights into the interior space and has a light
intensity of 720 lux compared to 540Lux (TC1)
What does this mean in the tropics?
It means TC2 (WWCP), just by its own nature and property, can lower the internal temperature
by 2C without any mechanical assistance and increases the internal light intensity from 540lux
to 720 lux. The narrow BHT range implies WWCP can resist external variation of temperatureand keep the internal environment more constant. Similarly the ECO in WWCP having narrower
range conducts less heat; this is fruitful to keep heat out in the day and keep heat in in the cold
night. WWCP performs better in infiltration and ventilation with its narrow value range. This
property is good in the tropics as design for ventilation is always encouraged. Also, when aircondition is used, WWCP is better to maintain the internal temperature, consumed less energy as
the fluctuation of heat loss and heat gain is smaller. It is better in keeping the internalenvironment constant with less energy. Its infiltration and ventilation values make it suitable in
the tropical conditions, especially design for natural ventilations
14.ConclusionsWood Wool Cement Panel (WWCP) has been used in temperate regions for the past 30 years butnot common in the tropics, lately, there are only less than 10 bungalows used WWCP in
Malaysia. There is no proper investigation and documentation into the suitability of this material
in the tropics. University Putra Malaysia (UPM) has been testing the materials using test cells
and recording is still ongoing.iii
The analysis using Tas software indicates that WWCP is comparable to the performance of brickand suitable in the tropics, especially in the areas of infiltration and ventilation, the performance
is better. There are other advantages of using WWCP, it is in modular system, each panel is in
600mmx2400m or 600mmx2100mm, the installation is faster and easier. The erections of wallpanels in a single storey house of area 6000mmx20000mm can be completed in two days,
traditional brick works takes about 10 days. This saves time, cost and ensure quality. As the
panels are lighter in weight than brick, the design of structural loads is less and save costs.
In short, WWCP is found to be a suitable material to be used as an alternative material to brick
in the tropics. Various thicknesses are available and the choice of application depends on cost,
and functional requirements of the buildings.
iDefinition from Help Section of Tas Software
iiDefinition from Help Section of Tas Software
iiiThe author involves in the test cells research process at present with UPM