Chapter 1—Thermal comfort and the development of bioclimatic concept in building design

\PERGAMON

Renewable and Sustainable Energy Reviews1 "0887# 2Ð13

0253Ð9210:87:, ! see front matter Þ 0887 Published by Elsevier Science Ltd[ All rights reservedPII] S 0 2 5 3 Ð 9 2 1 0 " 8 7 # 9 9 9 9 8 Ð 3

Chapter 0*Thermal comfort and thedevelopment of bioclimatic concept in building

designAli Sayigha\�\ A[ Hamid Mara_ab

aUniversity of Hertfordshire\ Reading\ U[K[bCollege of Engineering\ University of Qatar\ Doha\ Qatar

0[ Introduction

In the past few decades\ there have been several attempts to develop a systematicmethodology for adapting the design of a building to human requirements andclimatic conditions[ Such attempts include the development of the building bioclimaticcharts and Mahony tables[ These attempts were aimed at de_ning the appropriatebuilding design strategies\ for a certain region[ This chapter details an attempt toadopt the building bioclimatic chart concept as well as Mahony tables to Qatar\ whichis used as an example\ in order to determine the most appropriate building designstrategies[

1[ Thermal comfort

According to ASHRAE 44!63 standard ð0Ł\ thermal comfort is de_ned as {{Thatcondition of mind which expresses satisfaction with the thermal environment||[However\ the comfort zone is de_ned as the range of climatic conditions within whichthe majority of people would not feel thermal discomfort\ either of heat or cold[Thermal comfort studies either based on _eld surveys or on controlled climaticchambers[ The Fanger comfort equation and Humphrey|s Thermal Neutrality cor!relation are among the most commonly adopted concepts[

� Corresponding author[ Tel] 9933 90078 500253^ Fax 9933 90078 500254^ E!mail] asayighÝnet!com[co[uk

A[ Sayi`h\ A[ Hamid Mara_a:Renewable and Sustainable Ener`y Reviews 1 "0887# 2Ð133

1[0[ Fan`er thermal equation

Macpherson ð1Ł identi_ed six factors that a}ect thermal sensation[ These factorsare air temperature\ humidity\ air speed\ mean radiant temperature "MRT#\ metabolicrate and clothing levels[ He also identi_ed nineteen indices for the assessment of thethermal environment[ Each of these indices incorporate one or more of the six factors[

The Fanger comfort equation is the most commonly adopted[ It is based onexperiments with American college!age persons exposed to a uniform environmentunder steady state conditions[ The comfort equation establishes the relationshipamong the environment variables\ clothing type and activity levels[ It represents theheat balance of the human body in terms of the net heat exchange arising from thee}ects of the six factors identi_ed by Macpherson[ The satisfaction of eqn "0# is anecessary condition for optimal comfort[

"M:ADu#"0−h#−9[24ð0[81ts−14[2−PaŁ−"Esw:ADu#−9[9912"M:ADu#"33−Pa#

−9[9903"M:ADu#"23−ta#� 2[3×09−7fclðtcl¦162#3−"tmrt¦162#3Ł

¦fclhc"tcl−ta# "0#

Equation "0# contains three physiological variables^ the heat loss by evaporation ofsweat\ skin temperature and metabolic rate[ Based on his experimental data andothers\ Fanger proposed the following equations for these variables as functions ofthe internal heat production per surface area\ "H:ADu#

ts � 24[6−9[921"H:ADu# "1#

Esw � 9[31ADuð"H:ADu#−49Ł "2#

Substituting eqns "1# and "2# into eqn "0# Fanger derived the general comfort equation

"M:ADu#"0−h#−9[24ð32−9[950"M:ADu#"0−h#−PaŁ

−9[31ð"M:ADu#"0−h#−49Ł−9[9912"M:ADu#"33−Pa#−9[9903"M:ADu#"23−ta#

� 2[3×09−7fclðtcl¦162#3−"tmrt¦162#3Ł¦fclhc"tcl−ta# "3#

It is clear from eqn "3# that the human thermal comfort is a function of]

"i# The type of clothing tcl\ fcl"ii# The type of activity\ h\ V and M:aDu

"iii# Environmental variables V\ ta\ tmrt and Pa

1[1[ Predicted mean vote "PMV#

The thermal comfort equation is only applicable to a person in thermal equilibriumwith the environment[ However\ the equation only gives information on how to reachoptimal thermal comfort by combining the variables involved[ Therefore\ it is not

A[ Sayi`h\ A[ Hamid Mara_a:Renewable and Sustainable Ener`y Reviews 1 "0887# 2Ð13 4

directly suitable to ascertain the thermal sensation of a person in an arbitrary climatewhere these variables may not satisfy the equation[ Fanger used the heat balanceequation to predict a value for the degree of sensation using his own experimentaldata and other published data for any combination of activity level\ clothing valueand the four thermal environmental parameters[ As a measure for the thermal sen!sation index the commonly used seven point psycho!physical ASHRAE scale wasemployed[ Table 0 summarises the commonly used scales[ The term Predicted MeanVote "PMV# is the mean vote expected to arise from averaging the thermal sensationvote of a large group of people in a given environment[ The PMV is a complexmathematical expression involving activity\ clothing and the four environmentalparameters[ It is expressed by eqn "4#

PMV� "9[241e−9[931"M:ADu#¦9[921#ðM:ADu#"0−h#

−9[24ð32−9[950"M:ADu#"0−h#−PaŁ

−9[31ðM:ADu#"0−h#−49Ł−9[9912"M:ADu#"33−Pa#

−9[9903"M:ADu#"23−ta#−2[3×09−7fclðtcl¦162#3

−"tmrt¦162#3Ł¦fclhc"tcl−ta# "4#

here hc is calculated as follows]

hc � 1[94"tcl−ta#9[14 for 1[94"tcl−ta#9[14 × 09[3zV

hc �zV for 1[94"tcl−ta#9[14 ³ 09[3zV

The thermal sensation scales assumes equal intervals between the expressions ofthermal sensation[ Hence\ the degree of deviation from the neutral or optimal con!ditions of thermal comfort are transferred into numbers rather than expressions[ Suchtransformation of the facts from expressions to numbers enabled the workers tofurther investigate the percentages of responses of individuals to certain conditions[The conditions vary according to environmental\ human activity level and bodyinsolation factors[ Accordingly\ such conditions can be plotted in thermal comfortcharts[ From these charts the level of thermal comfort can be measured at certainconditions of the previously mentioned factors[ Fanger ð2Ł suggested such charts

Table 0Thermal sensation scales

Expression Cold Cool Slightly Neutral Slightly Warm Hotcool warm

ASHRAE 0 1 2 3 4 5 6Fanger −2 −1 −0 9 0 1 2


which were updated and modi_ed afterwards[ Based on more recent research Markusand Morris ð3Ł worked out 44 thermal comfort charts[ The scale used is similar toFanger|s PMV\ with neutrality at zero\ with negative values in the cold and positiveones on the warm[ The charts have two distinct advantages[ First\ they have beenvalidated over a wide range of conditions and not merely the normal {room|conditions[ Second\ they express judgements in degrees of discomfort "DISC# andthus equivalences can be found between cold and warm conditions in terms of acommon human response[ Between DISC −9[4 and ¦9[4\ 79) of the populationwill be satis_ed\ and between −0[9 and ¦0[9\ it drops to 69)[ The charts were basedon a range of human activities\ environmental conditions and body insolation factors]

"i# Clothing] 9[9 "nude#\ 9[5\ 9[8\ 1[3 and 3[9 clo["ii# Activity] 0\ 2 and 4 Met["iii# Air velocity] 9[0\ 9[4\ 1[9\ 4[9 and 09 ms−0[

Knowing the activities of the people inside a speci_c space\ their type of clothing andair velocity inside the space\ one can obtain from the thermal comfort charts thefollowing design parameters]

"i# The standard e}ective temperature\ SET["ii# The degree of discomfort\ DISC^"iii# The skin wettedness\ w "which is de_ned as the equivalent percentage of the

human body which is covered with moisture#[

The thermal comfort chart presented\ as an example\ in Fig[ 0 for the conditions of9[5 clo[ of clothing\ 9[0 ms−0 air velocity "still air# and 0[9 Met of activity "sedentary#[

1[2[ Thermal neutrality

Humphrey ð4Ł Auliciemes investigated the thermal neutrality of the human body[It was de_ned as the temperature at which the person feels thermally neutral "comfort!able#[ Their studies were based on laboratory and _eld works in which people werethermally investigated under di}erent conditions[ The results of their experimentswere statistically analysed by using regression analysis[ Figure 1 shows that thermalneutrality as a function of the prevailing climatic conditions[ Humphreys showed that84) of the neutral temperature is associated with the variation of outdoor meantemperature[ For free running buildings\ the regression equation is approximated by

Tn � 00[8¦9[423Tm "5#

A di}erent empirical correlation function was carried out by Auliciemes is

Tn � 06[5¦9[203Tm "6#

Based on the above equations\ the predicted neutral temperature for Qatar for thedi}erent months of the year are as indicated in Table 1[ Table 1 indicates thatAuliciemes overvalues the thermal neutrality temperatures for the winter months\


Fig[ 0[ The thermal comfort chart\ for the conditions] 9[5 clo\ 9[0 ms−0 and 0[9 Met ð3Ł[

while Humphrey does the same for the summer months[ The summer neutralitytemperature for Qatar is about 17[4>C whereas in winter it drops to about 12>C[

2[ Degree day method for estimating heating and cooling requirements for Qatar

The degree day method is a pure climatic concept to estimate the cooling andheating requirements at any location[ It can be visualized as the annual cumulativetime weighted temperature de_cit "heating degree!days# or surplus "cooling degree!days#[ A reference temperature is set and every days mean outdoor temperature iscompared with the reference temperature[ The di}erences are added for every day togive the annual number of degree days[ Table 2 lists the annual cooling and heatingdegree days for Qatar[ Two reference temperatures were considered\ according toASHRAE standard and Humpreys neutral temperature as indicated in Table 2[The reference temperatures for Qatar\ in accordance with ASHRAE standard\ aregenerally lower than that estimated by Humphrey|s equation[ This resulted in highercooling degree days and lower heating degree days with ASHRAE standard comparedto those obtained with Humphreys correlation[ It is also clear from Table 2 that the


Fig[ 1[ Correlation of outdoor mean temperature and thermal neutrality ð4Ł[

Table 1Thermal neutrality temperatures for Qatar

Month Humphreys AuliciemesTn">C# Tn">C#

J 19[8 11[6F 11[9 12[1M 12[4 13[1A 15[9 14[6M 18[1 16[4J 29[0 17[9J 20[9 17[4A 29[8 17[4S 18[7 16[7O 16[6 15[5N 14[4 14[3D 19[7 11[6


Table 2Degree day method applied to Qatar based on ASHRAE standard and neutrality temperature concept

Month Cooling Degree!Days Heating Degree!DaysTref � 15>C Tref � 07[2>C

ASHRAE Humphrey|s ASHRAE Humphrey|sTref � 15>C Tn � 17[4 Tref � 07[2>C Tn � 12>C

J 9 9 48 191F 9 9 62 084M 9 9 1 38A 20 6 9 9M 079 091 9 9J 116 041 9 9J 175 197 9 9A 179 192 9 9S 198 023 9 9O 89 14 9 9N 5 9 9 9D 9 9 57 022Total 0298 720 191 467

cooling requirements are high\ and generally\ extending from May to October[ Themonths of March\ April and November can be considered as being comfortable[

3[ Building bioclimatic charts

Bioclimatic charts facilitate the analysis of the climate characteristics of a givenlocation from the viewpoint of human comfort\ as they present\ on a psychrometricchart\ the concurrent combination of temperature and humidity at any given time[They can also specify building design guidelines to maximize indoor comfort con!ditions when the building|s interior is not mechanically conditioned[ All such chartsare structured around\ and refer to\ the {comfort zone|[ The comfort zone is de_nedas the range of climatic conditions within which the majority of persons would feelthermally comfortable[

3[0[ Ol`yays bioclimatic chart

Olgyays bioclimatic chart ð5Ł\ Fig[ 2\ was one of the _rst attempts at an environ!mentally conscious building design[ It was developed in the 0849s to incorporate theoutdoor climate into building design[ The chart indicates the zones of human comfortin relation to ambient temperature and humidity\ mean radiant temperature "MRT#\wind speed\ solar radiation and evaporative cooling[ On the chart\ dry bulb tem!


Fig[ 2[ Olgyays building bioclimatic chart ð5Ł[

perature is the ordinate and relative humidity is the abscissa[ The comfort zone is inthe centre\ with winter and summer ranges indicated separately "taking seasonaladaptation into account#[ The lower boundary of the zone is also the limit abovewhich shading is necessary[ At temperatures above the comfort limit the wind speedrequired to restore comfort is shown in relation to humidity[ Where the ambientconditions are hot and dry\ the evaporative cooling "EC# necessary for comfort isindicated[ Variation in the position of the comfort zone with mean radiant temperature"MRT# is also indicated[

3[0[0[ Limitations and problems impairin` the use of Ol`yays bioclimatic chartThe concept of the chart was based on the outdoor climatic conditions[ This resultedin some limitations in analysing the physiological requirements of the indoor environ!ment of the building[ Therefore the chart is applicable to a hot humid climate sincethere is no high range ~uctuations between indoor and outdoor conditions[

3[0[1[ Applicability of Ol`yays bioclimatic chart to QatarThe bioclimatic chart of Qatar is shown in Fig[ 3[ The twelve lines represent thedi}erent months of the year[ They represent the average daily maxima and averagedaily minima data of both relative humidity and dry bulb temperature[ The chartindicates that for the months of AprilÐJune\ October and November shading ven!tilation can be e}ective tools in restoring comfort[ On the other hand\ for the monthsof July\ August and September the temperature and relative humidity is so high thatonly conventional dehumidi_cation and air conditioning can restore comfort[ For the


Fig[ 3[ Olgyays chart applied to Qatar[

winter months "DecemberÐMarch# the chart indicates that solar radiation should beencouraged[ For example\ in January\ the radiation needed to bring the outdoorcondition to the lower limit of the comfort zone is about 599 Wm−1[

3[1[ Givoni|s bioclimatic chart

Givoni|s bioclimatic chart ð6Ł\ Fig[ 4\ aimed at predicting the indoor conditions ofthe building according to the outdoor prevailing conditions[ He based his study onthe linear relationship between the temperature amplitude and vapour pressure of theoutdoor air in various regions[ In his chart and according to the relationship betweenthe average monthly vapour pressure and temperature amplitude of the outdoor air\the proper passive cooling strategies are de_ned according to the climatic conditionsprevailing outside the building envelope[ The chart combines di}erent temperatureamplitude and vapour pressure of the ambient air plotted on the psychrometric chartand correlated with speci_c boundaries of the passive cooling techniques overlaidon the chart[ These techniques include evaporative cooling\ thermal mass\ naturalventilation cooling\ passive heating[

3[1[0[ Limitations of Givoni|s bioclimatic chartIn 0870 Watson ð7Ł identi_ed the limitations of Givoni|s bioclimatic chart analysis as]

"i# It can be applied mainly to residential scale structures which are free of anyinternal heat gains [


Fig[ 4[ Givoni|s building bioclimatic chart ð5Ł[

"ii# The ventilation upper boundary zone is based on the assumption that indoormean radiant temperature and vapour pressure are nearly the same as those ofthe external environment[ This necessitates a building of low mass and an exteriorstructure of medium to high thermal resistance provided with white externalpaint[

"iii# The thermal mass e}ectiveness is based on the assumption that all windows areclosed during the daytime\ a still indoor air and the indoor vapour pressure is 1mm higher than the outside[

3[1[1[ Applicability of Givoni|s bioclimatic chart to QatarThe chart applied to Qatar is shown in Fig[ 5[ The chart indicates that high massbuilding coupled with night time ventilation can e}ectively restore comfort for themonths of April\ May\ June\ October and November[ However\ for the months ofJuly\ August and September\ the high ambient temperature and humidity indicatethat passive techniques are ine}ective and conventional means "dehumidi_cation andair conditioning# are therefore essential to restore comfort in buildings[ Furthermore\passive heating can restore comfort from December through March[


Fig[ 5[ Givoni|s building bioclimatic chart applied to Qatar[

3[2[ Szokolay|s bioclimatic chart

Givoni\ in 0869\ published his analysis of the Index of Thermal Stress\ which wasfollowed by Humphreys ð4Ł in 0867 and Auliciemes in 0871 with their ThermalNeutrality equations[ Szokolay ð8Ł in 0875 brought these separate strands of thoughttogether and developed the concept that\ depending on the location and the peopleof that location\ there are\ in fact\ two comfort zones rather than one\ Fig[ 6[ Thezones are based on thermal neutrality correlated to the outdoor mean temperature"Tm# by eqn "7#]

Tn � 06[5¦9[20Tm "7#

Equation "7# is only valid under the following conditions]

"i# 07[4³Tn ³ 17[4"ii# The width of the comfort zone is 1 K at 49) relative humidity["iii# Humidity boundaries are based on ASHRAE standard 44!70 which set the lower

and upper limits at 3Ð01 g kg−0 moisture content "AH#["iv# Relative humidity should not exceed 89) RH curve[


Fig[ 6[ Szokolay control potential zone chart ð8Ł[

3[2[0[ Applicability of the control potential zones "CPZ# to QatarThe control potential zones indicate that the strategies which can be followed torestore comfort in buildings in Qatar are similar to those indicated by Givoni|sbioclimatic chart\ Fig[ 7[

4[ Problems impairing the use of the bioclimatic charts

Arens ð09Ł discussed the problems impairing the use of the bioclimatic charts[ Suchproblems include]

"i# The monthly average of wind\ humidity and temperature are a poor rep!resentation of the widely varying coincident occurrences of these variables[

"ii# The result of the graphic method is not a measurable quantity] during somemonths it will be seen that ventilation is inadequate to provide comfort\ but thenumber of hours in which this occurs during these months cannot be determined[

"iii# There is no provision for cloth changing and activity levels throughout the dayor seasons[

"iv# The charts do not account for acclimatization[ The e}ect of acclimatization andcomfort expectations should be taken into account especially when comfort


Fig[ 7[ Szokolay control potential zone applied to Qatar[

diagrams\ and buildings design guidelines\ are constructed for\ and applied in\warm:hot developing countries ð00Ł[

5[ Mahony tables

The Department of Development and Tropical Studies of the Architectural Associ!ation in London developed a methodology for building design in accordance toclimate[ The proposed methodology is based on three stages of design\ the sketchdesign stage\ the plan development stage and the element design stage[ For the purposeof systematic analysis during the three stages\ they introduced the Mahony Tables[The tables are used to analyse the climate characteristics\ from which design indicatorsare obtained[ From these indicators a preliminary picture of the layout\ orientation\shape and structure of the climatic responsive design can be obtained[ These tablesare brie~y described below[

5[0[ Climatic data

The climatic data such as dry bulb temperature\ relative humidity\ percipitationand wind are classi_ed into groups as described in Table 3[


Table 3Climatic data

Mean relative Humidityhumidity group

Below 29) 029Ð49) 149Ð69) 2Above 69) 3

Similarly the monthly mean maxima and minima of the site in question are comparedto the day and night comfort limits for each individual month\ according to the annualmean ranges given in Table 7 respectively "i[e[\ maxima with the day comfort limitand minima with the night comfort limits#[ The classi_cation is established as follows]

Above comfort limit HWithin comfort limit *Below comfort limit C

The humidity and comfort classi_cations are compared for each month to establishhumidity and arid indicators[

5[0[0[ Humidity indicatorsH0 Indicates that air movement is essential[ It applies when high temperature "day

thermal stress�H# is combined with high humidity "HG�3# or when the hightemperature "day thermal stress�H# is combined with moderate humidity"HG�1 or 2# and a small diurnal range "DR³ 09 C#[

H1 Indicates that air movement is desirable[ It applies when temperature withinthe comfort limit "day thermal stress�*# are combined with high humidity"HG�3#

H2 Indicates that precautions against rain penetration are needed[ Problems mayarise with even low precipitation\ but will be inevitable when rainfall exceeds 199mm per month[

5[0[1[ Arid indicatorsA0 Need for thermal storage[ This applies when a large diurnal range "09 C or more#

coincides with moderate or low humidity "HG�0\ 1 or 2#A1 Indicates the desirability of outdoor sleeping space[ It is needed when the night

temperature is high "night thermal stress�H# and the humidity is low "HG�0or 1#[ It may be needed also when nights are comfortable outdoors but hotindoors as a result of heavy thermal storage "day�H\ night�*\ HG�0 or 1and when the diurnal range is above 09 C

A2 Indicates winder or cold!season problem[ These occur when day thermalstress�C[


Table 4Recommendations for building design in Qatar

Element Recommendations

Layout Building oriented on east!west axis to reduce exposure to sunCompact courtyard planning

Spacing Open spacing for breeze penetration[Air movement Rooms single banked

Permanent provision for air movement[Openings Size] medium openings\ 19Ð39)

Position] north and south walls at body height on windward side[Walls and ~oors Heavy external and internal walls[Roofs Light insulated roofs[Outdoor sleeping Space for outdoor sleeping is required[

Table 5Air temperature

Temperature ">C# J F M A M J J A S O N D

Monthly mean max[ 10[9 11[0 15[2 20[2 27[5 28[6 30[2� 39[5 27[2 22[5 28[7 19[3Monthly mean min[ 01[3$ 03[8 05[7 11[9 14[7 17[9 18[6 29[9 17[1 14[9 19[8 01[7Monthly mean range 7[5 6[1 8[4 8[2 01[7 00[6 00[5 09[5 09[0 7[5 7[8 6[5

� Highest monthly mean^ $ Lowest monthly mean^ AMR � Annual mean range � Highest−Lowest � 17[8^ AMT � Annual mean temperature � "Highest¦Lowest#:1 � 15[8[

These tables are followed by the sketch design recommendations in which the designrequirements of a building can be derived[ The recommendations for the form of thebuilding are grouped under the following eight subjects] Layout\ space\ air movement\openings\ walls\ roofs\ outdoor space and rain protection[At this stage\ recommendations for the various size and protection of openings\ layoutplanning\ positioning\ glazing\ natural light and prevention of glare\ along with thetype of external walls\ roofs and ~oors\ could be indicated[

5[0[1[ Application of Mahoney|s tables in Qatar

The climatic data of Qatar is Tabulated in Mahoney|s Tables 5Ð00[ The recom!mendations of the climatic analysis for building design are summarized in Table 4[

6[ Conclusions

The following conclusions were arrived at]

"0# The summer neutrality temperature for Qatar is about 17[4>C\ whereas in winter


Table 6Comfort limits

AMT over 19>C AMT 04Ð19>C AMT under 04>C

Average R H HG Day Night Day Night Day Night

9Ð29 0 15Ð23 16Ð23 12Ð21 03Ð12 10Ð29 01 1029Ð49 1 14Ð20 06Ð13 11Ð29 03Ð11 19Ð16 01 1949Ð69 2 12Ð18 06Ð12 10Ð17 03Ð10 08Ð15 01 0869Ð099 3 11Ð16 06Ð10 19Ð14 03Ð19 07Ð13 01 07

R H] relative humidity^ HG] humidity group^ AMT] annual mean temperature[

Table 7Humidity\ rain and wind

R H "percentage# J F M A M J J A S O N D

Monthly mean max[a[m[ 76[0 73[7 70[4 63[2 58[6 47[6 68[3 73 72[0 76[5 78 76[6

Monthly mean min[p[m[ 38[4 41 27 21[6 13[0 06 14[4 22[2 22 32 37 40

Average 57[2 57[3 59 43 36 27 42 48 47 54 58 69Humidity group 2 2 2 2 1 1 2 2 2 2 2 2Rainfall "mm# 5[7 0[2 57[8 01[7 9 9 9 9 9 9 9 10[1Wind] prevailing NW NW SE NW NW NW NW NE SE NW NW NWWind] secondary NW N NW NE N N N N E N N NW

� Total rainfall "mm# 000^ R H] relative humidity[

it drops to about 12>C[ Their corresponding comfort zones are 15[4Ð29[4 and 10Ð14>C respectively[ According to those limits the period from May to Septemberrequires either mechanical air conditioning or other passive cooling strategy[

"1# According to the Olgyay method\ Fig[ 8\ ventilation is the most e}ective strategythat can be used "31)#\ whereas radiation for heating utilizes about 06 and 10)of the time the condition falls within the comfort zone and requires no strategy[Active air conditioning and:or dehumidi_cation utilizes about 10) of the time[

"2# Givoni|s method indicates that high mass building coupled with night time ven!tilation can e}ectively restore comfort "49)#\ Fig[ 09[ Furthermore\ dehu!midi_cation and passive heating utilizes 02 and 06) of the time respectively\whereas only 06) of the time falls within the comfort zone[

"3# Szokolay|s method indicates strategies which are similar to those obtained usingGivoni|s method[

"4# Mahony Tables indicate that high mass walls and light insulated roof should beused[ The high mass building and outdoor sleeping is an e}ective strategy "32)#[


Table 8Diagnosis

J F M A M J J A S O N D

Humidity group 2 2 2 2 1 1 2 2 2 2 2 2Temperature "9>C#

Monthly meanmax[ 10 11[0 15[2 20[2 27[5 28[6 30[2 39[5 27[2 22[5 18[7 19[3

Day comfortmax[ 18 18 18 18 20 20 18 18 18 18 18 18

Day comfortmin[ 12 12 12 12 14 14 12 12 12 12 12 12

Monthly meanmin[ 01[3 03[8 05[7 11 14[7 17 18[6 29 17[1 14 19[8 01[7

Night comfortmax[ 12 12 12 12 13 13 12 12 12 12 12 12

Night comfortmin[ 06 06 06 06 06 06 06 06 06 06 06 06

Thermal stressday C C * H H H H H H H H Cnight C C * * H H H H H H * C

H] above comfort limit^ *]within comfort limit^ C] below comfort limit[

Table 09Indicators

J F M A M J J A S O N D Total

Humid X X X 2H0 Air movementH1 Air movementH2 Rain protectionAridA0 Thermal storage X X X X X * * * * 4A1 Outdoor sleeping X X X X * * * * 3A2 Cold!season X X * * * * * * * * * X 2

Passive heating is required "14)# during the winter months and only 22) of thetime falls within the comfort zone[

"5# Table 01 compares the di}erent approaches "Olgyay\ Givoni\ Szokolay andMahony Tables# for building designs[ It lists the appropriate strategy to restorecomfort during the day and night independently[ The bioclimatic charts andMahony Tables indicate that in the early summer months "May and June#\ highmass building with night ventilation and outdoor night sleeping can restorecomfort[ Moreover\ during the peak summer months "JulyÐSeptember# high massbuilding along with dehumidi_cation and active air conditioning is required[


Table 00Design recommendations

Indicator total from Tabel "3# Recommendations

Humid Arid

H0 H1 H2 A0 A1 A22 9 9 4 3 2

Layout9Ð09 x 0[ Building oriented on east00 or 01 4Ð01 to west axis to reduce exposure

to sun9Ð3 x 1[ Compact courtyard planning

Spacing00 or 01 2[ Open spacing for breeze

penetration[1Ð09 3[ As 2\ but protect from

cold:hot wind9 or 0 x 4[ Compact planning[

Air movement2Ð01 x 5[ Rooms single banked[

Permenant provision for airmovement

0 or 1 9Ð4 6[ Double banked rooms withtemporary provision for airmovement[

0 or 1 5Ð01 As 69 1Ð01 As 69 9 or 0 7[ No air movement required

Openings9 or 0 9 8[ Large openings\ 39Ð79) of N

and S walls00 or 01 9 or 0 09[ Very small openings\ 09Ð19)

Any other conditions x 00[ Medium openings\ 19Ð39)

Walls9Ð1 01[ Light walls^ short time lag2Ð01 x 02[ Heavy external and internal

walls

Roofs9Ð4 x 03[ Light insulated roofs5Ð01 04[ Heavy roofs^ over 7 hours time

lag

Outdoor sleeping1Ð01 x 05[ Space for outdoor sleeping

required

Rain protection2Ð01 06[ Protection from heavy rain

needed


Fig[ 8[ Application of Olgyay method to Qatar[

Fig[ 09[ Application of Givoni method to Qatar[


Fig[ 00[ Application of Szokolay method to Qatar[

Fig[ 01[ Application of Mahony Tables to Qatar[

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Table 01Comparison of di}erent methods applied to Qatar

Month Olgyays Givoni Szokolay Mahony Tables

Jan Day * * * * * * * Passive heatingNight C Radiation C Passive heating C Passive heating C

Feb Day * * * * * * * Passive heatingNight C Radiation C Passive heating C Passive heating C

Mar Day * * * * * * * *Night C Radiation C Passive heating C Passive heating C

Apr Day H Ventilation H HMNV¦Ventilation * * H Thermal massNight * * * * * * *

May Day H Ventilation H HMNV H TMNV H Thermal mass¦Outdoornight sleep

Night H Ventilation H Ventilation H Ventilation HJun Day H Ventilation H HMNV H TMNV H Thermal mass¦Outdoor

night sleepNight H Ventilation H Ventilation H Ventilation H

Jul Day H Ventilation H HMNV H TMNV H Thermal mass¦Outdoornight sleep

Night H Active A:C H Dehumidi_cation H Active A:C¦Ventilation HAug Day H Active A:C H Dehumidi_cation H Dehumidi_cation H Thermal mass¦Outdoor

night sleepNight H Active A:C H Dehumidi_cation H Active A:C¦Ventilation H

Sep Day H Active A:C H HMV H TMNV¦Dehumidi_cation H *Night H Active A:C H NVM H Ventilation H

Oct Day H Ventilation H NVM H Ventilation H *Night H Ventilation H NVM H Ventilation H

Nov Day H Ventilation H NVM H Ventilation H *Night H Ventilation H NVM H Ventilation H

Dec Day * * * * C Passive heating * Passive heatingNight C Radiation C Passive heating C Passive heating C

H] above comfort limit^ *] within comfort limit^ C] below comfort limit[


References

ð0Ł Anon] ASHRAE 44Ð63[ð1Ł Macpherson RK\ The assessment of the thermal environment*a review[ Br[ J[ Indust[ Med[\ 0851^08[ð2Ł Fanger\ PO[ Thermal comfort\ analysis and applications in environmental engineering[ Florida]

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Chapter 1—Thermal comfort and the development of bioclimatic concept in building design

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Transcript of Chapter 1—Thermal comfort and the development of bioclimatic concept in building design