Environmental Engineering Reference
In-Depth Information
Table 20. Simulation results at optimum operating condition
Item
Simulation output
Ratio
Total radiation on tilt surface
3,780,000,000 kcal/year
1.0
Drop in solar radiation due to dust
195,000,000 kcal/year
0.052
Heat collection amount
2,212,000,000 kcal/year
0.585
Amount of heat supplied to heat
accumulator
1,950,000,000 kcal/year
0.516
Heat supplied to evaporator
1,808,000,000 kcal/year
0.478
Heat effectively used by evaporator
1,796,000,000 kcal/year
0.475
43,000 m
3
/year
Product water
76 m
3
/year
Collector cleaning water
42,900 m
3
/year
Effective product water
Heat collecting pump running hours
3,655 hr/year (10.0 hr/day)
Evaporator operating hours
8,546 hr/year (yearly average rate 97.6%)
Frequency of operator startup
13 times/year
Power consumption per m
3
5.1 kWh/m
3
1,496 kg/year (0.035 kg/m
3
product)
Anti-scalant consumption (Belgard EV)
5,577 kg/year (0.13 kg/m
3
product)
Sodium hypochlorite consumption (NaClO)
10.3. Evaluation of the Solar Plant
In this section we compare the planned values used in the design of the solar plant, the
experimental results of the research operation obtained during the first year of plant operation
and the values introduced in the simulation program which are based on the measured values.
The results are summarized in table 21. Column one of this table shows the design values;
column two the results of actual measured performance data and column three shows the
introduced in the simulation program.
(a) The solar collector field
The heat collection efficiency of the solar collectors was about 9% lower than that for the
basic design under the same weather conditions. The efficiency of a clean single collector was
measured at the manufacturer's laboratory under ideal operating conditions and was reported
as the catalog efficiency, η
o
c
, which can be represented by the following equation:
η
o
c
= 0.913 - 2.46
x
- 1.92
x
2
(64)
where
x
is a parameter defined as :
x
= {(
T
o
+
T
i
)/2 -
T
a
}/
I
t
and the unit of
o
C hr m
2
/kcal.
When a number of collectors are connected together to form a block in the solar collector
field, the efficiency of such a clean block was measured and found to fit the following
equation:
η
m
= 0.84 - 2.46
x
- 1.92
x
2
(65)
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