Environmental Engineering Reference
In-Depth Information
for studying the optimum operating conditions of the test plant and also for designing a
similar plant under different conditions.
10. Evaluation of the Test Plant
10.1. Optimum Operating Conditions
The simulation program of the test plant was run after inputting the values for the
following:
•
Performance of individual equipment of the plant obtained from the research
operation (for example, the collector efficiency y= 0.84 - 2.46 x - 1.9 x
2
, and the
maximum capacity of the evaporator = 6.0 m
3
/h).
•
Weather conditions for January through December 1985 (average solar radiation over
inclined surface = 5,589 kcal/m
2
day, average daily atmospheric temperature = 27.4
o
C, and average seawater temperature = 27.5
o
C).
•
Standard operating conditions of the test plant as shown in table 17.
Heating water quantity (variables) = 12, 13.5, 15, 16.5, 18, 19.5 and 21 m
3
/h.
•
Table 17. Operating condition of test plant for simulation calculations
Item
Value
1862 m
2
Collector absorber area
83.6 m
3
/h
Heat collection water flow
Frequency of solar collector cleaning
Once a month
68
o
C
Maximum brine temperature
36.7 m
3
/h
Seawater flow rate
17.5 m
3
/h
Feedwater flow rate
Evaporator startup temperature
Heating water temp. corresponding to 80% load
Evaporator shutdown temp.
Heating water temp. corresponding to 60% load
A summary of the results of the simulation is shown in table 18. As seen from this table,
a heating water quantity of 16.5 m
3
/h results in the maximum water production: 43,400
m
3
/year or 118.9 m
3
/day. However, the plant should not be operated such that TME110 (i.e.,
the number of hours the plant is operated at above 110% load) exceeds 5% of any months
total operating hours. The data in table 18 show the following in terms of TME110:
TME110 for April is 7.6% even if the heating water flow rate is reduced to 12 m
3
/h.
•
•
TME110 for the other months can be below 5% when the heating water flow rate is
16.5 m
3
/h or below.
By increasing the heating water flow to 18.0 or 19.5 m
3
/h without allowing TME110
to exceed 5%, the water production for the month concerned can be increased over
that for the heating water flow of 16.5 m
3
/h.
•
Since it was found that the quantity of heat collected in April exceeds the allowable
capacity of the evaporator, the collector absorber area for April needs to be reduced in order
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