1

RAG 121RAG 121ENVIRONMENTAL SCIENCEENVIRONMENTAL SCIENCE

LECTURE 4LECTURE 4

©Ar. Assoc.Prof. Ar.Dr.Hj.Abdul Majid Ismail

Website

http://www.hbp@usm.my/ventilation

2

LECTURE 4LECTURE 4 COMFORT COMFORT

Firman Allah– Katakanlah: Perhatikanlah apa-apa yang di

langit dan di bumi. Tetapi tidak bermanfaat keterangan dan peringatan bagi kaum yang tidak beriman.

(Surah Yunus ayat 110)

3

ISSUESISSUES OVERHEATED CONDITIONS

– INDOOR TEMPERATURE RISED UP HIGHER THAN THE UPPER COMFORT LIMIT

DIRECT SOLAR HEAT PENETRATION HOT ROOF OR HOT CEILING

TOO HUMID AND INSUFFICIENT AIR FLOW (STUFFY & STICKY)

ENCLOSED SPACE, ROOMS WITH INSUFFICIENT OPENINGS

TOO COOL (AIR-COND ROOMS) (HOTELS, OFFICES, AUDITORIUMS & HALLS)

4

DETERMINING FACTORS FOR DETERMINING FACTORS FOR COMFORTCOMFORT

OUR BODY NORMALLY EXPERIENCES TIREDNESS & REQUIRE REHABILITATION

TO BALANCE THESE MENTAL & PHYSICAL TIREDNESS – WE REQUIRE SOME FORM OF RECREATION, REST & SLEEP.

THIS NORMAL CYCLE WILL BE INTERRUPTED BY SOME EXTREME WEATHER / CLIMATIC CONDITIONS WHICH CAUSES DISCOMFORT.

5

THEREFORE, IT IS IMPORTANT TO MAKE SURE THAT THE CLIMATE INSIDE A BUILDING / HOUSE IS ALWAYS COMFORTABLE.

OCCUPANTS OF A BUILDING JUDGE THE QUALITY OF A BUILDING PHYSICALLY AND EMOTIONALLY.

HERE, THE SUBJECT OF STUDY CONCERN ONLY WITH PHYSICAL COMFORT.

COMFORT IN THE NON-PHYSICAL CONTEX WILL BE COVERED IN OTHER SUBJECT.

6

COMFORTABLE OR UNCOMFORTABLE CONDITION INFLUENCED BY PHYSICAL, PHYSIOLOGICAL & SOCIOLOGICAL FACTORS – CAN BE GROUPED INTO 2 CATAGORIES:

1. ENVIRONMENTAL OR CLIMATIC FACTORS AIR TEMPERATURE, RELATIVE HUMIDITY, AIR

MOVEMENT & RADIATION

2. HUMAN FACTORS METABOLIC HEAT PRODUCTION, ACTIVITIES &

CLOTHING, AND SUBJECTIVE FACTORS (AGE, SEX, HEALTH CONDITION, SKIN COLOUR, RACE & ACCLIMATIZATION).

7

EQUALIBRIUM BODY HEATEQUALIBRIUM BODY HEAT

BODY HEAT LOSS– METABOLISM – THE PROCESS OF FOOD

CHANGES INTO USEFUL ENERGY.– TOTAL HEAT METABOLISM = BASIC

METABOLISM + MUSCLE METABOLISM– EXCESS HEAT WILL BE DISSIPATED

THROUGH METABOLIC RATE & ACTIVITIES:

EXAMPLE: SLEEPING 130 – 160 WATT WALKING 290- 410 WATT

8

HEAT LOSS WILL BE BALANCED BY HEAT GAINED FROM THE ENVIRONMENT.

OUR INTERNAL BODY TEMPERATURE REQUIRED TO BE MAINTAINED AT 370C.

THEREFORE, FOR EQUILIBRIUM, HEAT WILL BE DISSIPATED & ENTER INTO OUR BODY THROUGH A NUMBER OF METHOD / PROCESS:

EQUILIBRIUM BODY HEAT:– HEAT GAINED:

MET = METABOLISM (BASIC & MUSCULAR)

CND = CONDUCTI ON (IN CONTACT WITH HOT OBJECT)

CNV = CONVECTION (IF AIR IS HOTTER THAN OUR SKIN)

RDN = RADIATION (FROM THE SUN, SKY & HOT OBJECT)

9

– HEAT LOST CND = CONDUCTION (IN CONTACT WITT

COLD OBJECT) CNV = CONVECTION (IF AIR IS COOLER) RDN = RADIATION (TO THE NIGHT SKY&

COLD SURFACES) EVN = EVAPORATION (WATER VAPOUR

& SWEAT)

– EQUILIBRIUM BODY HEAT: (MET - CNV CND EVN RDN) = 0

– IF > 0, HEAT DISSIPATED FROM THE BODY < 0, HEAT ABSORBED INTO THE BODY

10

EQUILIBRIUM BODY HEATEQUILIBRIUM BODY HEAT

RDNRDNMET

CNDCVN

EVN

11

CLOTHING SCALECLOTHING SCALE

0.5 CLO 1.0 CLO 2.0 CLO

MINIMUM 0.0 CLO = NO CLOTHING

MAXIMUM 4.0 CLO = POLAR CLOTHING

12

THERMAL INDEX OR THERMAL INDEX OR COMFORT SCALESCOMFORT SCALES

THE IMPORTANCE OF INDEX– THERMAL INDEX OR COMFORT SCALE IS A

COMMON SCALE WHICH REPRESENT THE FOUR CLIMATIC FACTORS (TEMPERATURE, HUMIDITY, AIR MOVEMENT & RADIATION).

– THE INDECES INCLUDE EFFECTIVE TEMPERATURE (ET), CORRECTED EFFECTIVE TEMPERATURE (CET), EQUATORIAL COMFORT INDEX (ECI) AND OTHERS.

– ALL THESE INDECES TAKE INTO CONSIDERATION ONLY HEAT & CLIMATIC EFFECT WITHOUT ANY SPECIFIC HUMAN FACTORS.

13

““CET” NOMOGRAM & ITS CET” NOMOGRAM & ITS FUNCTIONFUNCTION

SUITABLE FOR NORMAL CONDITION, FOR THOSE WITH NORMAL CLOTHING, THIN – INDOOR CLOTHING.

CREATED TO DEFINE TEMPERATURE INDEX I.E. EFFECTIVE TEMPERATURE AS A RESULT OF REFERING TO DBT & WBT & RADIATION (GLOBE TEMPERATURE).

14

““CET” NOMOGRAM CET” NOMOGRAM

15

GLOBE THERMOMETER IS USED TO MEASURE THE MEAN RADIATION TEMPERATURE.

GLOBE THERMOMETER CONSIST OF A NORMAL MECURY THERMOMETER WHICH IS PLACED IN A COPPER GLOBE WHICH WAS PAINTED MAT BLACK WITH A 15MM DIAMETER.

THE TEMPERATURE READING OBTAINED FROM THE THERMOMETER HAS TAKEN INTO CONSIDERATION THE EFFECT OF RADIATION.

RADIENT TEMPERATURE (GT)RADIENT TEMPERATURE (GT)

16

GLOBE THERMOMETERGLOBE THERMOMETER

COPPER GLOBE PAINTED MAT BLACK

MECURY THERMOMETER

15 mm

17

METHOD OF MEASURING VERY LOW METHOD OF MEASURING VERY LOW AIR SPEEDAIR SPEED

THERE ARE A NUMBER OF SELECTED EQUIPMENTS SUITABLE FOR MEASURING VERY LOW WIND SPEED.

HOT-WIRE ANEMOMETER & KATA THERMOMETER ARE VERY SENSITIVE INSTRUMENTS WHICH ARE APPROPRIATE IN MEASURING LOW WIND SPEED SUCH AS SPEED IN A HOUSE / ROOM.

18

SEQUENCE IN USING “KATA” THERMOMETER:– THE KATA THERMOMETER CONSIST OF A

TUBE OF GLASS FILLED WITH COLOURED SPIRIT.

– METHOD OF HANDLING: IMMERSED THE THERMOMETER INTO A JAR OF HOT

WATER MAKE IT DRY & HANG THE SPIRIT LEVEL WILL BE SEEN DROPPING WHEN

IT COOL DOWN THERE ARE 2 MARKS, NORMALLY AT 54.50C & 51.00C RECORD THE TIME TAKEN FOR THE SPIRIT TO DROP

DOWN FROM THE TOP TO THE LOWEST MARK USED A NOMOGRAM TO DETERMINE THE

APPROPRIATE RELATED TEMPERATURE

19

– SEQUENCE IN USING “KATA” NOMOGRAM:

STEP A:– MARK THE KATA FACTOR ON THE VERTICLE

SCALE ON THE FARMOST LEFT.– MARK THE COOLING TIME OBTAINED FROM THE

EXPERIMENT ON THE 1ST SLANTING SCALE .– CONNECT THE TWO POINTS WITH A STRAIGHT

LINE & MARK THE POINT OF INTERSECTION AT THE MIDDLE VERTICLE SCALE.

STEP B:– MARK THE READING OF DBT ON THE 2ND

SLANTING SCALE.– CONNECT USING A STRAIGHT LINE THE

INTERSECTION AT THE MIDDLE VERTICLE SCALE & THE DBT MARK ON THE SLANTING SCALE & READ THE APPROPRIATE AIR SPEED AT THE VERCLE SCALE ON THE FAR RIGHT.

20

““KATA” NOMOGRAM KATA” NOMOGRAM (SEQUENCE OF APPLICATION)(SEQUENCE OF APPLICATION)

KATA FACTORWIND SPEED (m/s)

COOLING POWER

COOLING TIME (s)

DBT (0C)1

2 3

21

““KATA” NOMOGRAMKATA” NOMOGRAM

22

SEQUENCE IN USING “CET” SEQUENCE IN USING “CET” NOMOGRAMNOMOGRAM

1. MEASURE THE RADIATION TEMPERATURE USING GLOBE THERMOMETER.

2. MEASURE THE AIR TEMPERATURE (WBT) USING A THERMOMETER.

3. MEASURE THE AIR SPEED USING ANEMOMETER OR KATA THERMOMETER.

4. MARK THE READING OF THE RADIATION TEMPERATURE / GLOBE ON THE VERTICLE SCALE ON THE RIGHTHAND SIDE OF THE NOMOGRAM.

23

5. MARK THE READING OF WBT ON THE VERTICLE SCALE ON THE LEFT HAND SIDE OF THE NOMOGRAM.

6. CONNECT THE TWO POINTS WITH STRAIGHT LINE.

7. CHOOSE THE APPROPRIATE WIND VELOCITY CURVE WITH THE READING OF ANEMOMETER/ KATA THERMOMETER.

8. MARK THE INTERSECTION POINT BETWEEN WIND VELOCITY CURVE WITH THE PRIVIOUS STRAIGHT LINE.

9. READ THE VALUE OF CET AT THE SLANTING LINE (USE INTERPOLATION TECHNIQUE)

24

APPLICATION OF “CET”APPLICATION OF “CET”

25

OPERATIVE TEMPERATURE (t0)– USED BY “ASHRAE” AS VARIABLES IN

EVALUATING THERMAL COMFORT FOR ACTIVITIES WITH DIFFERENT TYPE OF CLOTHING INSULATION.

– DEFINE AS: UNIFORM RADIATION TEMPERATURE AS A RESULT

OF BLACK ENCLOSURE WHEN THE OCCUPANTS TRANSFER HEAT AT THE SAME RATE BY RADIATION AND CONVECTION AS NORMALLY OCCURRED IN ACTUAL UNUNIFORM ENVIRONMENT

– THE ACCEPTABLE MEAN TEMPERATURE & HUMIDITY IS DEFINED BY THE HATCHED AREA IN THE PSYCHOMETRIC CHART.

– THE MAXIMUM WIND SPEED IS 0.8m/s

26

– PSYCOMETRIC CHART “OPERATIVE TEMPERATURE” WITH ACTIVITIES AT 1.2met.

27

COMFORT ZONECOMFORT ZONE

DEFINITION:– A RANGE OF CONDITION WHEN AT

LEAST 80% OF THE OCCUPANTS FEEL COMFORTABLE.

– OR A RANGE OF CONDITION WHEN THE MAJORITY OF THE OCCOPANTS DO NOT FEEL TOO HOT OR TOO COOL.

28

FINDINGS FROM RESEARCH IN THIS FIELD INDICATED THAT:

1. THE COMFORT ZONE VARIES FROM ONE LOCATION TO ANOTHER

2. DETERMINED BY LOCATION

THE COMFORT ZONE IS BOUNDED BY:1. WIND SPEED

SPEED < 0.15m/s, FEELING OF STUFFINESS SPEED > 1.5m/s, SIDE EFFECT SUCH AS PAPER &

DUST BLOWN OVER THE MOST ACCEPTABLE MEAN WIND SPEED IS

ABOUT 1.5 m/s.

2. LEVEL OF HUMIDITY– THE BEST “RH” LEVEL IS BETWEEN 30% 65%.

29

IF THE AIR TEMPERATURE IS TOO LOW, RADIATION IS NEEDED TO INCREASE THE TEMPERATURE TO A COMFORTABLE LEVEL. AT THIS STAGE, ADDITIONAL WIND SPEED MAY CAUSED ADDITIONAL FEELING OF TOO COOL “WINDCHILL”.

IF THE TEMPERATURE IS TOO HOT & THE HUMIDITY IS ALSO HIGH, WIND VELOCITY CAN HELP TO REMEDY THIS UNCOMFORTABLE CONDITION BY INCREASING THE EVEPORATION PROCESS OF THE SKIN & CREATING A PHISIOLOGICAL COOLING.

30

BIOICLIMATIC CHARTBIOICLIMATIC CHART THIS IS NOT AN INDEX THE CHART COMBINED THE FOUR

CLIMATIC ELEMENTS INTO A SINGLE DIAGRAM TO SHOW THE INTER RELATIONSHIP BETWEEN ONE ELEMENT AND ANOTHER.

THE COMFORT ZONE IS REPRESENTED BY THE HATCHED AREA.

IF ANY UNCOMFORTABLE CONDITION OCCUR, THE RELIEVING METHOD CAN BE PREDICTED BY MOVING THE UPPER OR LOWER COMFORT BOUNDARIES.

31

BIOCLIMATIC CHARTBIOCLIMATIC CHART

32

COMFORT LIMITS COMFORT LIMITS FOR THE TROPICS: FINDINGS BY FOR THE TROPICS: FINDINGS BY

RESEARCHERSRESEARCHERSRESEARCHER UPPER LIMIT LOWER LIMIT

1 SINGAPORE (ELLIS,1952) 25.50C (ET)

29.40C (DBT)

22.70C (ET)

24.40C (DBT)

2 SINGAPORE (WEBB,1960) 27.70C (ECI) 25.50C (ECI)

3 S.MALAYSIA (WEBB, 1952)

27.20C (ET)

30.00C (DBT)

25.00C (ET)

26.60C (DBT)

4 S.MALAYSIA (WYNAHAM, 1964)

27.00C (ET) NONE

5 S.MALAYSIA

(A.MALIK S, 1993)

(RH 45% - 80.6%)

28.50C (DBT) 25.50C (DBT)

33

COMFORT ZONE “RAJEH 1989”COMFORT ZONE “RAJEH 1989”

34

COMFORT ZONE “MALEK 1992”COMFORT ZONE “MALEK 1992”

35

COMFORT ZONE “ADNAN 1997”COMFORT ZONE “ADNAN 1997”

36

METHOD OF SOLVING THE METHOD OF SOLVING THE PROBLEM OF UNCOMFORTABLE PROBLEM OF UNCOMFORTABLE

CONDITIONCONDITION1. IN HOT-HUMID TROPICAL COUNTRIES, IF

THE VALUES OF THE FOUR CLIMATIC FACTORS ARE FOUND TO BE OUTSIDE THE COMFORT ZONE, THE POSSIBLE SOLUTIONS ARE:

– INCREASE AIR MOVEMENT– REDUCE RADIENT HEAT

2. MAXIMISING AIR MOVEMENT & AT THE SAME TIME MINIMISING DIRECT SOLAR RADIATION PENETRATION, EXTREME INCREASED IN TEMPERATURE INDOOR CAN BE PREVENTED & RADIATION HEAT CAN BE REDUCED.

37

3. WINDOW (OPENING):– OPENABLE / CONTROL & PROPERLY

SHADED4. INCORPORATE ARCHITECTURAL

FEATURES SUCH AS SHADING DEVICES, BALCONIES, FINS, & OTHER HEAT INSULATION MATERIALS AND DESIGN WHICH CAPABLE IN PREVENTING AND REDUCING ANY HEAT GAINED.

5. INCORPORATE ANY DESIGN FEATURES WHICH ARE CAPABLE OF PERFORMING AS “CLIMATIC FILTER”.