Docstoc

Sangkertadi-Indoor Thermal Comfort-Tropical Humid

Document Sample
Sangkertadi-Indoor Thermal Comfort-Tropical Humid Powered By Docstoc
					9th SENVAR + 2nd ISESEE, Selangor, Malaysia, 1-3 December 2008


Thermal Comfort Comparison of Traditional Architecture and Modern Style
Housing in North Sulawesi - Indonesia

Sangkertadi1, A. Tungka1 , R. Syafriny2
1
 Department of Architecture, Faculty of Engineering, Universitas Sam Ratulangi, Manado, Indonesia
2
 Department of Urban & Regional Planning, Faculty of Engineering, Universitas Sam Ratulangi, Manado,
Indonesia
t_sangkertadi@yahoo.com

      ABSTRACT: The built form of the traditional Indonesian house is considered to be a prime example of
      environmental design response to regional climate conditions. Recently, in general, modern
      small/medium housing types in Indonesia has not followed the same design principles. In comparison
      with their traditional counterparts, they are of a relatively heavyweight construction; they often suffer
      from low levels of natural ventilation. The indoor environmental conditions of the modern houses are,
      generally considered thermally unsatisfactory. This study is concerning thermal sensation evaluation
      for both, traditional types and modern style of housing in Indonesia. The ten traditional houses of
      Minahasa (North Sulawesi Province) and the ten modern style houses have been, taken as house
      samples. 60 adults who were living in these houses have been taken as subject samples. Comparisons
      of thermal sensation response from the residents of these two types of housing may allow us in giving
      recommendations of housing construction quality and policy. The methods used in this research are
      numerical simulation (calculation of building heat transfer and thermal comfort) and field studies
      (questionnaires for thermal sensation and thermal environment measurement). Some of the results
      show that the respondents may feel thermally comfortable in an enclosure environment with a low air
      velocity where air temperature is in maximum of 29°C, with air humidity is about 60 %. By simulation,
      these climatic environments give a slightly uncomfortable condition, where the DISC scales are about
      1 to 1.5. Therefore, there is a different about 1 scale between theoretical approach and field
      observation.

      Keywords: Traditional Architecture, Tropical Humid, Thermal Comfort


1. INTRODUCTION

1.1. General background
In many hot countries, and also in the countries with temperate climate having hot summers, it is
interesting in utilizing passive and low-energy system for cooling the buildings, both residential and
commercial. This interest is motivated by the desire to conserve energy and to reduce the summer peak
demand for electricity caused by air-conditioning. People who are living in the regions under the hot and
humid climate since very long time ago were progressively succeed to control this climate condition
using their traditional architecture solution. Large openings, long overhangs and local materials used in
traditional constructions play an important role in optimizing ventilation rate and indoor thermal quality.
The built form of the traditional Indonesian houses are considered to be a prime example of environmental
design to response the regional climate conditions. It has a low thermal mass, extensive solar shading, and
a large number of ventilation openings.
Recently, in general, modern small/medium housing types in Indonesia (Perumnas / RSS, T-36, T-45, etc)
have not followed the same design principles. In comparison with their traditional counterparts, they are
built of a relatively heavy-weight construction, they often suffer from low levels of natural ventilation.
The environmental condition which produced by these housing types are generally considered to be
thermally unsatisfactory, and there has been a recent move towards the development of designs which
offer the thermal performance of the traditional house, whilst using modern construction technique and
low cost materials.

Paper number: 31917014
9th SENVAR + 2nd ISESEE, Selangor, Malaysia, 1-3 December 2008
The study is concerning thermal sensation evaluation for both, traditional types and modern styles of
housing in Indonesia. Five Minahasa traditional houses (in North Sulawesi Province, Sulawesi island) and
five modern style houses in Manado have been taken as house types samples. Sixty adults people (both,
men and women)who are living in these houses have been taken as random subject samples. Comparisons
of thermal sensation responds from the residents of these two types of housing, may allow us in giving
recommendations of housing construction quality and policy.

1.2. Indonesia Tropical Traditional Shelter : natural strategy to achieve thermal comfort
Indonesia, an archipelago nation in South-East Asia contains more than 13,000 islands is located in the
tropical region (8° North and 13° South). Because of its equatorial position, Indonesia is endowed with a
tropical climate, aired by the trade winds. With a high pluviometry annual average. Indonesia is then
characterized by a hot and humid climate. December, January, and February cover the wet season in many
areas in Indonesia. March, April and May represent the transition from the wet to the dry season in many
areas in Indonesia.
In many traditional buildings, both primitive and vernacular, some ingenious solutions to the architectural
problems of resisting extremes of weather and maintaining a comfortable indoor climate can be seen.
Traditional shelters of tropical region (hot humid climate) are usually lightweight in order to allow rapid
cooling down and has larges openings to allow the maximum possible breeze penetration. These openings
are fully protected from the sun and from penetration by driving rain.
         In Indonesia, the existence of a wide variety of traditional village and house styles as the product
of the cultural groupings; the country consists of many islands, many worldviews, languages, ways of life
and social culture. Building technology is largely dictated by the nature of available materials.
Traditionally one of building components, which epitomizes shelter and which perhaps, dominates all
buildings is the roof. The importance of the roof as a major architectural form is underlined by the need to
shelter from the hot sun and the rain. The Indonesian builders, for instance, have applied what they term as
payung, or the umbrella principle to develop roof forms.
From the view of general form, we can regrouping the Indonesian traditional shelter into two basic forms :
stilted construction, and non-stilted construction. In Java and Bali regions, the style of traditional shelters
are in the group of non-stilted construction. Their traditional houses are elevated about only 50 cm from
exterior surface. In many regions of Indonesia, found the tropical house on stilts. In North Sulawesi
Province, especially in Manado and Minahasa Region, since several years ago, the style of Minahasa
traditional architecture (stilted construction) is appreciated by modern people. Many of building
components are based on timber technology (wall, skeleton, ceiling and floor), only for the roof they use
zinc or aluminium. They build their own houses using knock-down technology. Even these houses are
actually sold in CKD (Completed Knock Down) package.
         In this study, typically Minahasa traditional shelters are taken been as samples (Figure 1). In
Minahasa region, actually, due to the penetration of western culture, the materials of traditional shelter
have been replaced by modern typically material construction such as zinc for roof, concrete for floor and
for skeleton structure.




                               Figure 1 : Typically of Minahasa traditional house. A knock down
                               construction with an effort to appreciate the eco-design principles

Paper number: 31917014
9th SENVAR + 2nd ISESEE, Selangor, Malaysia, 1-3 December 2008
        Actually it is very difficult to find a real traditional Minahasa house that using ijuk or rumbia as
material roofing. The basic built form of real Minahasa traditional house is considered to be a prime
example of environmental design in response to regional climate conditions. It has a low thermal mass,
extensive solar shading, and large number of ventilation openings (Figure 3).

1.3. Policy of housing development in Indonesia : eco-design is not a priority approach
     Construction of modern houses in Indonesia started since Dutch Colonization, and affected by
technology in early 1950s. The increasing population year by year in urban area has caused problem for
people to get houses. A lot of efforts have been made to solve the problem by cooperating with the other
parties. Some of these efforts have been formulated to typical housing policies such as implementation
project of Perumnas (National Housing Corporation). In order to achieve a target of housing demand that
can reach more than 800.000 units a year, it is used a strategy based on low price, simplification of
construction and efficiency room design. The building is usually single story and has a main entry door at
the front building and additional at the side or the rear of the building. The houses use red brick for
masonry walls and a timber roof structure. The opening ratio to the walls (windows - wall ratio) is usually
not exceeding to 20%. The Height from floor to ceiling is about 3 meters. The minimum area of outdoor
space (with BCR/ Building Coverage Area of + 50 %) and the building density at neighborhood may
cause unsuccessfully of the wind crossing the house. These modern houses are often criticized because of
their poor indoor thermal conditions when compared with traditional houses. The main reason for this is
the behavior of the building materials used and the ventilation system, which can cause heat accumulation
inside the house.

1.4. Brief review on indoor thermal comfort study
         In agreement with ASHRAE (1985), thermal comfort for a person is here defined as “that
condition of mind which expresses satisfaction with the thermal environment”. Thermal neutrality for a
person is defined as the condition in which the subject would prefer neither warmer nor cooler
surroundings. The reason for creating thermal comfort is first and foremost to satisfy man’s desire to feel
thermally comfortable, in line with his desire for comfort in other directions. Man’s intellectual, manual
and perceptual performance is in general highest when he is in thermal comfort. The most important
variables which influence the condition of thermal comfort are: activity level (heat production in the
body), thermal resistance of the clothing (clo-value), air temperature, mean radiant temperature, relative
air velocity and water vapor pressure in ambient air.

                            Table 1: The definition of ASHRAE and DISC scales

                            ASHRAE (PMV) scale                      DISC scale
                         Numerical     Feelings note    Numerical        Feelings note
                           scale                          scale
                            -3              cold
                            -2              cool
                            -1          slightly cool
                             0        Neutral/comfort      0               comfortable
                             1         slightly warm       1         slightly uncomfortable
                             2              warm           2             uncomfortable
                             3               hot           3           very uncomfortable
                                                           4               untolerable

The discomfort associated with exposure to warm and humid environments is attributed to the conscious
awareness of perspiration and an elevated body temperature. The secretion of sweat onto the skin surface
permits the dissipation of metabolic heat from the body by evaporation when the loss of heat by radiation
and convection is insufficient to maintain thermal balance. Underlined by Berglund (1986) that in warm
conditions in the resting, individual and with increased metabolic levels associated with work and
exercise; it was recognize that unpleasantness and thermal discomfort are associated with sweating, rather
than skin or body temperature. The research on thermal comfort for hot and humid environment of Sugini
Paper number: 31917014
9th SENVAR + 2nd ISESEE, Selangor, Malaysia, 1-3 December 2008
(2005) concludes that PMV is not effective in predicting the real indoor thermal comfort of classrooms in
the warm humid climate zone.
The DISC scale that represent a correlation introducing sweat rate and percentage of skin wetness is more
adapted to be used for prediction of thermal feeling in hot and humid environment (Berglund, 1986
Sangkertadi, 1994) .




                                                                                         .
                         Figure 2 : Comfort zone using DISC scale (Sangkertadi , 1994)

2. METHODOLOGY

The methodology of the study is based on the field observation, measurement and simple calculation. The
field observation on human thermal respond was chosen since it opens more fruitful areas of study in
searching of an understanding of people’s respond to their natural environment.
Ten traditional Minahasa style houses and ten actual low-middle houses (all of in Manado) were chosen as
building samples (Figure 3). Sixty subjects (3 persons of each house) were participated and only for adult
persons, male or female in good health. Each subject wore in their customary tropical wear (about 0.5 to
0.6 clo). They were free to dress as they liked for their daily routine. The openings of the houses were rest
in its position usually, where the door was normally, closed, and the windows were partially opened. The
observations have been taken place in hot season: July 1996 and August 2005 and carried out at the time
interval from 07.00 a.m to 07.00 p.m. Each respondent fills the questionnaire on thermal feeling in the
living room hourly. We obtain then 60 votes for each hour and 780 votes of the total, during the
observation from 07.00 am to 07.00 pm.
At the same time, the indoor thermal environment (air temperature, humidity, and wind speed) were
measured using digital thermo hygrometer and anemometer. Simple calculation of thermal comfort scale
(PMV and DISC) was then realized to make a comparison with the results from field observation. The
equations for this calculation refer to Sangkertadi (1994), Fanger (1970) and Fauconnier et al (1987)

3. RESULTS

The results of the observations on thermal feelings of the residents, are tabulated in the table 2 and 4.
From the table 1 it is shown that according to the respondents there is a considerable different thermal
perception of indoor climate in traditional houses and in modern houses. Table 3 shows the result of air
temperature measurement in the living room of each house. This results indicate that mean indoor air
temperature of traditional houses is lower than in modern houses. Figure 4 shows the comparison of
thermal feeling votes of the persons who were living in traditional houses and in modern houses. In the
morning period from 07.00 a.m to 09.00 a.m the indoor environment traditional houses serve more
comfortable and cooler than the condition in modern houses. From the time interval of 10.00 a.m to 05.00
p.m, the condition of indoor environment of modern houses is warmer compared to indoor climate of the
traditional houses. Generally, the respondents may feel thermally comfortable in an enclosure
environment with a low wind speed (0.2 m/s maximum) where air temperature is about 290C (Table 4). By

Paper number: 31917014
9th SENVAR + 2nd ISESEE, Selangor, Malaysia, 1-3 December 2008
calculation, these climatic environments give a slightly uncomfortable condition, where the DISC scales
are about 1 to 1.5. Therefore, there is a different about 1 scale between theoretical approach (by
calculation) and field observation. According to Mas Santosa (1986) (based on his field observations in
1984 with over the 2000 respondents), Indonesian people feel thermally comfortable in an ambient where
air temperature is in the interval of 25.4°C and 28.6°C. Therefore, there is also a different with our actual
observation. However, according to Lippsmeier (1994), comfort’s zone for human in the tropics is in the
interval of 22.5°C to 29.5°C.
Figure 5 shows the comparison of the results obtained by field observations and calculations. It can be
seen that the results by calculation are over estimated comparing to the results from questionnaires with
maximum different of 2 scales.

                              Table 2 : Votes obtained by questionnaires




       Table 3 : Results of indoor air measurement. T: traditional house; M: modern houses




Paper number: 31917014
9th SENVAR + 2nd ISESEE, Selangor, Malaysia, 1-3 December 2008




                         Figure 3: Architectural sketch of some of sample houses.
Paper number: 31917014
9th SENVAR + 2nd ISESEE, Selangor, Malaysia, 1-3 December 2008
                                Table 4 : Percentage of votes on thermal feeling

                  Thermal Feeling    Scale of                 Air temperature (0C)
                                     Comfort    28 + 0.5     29            30 + 0.5   31

                        Cold           -3        11%
                        Cool           -2        15%         8%
                   Slightly cool       -1        31%        12%
                      Comfort           0        43%        77%             33%
                   Slightly warm       +1                    3%             44%       44%
                       Warm            +2                                   23%       32%
                        hot            +3                                             24%




  Figure 4 : Comparison of thermal feeling votes of persons who were living in traditional house and in
                                            modern house




  Figure 5 : Comparison of thermal feelings by vote and calculation (using DISC equations procedure)

Paper number: 31917014
9th SENVAR + 2nd ISESEE, Selangor, Malaysia, 1-3 December 2008


4. CONCLUSION

    In this study, indoor thermal performances of actual Indonesian modern house (10 sample buildings)
and Minahasa traditional house (10 sample buildings) were analyzed using two approaches: field studies
and calculation.
The residents of the sample houses (3 respondents of each house, from totally of 60 respondents) are the
subjects in this field observations with objective to obtain indoor thermal satisfactory responses during
daytime of both traditional and modern houses. At the same time, indoor thermal climate such as air
temperature, humidity and air velocity were measured. The results show that for this population, the
maximum air temperature accepted (feel comfortable) in the period of daytime is 29°C, with a calm air
velocity and a relative air humidity about 60%. At the afternoon, indoor air temperature of traditional
house cooling down rapidly following the down-line of outdoor air temperature. The modern house
however retained a higher air temperature until at the beginning of nighttime.

REFERENCES

A S H R A E, Handbook Fundamentals (1985), New York : American Society of Heating, Refrigerating
        and Air Conditioning Engineers
Berglund L.G, Cunningham D J, (1986). Parameters of Human Discomfort in Warm Environment,
        ASHRAE Transaction, vol 92 part 2B,
Fanger P O Thermal comfort. (1970). New York : Mac Graw Hill
Fauconnier R, Guillemard P, Grelat A, (1987). Algorithmes BILBO et BILGA, ANNALES ITBTP, no
        458.
Lippsmeier.G (1994) Bangunan Tropis (Indonesian version), Jakarta : Erlangga
Mas Santosa (1986), Climatic factors and their performance on the design of buildings in hot humid
        country with special reference to Indonesia, (Phd thesis), University of Queensland.
Sangkertadi, (1994) Contribution a l ‘etude du comportement thermoaeraulique des batiments en climat
        tropical humide. Prise en compte de la ventilation naturelle dans l’evaluation du confort. These
        Doctorat, INSA de Lyon
Sugini, (2005) The effectiveness of the PMV model in predicting the quality of thermal comfort in learning
        environments in a warm humid tropical zone, Proc. of Seminar on Environmental Architecture
        2005 Yogyakarta




Paper number: 31917014

				
DOCUMENT INFO
Shared By:
Tags:
Stats:
views:345
posted:8/27/2010
language:English
pages:8