Page 164 - Design of Solar Thermal Power Plants
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3.2 HELIOSTAT FIELD EFFICIENCY ANALYSIS 149
Proportions of various factors in receiver heat loss are shown in
Fig. 3.18, according to which, reflection and radiation heat losses
have accounted for a comparatively large proportion. Therefore, the
solar selective coating on the interior surface of absorber is of great
significance. Conductive heat loss is insignificant, which can be
almost neglected.
Along with the increase of the dimension of aperture of receiver,
intercept factor of receiver increases as well; meanwhile, the heat
loss also starts to grow. Fig. 3.19 reveals the variation of cavity
receiver heat loss at the design point along with the variation of the
dimension of aperture of receiver. At off-design points, it is
necessary to calculate the dimension of facula in the concentration
field by applying the concentration field calculation software, and
then calculate the intercept factor of receiver before substituting it
into P AP in Eq. (3.33).
FIGURE 3.18 Heat losses in various parts of cavity receiver.
FIGURE 3.19 Variation of heat loss of cavity receiver at the design point along with the
dimension variation of aperture of receiver.
