ابدأ بالتواصل مع الأشخاص وتبادل معارفك المهنية

أنشئ حسابًا أو سجّل الدخول للانضمام إلى مجتمعك المهني.

متابعة

What is U value? And how to find the U values?

user-image
تم إضافة السؤال من قبل adnan akhter , Project QA/QC Engineer , Radiant (UCC Qatar)
تاريخ النشر: 2016/12/15
Muhammad Arsalan Siddiqui
من قبل Muhammad Arsalan Siddiqui , Associate Director (MEP) , JLL

U value in HVAC is the amount of heat transferred per meter per degree by the material

More U more heat transfer. The reciprocal of U is R (resistance) so more R less heat transfer

 

There are certain U values for certain material which you will find in ASHRAE fundamentals as property of materials.

The overall U value is taken when the wall has many components like there will be a plaster or cladding so all the values are sum up as R not U and then overall U value is calculated,.

 

Hope this will work

Muhammed mustafa khan
من قبل Muhammed mustafa khan , Mechanical Engineer, LEED AP® Building Design & Construction , Saudi Consolidated Engineering Consultants (Khatib & Alami)

U value is Overall heat transfer coefficient or the rate at which Heat transmits through a building component such as Wall, Roof etc. If U value is low then heat tranmittance is also less. U-value is the inverse of R-value.R-Value known as Thermal resistance is the ability of a material to prevent the tranfer of heat.The U-value of a construction component of several layers can be calculated using formula as below:U =1 / R1 + R2 + R3 or ∑ R. U value is used to calculate heat transmission through a building element with formula Ht = U A dt. Ht = heat flow (Btu/hr). U = overall heat transfer coefficient, (Btu/hr ft2 F). A = wall area (ft2). dt = temperature difference (F).

chetan sharma
من قبل chetan sharma , Senior project engineer , trinity engineering services

u value is the measure of heat transfer coefficient which is employed in building services when assigning heat load calculation for the building .which is equal sum of the total materials used up ,generally in uae we employ hollow blocks with insulation board on between to reduce u value.

Haitham El shinnawy
من قبل Haitham El shinnawy , Head of Mechanical Engineering Department , Universal Contracting Company-Unico

U value is the measure of overall value of a building insulation to heat transfer. It could collected depending on addition of all the architectural resistances of the member components. It could be calculated by finding the reciprocal of the sum of all materials making the building member.

Martin Thomas vaz
من قبل Martin Thomas vaz , Senior Mechanical Engineer- Supervision consultant , ALKASHAF INTERNATIONAL-DESIGN AND ENGINEERING CONSULTANCY

In cooling load estimation, U factor is used as a heat transfer coefficient applicable to partition walls, external walls, glass wall, glass windows, skylights materials etc.

U factor specifies the heat transfer factor of the materials used in fabrication of the above partitions, and glasses.

Standard values as a thumb rule to be followed for this U factor.

 

Please refer Ashrae for the different U values of different materials.

NASAR MOIN KHAN   PMP®
من قبل NASAR MOIN KHAN PMP® , MECHANICAL SUPERINTENDENT , SATCO

U-value is more of an engineering term which describes thermal performance. It has traditionally been applied to materials such as window ,wall, floor or roof 

U-Value (of building element) = 1 / (Rso + Rsi + R1 + R2 …)

Rso  is  fixed external resistance

Rsi is the fixed internal resistance

R1 & R2  is resistivity of all elements

المزيد من الأسئلة المماثلة