POWER May 2012 - 68

WATER MANAGEMENT
for the month. Rather, equivalent full power
operation should be calculated. The equivalent
full power operating hours can then be
used in conjunction with the thermal design
cases to accurately model water usage.
The operating profile predicts total power
production for a typical January day of
765 MWh. The conventional thermal design
approach assumes power production
of 255 MW during steady-state operation
over a 7-hour period. So, on a typical January
day, the plant effectively operates at
255 MW for a period of 3 hours. Multiply
by the number of days in January (31) and
the plant effectively operates at full power
Table 1. A typical CSP plant operating profile. The yellow regions indicate no solar energy is recovered. The green areas are the
hours during which solar energy is recovered. The average power in kilowatts is shown for each hour. Because the time period is 1 hour, the
power in kilowatts is numerically the same as the energy generation, in kilowatt-hours. Source: WorleyParsons
Average power per hour (kW)
Hour of the day
0.5
1.5
2.5
3.5
4.5
5.5
6.5
7.5
8.5
9.5
10.5
11.5
12.5
13.5
14.5
15.5
16.5
17.5
18.5
19.5
20.5
21.5
22.5
23.5
Other operating parameters
Avg. temp. (24 hours)
Avg. temp. (operating hours)
Total MWh produced
Number of days
Jan.
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Feb. Mar. Apr. May June July Aug. Sept.
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 23.53 101.08 131.06 64.85 22.21
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Oct. Nov. Dec. Average
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 87.43 158.97 219.44 246.16 191.70 161.74 149.05 84.80 15.32
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
28.56
0.00 109.55
31.99 68.58 192.95 217.86 228.29 245.46 211.16 195.35 210.71 168.11 104.42 32.06 158.91
90.31 111.04 192.43 221.84 236.94 244.02 208.88 211.39 218.00 171.63 113.85 84.57 175.41
93.53 100.74 193.28 219.01 227.01 243.23 231.61 206.25 214.74 164.56 110.04 86.54 174.21
94.64 90.38 184.90 222.30 228.71 239.21 227.69 201.96 210.36 160.59 104.67 76.33 170.14
100.05 78.77 183.84 233.23 229.59 243.22 214.19 213.95 201.12 173.66 113.59 87.39 172.72
109.41 94.48 195.57 233.31 225.48 243.40 222.68 215.15 202.24 189.09 124.11 103.88 179.90
128.18 120.94 183.71 198.64 223.52 242.63 216.50 215.38 194.99 191.88 135.09 122.53 181.17
116.99 154.20 178.15 190.90 220.48 234.58 223.37 212.59 199.80 168.90 77.83 92.84 172.55
0.00 43.16 133.38 154.84 187.48 207.83 196.66 173.42 134.70 10.02
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
67
73
765
31
73
80
0.00
0.00
0.00
0.00
0.00
0.00
0.00
79
86
31
0.00 54.02 112.35 97.28 42.82
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
86
95
30
92
98
31
0.00
0.00
0.00
0.00
0.00
0.00
98
106
30
0.00
0.00
0.00
0.00
0.00
0.00
101
107
31
0.00
0.00
0.00
0.00
0.00
0.00
102
108
31
1.30
0.00
0.00
0.00
0.00
0.00
0.00
98
105
30
0.00
0.00
0.00
0.00
0.00
0.00
0.00
90
97
862 1,726 2,074 2,382 2,633 2,307 2,072 1,937 1,483
28
31
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
77
84
899
30
65
73
686
31
Total energy produced (MWh) 23,718 24,144 53,495 62,233 73,843 78,994 71,504 64,238 58,110 45,981 26,968 21,270
Table 2. Three thermal design cases for the typical CSP plant described in Table 1. This design program defines the
water flows for the 255-MW CSP project for the three design cases normally used for a conventional thermal plant. There are problems with using
this standard approach for CSP plant design. Source: WorleyParsons
Tower
Dry bulb
Thermal
case
1
2
3
68
Configuration
Hot day
temperature
(F)
112.90
Annual average 83.20
Winter day 50.00
Wet bulb
temperature
(F)
78.60
57.80
41.70
Ambient
pressure
(psia)
Net
power
(MW)
14.67 250
14.67 254
14.67 255
evaporation
rate
(gpm)
113.13
83.76
35.82
Total deminerallized
water
usage
(gpm)
164.48
164.48
164.45
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Boiler
blowdown
quench
water (gpm)
61.98
61.98
61.97
Boiler blowdown
(gpm)
98.38
98.38
98.35
Quenched
boiler blowdown
(gpm)
116.19
116.18
116.16
High
pressure
blowdown
(lb/hr)
49,168
49,168
49,153
Total steam
flow (lb/hr)
2,409,248
2,409,248
2,408,534
POWER | May 2012
0.00 103.46
0.00
0.00
0.00
0.00
0.00
0.00
0.00
25.65
0.00
0.00
0.00
0.00
0.00
0.00
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POWER May 2012

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