PHYS 1107 Lecture Notes - Lecture 12: Reflection Coefficient, Pressure Coefficient, Solar Thermal Collector
Equation Sheet AR1B025_D4_Thermal
Heat transfer
cond
dT
qdx
λ
=−
c
d
r
λ
=
( )
12ii
i
QUATT=−
∑
with A = area
( )
12conv conv
qTT
α
=−
tot i c a
RrRr=+ +
tot conv rad cond
αα αα
=++
1
tot
UR
=
Ventilation
3600
ventilation
ncVT
Q
ρ
∆
=
with n in h-1
Fourier equation
222
222
TTTT
a
txyz
∂∂∂∂
=++
∂∂∂∂
ac
λ
ρ
=
Radiation transfer between two parallel surfaces with temperature T1 and T2.
( ) ( )
( )
44 84 4
12 12 12
5.67 10
sres res res
qTT TT TT
es e α
−
=−=⋅−≈−
12
111
1
res
eee
=+−
approximation:
( )
12rad res
qTT
α
≈−
3
12
42
res res
TT
αes
+
=
when T1 and T2 are close to room temperature.
2014_2015_Q2 1
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Moisture
100
w
s
p%
p
ϕ
=
relative humidity
4030 18
18 956 235
100
.
.T
s
pe
−+
=
with T in °C
Ground duct
heat flow through fluid or gas through a duct
xx
qvAcT
ρ
=
temperature in a round ground duct (radius r)
( )
2
*
l
x
Rvr c
xinsoil soil
TTTe T
ρ
−
=− +
Solar collector
sun sun
Q q abs t A=
with Abs the absorption coefficient and t the transmission coefficient
1t r abs++ =
with t = transmission coefficient, r = reflection coefficient, abs = absorption coefficient
convection _ inside radiation _ transmitted radiation _ inside
radiation _ outside
qq q
g _ value SHGC=Solar Transmission Factor = q
++
=
1-mass model
( )
12 2
t
TTTexp T
RC
=− − +
a
RC cd r
ρ
=
2014_2015_Q2 2
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Document Summary
Heat transfer q cond dt dx r c. 1 i i with a = area q conv conv. R tot r r i c r a conv rad tot cond. Radiation transfer between two parallel surfaces with temperature t1 and t2. e s res q s. 3 (cid:183) (cid:184) (cid:185) when t1 and t2 are close to room temperature. Ground duct heat flow through fluid or gas through a duct q x v a c t = x temperature in a round ground duct (radius r) Q sun q abs t a sun with abs the absorption coefficient and t the transmission coefficient r abs. 1 t with t = transmission coefficient, r = reflection coefficient, abs = absorption coefficient g _ value. Shgc=solar transmission factor = q convection _ inside q radiation _ transmitted q radiation _ inside q radiation _ outside.
