The Assessment of Thermal Comfort of Living Environment in Tsunami Disaster Place

Overview

On 26th December 2004, tectonic earthquake with 8.9 scales had attacked west of Sumatra-Indonesia and Banda Aceh as the capital city of Acehnese province (located in northern of Sumatra) as well. It was then followed by tsunami wave rolling up over the shore and town, which caused a lot of destructions to any building constructions and the surrounding environment.

This disaster has caused many alterations particularly on climate change, which is felt uncomfortable individually. It is due to the raised temperature, humidity and the air velocity, which makes the people living in that area feel the environment much warmer than it was. This phenomenon is agreed by ISO 7730, which defines thermal comfort as the air condition in one area once it changes it makes any one in that place feel uncomfortable.

In order to know the uncomfortable thermal, this study needs an empirical approach through study case in a dwelling in the affected place in one of sub districts in Banda Aceh town that is Meuraxa.

The aims of this study are:

•To predict the internal thermal comfort in a residence
•To asses the internal thermal condition in residences affected by tsunami disaster

Thermal comfort prediction

The prediction of thermal comfort can be determined by some subjective scale index, they are:

•PMV-Index (Predicted Mean Vote)
•PPD- Index (Predicted Percentage of Dissatisfied)

Predicted Mean Vote (PMV-Index)

PMV is an environmental thermal condition which is statistically regarded as cold, cool, slightly cool, neutral, slightly warm, warm, and hot. The PMV scale is a seven point thermal sensation scale ranging from -3 (cold) to +3 (hot), where 0 represents the thermally neutral sensation.

Predicted Percentage of Dissatisfied (PPD-Index) 

This parameter is aimed to predict how many people feel uncomfortable due to a particular thermal condition in one room. Figure 2 shows the relation between PPD and PMV.

The PMV scale either -2 or +2 is regarded comfortable by around 75 % of the occupants (PPD=25%), PMV scale of -1 and +1 are regarded comfortable by around 25% of the occupants (PPD=75%), while PMV scale of 0 is regarded comfortable by only 5% of the occupants (PPD=5%).

 

Figure 2. The relation between PPD and PMV.

The method of assessing thermal comfort.

Based on the International standard ISO 7730, the determination of PMV and PPD scale index can be achieved by a direct measurement in a living environment with the measuring instruments (thermal comfort meter) and its software, they are Thermal comfort data logger type 1221 and its software type 7301 and comfort module UA1276, Air tech instrumentation, INNOVA,Denmark.

In order to know the index value of PMV and PPD, this study carried out the measurement with the instrument of thermal comfort data logger type 1221 related to computer, PC and its software type 7301 that is run by window program TM 3.1. The result is displayed in the computer screen as the result of the measurement done by software 7301. This result can be displayed in a graphic curve representing the temperature, the air humidity, the air velocity and the index value of PMV and PPD.

From those thermal curves, the assessment of either comfort or discomfort rate in living environment in places affected by tsunami disaster can be done.

Case study : Meunasah (prayer room)

The case study analysed the internal thermal comfort in meunasah (prayer room) located in lambung village, Meuraxa sub district, Banda Aceh.

Generally Meunasah is functioned as prayer room besides facilitating the gathering place used to discuss the village problems. In addition it is also used by teenagers as the resting place and even for sleeping.

Nowadays, Meunasah is used either as the security camp or home for the tsunami victims or refugees. It is constructed with zinc roof, timber wall and wooden floor, which is, raised 0.8 m from the ground.

The measurement was done at 4.05 pmwhen the sun position was in the western. Picture 9 shows that the internal temperature was 32.200C, which was relatively higher, compared with the standard internal temperature. Other result, picture 10 shows that the average of air velocity was 0.41m/s, which was relatively very high as well that it could cause the human body dry.

Picture 11 and 12 display the graphic curves of PMV and PPD index in meunasah in the scale of 2.57 and 94.72% respectively. These index values mean that 95% of the occupants don’t feel comfortable.

From those analyses of internal thermal comfort, it can be concluded that:

  1. The prediction of internal thermal comfort based on ISO 7730 explains that the thermal condition of living space in places affected by tsunami disaster is not comfortable.
  2. All thermal parameters value achieved in this study proves that there has been an indoor climate change in places affected by tsunami disaster due to the unbalance thermal environment influenced by Tsunami disaster.

 References 

  • ISO 7730, Moderate Thermal Environments- Determination of The PMV and PPD Indices and Specification of The Conditions for Thermal Comfort, 1995
  • Technical Documentation, 1221Thermal Comfort Data Logger, 7301 Application Software, INOVA Air Tech Instruments, 1999
  • Worker, Howard V, Energy Conservation Design resource Handbook, 1979
  • Threlkeld, Thermal Environmental Engineering. 2nd edition Prentice-Hall International, 1970
  • Standar, Tata Cara Perancangan Konservasi Energi Pada Bangunan Gedung, Departemen Pekerjaan Umum, SK.SNI I-14-1993.


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