Riyadh - School of Architecture

DESIGN GUIDELINEOBJECTIVE \ ELEMENT1.HEAT AVIODANCEMinimize Heat Gain in FirstHand2.PASSIVETHERMAL TRANSFERBalancing & Taking Advantageof Dirunal TemperatureExtreme3.CONTROLLEDVENTILATIONSelective Screening andModificationWALLOrientationEspecially for elongated building(L>W), they should align to theEast-West axis, Ideally should tilt25deg. toward SE to avoid westernfacing. It is easier to shadethe envelope on North and Southbecause of high angle of sun.THERMAL MASSHeavily constructed (thick not less then 300mm)wall should be used, or even roof to provide a largeheat bank to store up daytime heat for nighttimewarming use. Exact setup depends on capacityand amount of time lag required, careful calculationis needed.*DefinitionThermal Mass is the ability of a material to absorb, store, then in a later time releaseit, to help maintain a more even temperature profile in a day. Good ThermalMass material depends on its heat capacity (kJ/m3K) and its thermal conductivity(W/mK). Example of good thermal mass include brick, earth, stone,and concreteCOLOURLight /reflective colour would minimize heat gainon exterior. For interior, cool/ bright colour wouldhelp light distribution and psychological comfort.While dark colour could be use on ground exposedonly in winter for heat gain, and also onspot where glare to interior would be problem.SHADING DEVICEDevices like louver could be adopted to protectbuilding envelope from excessive heat gain. East-West and North-South should use vertical andhorizontal system respectively for their sun angle.Design should ensure the device doesn’t adsorbtoo much heat to become a source of heat tothe building. Textured wall could work in similarways by self shading itself through profile.Compact VolumeMinimize building surface to volume(S/V) ratio to minimize surfacearea exposed to heat gain.ROOFROOF FORMBarrel vault or dome are idealplanform for max. surface area toheat dissipation and min. area forsolar exposure.DOUBLE ROOFProvide a ventilated air layer in betweentwo roof help bring awayroof heat gain. A more economicalternative is to use false ceiling toprovide that air gap. Effective airexchange in the gap is crucial.INSULATIONAddition of Insulation outside of thermal mass improvesthermal mass efficiency (fewer mass needed)although it is not a necessary. Both wall androof of building can adopt such treatment. Extralayer need to be provided to protect the externalinsulation.OPENINGSIZE & POSITIONOpening should be done in a wayto block out high angle sun at hotseason and admit low angle sunin cooler time.East and West opening shouldbe restrained, espeically the laterone.TRANSFORMABLEIf operation allows, opening canbe partly closed off in the dayand open up at night, by meanslike controllable cover. It will helpminimize admittance of too muchhot, dusty air in day and increasecross ventilation or radiation lossat night to cool down the building.Utilizing heat transfer potentialLIMITED, SMALL, HIGHIn hot-dry climate, air temperaturecan go above blood temperaturewhich renders ventilation at occupantlevel undesirable. Also thereis frequent harzard of Sand storm.Therefore opening should be keptto the minimum and small in size.High window is preferred to onlyfulfill need of air exchange.WIND TOWERWind Tower works in system of air intake and outake by differencein air pressure and temperature. The former is acheived when openingis either facing wind direction or opposing it to create intake andsuction respectively. Multidirectional wind shaft help system functionunder varies wind direction. Heating of the chimney enhance day exhaustand night air exchange to outside. Wind Tower could work withhumidifier to cool air through evaporative cooling