Evaluation of Outdoor Thermal Condition in High Density

Settlement at Sade Traditional Village

Eka Susanti

and Desak Putu Damayanti

Research Station for Housing on Region II Denpasar, Research Institute for Human Settlement,

Ministry of Public Work, Indonesia

Keywords: Outdoor Thermal Condition, Thermal Comfort, High-density Settlement, Sade Traditional Village

Abstract: Thermal comfort depends on the macro and microclimatic conditions of the surrounding environment. To a

large extent, the climate temperature condition is impacted by high-density settlement. One of the areas

addressed in this study is Sade traditional village, it is one of traditional settlement that has a dense pattern of

the building and located in hilly areas with a linear grid pattern. However, the cooling temperature process is

significantly fast compared to a highly dense building in low altitude areas. In particular, this paper presents

an evaluation of outdoor thermal condition at the high-density settlement in order to know the causal

relationship between mass and building composition on the residential scale versus the outdoor thermal

condition. The simulation method is used to analyse the research location using ENVI-Met software.

Temperature, wind speed, and humidity are parameters being investigated in this case. The result revealed

thermal comfort is quite constant and on a normal threshold; Temperature: 18

C - 25

C, wind speed: 0.5 m/s

– 0.8 m/s, humidity: 68 %-74 %. Tightly building configuration and minimum of vegetation, influence on the

rising temperature in a day, it makes a relatively fast evaporation process. The narrow distance between the

grids makes the wind speed more increasing and accelerating the cooling process of temperature.

1 INTRODUCTION

Thermal comfort is determined by the physical

environment, such as air temperature, relative

humidity, wind speeds. These three factors have

interrelated relationships to achieve thermal comfort.

In humid tropical climates, the buildings are generally

designed with a natural memorising system that

maximizes the quality of temperature and humidity to

be able to cool the building structure or the

achievement of thermal comfort. Some factors of

building and environmental influence are the position

of building against the environment, the orientation

of buildings, the layout of the mass of buildings

against the direction of the sun and the direction

comes to wind. One factor of the comfort of residents

can be achieved by observing the layout of the mass

and density of buildings (distance between buildings)

and the influence of barriers, both vegetation and

buildings that resulted in declining quality of the

avoidance of the building Because of the insisting

influence in an area. "Building density", the

immutable influence in an un-possible area is the

cause of the underachieving Comfort. The high

density of buildings will increase the level of

resistance to wind energy consumption, as one natural

energy to achieve comfort ". The phenomenon in the

study site is that the buildings are organized in a

tightly lined and dependent on the existence of

existing roads so that the temperature, humidity, and

wind speed in a traditional village of Sade need to be

further researched to know by correct density of

buildings determined by the distance between

buildings affects the thermal comfort. Based on the

description, the traditional village settlements of Sade

have a mass-based layout. Based on the layout of the

time, the behaviour of the wind has varying flow

patterns and speeds depending on the distance

between the building and the state of the existing

road. In this case, it can affect the quality of natural

aspiration performance of the settlement as well as

physiological comfort of the resident. Building

density is influenced by the distance between

buildings, building height, and building dimensions.

These three conditions affect wind speed,

temperature, and humidity. But in the case of Sade

traditional village house dimension of building and

building height are all the same, so that distinguishing

factor is only the distance between buildings. In this

study, it was devoted to research thermal comfort in

Susanti, E. and Damayanti, D. P.

Evaluation of Outdoor Thermal Condition in High Density Settlement at Sade Traditional Village.

DOI: 10.5220/0013056600002836

Paper published under CC license (CC BY-NC-ND 4.0)

In Proceedings of the 10th Architecture Research and Design Conference (AR+DC 2019), pages 55-59

ISBN: 978-989-758-767-2; ISSN: 3051-7079

particular the influence of building density and

pattern mass.

1.1 Selected Area

Sade traditional village is located at Rembitan

Village, Pujut Sub-District, Central Lombok District,

West Nusa Tenggara Province. The overall area is

7.340 m

and altitude 115 m above sea level. The

orientation of the village led to the West-East, facing

the direction of the sunrise. Sade Village located on

hilly areas with even and wavy topographical

conditions. Climate conditions at this location tend to

dry in the dry season. The character of the ground

surface is dry and barren. The characteristic of Sasak

architecture dominated from building until the

arrangement of the settlement. The area built of an

entire village is 2.997 m

. Population and density are

pretty high while there is no territorial expansion and

development remained concern on these areas. The

percentage of area built of about 40 % consists of 120

mass of building and village’s street. The average

volume of the building varies 38 m

– 48 m

. The

Settlements use grid patterns, clusters separated by

linear village’s streets. Building conditions are quite

dense, generally building at Sade village uses

thatched as roof and bamboo woven as wall. The

street is the only open area on this village. The streets

are mostly covered by ground surface shielded with

concrete paving material. Regarding vegetation, there

are only few large trees with medium density on the

entrance of the village.

2 METHODOLOGY

Simulation was chosen as a method for its reliability

in investigating the causal relationship between mass

and building composition on the residential scale

against the outdoor thermal condition. The research

location was analysed by ENVI-Met V3.1, and the

parameters such as temperature, wind speed, and

humidity are evaluated. Calibration between

measured and simulated data are aimed to increase

the reliability of the result to perform predictive study

on high-density effect to thermal performance

2.1 Selection of Typical Day

Based on the last 10 years macroclimate data

from the Indonesian Agency for Meteorology,

Climatology, and Geophysics (BMKG) of West

Nusa Tenggara, indicating May is the transition

between the hot to the cold months. The

maximum temperature has begun to decline to

the minimum temperature. Minimum

temperature occurs between June and August

(dry season). For the West Nusa Tenggara

region, an average of air temperature in a year is

26.5 °C and an average humidity rate is 82%. In

May, the average temperature of the last 10 years

reaches 26.7 °C, the average wind speed reaches

4 m/s and the average of humidity reaches 83%.

Simulation timing is adjusted to the retrieval of

field data so that the data is more valid and know

how much the difference between simulated

results and field measurements. Accordingly,

this study selected the day of May 12 as a

simulation day. From this BMKG data, will be

used as an input simulation program on the

ENVI-Met software V-3.1. The simulation is

done for 24 hours to know the fluctuations that

occur in accordance with the running process on

the software Envi-Met V-3.1.

2.2 Characteristic of Settlement Model

Modelling simulation on ENVI-Met has different grid

settings on each model according to the extension of

the area to be simulated. Area of Sade Traditional

Village is 7.340 m

with a build area of 2.997 m

. The

village has communal typology, with the same typical

and compact housing. ¼ of the build area will be used

as a representation, with the simulation area is 749.3

. The surrounding environment of buildings and

vegetation in the settlement are in accordance with

the actual condition, to determine the impact of

environmental conditions on the overall thermal

performance of the settlement. There are modelling

simplification for the curve-shaped building. The

shape of the building is interpreted with a beam

whose outer size can be adjusted so that the shape

becomes simpler. While the size of the grid can only

simulate with integers, it is necessary to do the

simplification of numbers close to the actual number.

Basic parameters that will be input and transition

existing condition to the simplification of modelling

according to the capacity ENVI-met simulation can

be seen in the Table 1.

AR+DC 2019 - Architecture Research and Design Conference

Table.1 Simulation model of sade traditional village using

Envi-met

2.3 Climate Data Verification

Stimulation and Measurement

Result

The macroclimate in West Nusa Tenggara Province

is used as input in the simulation process in this

research. To what extent the compatibility of thermal

performance between simulation and measurement in

real condition, in order to study and intensify the

understanding of the deviation in these two data

results. In general, thermal data of specific building is

verified by comparing outside temperature based on

real condition and outside temperature from BMKG

in the past 10 years (micro climate simulation results).

The comparison on To was made for Sade

Traditional village in West Nusa Tenggara. Based on

the comparison the average outside temperature for

West Nusa Tenggara reached 25.4o C, whilst average

temperature data obtained from BMKG in the past 10

years show 25.3. The disparity for average

temperature is 0.1o C, whereas at the highest

temperature day the difference is around 1-2o C. As

can be seen from Table 2 To profile from field

measurement and BMKG in West Nusa Tenggara

region have a similar curve.

Table 2 To profile from BMKG the past 10 years and To

field measurement

In examining building performance, the main focus in

this research is on thermal comfort produced by the

building. The comfort condition range on sensory

level known as neutral temperature. Neutral

temperature is a thermal condition when a person

does not feel heat nor cold. The equation to determine

the neutral temperature is Tn = 17.6 + 0.31 x Tav, Tav

is average temperature outside in a month when the

measurement is performed. This data obtained from

BMKG data record and it acquired that Tav value for

Sade Traditional Village is – 26.7

C. The comfort

range is taken from +2 °C above and below neutral

temperatures (Tn) (De Dear, R. J, and Auliciems,

1985). For micro-climate in Sade Traditional village,

the value of neutral temperature is Tn = 25.9 °C.

At table x.x the maximum difference is up to 4

C at

12.00, while for the overall average difference of only

1.2

C. This difference is affected by the contour of

the ridge, vegetation, overall density settlements and

climate conditions fluctuation. The condition

mentioned above causes change temperature

influenced by the environment outside of the

courtyard. Comparison with the results of the Tn

counting, thermal comfort limit of 29

C and a lower

limit of 24

C. The difference in field temperature

range with BMKG is still included in the boundary of

outdoor temperature deviation tolerance, therefore,

the outside temperature data (To) BMKG can be used

to present the actual To condition in the field with

relatively small fault levels

3 RESULT AND DISCUSSION

3.1 Outdoor Thermal Condition

There are three Envi-met simulated time scenarios,

represents morning, afternoon and evening

conditions. Orientation, the ratio of buildings to land

area, and the typological pattern of settlements impact

how wide the surfaces being exposed on solar

radiation. Sade Traditional Village is oriented west-

east, so it will be exposed fully to the sun during the

Evaluation of Outdoor Thermal Condition in High Density Settlement at Sade Traditional Village

day and tends to be shaded in the morning and

evening. Figure 1, contrast in shades composition

shows the temperature change pattern, in which rises

from morning to evening. The dense of mass

composition of settlement, make a slight surface

exposed to solar radiation. In the morning

temperature increase tends to be slow due to shading

occurring. At 08.00, the average outside temperature

of the building (To) is about 18-20 °C. In west

orientation is domination by orange shades. Solar

radiation affects the increase of outdoor temperature

in this area. On the other side of the settlements in the

dominance of green shades that shows the low

temperature in the settlement that is not exposed to

solar radiation. Grid mass patterns cause shading in

the unexposed part of sunlight. At 12.00 The Sun is

right above so that the surface can be exposed to more

sun. The temperature rises up to 3 °C with an average

of about 23-25 ° C. there is minimum vegetation

around building and street so that many surfaces are

exposed and slightly shaded area.

Figure 1. Outdoor Temperature of Sade traditional Village

The ground surface of the street will be fully

exposed to solar radiation. It has the potential to raise

the outdoor temperature so that the surface

temperature is more dominant red and orange shades

at settlement. At 16.00 the position of the sun begins

to set, the sun-exposed area begins to decrease and the

shading occurs. Settlements in the southeast are more

exposed to the sun so it is dominated by red shades.

In the afternoon, the process of heat release from the

ground and building surfaces, the time lag of the heat

release process is what causes the red shades more

evenly.

Temperature averages around 25 °C, followed by

slowly decreasing the temperature to the night.

Temperature averages around 25 °C, followed by

slowly decreasing the temperature to the night. For

the high-density residential scale, resulting in the

temperature is quite low. It is affected by the location

of the hilly area and the linear typology of the

settlement. The high density of the building on the

Sade traditional village affects the shading factor and

the number of surfaces exposed to solar radiation.

These factors affect the thermal fluctuations

generated on the macro scale in the entire village.

3.2 Outdoor Wind Speed Condition

The ventilation of the settlement is impacted by the

building density as shown in Figure 2. The distance

between the buildings is close enough, making the

airflow tend to be static. Average wind speed in 24

hours reaches 0.33 to 1.5 m/s. The area around the

building is dominated by blue shades with evenly

spread, the wind speed is relatively low between 0.5

– 0.8 m/s. Sade Traditional village located in hilly

area, and altitude 115 m above sea level. A linear

settlement pattern and a lack of vegetation, enabling

smoother airflow on unhindered areas of the building,

especially on the village Street area that separates

between clusters. Figure 2 shows at each simulation

time, the village Street area is dominated by a green

shades indicating higher air fluctuations. The average

wind speed in this area is 1m/s to 1.4 m/s. Observed

from the time change, wind speeds are decreasing

from day to evening and will increase at night to the

morning. Overall, the density of buildings in Sade

village causes constant airflow and minimal

turbulence. Grid patterns on settlements allow for air

fluctuations, narrow village streets cause higher wind

pressure and can accelerate outdoor temperature

cooling.

Figure 2. Outdoor Wind Speed of Sade traditional Village

3.3 Outdoor Humidity Condition

Sade Traditional Village is including in communal

type settlement, the distance between buildings is

quite tightly. Figure 3 shows the settlement

dominated with green, yellow and orange shades at

AR+DC 2019 - Architecture Research and Design Conference

08.00, heading 16.00 humidity is getting lower with

dominated by blue shades. The shades distribution of

isocontour represents a constant average of humidity

ranging from 68 – 74%. Humidity in the all-day not

increasing significantly. The higher the position of

the sun, the lower the humidity. This is due to the

tightly building configuration and minim of

vegetation. Temperature increase and accelerate the

evaporation process. The narrow grid on the

settlement make wind speed more increasing and

accelerate the temperature cooling process. Figure 3

revealed humidity cycle decreases in the morning to

the afternoon, then rises back in the afternoon.

Figure 3. Outdoor Humidity of Sade traditional Village

4 CONCLUSIONS

This paper studies the causal relationship between

mass and building composition on the residential

scale with the outdoor thermal condition. Parameter

focus on temperature, wind speed, and outdoor

humidity condition. As it has been known from the

results of field observations, Sade traditional village

that has a dense pattern of the building and located in

hilly areas with a linear grid pattern. However, the

cooling temperature process is significantly fast

compared to a highly dense building in low altitude

areas. Simulation results showed, the thermal

comfort is quite constant and on a normal threshold,

as can be seen from several parameters such as;

Temperature: 18

C - 25

C, wind speed: 0.5 m/s – 0.8

m/s, humidity: 68 %-74 %. At the middle of the day,

a settlement is fully exposed to solar radiation, it can

increase the temperature until 3

C. Surprisingly the

airflow pressure is increasing yet on the open space

area the distance between the buildings is close

enough. The average wind speed in this space reaches

until 1.5 m/s. It revealed a linear grid pattern on Sade

Traditional Village plays an important role in

enhancing outdoor thermal comfort. In addition, the

location in the hilly area tends to be windier than the

lowland, allowing for more wind flow so as to

accelerate the air cooling process.

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Evaluation of Outdoor Thermal Condition in High Density Settlement at Sade Traditional Village