A User's Manual for DELSOL3 - prod.sandia.gov - Sandia National ...

where
Case (1): D 2 4.0 m
1
hforced = (-)(0.3 -k 0.488(Re)0.5(1.0 -k (28a,ooo
D
Case (2): 4.0 < D L. 125.0 m
Case (3): D > 125.0 m
hforced = 14.0
Re 0.625 0.80
) ) )(0.04199)
For a cavity receiver, the convection heat loss is calculated as (Reference 7):
Qonv = Qforced + Qnnt
Qnrrt = 5,077Acw
A aperture area
W,, = aperture width
A,, = approximation to total area inside of cavity
=n + RWC AV x HC AV
NRWCAV
2 = cavity depth (radius)
HCAV = height of heat absorbing surface
b) IRADFL = 1, Scaled Approximation of Receiver Efficiency
(I1I.G - 8)
Both the design point and a yearly average efficiency are calculated based on
the assumption that the power loss due to radiation and convection is propor-
tional to either: 1) the area of an external receiver, or 2) the total aperture area
in a cavity design; i.e.,
PLOST,R = ~ RAR
where AR = external receiver, total aperture, or total flat plate area,
(YR = proportionality factor.
(1II.G - 9)