Page 34 - مشروع تخرج 1

We will assume losses factor = 1.0985 for any losses didn’t count

̇ = . (3.2)
̇
= 72.83 * 1.0985

= 80 MW

The solar energy in the collector can be found by this relation.

̇
= . (3.3)

= 39.2 * 1000
= 39200 = 39.2 kW per collector .

The thermal losses (Q loss) of the absorber to the cover is

4
4
̇ = . . . ( – ) + . ℎ . ( − ) (3.4)

Radiation convection
Where T sky and h out calculated from equations below :
1.5
= 0.0552 . (3.5)
1.5
= 0.0552 * (25+273.15)
= 284.17 K = 11.02 °C

−0.48
ℎ = 4 . 0.58 . (3.6)
If the wind speed (V w) is selected at 1 m/s, which is a typical value, then we will
get h out ≈ 10 W/m2K [4].

Our system is studied as steady-state conditions so the convention thermal losses
between absorber and cover are neglected due to the vacuum between them.
furthermore, the thermal losses from the absorber to the cover are equal to the losses
from the cover to the ambient as the system steady-state.

The number of parabolic trough solar collector that we need for our energy
requirement is given by :

̇

= (3.7)

̇
= 80,000/39.2

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