Building Science 1

SCHOOL OF ARCHITECTURE, BUILDING & DESIGN Modern Architecture Studies in Southeast Asia (MASSA) Research Unit Bachelor of Science (Honours) (Architecture) BUILDING SCIENCE 1 [ARC 2412]

Project 1: Human Perception of Comfort Level

TEAM MEMBERS: Astriyani Feiven Chee Lee Min Mohammad Syarulnizam Mohd Nasir Nadia Othman Syed Zain Syed Azman

0311678 0312004 0308860 0302549 0303423 0304845

CONTENTS Summary 1.0 Introduction 1.01 Aims & Objectives 1.02 Human Perception of Thermal Comfort 1.1 Site Location 1.1.1 Site Plan 1.1.2 Orthographic Drawings 1.1.3 On-Site Photos 1.1.3.1 Outdoor Photos 1.1.3.2 Indoor Photos 1.4 Task and Project Procedures 1.4.1 Limitations 2.0 Methodology for Data Collection 2.1 Temperature and Relative Humidity 2.2 Wind Movement and Ventilation 2.3 Sun path 3.0 Results and Analysis 3.1 Temperature and Relative Humidity 3.1.1 Table 3.1.2 Graph 3.1.3 Bioclimatic Chart 3.2 Climatic Factors 3.2.1 Macro-climatic Factors 3.2.2 Micro-climatic Factors 3.3 Wind Movement 3.3.1 Windrose Diagram 3.3.2 Natural Ventilation 3.3.3 Stack Ventilation 3.4 Thermal Analysis 3.5 Solar Analysis 3.5.1 Solar Radiation 3.5.2 Stereographic Diagram 3.5.3 Sun Path Diagrams and Shading Patterns 3.5.4 Shading Device 3.6 Sun Ray Diagrams 3.7 Materials 4.0 Conclusion 5.0 References

3 4 5 6 7 8 - 10 11 12 - 13 14 15 15 16 17 17 18 18 - 20 20 - 22 23 24 25 - 26 27 28 - 30 31 32 - 33 34 35 36 - 38 39 - 40 41 - 42 43 - 44 45 46

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Summary This project was tasked to investigate the factors that affect the thermal comfort of occupants in a particular space in a residential building. Also, by understanding the human perception of thermal comfort as well as the contributors of thermal comfort, this will aid us in our investigation.

After selecting our site, we were to use Hygro-Thermometer to record the temperature and relative humidity of our selected indoor space. Values of indoor temperature and relative humidity are obtained and used to compare with the outdoor values across a span of three days. We have obtained hourly values of indoor temperature and relative humidity dating from 5th September 2013 to 8th September 2013. A relationship between the indoor and outdoor values as well as a relationship between temperature and relative humidity were then established.

We were then to determine the comfort level of the room and thereafter, understand the factors that contribute to the comfort level of the room such as the type of building materials that are used for the structures of the buildings, the amount of shading device that would intercept any direct sunlight that may enter the building as well as fenestrations, sufficient ventilation and site context that would also affect the thermal performance of the room itself.

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1.0

Introduction

1.0.1 Aims and objectives The aim of this project is to understand the principles of heat transfer, identify environmental conditions related to factors such as site conditions and climate. We are also required to establish a relationship between the solar effects of the sun on the thermal performance of the residential structure which we have to proposed to study. Also, factors such as ventilation, types of building materials used as well as air movement are important to comprehend the thermal impacts on the structure.

Objectives 

Identify and define principles of heat transfer in relation to the building and its occupants



Understand the definition and factors that affect thermal comfort



Analyze impacts of thermal comfort factors on a space and in a said space



Criticize design of the space in terms of thermal comfort with reference to MSI 1525 and UBBL

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1.0.2 Human Perception of Thermal Comfort Thermal comfort is the condition of the mind that expresses satisfaction with the thermal environment. There are six factors that affect the level of thermal comfort consisting of both environment and personal factors. Personal factors are the characteristic of the user and Environmental factor are conditions of thermal environment.

The personal factors are clothing insulation and metabolic rate. Thermal comfort is dependent on the insulating effect of clothing on a wearer. Clothing is both a potential cause of thermal discomfort as well as a control for it as we adapt to the climate in which we live. As for the metabolic rate, different people have different metabolic rate that can vary due to the environment and activity level. The more physical work we do, the more heat we produce. The more heat we produce, more heat is required to be lost.

Environmental factors include air temperature, radiant temperature, air velocity and humidity. Air temperature is the temperature surrounding the user with respect to time and location. The human body’s primary response is towards the change in temperature. Thermal radiation is heat that radiates from a warm object and also may be present if there are heat sources in an environment. Air velocity is described as the rate of air movement across the user. It is an important factor in thermal comfort because people are sensitive to it. Humidity is dependent on the amount of water vapour that is present in the atmosphere.

Thermal discomfort has been known to lead to sick building syndrome symptoms. The combination of high temperature and high relative humidity serves to reduce thermal comfort.

Through our observations and data analysis, factors affecting thermal comfort are acknowledged with references from the standardized values in GBI MS 1525:2007 (Code of Practice on Energy Efficiency and Use of Renewable Energy for Non-Residential Buildings)

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1.1

Site Location

Petaling Jaya is made up of mostly residential areas and a fair amount of industrial areas. Petaling Jaya is well linked with Kuala Lumpur and the rest of the country by road. The main Kuala Lumpur-PJ link is the Federal Highway, which goes through the middle of PJ and continues to Subang Jaya, Shah Alam, Klang and Port Klang.

Petaling Jaya is one of the wettest cities in Malaysia. It is warm with an average maximum of 30 degrees C and receives heavy rainfall all year round, roughly more than 3,300 mm (130 in) of average rainfall annually. Petaling Jaya has no particular true dry season but June and July are the driest months. Mostly each month average rainfall receives more than 200 mm (7.9 in) of rainfall. Thunderstorms and extreme rainstorms are common in Petaling Jaya and it is one of the highest lightning strike areas in Malaysia.

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1.1.1 Site Plan

Address: No. 1, Jalan 6/28, 46000 Petaling Jaya, Selangor Building type: Single-storey bungalow house

Section 6 is a serene and peaceful residential area in the older part of Petaling Jaya. This area is a matured neighbourhood with sufficient amenities and commercial areas to cater to its residents.

The chosen site is surrounded by many other bungalows and terraces. Most houses in that area have undergone renovations to alter the usage of materials that may have been worn out over time. Trees and shrubs surround the compound of each house to maintain environment cohesion and acts as a cooling effect to the surroundings.

Vehicles that travel around the area have their own peak time. As it is located near a school, the road surrounding the house will generally be busy during peak hours which around 12pm and 6pm.

A brick wall separates each house with a 3 metres wide area in between houses.

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1.1.2 Orthographic Drawings

Ground Floor Plan (Area marked in red is the area that is used for site study)

South Elevation

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East Elevation

West Elevation

North Elevation

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Longitudinal Section

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1.1.3

On-site photos 1.1.3.1

Exterior Photos

Car Porch

Side Entrance

Elevation of side entrance with water feature to the right of the photo.

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1.1.3.2 Interior Photos Living Area

Living area indicating the two openings where most sunlight streams into the room as well as the indoor shading devices that are used.

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Living area facing the curved stairway to the attic.

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1.4 Task and Project Procedures In order to identify and define the principles of heat relation to the building, the task of this project is to analyze the factors that relate or affect the thermal comfort by finding out the range of room temperature that is within the human perception of comfort level.

The main factors that contribute to the changes of thermal comfort and the identification methods used are shown in the table below.

Factors relating to thermal comfort

Method used to identify

Air temperature -Indoor temperature

-Data logger

-Outdoor temperature

-Online database

Relative Humidity -Indoor relative humidity

-Data logger

-Outdoor relative humidity

-Online database

Air Velocity

Wind rose diagram

Radiant Temperature (solar)

-Sun path diagram, sun shading pattern

A data logger was placed at the chosen space which then recorded the data of the indoor temperature and relative humidity over a period of 72 hours. While, the data for the outdoor temperature and outdoor humidity were determined from an online database. (link of the website) A temperature versus humidity dual -axis chart is plotted based on the data collected to indicate a better relation between temperature and relative humidity, for further discussion and analysis. A bioclimatic chart which shows the relationship between air speed, thermal energy, temperature and relative humidity is also created to depict the human comfort region/zone.

From the information that illustrated in the sun path diagrams and wind rose diagram, a more in depth analysis has been carried out in order to study the effects of the sun and other relating factors such as thermal mass, thermal insulation, air movement etc. on the thermal performance of the building.

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1.4.1 Limitations The space chosen to carry out the whole study is limited to only one small part of the building. Furthermore, data for the indoor temperature and relative humidity was also only recorded over a period of 72 hours. Besides, data from a nearby location had to be used due to the specific data concerning wind speed right at the spot of the chosen space could not be determined. Therefore, the information might not be an accurate representation of the thermal performance for the entire building.

Systematic errors due to the handling of the data logger or the malfunctioning of the data logger itself could have affected the overall result as well.

2.0 Methodology for Data Collection

With a Hygro-thermometer, we were to measure the indoor temperature (in Degrees Celsius) and indoor Relative Humidity (%). These readings were to take place at regular intervals and we have set the hygro-thermometer to take readings at every 3600s (1 hour) intervals. The readings were recorded by the data logger over a period of 3 days and the data was then transferred from the SD card which it was

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stored in, onto an excel spreadsheet. These values are then used to plot a graph and compared to outdoor temperature and relative humidity values.

2.1 Temperature and Relative Humidity The thermo/hygrometer data logger that provided was used to obtain and to record indoor temperature and relative humidity. First the data logger was set to record temperature and relative humidity per hours in 72 hours period. Then it was placed 1 m above the ground level in the chosen room that can be seen from the floor plan below where the room would be at least disturbances by active cooling, human interfere and heat or sun light. Human perceptions that cause some interfere in that room also had been used to analyze the recorded data. While the outdoor temperature and relative humidity data was obtain from the online weather reports.

From our observation on the site, on sunny days the outdoor feels strongly hot, especially most of the exterior of the site covered by concrete that

can

reflect

back

the

heat.

Meanwhile in the indoor areas feel cooler than outdoor with fan on and wall and glass that shade us from direct heat. Therefore we also record the weather condition and human activity in that 72 hours period to see how it impacts the indoor temperature and humidity.

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2.2

Wind Movement and Ventilation

A windrose diagram is a tool that is used to illustrate the frequency of wind, wind speed and wind direction in a particular area. Data from all these factors are acquired 3 days during which the data logger was placed in the area we are conducting our observations. This data was gathered from online weather reports and a windrose diagram was then drawn up to illustrate the average air velocity and directions in which most of the wind was coming from towards our site.

By acknowledging the openings around the area in the house which we have chosen to study, we are able to understand the efficiency of the placements of these openings with response to that of the wind movements mentioned above. By highlighting the openings such as doors and windows that are present within that area of study as well as taking note of any obstrusive structures such as walls that may hinder the movement of wind through the house will aid us in understanding the amount of breeze that enters the house

2.3

Sun Path Sun path refers to significant changes of the position of the sun as the Earth

rotates and orbits around the sun. The local latitude and the rising and setting position of the sun which based on the time of the year have significant effects on the sun paths, hence affects the lighting behaviors and heating characteristics of the sun.

A sun path diagram is a tool to illustrate the daily and annual changes in the path of the sun for a location through the sky via a 2-dimensional diagram. It provides the summary of solar position, at every time of the day and day of the year, by its azimuth and altitude readings. Therefore, sun path diagrams are used to ascertain solar access that architects and designers can refer to when considering shading requirements and design options.

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3.0 Results and Analysis 3.1 Temperature and Relative Humidity The data that was recorded and obtained from the data logger and online weather report are used to generate a table to see the relationship between outdoor and indoor temperatures, outdoor and indoor relative humidity and the relation between temperature and relative humidity.

3.1.2 Table

Temperature

Date 9/5/13 9/5/13 9/5/13 9/5/13 9/5/13 9/5/13 9/5/13 9/5/13 9/5/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13 9/6/13

Time Indoor 15:24:43 28.5 16:24:42 28.3 17:24:42 28.2 18:24:42 28.2 19:24:42 28.2 20:24:42 28.1 21:24:42 27.8 22:24:42 27.6 23:24:42 27.4 0:24:42 27.4 1:24:42 27.3 2:24:42 27.1 3:24:42 27 4:24:42 27 5:24:42 27 6:24:42 27 7:24:42 27 8:24:42 26.7 9:24:42 26.7 10:24:42 26.9 11:24:42 27.3 12:24:42 27.8 13:24:42 28.1 14:24:42 28.9 15:24:42 28.7 16:24:42 29.3 17:24:42 29.4 18:24:42 28.8 19:24:42 28.8 20:24:42 28.7

Relative Humidity

Outdoor Indoor 29 66.2 30 66.5 30 67.3 29 67.1 28 68.4 26 63.7 25 63.7 25 63 25 69.1 25 62.1 24 61.7 24 59.5 24 56.2 24 64.4 24 69.9 24 72.1 24 74.6 25 74.7 25 72.4 26 73.1 27 73 28 73 28 71.5 29 67.9 30 70.4 30 67.3 30 67.2 29 69.9 28 69.6 27 68.3

Outdoor 70 70 70 74 79 84 89 89 89 89 94 94 94 94 94 94 94 89 89 84 79 79 74 70 70 70 70 74 79 84

External Condition Sunny Sunny Sunny Sunny Sunny Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Sunny Sunny Sunny Sunny Sunny Sunny Sunny Sunny Sunny Sunny Sunny Sunny Partly Cloudy

Human Activity Seated Seated Seated Seated Walking About Walking About Walking About Walking About Walking About No Activity No Activity No Activity No Activity No Activity No Activity Walking About Walking About Swiping/Moping Walking About Walking About Walking About Walking About Walking About Walking About Seated Seated Seated Seated Seated Seated

Clothing Value 0.57 0.57 0.57 0.57 0.57 0.57 0.57 0.57 0.57 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.57 0.57 0.57 0.57 0.57 0.57 0.57 0.57 18 0.57 0.57 0.57

9/6/13 9/6/13 9/6/13 9/7/13 9/7/13 9/7/13 9/7/13 9/7/13 9/7/13 9/7/13 9/7/13 9/7/13 9/7/13 9/7/13 9/7/13 9/7/13 9/7/13 9/7/13 9/7/13 9/7/13

21:24:42 22:24:42 23:24:42 0:24:42 1:24:42 2:24:42 3:24:42 4:24:42 5:24:42 6:24:42 7:24:42 8:24:42 9:24:42 10:24:42 11:24:42 12:24:42 13:24:42 14:24:42 15:24:42 16:24:42

28.6 28.5 28.4 28.2 28.2 28.1 28 27.9 27.8 27.7 27.4 27.2 27.5 27.8 28.3 28.9 29.2 29 29.4 29.8

27 27 26 26 26 26 25 25 25 25 25 25 27 28 30 31 31 31 31 27

71.1 71.9 72 70.5 70 70.8 71.8 71.5 71.2 71.3 72.9 75.6 75.3 74.9 70.9 67.8 62.7 62.4 62.1 64.8

84 84 89 89 84 89 94 89 94 94 89 89 94 84 79 66 66 62 66 79

9/7/13

17:24:42

28.9

27

70.4

79

9/7/13

18:24:42

28.7

25

73.3

94

9/7/13 9/7/13 9/7/13 9/7/13 9/7/13 9/8/13 9/8/13 9/8/13 9/8/13 9/8/13 9/8/13 9/8/13 9/8/13 9/8/13 9/8/13 9/8/13 9/8/13 9/8/13 9/8/13 9/8/13 9/8/13

19:24:42 20:24:42 21:24:42 22:24:42 23:24:42 0:24:42 1:24:42 2:24:42 3:24:42 4:24:42 5:24:42 6:24:42 7:24:42 8:24:42 9:24:42 10:24:42 11:24:42 12:24:42 13:24:42 14:24:42 15:24:42

28.7 28.7 28.5 28.5 28.4 28 27.9 27.7 27.6 27.6 27.6 27.6 27.3 27.3 27.5 27.8 28.4 29 29.5 29.7 29.1

26 25 25 25 25 25 25 25 25 25 25 25 25 25 26 27 29 30 32 29 28

76.4 75.2 77.1 76 76 61.5 60.2 58.3 63.2 69.3 71.9 72.8 75.6 77.1 76.5 75 68.3 64.3 60.3 61.1 67.6

94 89 89 94 94 94 94 94 94 94 94 94 94 94 94 89 89 74 89 74 89

Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Sunny Sunny Sunny Sunny Sunny Sunny Sunny Sunny Sunny Thunderstor m Thunderstor m Thunderstor m Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Partly Cloudy Sunny Sunny Sunny Sunny Sunny Sunny Showers Showers

Seated Seated Walking About Walking About No Activity No Activity No Activity No Activity No Activity Walking About Swiping/Moping Walking About Walking About Walking About Packing Packing Packing Packing Packing Packing

0.57 0.57 0.57 0.57 0.96 0.96 0.96 0.96 0.96 0.96 0.74 0.74 0.74 0.74 0.74 0.74 0.57 0.57 0.57 0.57

Walking About

0.57

No Activity

0.57

No Activity Walking About Walking About Walking About Walking About No Activity No Activity No Activity No Activity No Activity No Activity Walking About Swiping/Moping Seated Seated Seated Walking About Walking About Walking About Walking About Walking About

0.57 0.57 0.57 0.57 0.57 0.74 0.74 0.74 0.74 0.74 0.74 0.74 0.57 0.57 0.57 0.57 0.57 0.57 0.57 0.57 0.57 19

max average min

29.8 28.097 26.7

32 26.712 24

77.1 69.078 56.2

94 85.10 62

3.1.3 Graph 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20

Indoor

15:24:42

12:24:42

9:24:42

6:24:42

3:24:42

0:24:42

21:24:42

18:24:42

15:24:42

12:24:42

9:24:42

6:24:42

3:24:42

0:24:42

21:24:42

18:24:42

15:24:42

12:24:42

9:24:42

6:24:42

3:24:42

0:24:42

21:24:42

18:24:42

15:24:43

Outdoor

From the table and chart above, we are able to see that there is a difference of 1 to 3 degree celcius between outdoor and indoor temperatures where the highest indoor temperature of 29.8 Degrees Celsius was recorded on 7th September and the lowest temperature of 26.7 Degrees Celsius was recorded on 6th September.

Similarly, the highest outdoor temperature was 32 Celsius on 8th September and the lowest indoor temperature of 24 Degrees Celsius was recorded on the same day.

Over the 3 days, the calculated average temperatures for indoor and outdoor temperatures are 28 Degrees Celsius and 26 Degrees Celsius respectively with the indoor temperature being more constant where there are lesser fluctuations when compared to the outdoor temperature. As the outdoor temperature gets heated up due to heat from the sunlight, the indoor temperatures also increases due to other thermally dependable factors such as building orientation and properties of building materials.

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100

90 80 70 60 50

Indoor

40

Outdoor

30 20 10

15:24:42

12:24:42

9:24:42

6:24:42

3:24:42

0:24:42

21:24:42

18:24:42

15:24:42

12:24:42

9:24:42

6:24:42

3:24:42

0:24:42

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12:24:42

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6:24:42

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15:24:43

0

Outdoor and indoor relative humidity bear a larger percentage difference of 4 to 40 percent when compared to the difference between outdoor and indoor temperature that range from 1 to 3 degrees. The highest indoor Relative Humidity of 77.1% was observed on the 8th of September and the lowest indoor relative humidity of 56.2% was observed on 6th September. The highest and lowest relative humidity are 94% and 62% respectively where the former occurs on the second and third day of observation while the latter is observed on the 7th of September.

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In order to establish a relationship between Relative Humidity and Temperature, both data have to be merged into one chart. From the illustration above we can see that relative humidity and temperature are inversely co-related. When the outdoor humidity level reaches its highest percentage of 94%, the outdoor temperature drops to its lowest, 24 Degrees Celsius, on a partly cloudy day.

Meanwhile, on a sunny day in our last day of data observations, outdoor temperature peaks at 32 Degrees Celsius while the outdoor relative humidity fluctuates drastically which is most probably due to the change in weather condition from sunny to rainy.

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3.1.3 Bioclimatic Chart

A bioclimatic chart is a graphical means of representing the human comfort region. It illustrates the relationship between the air movement, dry-bulb temperature and relative humidity Data that is collected in a span of three days by the hygro-thermometer are set up in a table and the average of the data collected was calculated. The average of the dry bulb temperature taken is 29 degrees celcius while the average relative humidity taken is 69 percent.

By plotting these two values on the bioclimatic chart, it indicates that the living room (our site of observation) is not within the comfort zone. Therefore, to achieve a thermal comfort, a wind speed of 0.4 m/s needs to be introduced to achieve comfort level or stimulated ventilation has to be initiated to produce better air movement within this particular area.

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3.2

Climatic Factors

3.2.2

Macro-climatic Factors

Macroclimate refers to the climate of a larger area such as the climate of a particular region, which in this case, refers to the climate of Petaling Jaya. Most often, structures or residential areas are constructed with knowledge of the macroclimate system but design changes cannot alter the macro-climatic conditions of a sitespecific area.

From the online weather data for Petaling Jaya, we are able to extrapolate, the general climatic conditions of the entire area of the site which we are investigating. As such, from these data, we are able to understand the large-scale factors that affect the thermal conditions of the building.

Unlike terrace-linked houses, the structure we are studying is a bungalow lot where there is a significant amount of separation between each house and the next.

Also, given that this is a low density housing area, vehicle traffic within this area is rather low except during peak hours. This thus, affects the thermal conditions of the site which we are investigating.

The distance of the house from the main road also affects the thermal conditions of the house. Since the house is located a fair distance away from the 24

main road, the amount of heat generated from vehicular activity may not affect the thermal conditions of the house.

Also, since wind travels from a high pressure to a low-pressure area, given the low-density housing and low vehicular activity within the vicinity, winds are expected to travel into this area from the mainly bustling main roads and commercial districts.

3.2.1 Micro-climatic Factors

Microclimate refers to the variations in localized climate around or within a particular building, which is influenced by factors such as topography, urban form and vegetation. The following are factors that affect the microclimate of a particular building.

Outside Designers’ Control

Within Designers’ Control

Area and Local Climate

Spacing and Orientation of building

Site surroundings

Location of open spaces

Site Shape

Form and Height of Buildings

Topographic Features

Number of Openings

Surrounding Buildings

Tree Cover Ground Profiling Wind Breaks Surrounding Surfaces

This house which is located in a low-density residential area where one house is situated a few metres away from any neighbouring house thus, providing better air ventilation and circulation where the area of the house which we are investigating faces the east, allows sunlight to penetrate easily into the living room. The luscious greenery that surrounds the building helps to shade and cool the interior of the building through evapotranspiration that can reduce temperatures by 3 to 6 Degrees Celsius during daytime.

At noon when the sun is at its highest position, parts of the outdoor area that are covered with tiles feel hotter because the tiles reflect heat. The placement of brick walls and obstructions of wall structures to the western part of the house hinder most of the wind which come from northwest direction from entering the building.

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The curved staircase at the center of the house provides an access to the attic space while the gable roof allows passive ventilation to occur through the initiation of air circulation by allowing the transmission of cold air and hot air into and out of the building.

Also, the presence of a garden to the east of the house acts as a heat absorber and reduce ground reflected solar rays which would otherwise be caused by paved or tiled ground.

The water feature located near the entrance also aids in moderating the effects of high temperatures on a hot day.

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3.3

Wind Movement 3.3.1

Wind Rose Diagram

Based on the illustration above, from the data we have obtained from the online weather reports, it is observed that most of the wind is originating from the North West direction while the building itself faces North. Thus, the walls of the house 27

itself as well as the neighbouring houses obstruct these oblique winds and as such, not much wind is able to pass through the interior section of the building. Despite that, wind speeds of up to 11km/h were still observed coming from the North and this wind could then be harnessed to passively cool the house.

3.3.2 Natural Ventilation

Natural ventilation is a type of wind intake and exhaust system that utilizes existing thermodynamic forces within a building without the use of electrical machinery to initiate the movement of air such as fans or air conditioning units. As the temperature of air within a particular space such as in this case, the living room, increases, this amount of air expands and as the difference in the column of warm air and cool air is more apparent, the faster the warm air rises and gets exhausted from the building.

The wind rose diagram illustrates the directions in which most of the wind is coming from. As such, by establishing a section, we are able to observe how cold air enters from the North side of the building and gets exhausted from the South side of the building.

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However, due to the placement of several wall structures, from the plan, we are able to observe that the wall structures highlighted in red impede the natural flow of the wind from the North end of the house. Thus, the inflow and outflow of air movement in the house from the North side of the house cannot be established.

Hence, there is little to no passive cooling unless when wind originates from the North East side of the house and enters the living room through the door located at the East side of the house as illustrated above.

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The above diagrams illustrate the difference in wind movement during the day and at night while acknowledging the context of neigbouring houses and surrounding trees.

During the day, since outdoor temperatures are far higher than indoor temperatures, and this sees the area outside the building as a lower pressure area causing hot air to be exhausted from the building and less warm air enters the building since the interior of the building is a high pressure area and that wind travels from a high to low pressure area.

On the flipside, the contrast in air temperatures can get significantly high too and this will see the outdoor temperature to be much lower than indoor temperature and as such marking a high pressure area outdoors. This thus causes wind to travel into the building which now represents a low pressure area. Thus, wind will eventually enter the living room through fenestrations in the building.

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3.3.3 Stack Ventilation

Stack ventilation is a form of natural ventilation where vertical pressure differences are developed by thermal buoyancy and since warm air inside is less dense than the cooler air outside, this warm air will try to escape from higher parts of the building where in this case through vents in the attic as well as the gable roof where warm air is able to escape.

Since stack ventilation is more pronounced with a higher amount of stack, this suggests that the height of stack is a crucial factor for the success of warm air being exhausted through stack ventilation. While it is probable for stack ventilation to occur for a scenario like this where the structure is a one-storey bungalow, the effects of stack ventilation are rather minimal.

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3.4

Thermal Analysis Thermal analysis is a form of investigation where the properties of materials

are studied with relation to changes in temperature. It is also a term used to study heat transfer through structures.

The bricks walls around the house act as a temperature stabilizer. Bricks have excellent thermal mass, which is able to retain heat when the house is subjected to a temperature differential. The more external brick walls you have, the more heat loss you will experience. So a detached house loses more heat than a mid-terrace one.

Also, some old houses with solid external walls may have extensions built with cavity walls.

The typical Malaysian house receives most of its solar heat gain from the roof.

The typical roof receives from 50% to 85% of the total solar radiation. For an intermediate single story terraced house where the roof makes up nearly 70% of the building envelope exposed to the sun, roof insulation becomes all-important to keep the

home

cool.

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The pitched clay tile roof with insulation used in the design of the house minimizes heat gain during the day. Clay tiles have superior reflectance of solar and thermal energy of up to 86 percent. On a sunny day, the area at the attic traps moisture. At night when the temperature outside cools down, the heat trapped inside will be released from the walls and roof. This will help in regulating the interior temperature of the house.

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3.5 Solar Analysis 3.5.1 Solar radiation

Solar radiation is a radiant energy that is emitted by the sun, particularly electromagnetic energy, in many forms such as visible light, ultraviolet rays, X-rays and infrared radiation. Solar radiation is high on clear, sunny day. Solar radiation can affect the thermal performance of a building by transmitting heat directly to the surface of certain materials or through openings, thus, it has been one of the key elements that affects the design process.

Solar radiation through roofs In a typical Malaysian terraced house, horizontal surface of the roof receives the majority of the solar radiation delivered to a house. Therefore, reducing the solar heat gain through the roof should be the first priority for keeping the home cool.

Weatherproofing materials or membranes are used to ensure that no solar radiation is directly transmitted through the roof.

Solar radiation through windows Transparency of windows allows the major portion of the solar radiation to penetrate directly into the interior of the building where only a small portion is reflected back and absorbed. Therefore, curtains, which act as internal shading devices, are usually hung at the windows and sliding doors in order to block the direct sunlight. However, the heat is transmitted to the curtain and trapped between the glass and the curtain thus remitting heat into the building’s interiors.

Solar radiation through walls Unlike fenestrations when solar radiation is incident on an opaque building wall, a part of it is absorbed while the remaining part is reflected back. A fraction of the radiation absorbed is then transferred to the interiors of the building.

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3.5.2 Stereographic Diagram The openings in the living room faces the east where solar heat gain is more apparent from dawn to noon. However, the trees planted in the east provide morning shade and prevent solar heating from the direct sunlight. At exactly 12pm when the sun is directly above the house, sunlight and heat will be directed onto the roof, hence, causing the pitched roofs to absorb most of the heat. Without proper insulation, heat that is trapped in the roof may be transferred into the main building and cause thermal discomfort.

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3.5.3 Sun path diagrams and shading patterns

6th of September, 09:30 At 0930 when the sun is shining from the East, the canopies of the trees help shade the openings of the living room from receiving any direct sunlight or heat gain from the roof.

6th of September, 12:30 The sun crosses the meridian and is at its highest elevation in the sky. More heat is gained due to the direct sunlight from the top.

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6th of September, 15:30 During the late afternoon as the sun travels further to the west, the Western part of the building receives most sunlight and heat from the sun and as such, shading devices such as the roof eaves, help protect our place of study which is the living room from the overbearing sunlight and intense heat.

6th of September, 18:30 As the sun begins to set over the horizon, this is when the living room receives the least amount of direct sunlight and heat since the area is blocked by most of the western section of the building.

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Spring Equinox (21st March) 12:30

Autumn Equinox (21st September) 12:30

Summer Solstice (21st June) 12:30

Winter Solstice (21st December) 12:30

The diagrams above show the sun shading patterns during equinoxes and solstices.

The sun is more towards the south during the winter solstice. Because of that, the building will be more exposed to sunlight when compared to that in summer solstice when trees and bushes to the East corner of the house can be utilized for shade.

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3.5.4 Shading devices

Solar radiation absorbed on the building surfaces will cause an increase in room temperature. Therefore, shading devices are important to prevent any ingression of solar radiation that will cause thermal discomfort.

Exterior shading devices External shading devices intercept the solar energy before entering the room which would result in energy savings by reducing direct solar gain through windows.

They are incorporated in the building’s facade to limit internal heat gain resulting from solar radiation.

Extruded window frame Extruded window frame acts as an obstruction thus, preventing direct sunlight penetration. It blocks the sunlight to a certain degree from entering the internal space through windows.

Roof eaves The use of fixed overhangs that are found in the roof eaves and balcony provides additional shade for the windows and walls. This assists in cooling the house by reducing the amount of solar radiation that enters the building.

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Internal shading devices Internal shading devices usually are adjustable and allow occupants to regulate the amount of direct light entering the space, but is less efficient compared to external shading devices.

Curtains Curtains reduce the transfer of heat between the interior and exterior of a building through the glass of the windows. Although it provides internal shading, it is not efficient in blocking out solar radiation. It also eliminates views and impedes air movement.

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3.6 Sun Ray Diagrams

Summer solstice (21st June) 0930

Winter solstice (21st December) 0930

The diagrams above illustrate the sun rays that are casted onto the main living room area during the winter and summer solstice on the 21st of June and 21st of December respectively at 0930. From these diagrams, we are able to deduce that sunlight gets to penetrate through the building more during the summer solstice compared to that during the winter solstice.

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Summer solstice (21st June) 1230

Winter solstice (21st December) 1230

Autumn Equinox (21st September) 1230

The three diagrams above indicate the sun’s rays at 1230 during different times of the year. Based on the direction of the sunrays, we can see that the east side of the building receives more radiation from the sun during the summer solstice when compared to that in the winter solstice. However, during the autumn equinox, the roof of the building receives the most of the sun radiation since, the path of the sunrays are almost directly perpendicular to the ground.

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3.7

Materials U value is a measure of heat loss in a building element such as a wall, floor or

roof. It can also measure how well parts of a building transfer heat. This means that the higher the U value, the worse the thermal performance of the building envelope.

1. Brick buildings have excellent heat retaining properties. Brick walls can absorb and store heat energy, releasing it slowly overtime. Hence, it is good in stabilizing temperature especially to reduce the artificial heating and cooling usage in an area.

Brick is also good for acoustic performance as it reduces external sound. The best brick wall is the double cavity wall, which fills the gap in between bricks, keeping the warmth in to save energy. It can also help reduce condensation within the house.

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2. Clay tiled roofs work as energy savers. Just like the brick wall, clay tiles help to reduce energy dependency. It is able to reflect heat from the sun and has an ability to insulate by keeping temperatures warm. Clay tiles can reduce the amount of energy needed to keep a comfortable temperature in your home.

3. Marble flooring is an excellent conductor of heat when compared to other common materials used for flooring. This is because the mass of marble is so great that it takes considerably more heat to raise its temperature up to ambient temperature.

When marble is kept in the shade, it gets cooler even though the outside temperature is high.

4. Gypsum plasterboard utilized for the ceiling has a low thermal conductivity.

Gypsum is able to store humidity when a space is humid and will release the humidity when the air becomes too dry. The plasterboard also has the ability to store heat. As temperature increases, heat will be absorbed and will then be re-radiated back out when the temperature of the space decreases.

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4.0 Conclusion From the data and observations which we have obtained, we conclude that our area of study is not within the thermal comfort zone. Most of the thermal discomfort is attributed to the poor passive cooling in the house. Wind that comes from the North can barely be harnessed due to the poor placement of structural walls. Also, given that the structure we’re investigating is a single storey building, with no proper insulation between the roof and main building, heat trapped within the roof may be transferred to the living room seamlessly thus, further causing thermal discomfort.

Also, while the trees and bushes to the East of the bungalow can be utilized for shade from the direct of sunlight and heat from the sun, the poor placement of window in the living room which faces the East means that sunlight is still able to penetrate into the living room between dawn to noon.

Also, for solar anomalies such as when the position of the sun is further south during the same time on different months, this indicates that certain shading devices may prove to be dysfunctional and thus, solar radiation may prove to be a threat to thermal discomfort during these months.

As such, by weighing out the factors that contribute to the thermal discomfort of the area, poor structural placements, building layout and openings are the main contributors to the high levels of thermal energy in the house.

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5.0

References

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Green Globes. (2012). Advanced Technologies and Practices: External Shading Devices. Retrieved from http://www.greenglobes.com/advancedbuildings/_frames/fr_t_lighting_ext_sha ding_devices.htm Gypsum Unique Properties, Retrieved September 26th, 2013, from http://www.eurogypsum.org/properties Malaysia Clay Brick (2011). Retrieved September 26th, 2013, from http://www.myclaybrick.com/html/whybrick-claybrickadvantage.html New-learn.info (2013). Thermal Comfort. [online] Retrieved from: http://www.newlearn.info/packages/clear/thermal/index.html [Accessed: 30 Sep 2013] Newport Corporation. (1996-2013). Introduction to Solar Radiation. Retrieved from http://www.newport.com/Introduction-to-Solar Radiation/411919/1033/content.aspx abc Sun Control, LLC. (2011).

Rp5.ru (2013). Weather Diary in Subang (airport). [online] Retrieved from: http://rp5.ru/Weather_Diary_in_Subang_(airport) [Accessed: 24 sep 2013] Stack Ventilation. Retrieved from http://www.architecture.com/SustainabilityHub/Designstrategies/Air/1-2-1-2 Naturalventilation-stackventilation.aspx Thermal Mass (2013), Retrieved September 26th, 2013 from http://greenpassivesolar.com/passive-solar/building-characteristics/thermalmass/

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