Nyob rau hauv cov ntsiab lus ntawm lub zog-npaum lub tsev, "U-tus nqi" feem ntau yog hais txog cov thermal conductivity ntawm ib yam khoom los yog cov khoom, los yog U-factor los yog U-value, uas yog ib qho kev ntsuas ntawm lub peev xwm ntawm cov khoom mus rau kev hloov. cua sov ib chav tsev ntawm qhov kub thiab txias sib txawv ntawm ib chav tsev ntawm lub sij hawm los ntawm ib chav tsev ntawm qhov chaw, thiab feem ntau yog qhia nyob rau hauv units ntawm W / m²-K (watts ib square meter ib kelvin).
Qhov qis dua U-tus nqi, qhov zoo dua cov rwb thaiv tsev ntawm cov khoom siv thiab qhov ua tau zoo ntawm kev txwv tsis pub hloov cov cua sov, yog li kev txhim kho lub zog ntawm lub tsev. Hauv kev tsim lub tsev tsim hluav taws xob, xaiv cov khoom siv nrog U-tus nqi qis yog qhov tseem ceeb los txo qis kev siv hluav taws xob rau cua sov thiab cua txias.
Txawm hais tias U-tus nqi (lossis U-factor) yog universal, U-values tuaj yeem qhia nyob rau hauv txawv units. Hauv ntau lub tebchaws, U-tus nqi yog qhia hauv SI units.
Hauv ntau lub tebchaws, U-tus nqi tau qhia tias yog SI units,
W / (m2⋅K):
Hauv Tebchaws Meskas, U-tus nqi yog qhia raws li British thermal units (Btu) ib teev-square feet-degrees Fahrenheit.
Btu/(h⋅ft2⋅°F)
Thoob plaws hauv daim ntawv no, U-tus nqi raug qhia raws li SI tshwj tsis yog hais tias lwm yam. Txhawm rau hloov SI rau Teb Chaws Asmeskas cov kev cai, faib los ntawm 5.678.
Thermal conductivity yog qis dua nyob rau hauv zoo-insulated feem ntawm lub tsev thiab siab dua nyob rau hauv tsis zoo insulated feem. u-tus nqi coj mus rau hauv tus account poob vim hluav taws xob hluav taws xob, hluav taws xob convection, thiab hluav taws xob conduction.
Txawm hais tias cov chav nyob ntawm thermal conductivity yog tib yam li cov hluav taws xob hloov hluav taws xob, thermal conductivity sib txawv hauv qhov sib txawv ntawm cov hluav taws xob hloov hluav taws xob tsuas yog siv los piav qhia txog kev hloov hluav taws xob hauv cov kua dej, hos thermal conductivity yog siv los ua kom yooj yim sib npaug nrog ntau hom sib txawv ntawm thermal resistance.
Nws tau piav qhia los ntawm kev sib npaug hauv qab no:
φ = A × U × (T1 - T2) qhov twg Φ yog lub tshav kub hloov hauv watts, U yog thermal transmittance, T 1 yog qhov kub ntawm ib sab ntawm cov qauv, T 2 yog qhov kub ntawm sab nraud ntawm cov qauv , thiab A yog thaj tsam hauv square meters.
Kev xa hluav taws xob ntawm cov phab ntsa thiab lub ru tsev feem ntau tuaj yeem suav nrog ISO 6946 tshwj tsis yog tias muaj cov hlau txuas txuas hluav taws xob, qhov twg ISO 10211 tuaj yeem siv. Rau feem ntau hauv pem teb, ISO 13370 tuaj yeem siv. Rau feem ntau lub qhov rais, cov thermal transmittance tuaj yeem suav nrog ISO 10077 lossis ISO 15099.
ISO 9869 piav qhia yuav ua li cas sim ntsuas cov thermal transmittance ntawm tus qauv. Kev xaiv ntawm cov ntaub ntawv thiab qhov zoo ntawm lub installation muaj qhov tseem ceeb ntawm kev ua tau zoo ntawm qhov rais rwb thaiv tsev. Lub framing thiab ob chav sealing ntawm lub qhov rais system yog cov ntsiab lus tsis muaj zog ntawm qhov rais rwb thaiv tsev.
Post lub sij hawm: Aug-15-2024