passive solar architecture building materials

8/18/2019 Passive Solar Architecture Building Materials

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Passive solar architecture

Module 1

Climate and human thermal comfort:

Building materials


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ndoor thermal comfort


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ndoor thermal comfort


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Adoptive thermal comfort


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!ut "oor "esign Conditions

timum outside climatic data that must be taken into account when developing tst design to suit specic procedures.


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!ut "oor "esign Conditions

timum outside climatic data that must be taken into account when developing tst design to suit specic procedures.


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Main factors determining the thermalresponse of a building

heat gains or losses through various structural elements,

#$ %&' #

wallswindowsroof and (oorinternal heatloads

rate ofventilation


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)hermal properties of

*uilding Materials

• k-Value, )hermal conductivity, the time rate of steadystate heat (ow through a unit area of a homogeneousmaterial induced by a unit temperature gradient in adirection perpendicular to that unit area.

• k'value is measured in +&m.

• )hermal conductivity is an inherent property of a material,like sti-ness or density


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*uilding Materials

• -Value , known ocially as thermal transmittance. )his ismore of an engineering term used to designate the thermalperformance of a system as opposed to a homogeneousmaterial.

– )ransmittance, thermal, the heat transmission in unit timethrough unit area of a material construction assembly,induced by unit temperature di-erence between theenvironments on each side.

– 0'value of a single component is given by the formula 0 k &l

–

0nits +&m#

2.3 +&m#


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*uilding Materials

• !-Value 4esistance, thermal, the 5uantity determined by thetemperature di-erence, at steady state, between two denedsurfaces of a material or construction that induces a unit heat (owthrough a unit area.

• t is inverse of 0 value 41&0

• +e have to use 4'values in thermal calculations because we can6tadd up the 0'values of each component in a thermal ob7ect 8 but

we can add up each component6s value to get the total 4'value 9theconvention is that little 6r6 is used for the components and big 646 isused for the whole thermal ob7ect:.

• ;o 4 r1 % r# % r< % r$ and so on. =ach individual r is the inverseof the u'value, so r l & k, thickness divided by conductivity.


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=C*C 0 values


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ist of materials and their 0values

• *rick 1BB mm thk 0 value #.B+&m#

• 4oof $ inch concrete 0 value3.$ +&m#

•

1 inch Plaster 0 value 1.BB• Air layer 1'$ inch

• nsulation

• # inch DP; B.3E+&m#

• < inch DP; B.$#+&m#

• 4 1&0

• 4 41%4#%4


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=>cercises

• 1BBmm *rk% $ inch air layer% 1BBmm *rick

• 1 inch plaster % 1BB mm *rick% 1 inchplaster

• 1 inch plaster % # inch wallinsulation%1BBmm *rick% 1 inch plaster

• 1 inch plaster% < inch roof insulation % $inch concerete % 1 inch plaster

• Check which specications are =C*Ccompliant


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)hermal Mass

• )hermal mass is a material6s resistance to change in temperature as heat is added orremoved, and is a key factor in dynamic heat transfer interactions within a building. )hefour factors to understand are? density, specic heat, thermal capacity, and thermal lag.

• "ensityDense materials usually store more heat.

• "ensity is the mass of a material per unit volume. n the mperial system, density is given as lb&ft pressed as *tu&lb JIH in the ; system, it is e>pressedas k&'kg ( . t takes less energy input to raise the temperature of a low'specic'heat material than

that of a high'specic'heat material.

1 kg mass

density #BBBkg.&m<


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• )hermal *apacity +)hermal assDensity x Specifc Heat = How much heat can be stored per unit volume

• )hermal capacity is an indicator of the ability of a material to store heatper unit volume. )he greater the thermal capacity of a material, the moreheat it can store in a given volume per degree of temperature increase.

)hermal capacity for a material is obtained by taking the product of density

and specic heat. 0nits are K&.

• )hermal ag +)ime agWith high thermal mass it can ta!e hours or heat to "ow rom one side othe envelope to the other.

• )his slowing of the (ow of heat is called Lthermal lagL 9or time lag:, and is

measured as the time di-erence between peak temperature on the outsidesurface of a building element and the peak temperature on the insidesurface.
http://en.wikipedia.org/wiki/Heat_capacityhttp://en.wikipedia.org/wiki/Heat_capacity

passive solar architecture building materials

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