Proceedings

2d lnternational Seminar and Workshop on Ecological Architecture and Environment in the Tropics 17 - 19 February 2005

Environment-Man-Building Centre of Education (LMB) Soegrjapranata Catholic University Semarang-lndonesia

Proceedings

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2ld lniernationai Seminar and Workshop on EcologicalArchitecture and Environment in the Tropics

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19 February 20O5

Edited by Petra Widmer Environ ment-M an-Building Centre of Education (LM B)

Soegijapranata Catholic University Semarang - lndonesia

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PENERBIT KANISIUS (Anggota ll(APl) Jl. Cempaka I, Deresan, Yogyakarta 55281 Kotak Pos 1125ffk, Yogyakarta 55011 Telepon (0274) 588 783; Fax (0274) 563 349 Website: www.kanisiusmedia.com E-mail: [email protected]

SOEGIJAPMNATA UNIVERSIW PRESS Jl. Pawiyatan Luhur lV/1 Bendan Duwur, Semarang 50234

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Kotak Pos 8033/SM, Semarang 50232 Telepon (024) 831 6'1 42 - 844 15 55 (hunting), Website: www.unika.ac.id E-mail: [email protected]

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The "vote shifting'as explained above, might be accounted for by the following reasons. Firstly, people could be more stringent when voted for thermal sensation rather than for comfort perception. This indicates that comfort assessment is not only based on lhe thermal sensation but to a certain edent other non-physiological factors. lt might be in the form of psychological factors such as expectation, and emotional background IFountain et.al. 1996]. Secondly, there is a tendency for occupants in NV buildings in the tropics to perceive cold sensation (coolness) as comfortable [Feriadi et.al 2002, 2003, Wong et.al 2002].

Adaption Observational Analysis During the survey, the resporrdents were asked about their propensity on seven common adaptive actions in the event that they experience uncomfortable conditions. The lists of adaptive actions were arranged according to the level of their modification ef{orts. lt gradually

increases from only regulating their body by drinking more water, taking shower more frequentty, changing with light clothing to more extreme actions such as switching on the Fan or AC (high-energy consumption). The respondents were asked to choose how likely they would choose for each adaptive action as described in the questionnaire. This investigation was useful to attain the following information:

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How likely the adaptive actions actually occurred everyday People's preference towards various options of personal controts to make them more thermally comfortable inside their houses. People's decision whether they like to use thermoregulatory response (body/personal adjustment) or modify their uncomfortable environment

By interpreting 'often' as lhe central of neutrality in their tendency of usage, it is assumed that'always" and'most likely" are the two positive scales towards occupant preference. On lhe contrary, "seldom" and "very unlikely" indicate their preference for not practicing it. For the purpose of clear analysis, the various adaptive actions were illustrated using horizontal accumulative percentage bar chart, and the results are displayed in Figure 3. Figure 4 displays the results where adaptive action of opening windows are highly preferred by occupants with the percentage of 79.9 %, followed by getting more drink (69.9 %). The preferences of changing clothing and switching on the fan constitute about 60.2 % and 56,4 % respectively. Going out to cooler places and taking bath more frequently showed about the same percentage ot 28 o/o. Switching on the AC is voted as the least favorable 2nd international seminarand workshop on ecological architscture and environment in the LMB Center oteducation - Soegijapranata Catholic University, Februari 2005

tropics

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action (3 o/o) fnis is perhaps due to the fact that {he number of percentage of.houses with AC is very limited and energy cost implication which are obviously t"" u".i'iv the average income lndonesian family. "rlr".rs"!'i"

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The above findings can be used not only as an information on the percentage of "likeliness to happen' (occrnence) but also on the people preference in choosing aliernate actions to make their conditions more comfortable. ln general, it can be said th;t occupants prefer to employ environmental control (such as window and fan) first before they resort to personal adjustment, which involve some thermoregulatory responses of their bodies. The fact that nearly all population in lndonesia is staying also in their NV houses underlines the importance of proper NV design. Architects who design houses in lndonesia should pay greater attention to occupant feedback and comfort. ln hot and humid environment, providing sufficient air movement should be of imperative considerations during the design phase. From this study, natural wind cooling effect was found to be gainful for the occupant's thermal comfort. Further analysis is caried out on the usage of windows, fan and AC ancl the results are presented in Tables 1 - 3. The usage is divided into four time slots: morning (7-12 AM), afternoon (1-6 PM), evening (7-12'PM) and night (1-6 AM). The shaded boxes represent the six hours duration of the climatic control usage in their daily activities and each row represents a unique combination of the time slots. The information provided are useful to understand further on how people in the tropics tend to operate the various environmental controls to create their indoor environment as comfortable as possible. The time duration on the usage of the three environmental controls (windows, fans and AC) indicate the preference to use and also to a certain extent the people's choice and concern for energy consumption related on the usage of each control in their homes, Detailed analysis of the usage of environmental control is presented in Tables 1 to 3 with their discussions.

2nd international seminar and workshop on ecological archibcture and environment in the tropics LMB Center ofeducation - Soegiapranata Catholic University, February 2005

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Table

1:

The usage ofAir Conditioner

Only 34 subjects (6.5 %) who own AC system in their houses. For those who have it, they use AC only for about six hours per day especially in the afiernoon (38.2 %) and evening (17.6 Vo). The highest AC usage (61.8 %) in the afternoon implies that this period of time might be the most uncomfortable condition to cope with by passive cooling strategy. Th€ finding is different from Singapore's result which showed the AC usage was mainly for the night time for sleeping. Table

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The usage of fans

About 18.1 % of respondents do not have a fan in their houses. For the people who install them, the f:ns are commonly switched on in the afternoon (78.'l o/o). The other time slots reveal similar proportion of distribution with the percentage between 25 - 33 o/0. Large percentage in the aftemoon implies that on this time slot thermal condition is uncomfortable with still air. About 61.4 % said that they limit the use of fans for about six hours a day.

znd internatjonal seminar and workshop on ecological architeclure and environment in the tropics LMB Center of education - Soogijapranata Catholic Uniwrsity, Feb.uary 2005

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Table

3:

The usage of Bedroom windows

About 87.6 0/6 occupants like lo open their bedroom windows in the morning. The percentage who open the window at night is very small (8.6 %), this could be due to security reason. More than one third (37 %) of the occupants only open the bedroom windows in the moming for about six hours. lt is also observed that about 31.7 o/o of the occupants open their bedroom windows for about 18 hours a day. Figure 5 is used to illustrate the dynamic process of adaptive behavior. At first, justification on the thermal comfort is influenced by subjective factors such as previous expectation, preference etc. lt is believed that thermal perception is not based on the discrete human cognitiv€ process but rather similar to accumulative process. lf the person is dissatisfied with the uncomfortable condition, they take some regulative (conective) actions, which can be classified in general as personal and environmental adjustments. Personal adjustments involve various Conscious actions that related to human body such as getting more drink, changing cloth etc. Environmental adjustments are in the form of active controls over the indoor spaces such as opening window, switching on fan etc.

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There are enormous possible combinations of actions that had been described earlier. lf similar thermal condition occur everyday (or within certain cycle of life), the occupants adjus! ment become their habitual actions which gradually lead to what is called adaptation. lf it can create effectively more comfortable conditions, positive adaptation input is sent to the hunran persona! perception knowlcdgo. lf it fails to providc comforl, it exoggoi'alcs lnto nog$tivo adaptation input. The uncomfortable tlrermal experiences are store in hurnan cognitive and expectation. When occupant encounters a similar thermal environment in the future, she/he already has certain perception and thus atfects their expectation. This understanding gives possible explanation on why thermal acceptability measured in TCV or Bedford scale (contfort perception) was higher compared to TSV or ASHRAE scale (figure 3). Thermal comfort acceptability is closely linked to the ability of the occupant to modify (control) their environmental condition. 2nd international seminar and workshop on ecological architecture and environment in the tropics LMB Centet of education - Soegijapranata Catholic University, February 2005

Conclusion This study has sholvn that based on TSV-ASHRAE and TCV-Bedford scale, occupdnts staying in NV housing show higher thermal comfort as compared to what pMV has piedicted. Thermal comfort is to a great elitent influenced by non-physiologicat factors whif go beyond

the six factors wfrich have been taken into account in PMV modeling. lt is believed that adaptive actions have conhibuted in some positive ways to the higher level of thermal comfort. When the occupants have freedom to madiry environment and make necessary adjustment, they always use them to compensate the less comfortable thermal conditions. The study discussed the occupant's behavior in utilizing the various environmential and personal controli to make themselves thermally comfortable. The study also relrealed the tendency of the occupants to modify the hot and humid living environment by creating a higher air movement (tuming on fans, opening the windows). Occupant's adaptive adjustments such as drinking more water, changing clothes, and tiaking bath more frequently are also favorable as compared to switching on the AC. Through the statistical analysis, some discrepancies were observed between neutral (comfort) and preferred thermal sensation (Figure 1 and 2). Under hot and humid tropical climate, people prefer cooler environment condition (at TSV -3), which is considerably much lower as compared to what the general requirement of comfort condition as specilied by lnternational standard of thermal comfort such as ISO 7730, ASHRAE 55. These findings imply that neutral thermal condition- (temperature) had been interpreted by people in the kopics as an acceptable condition (temperature) even though $ey ought to employ (optimize) their efforts(such as using fan, opening windows, changing clothing etc) to make them feel thermally cqmfortable. These adaptive actions are become part of their daily life and indirectly dictate their thermal comfort expectation in NV buildings. When they were asked about the temperature they would prefer, they always choose much cooler environment whereby they won't require making any adjustment on their bodies and/or environments. Undoubtedly, adaptive behavior and psychological factors play an impolant part in thermal comfort perception for NVB. The main challenge for further research is to quantifo these factors into simple and more accurate thermal comfort modeling. The expectation factor needs to consider not only the previous AC exposure but also the ability to control the environment in the form of personal and environmental adjustment. Finally, the finding is expected to spur the effort to explore and develop more occupant c€ntred strategies that may contribute to social and environment benefits, reducing energy consumption and increasing people satisfaction.

Reference Brager GS, De Dear RJ. 1998. Thermal Adaptation in the Built Environment A Literature Review. Energy and Buildings Joumal2T:83-96. Brager GS, De Dear RJ. 2OOO. A Standard for Natural Ventilation. ASHRAE Joumal edOctober: page 21-28. CEN - ISO 7730. (1995). Moderate Thermal Environmehts - Determination of the PMV and PPD lndices and Specification of the Conditions for Thermal Comfort. Fanger, P.O. (1970). Thermal Comfort Analysis and Applications in Environmental Engineer. ing. Mc Graw Hill. New York. Feriadi, H., Wong, N.H., Sekhar, C., & Cheong, K.W. (2002). Rede{lning thermal comfort standard for naturally ventilated buildings in tropics (singapore and lndonesia perspective). Proceeding of 9t' NDOOR AIR conference, (pp. 1 10-115). California - USA. Feriadi, H., Wong, N.H., Chandra, S., & Cheong, K.W. (2003). Adaptive Behaviour and-Thermal Comfort in Singapore's Naturally Ventiiated Housing. Building Research and lnformation Joumal v:31 , pp 13-23. Spon Press.UK. Finney, D.J. (1962). Probit Analysis. Cambridge Univ. Press. UK' 2nd internitional seminar and workshop on ecologic€l ardliteclure and environment in the tropics LMB Center of education - Soegijapranata Catholic University' February 2005

cail B, De Dear R. 1996. Expectations of lndoor Climate Cpntrol. Energy aN Buildings24 i1Z$1A2. Mahdavi A, s Kumar. 1996. lmplications- oJ lirdoor climate for comfort, Energy and Environment. Eneryy aitct Bui@ngi Joumal24 :167-.177. Wory \Y, H. Feriadi, P.Y. Lim, K.W. Tham, C. Sekhar and K.W. Cheong. 2002. Themat comfort Erraluation of Naturaly Ventirated pubric Housinj in sing"p;r". Biiaing'iii Envitonment joumal volume 37 :- 126Z-1222 . Elsevier Science. US. .- ' Fountain_ M,

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tsBN 97s21-1 1 04-2