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Generation of typical solar radiation year for China
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Renewable Energy 31 (2006) 1972–1985 www.elsevier.com/locate/renene
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Generation of typical solar radiation year for China Zhou Jin, Wu Yezheng, Yan Gang School of Energy and Power Engineering, Department of Refrigeration and Cryogenic Engineering, Xi’an Jiaotong University, Xi’an, 710049, China Received 14 April 2005; accepted 12 September 2005 Available online 9 November 2005
Abstract Applying the daily global solar radiation data measured at least 10 years, the typical solar radiation year for 30 meteorological stations in China is generated using the Finkelstein–Schafer statistical method. Based on the typical solar radiation data obtained, the geographical difference of solar energy resource of these 30 stations was also analyzed. The results in this paper will fill this gap that complete and detailed typical solar radiation data are not available for China, and will be useful to the designers of solar energy conversion and utilization devices. r 2005 Elsevier Ltd. All rights reserved. Keyword: Global solar radiation; Typical solar radiation year; China
1. Introduction Currently, coal supplies about 75% of the total energy consumption, and this level of energy consumption causes a series of environmental pollution. Furthermore, with the increase in energy demand, the issue of energy shortage becomes increasingly serious [1]. Since there is more and more concern on energy conservation and environmental protection, interest has been increasingly focused on the use of solar energy in China. Solar energy, as a clean energy source and one kind of renewable energy, is abundant in China. More than two-thirds of area in China receives an annual solar radiation that exceeds 5.9 GJ/m2 with more than 2200 h sunshine per annum [2]. Government targets for solar energy utilization are about 3% of total energy use by 2010 [2]. In this respect, the importance of solar radiation data for the design and efficient operation of Corresponding author. Tel.: +86 29 8266 8738; fax: +86 29 8266 8725.
E-mail address: [email protected] (Y. Wu). 0960-1481/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.renene.2005.09.013
ARTICLE IN PRESS J. Zhou et al. / Renewable Energy 31 (2006) 1972–1985
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solar energy systems and associated energy storage system has been recognized in recent years. For the appropriate and accurate design of solar energy conversion and utilization devices, an accurate knowledge of the solar radiation data is of vital importance. Although, in recent years, many individual studies [3–13] have been carried out on this subject for different locations of China, a complete and detailed typical solar radiation data are not available for China. In this study, typical solar radiation data for 30 meteorological stations of China were generated using the long-term daily global solar radiation records. 2. Data used and methods of analysis 2.1. Database The measurement of solar radiation has been made at relatively few meteorological stations in China. Of the 194 stations in China where weather data are available from the China Meteorological Administration, only 122 of them have records of global radiation. Due to space limitation, typical solar radiation data of 30 stations were calculated using daily global solar radiation measured during at least 10 years between 1957 and 2000 in this study. Information for the meteorological stations and the periods of the data considered are given in Table 1. These stations cover a latitudinal range from 20.031 to 45.751 and a longitudinal range from 87.621 to 126.771, and have largely varied altitude from 3 to 3649 m. All the major biomes within China are represented. In the database given in Table 1, there were missing and invalid measurements in the data and they were marked and coded as 32744 or 32766 in the data The missing and invalid measurements, accounting for approximately 0.25% of the whole database, were replaced with the values of preceding or subsequent days by interpolation. In the calculations, if more than 5 days’ measurements were not available in a month, the month was excluded from the database. 2.2. Method Finkelstein–Schafer (FS) statistics [14] are the common methodology for generating typical weather data [15–21]. This method is an empirical methodology for selecting individual months from different years over the available period. According to FS statistics, if a number n of observations of a variable x are available and have been sorted into an increasing order x1, x2,y, xn, the cumulative frequency distribution function (CDF) of this variable is given by a function S n ðxÞ which is defined as follows: 8 0 for xox1 ; > < (1) Sn ðxÞ ¼ ðk 0:5Þ=n for xk pxoxkþ1 ; > : 1 for xXxn : The FS statistics by which comparison between the long-term CDF of each month and the CDF for each individual year of the month was done are calculated
ARTICLE IN PRESS J. Zhou et al. / Renewable Energy 31 (2006) 1972–1985
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Table 1 Geographical location and weather database of the meteorological stations used in study #
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Location
Beijing Changchun Changsha Chengdu Chongqing Fuzhou Guangzhou Guiyang Haerbin Haikou Hangzhou Hefei Huhehaote Jinan Kunming Lanzhou Lasa Nanchang Nanjing Nanning Shanghai Shenyang Taiyuan Tianjin Wuhan Wulumuqi Xian Xining Yinchuan Zhengzhou
Lat. (1N)
39.80 43.90 28.22 30.67 29.58 26.08 23.17 26.58 45.75 20.03 30.23 31.87 40.82 36.68 25.02 36.05 29.67 28.60 32.00 22.82 31.17 41.73 37.78 39.08 30.62 43.78 34.30 36.72 38.48 34.72
Long. (1E)
116.47 125.22 112.92 104.02 106.47 119.28 113.33 106.72 126.77 110.35 120.17 117.23 111.68 116.98 102.68 103.88 91.13 115.92 118.80 108.35 121.43 123.45 112.55 117.07 114.13 87.62 108.93 101.75 106.22 113.65
Alt. (m)
31 237 68 506 259 84 42 1074 142 14 42 28 1063 52 1892 1517 3649 47 9 73 3 45 778 3 23 918 398 2295 1111 110
Daily global solar radiation Period
Record time (year)
1957–2000 1959–2000 1987–2000 1961–2000 1988–2000 1961–2000 1961–2000 1961–2000 1961–2000 1961–2000 1961–2000 1961–2000 1959–1968 1961–2000 1961–2000 1959–2000 1961–2000 1961–2000 1961–2000 1961–2000 1991–2000 1961–2000 1961–2000 1959–2000 1961–2000 1959–2000 1961–2000 1959–2000 1961–2000 1961–2000
44 42 14 40 13 40 40 40 40 40 40 40 10 40 40 42 40 40 40 40 10 40 40 42 40 42 40 42 40 40
according to: FSðy; mÞ ¼ ð1=nÞ
n X
jCDFm ðxi Þ CDFy;m ðxi Þj,
(2)
i¼1
where CDFm is the long-term and CDFy,m is the short-term (for the year y) cumulative distribution function of the daily variable x for the month m, xi is an order sample value in a set of n observations sorted in an increasing order, and n is the number of daily readings of the month. Finally, the representative year for each month of the data set was determined on the basis that the representative year is that of the smallest value of FS, i.e. TRY ¼ minðFSÞ.
(3)
ARTICLE IN PRESS J. Zhou et al. / Renewable Energy 31 (2006) 1972–1985
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3. Results and discussion By applying the above procedure and the data at the 30 stations listed in Table 1, the CDFs are calculated for daily global solar radiation and for each selected month over the whole selected period of years, as well as over each specific year in the selected period. Then, for each month, the FS statistic is estimated for every year, and the typical solar radiation year was formed consisting of the selected months with the smallest values of FS.
Global solar radiation (MJ/m2 day)
30 Typical year Average year Worst year
25
20
15
10
5 Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month Fig. 1. Annual variation of monthly mean daily values of long-term global solar radiation for the whole period, for the selected typical solar radiation year and for the worst year.
30
ITRY (MJ/m2 day)
25 20 15 10 5 0 0
5
10
15
20
25
30
Long-term measured global solar radiation (MJ/m2 day) Fig. 2. Comparison of monthly average daily values of long-term global solar radiation data and ITRY for 30 stations of China.
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Table 2 The typical solar radiation years with minimum (min) FS and monthly mean of daily global solar radiation (ITRY) for China Station
Month
Year
Min FS
ITRY (MJ/m2day)
1
Beijing
January February March April May June July August September October November December
1977 1979 1966 1990 1984 1961 1978 1961 1973 1975 1965 1984
0.027 0.035 0.029 0.018 0.034 0.025 0.030 0.029 0.028 0.035 0.024 0.033
8.56 12.09 15.07 18.47 21.00 21.10 17.85 16.52 15.96 12.83 8.97 7.28
2
Changchun
January February March April May June July August September October November December
1998 1993 1995 1999 1972 1972 1960 1995 2000 1978 1964 1994
0.021 0.027 0.027 0.026 0.027 0.029 0.032 0.030 0.025 0.023 0.026 0.030
7.35 11.22 14.29 17.18 19.99 20.25 17.35 16.21 15.30 11.60 7.57 5.93
3
Changsha
January February March April May June July August September October November December
1994 1991 1996 1996 1998 1994 1991 1994 1994 1988 1987 1988
0.035 0.039 0.028 0.036 0.032 0.021 0.040 0.055 0.032 0.041 0.040 0.041
5.49 6.12 7.23 11.39 14.24 14.75 17.44 16.85 12.59 10.85 7.32 7.21
4
Chengdu
January February March April May June July August September October November December
1981 1976 1978 1977 1990 1975 1969 1962 1990 1968 1976 1999
0.019 0.024 0.030 0.024 0.023 0.023 0.028 0.021 0.031 0.024 0.029 0.025
5.20 6.39 9.65 12.20 13.55 13.83 14.65 14.08 9.11 7.03 5.51 4.52
#
ARTICLE IN PRESS J. Zhou et al. / Renewable Energy 31 (2006) 1972–1985
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Table 2 (continued ) Station
Month
Year
Min FS
ITRY (MJ/m2day)
5
Chongqing
January February March April May June July August September October November December
1994 1999 1996 1994 1988 1994 1997 1989 1993 1992 1991 1993
0.034 0.023 0.031 0.037 0.023 0.021 0.022 0.040 0.028 0.035 0.031 0.028
3.57 4.46 6.83 9.70 12.02 12.30 15.63 15.34 10.18 5.81 4.12 3.01
6
Fuzhou
January February March April May June July August September October November December
1993 1981 1982 1972 1970 1981 1985 1970 1994 1983 1998 1993
0.028 0.038 0.033 0.025 0.022 0.029 0.020 0.028 0.037 0.020 0.026 0.045
8.11 7.43 9.09 11.97 13.17 14.14 18.87 17.80 13.68 11.70 9.17 8.78
7
Guangzhou
January February March April May June July August September October November December
1978 1978 1996 1961 1984 1979 1971 1972 1996 1986 1978 1983
0.035 0.025 0.029 0.037 0.023 0.028 0.023 0.031 0.032 0.030 0.022 0.025
8.64 7.60 7.99 10.12 12.29 13.10 15.67 14.65 14.26 13.35 12.25 10.72
8
Guiyang
January February March April May June July August September October November December
1981 1996 1977 1999 1985 1990 1979 1984 1990 1961 1989 1978
0.031 0.042 0.028 0.022 0.018 0.025 0.034 0.023 0.025 0.024 0.036 0.029
4.88 7.01 9.42 11.63 12.67 12.15 14.06 14.67 12.02 7.90 6.08 5.67
9
Haerbin
January February
1982 1988
0.026 0.024
6.23 9.50
#
ARTICLE IN PRESS J. Zhou et al. / Renewable Energy 31 (2006) 1972–1985
1978 Table 2 (continued ) #
Station
Month
Year
Min FS
ITRY (MJ/m2day)
March April May June July August September October November December
1972 1984 1980 1976 1986 1999 1967 1979 2000 1967
0.025 0.030 0.026 0.030 0.024 0.032 0.028 0.035 0.024 0.036
14.11 16.33 19.28 20.40 18.15 16.52 13.96 10.40 6.87 4.56
10
Haikou
January February March April May June July August September October November December
1962 1972 1995 1977 1976 1972 1987 1990 1994 1980 1989 1993
0.033 0.034 0.042 0.029 0.029 0.035 0.035 0.023 0.024 0.029 0.034 0.028
8.36 8.74 11.43 15.31 17.82 17.88 19.60 17.83 15.04 13.08 10.89 9.38
11
Hangzhou
January February March April May June July August September October November December
1970 1997 1969 1972 1983 1984 1975 1996 1983 1990 1990 1990
0.024 0.034 0.026 0.033 0.026 0.036 0.031 0.027 0.028 0.024 0.034 0.030
6.87 8.56 9.87 13.00 14.14 12.84 18.17 17.07 12.65 10.63 8.30 7.55
12
Hefei
January February March April May June July August September October November December
1979 1991 1979 1977 1971 1998 1975 1984 2000 1995 1990 1970
0.028 0.029 0.021 0.035 0.024 0.031 0.033 0.028 0.027 0.018 0.036 0.017
7.34 8.73 10.73 12.85 15.70 16.12 16.38 16.60 12.45 10.71 8.54 7.38
13
Huhehaote
January February March April
1965 1965 1966 1966
0.046 0.060 0.064 0.045
9.91 13.86 16.13 19.87
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Table 2 (continued ) #
Station
Month
Year
Min FS
ITRY (MJ/m2day)
May June July August September October November December
1960 1964 1962 1965 1961 1965 1963 1965
0.033 0.026 0.027 0.063 0.031 0.052 0.027 0.059
22.42 25.86 22.57 22.44 17.00 14.48 10.04 8.16
14
Jinan
January February March April May June July August September October November December
1993 1974 1973 1966 1970 1986 1961 1979 1977 1977 1972 1990
0.035 0.035 0.024 0.029 0.027 0.037 0.023 0.035 0.032 0.029 0.031 0.031
7.86 10.20 13.94 16.55 20.09 19.78 16.22 16.03 14.75 11.23 8.33 7.07
15
Kunming
January February March April May June July August September October November December
1997 1996 2000 1998 1966 1996 1969 1977 1982 1961 1982 1993
0.035 0.042 0.045 0.028 0.039 0.022 0.026 0.027 0.025 0.024 0.036 0.027
14.07 16.47 17.76 19.91 17.84 15.06 14.50 13.88 13.71 11.62 11.38 11.96
16
Lanzhou
January February March April May June July August September October November December
1988 1967 1972 1963 1990 1991 1976 1984 1989 1990 1971 1971
0.025 0.031 0.030 0.032 0.024 0.029 0.027 0.032 0.021 0.035 0.017 0.029
7.90 11.71 14.47 18.17 20.91 21.34 19.83 19.17 14.68 11.32 8.85 7.00
17
Lasa
January February March April May June
1995 1998 1986 1976 1971 1976
0.033 0.034 0.023 0.034 0.016 0.031
15.96 18.26 20.36 22.33 25.49 26.31
ARTICLE IN PRESS J. Zhou et al. / Renewable Energy 31 (2006) 1972–1985
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Station
Month
Year
Min FS
ITRY (MJ/m2day)
July August September October November December
1985 1976 1979 1996 1977 1977
0.041 0.026 0.021 0.041 0.035 0.047
23.84 22.06 20.91 19.27 16.63 14.57
18
Nanchang
January February March April May June July August September October November December
1995 1997 2000 1978 1972 1997 1985 1972 1995 1994 1970 1976
0.033 0.031 0.025 0.028 0.025 0.028 0.027 0.025 0.027 0.035 0.033 0.021
6.86 8.12 8.60 11.99 14.17 15.01 19.80 19.20 15.77 12.37 9.40 8.02
19
Nanjing
January February March April May June July August September October November December
1975 1991 1961 1997 1978 1966 1963 1983 2000 1982 1985 1961
0.027 0.029 0.027 0.027 0.034 0.030 0.024 0.034 0.026 0.035 0.032 0.027
8.00 9.65 11.77 14.41 16.02 15.91 16.94 17.17 12.73 10.97 9.39 7.73
20
Nanning
January February March April May June July August September October November December
1992 1979 1968 1966 1976 1971 1963 1978 1962 1968 1993 1990
0.027 0.035 0.026 0.022 0.024 0.033 0.029 0.032 0.032 0.029 0.035 0.041
7.27 7.88 7.72 11.16 14.83 16.33 17.82 16.41 16.79 14.11 11.17 9.84
21
Shanghai
January February March April May June July August
1997 1995 1997 1993 1996 2000 1997 2000
0.031 0.030 0.043 0.024 0.033 0.031 0.057 0.024
7.16 10.37 10.84 14.54 17.27 15.39 15.80 16.04
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Table 2 (continued ) #
Station
Month
Year
Min FS
ITRY (MJ/m2day)
September October November December
1995 1993 1994 1992
0.034 0.025 0.045 0.032
14.97 11.81 8.36 7.43
22
Shenyang
January February March April May June July August September October November December
1992 1964 1978 1978 1998 1973 1990 1984 2000 1993 1998 1997
0.019 0.028 0.028 0.032 0.018 0.023 0.015 0.027 0.024 0.024 0.022 0.025
6.95 10.60 14.18 17.71 19.50 19.11 16.91 15.76 15.28 11.31 7.39 6.00
23
Taiyuan
January February March April May June July August September October November December
1975 1964 1964 1977 1975 1971 1985 1964 1983 1989 1974 1977
0.032 0.036 0.028 0.029 0.033 0.024 0.026 0.038 0.036 0.027 0.037 0.032
9.35 11.39 14.63 18.04 20.78 20.91 19.17 18.05 14.19 12.28 8.49 7.56
24
Tianjin
January February March April May June July August September October November December
1977 2000 1987 1974 1993 1982 1981 1989 1992 1976 1996 1988
0.021 0.036 0.022 0.026 0.033 0.029 0.022 0.029 0.035 0.030 0.032 0.033
7.98 11.20 14.72 18.61 21.14 20.86 17.73 16.60 15.34 11.43 8.49 6.76
25
Wuhan
January February March April May June July August September October
1979 1975 1977 1979 1964 2000 1963 1998 1977 1977
0.027 0.027 0.032 0.035 0.033 0.028 0.031 0.038 0.025 0.040
7.30 8.17 10.45 13.35 14.75 16.58 17.97 17.21 13.90 11.06
ARTICLE IN PRESS J. Zhou et al. / Renewable Energy 31 (2006) 1972–1985
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Station
ITRY (MJ/m2day)
Month
Year
Min FS
November December
1990 1976
0.042 0.026
8.41 7.53
26
Wulumuqi
January February March April May June July August September October November December
1986 1986 1981 1966 2000 1982 1961 1971 1974 1968 1981 1986
0.039 0.038 0.035 0.030 0.027 0.030 0.024 0.028 0.027 0.024 0.033 0.035
5.56 8.00 12.10 17.24 21.96 22.77 22.72 20.36 16.78 11.67 6.58 4.44
27
Xian
January February March April May June July August September October November December
1994 1987 1975 1998 1967 1991 1962 1961 1967 1986 1968 1972
0.026 0.030 0.036 0.023 0.032 0.032 0.027 0.045 0.035 0.027 0.022 0.043
7.35 8.93 11.66 14.44 16.84 17.80 17.94 16.79 11.61 9.37 7.65 6.96
28
Xining
January February March April May June July August September October November December
1979 1974 2000 1982 1973 1974 1972 1988 1979 1962 1978 1979
0.042 0.030 0.037 0.024 0.021 0.034 0.035 0.037 0.022 0.020 0.036 0.051
10.42 12.97 16.43 19.57 21.31 22.35 20.73 20.05 15.20 13.14 10.86 9.27
29
Yinchuan
January February March April May June July August September October November December
1997 1995 1987 1977 1983 1977 1965 1990 1988 1996 1974 1985
0.026 0.026 0.028 0.028 0.027 0.029 0.037 0.031 0.032 0.030 0.039 0.043
10.02 13.38 16.71 20.21 22.49 24.26 23.40 19.16 17.01 13.72 10.42 9.01
ARTICLE IN PRESS J. Zhou et al. / Renewable Energy 31 (2006) 1972–1985
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Table 2 (continued ) #
Station
Month
Year
Min FS
ITRY (MJ/m2day)
30
Zhengzhou
January February March April May June July August September October November December
1994 1981 1988 1986 1999 1982 1993 1985 1971 1971 1966 1990
0.028 0.024 0.027 0.029 0.034 0.036 0.029 0.027 0.032 0.029 0.031 0.030
8.58 10.61 12.99 16.34 18.87 20.29 17.35 15.87 13.23 11.29 9.23 7.56
40 Beijing Chengdu Haerbin
35
ITRY (MJ/m2 day)
30
Haikou Lasa Wulumuqi
25 20 15 10 5 0 Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month Fig. 3. Comparison of ITRY with six stations in Table 1 as example.
In Fig. 1, with Beijing as example, the mean monthly values of daily global solar radiation are given for the typical solar radiation year, for the long-term measurements and for the most unfavorable values of FS for each month in the period. As can be seen from Fig. 1, the difference between ITRY and the long-term measurements for each month is small, whereas difference between ITRY and the value for the most unfavorable values of FS for each month is high. This can also be found for other stations, and the comparison between ITRY and the long-term measurements for all the 30 stations was shown in Fig. 2. The typical solar radiation year with minimum FS for monthly mean global solar radiation for the 30 stations listed in Table 1 are given in Table 2. These data would be useful for the utilization of the solar energy in China. As listed in Table 1, the minimum and maximum values of monthly mean of daily global solar radiation on a horizontal surface (ITRY) of the 30 stations are, respectively, 3.01 MJ/m2 in December in Chongqing, and 26.31 MJ/m2 in June in Lasa, with an annual average value of 13.30 MJ/m2.
ARTICLE IN PRESS J. Zhou et al. / Renewable Energy 31 (2006) 1972–1985
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Annual average of ITRY (MJ/m2 )
25
20
15
10
5
0 2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Station number Fig. 4. Comparison of annual average value of ITRY for the 30 stations.
Fig. 3 shows monthly mean of daily global solar radiation data (ITRY) of the typical solar radiation year for six stations selected from Table 1. As shown in Fig. 3, the difference of ITRY for each month varies substantially between stations. The annual average value of ITRY was shown in Fig. 4. It can be seen from Fig. 4 that there is a remarkable difference between the solar energy resources of different stations. This difference is brought by different cloud formation and sunshine duration in the 30 stations. By using Fig. 4 and the geographical information of 30 stations in Table 1, it can be concluded that there was relatively abundant solar energy resource in northern and western China, and relatively low in inner and southeastern China. This agrees with our former study [12]. 4. Conclusion Solar radiation data, especially the typical solar radiation data, is very important for calculations concerning many applications in the field of thermal engineering. Based on data at 30 meteorological stations in China, typical solar radiation year for daily global solar radiation for these 30 stations are produced using at least 10 years’ measured data. It is found that there is good agreement between long-term data and typical data on a monthly basis. Finally, the geographical difference of solar energy resource of the 30 stations was analyzed. It is found that the solar energy resource in northern and western China is abundant, whereas it is relatively low in inner and southeastern China. Because a complete and detailed typical solar radiation data are not available for China, the work in this paper will fill this gap and will be useful to the designers of solar energy conversion and utilization devices. References [1] Xiao C, Luo H, Tang R, et al. Solar thermal utilization in China. Renew Energy 2004;29(9):1549–56.
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[2] Junfeng L, Wan Y-H, Ohi JM. Renewable energy development in China: resource assessment, technology status, and greenhouse gas mitigation potential. Appl Energy 1997;56(3–4):381–94. [3] Wenxian L. General correlation for estimating the monthly average daily direct radiation incident on a horizontal surface in Yunnan Province, China. Sol Energy 1988;41(1):1–3. [4] Wenxian L, Enrong L, Wenfeng G, et al. Distribution patterns of diffuse solar radiation in Yunnan province, China. Energy ConversManage 1996;37(5):553–60. [5] Wenxian L, Tao L, Shaoxuan P, et al. Estimation and distribution patterns of direct solar radiation in Yunnan Province, China. Energy Convers Manage 1996;37(5):561–7. [6] Wenxian L, Enrong L. Correlations between monthly average global solar radiation on horizontal surfaces and relative duration of sunshine in Yunnan Province, China. Renew Energy 1998;13(3):355–62. [7] Wenxian L, Wenfeng G. Correlations for estimating monthly average global and diffuse solar radiation on horizontal surfaces at Tengchong, China. Energy Convers Manage 1999;40(5):505–8. [8] Wenxian L, Wenfeng G, Shaoxuan P, et al. Ranking the overall performance of eight sunshine-based global solar radiation models with a nonparametric statistical procedure. Energy Convers Manage 1999;40(3):233–41. [9] Shaoxuan P, Wenxian L. Correlations to estimate monthly total solar radiation on horizontal surfaces at Kunming, China. Energy Convers Manage 2000;41(4):367–74. [10] Rensheng C, Ersi K, Jianping Y, et al. Estimation of horizontal diffuse solar radiation with measured daily data in China. Renew Energy 2004;29(5):717–26. [11] Rensheng C, Ersi K, Jianping Y, et al. Validation of five global radiation models with measured daily data in China. Energy Convers Manage 2004;45(11–12):1759–69. [12] Jin Z, Yezheng W, Gang Y. Estimation of daily diffuse solar radiation in China. Renew Energy 2004;29(9):1537–48. [13] Jin Z, Yezheng W, Gang Y. General formula for estimation of monthly average daily global solar radiation in China. Convers Manage 2005;46(2):257–68. [14] Finkelstein JM, Schafer RE. Improved goodness of fit tests. Biometrika 1971;58(3):641–5. [15] Said SAM, Kadry HM. Generation of representative weather-year data for Saudi Arabia. Appl Energy 1994;48(2):131–6. [16] Marion W, Urban K. User’s manual for TMY2 s. Colorado, USA: National Renewable Energy Laboratory; 1995. [17] Petrakis M, Kambezidis HD, Lykoudis S, et al. Generation of a typical meteorological year for Nicosia, Cyprus. Renew Energy 1998;13(3):381–8. [18] Argiriou A, Lykoudis S, Kontoyiannidis S, et al. Comparison of methodologies for TMY generation using 20 years data for Athens, Greece. Sol Energy 1999;66(1):33–45. [19] Gazela M, Mathioulakis E. A new method for typical weather data selection to evaluate long-term performance of solar energy systems. Sol Energy 2001;70(4):339–48. [20] Shaltout MAM, Tadros MTY. Typical solar radiation year for Egypt. Renew Energy 1994;4(4):387–93. [21] Fagbenle RL. Generation of a test reference year for Ibadan, Nigeria. Energy Convers Manage 1995;30(1):61–3.
Renewable Energy 31 (2006) 1972–1985 www.elsevier.com/locate/renene
Data Bank
Generation of typical solar radiation year for China Zhou Jin, Wu Yezheng, Yan Gang School of Energy and Power Engineering, Department of Refrigeration and Cryogenic Engineering, Xi’an Jiaotong University, Xi’an, 710049, China Received 14 April 2005; accepted 12 September 2005 Available online 9 November 2005
Abstract Applying the daily global solar radiation data measured at least 10 years, the typical solar radiation year for 30 meteorological stations in China is generated using the Finkelstein–Schafer statistical method. Based on the typical solar radiation data obtained, the geographical difference of solar energy resource of these 30 stations was also analyzed. The results in this paper will fill this gap that complete and detailed typical solar radiation data are not available for China, and will be useful to the designers of solar energy conversion and utilization devices. r 2005 Elsevier Ltd. All rights reserved. Keyword: Global solar radiation; Typical solar radiation year; China
1. Introduction Currently, coal supplies about 75% of the total energy consumption, and this level of energy consumption causes a series of environmental pollution. Furthermore, with the increase in energy demand, the issue of energy shortage becomes increasingly serious [1]. Since there is more and more concern on energy conservation and environmental protection, interest has been increasingly focused on the use of solar energy in China. Solar energy, as a clean energy source and one kind of renewable energy, is abundant in China. More than two-thirds of area in China receives an annual solar radiation that exceeds 5.9 GJ/m2 with more than 2200 h sunshine per annum [2]. Government targets for solar energy utilization are about 3% of total energy use by 2010 [2]. In this respect, the importance of solar radiation data for the design and efficient operation of Corresponding author. Tel.: +86 29 8266 8738; fax: +86 29 8266 8725.
E-mail address: [email protected] (Y. Wu). 0960-1481/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.renene.2005.09.013
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solar energy systems and associated energy storage system has been recognized in recent years. For the appropriate and accurate design of solar energy conversion and utilization devices, an accurate knowledge of the solar radiation data is of vital importance. Although, in recent years, many individual studies [3–13] have been carried out on this subject for different locations of China, a complete and detailed typical solar radiation data are not available for China. In this study, typical solar radiation data for 30 meteorological stations of China were generated using the long-term daily global solar radiation records. 2. Data used and methods of analysis 2.1. Database The measurement of solar radiation has been made at relatively few meteorological stations in China. Of the 194 stations in China where weather data are available from the China Meteorological Administration, only 122 of them have records of global radiation. Due to space limitation, typical solar radiation data of 30 stations were calculated using daily global solar radiation measured during at least 10 years between 1957 and 2000 in this study. Information for the meteorological stations and the periods of the data considered are given in Table 1. These stations cover a latitudinal range from 20.031 to 45.751 and a longitudinal range from 87.621 to 126.771, and have largely varied altitude from 3 to 3649 m. All the major biomes within China are represented. In the database given in Table 1, there were missing and invalid measurements in the data and they were marked and coded as 32744 or 32766 in the data The missing and invalid measurements, accounting for approximately 0.25% of the whole database, were replaced with the values of preceding or subsequent days by interpolation. In the calculations, if more than 5 days’ measurements were not available in a month, the month was excluded from the database. 2.2. Method Finkelstein–Schafer (FS) statistics [14] are the common methodology for generating typical weather data [15–21]. This method is an empirical methodology for selecting individual months from different years over the available period. According to FS statistics, if a number n of observations of a variable x are available and have been sorted into an increasing order x1, x2,y, xn, the cumulative frequency distribution function (CDF) of this variable is given by a function S n ðxÞ which is defined as follows: 8 0 for xox1 ; > < (1) Sn ðxÞ ¼ ðk 0:5Þ=n for xk pxoxkþ1 ; > : 1 for xXxn : The FS statistics by which comparison between the long-term CDF of each month and the CDF for each individual year of the month was done are calculated
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Table 1 Geographical location and weather database of the meteorological stations used in study #
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Location
Beijing Changchun Changsha Chengdu Chongqing Fuzhou Guangzhou Guiyang Haerbin Haikou Hangzhou Hefei Huhehaote Jinan Kunming Lanzhou Lasa Nanchang Nanjing Nanning Shanghai Shenyang Taiyuan Tianjin Wuhan Wulumuqi Xian Xining Yinchuan Zhengzhou
Lat. (1N)
39.80 43.90 28.22 30.67 29.58 26.08 23.17 26.58 45.75 20.03 30.23 31.87 40.82 36.68 25.02 36.05 29.67 28.60 32.00 22.82 31.17 41.73 37.78 39.08 30.62 43.78 34.30 36.72 38.48 34.72
Long. (1E)
116.47 125.22 112.92 104.02 106.47 119.28 113.33 106.72 126.77 110.35 120.17 117.23 111.68 116.98 102.68 103.88 91.13 115.92 118.80 108.35 121.43 123.45 112.55 117.07 114.13 87.62 108.93 101.75 106.22 113.65
Alt. (m)
31 237 68 506 259 84 42 1074 142 14 42 28 1063 52 1892 1517 3649 47 9 73 3 45 778 3 23 918 398 2295 1111 110
Daily global solar radiation Period
Record time (year)
1957–2000 1959–2000 1987–2000 1961–2000 1988–2000 1961–2000 1961–2000 1961–2000 1961–2000 1961–2000 1961–2000 1961–2000 1959–1968 1961–2000 1961–2000 1959–2000 1961–2000 1961–2000 1961–2000 1961–2000 1991–2000 1961–2000 1961–2000 1959–2000 1961–2000 1959–2000 1961–2000 1959–2000 1961–2000 1961–2000
44 42 14 40 13 40 40 40 40 40 40 40 10 40 40 42 40 40 40 40 10 40 40 42 40 42 40 42 40 40
according to: FSðy; mÞ ¼ ð1=nÞ
n X
jCDFm ðxi Þ CDFy;m ðxi Þj,
(2)
i¼1
where CDFm is the long-term and CDFy,m is the short-term (for the year y) cumulative distribution function of the daily variable x for the month m, xi is an order sample value in a set of n observations sorted in an increasing order, and n is the number of daily readings of the month. Finally, the representative year for each month of the data set was determined on the basis that the representative year is that of the smallest value of FS, i.e. TRY ¼ minðFSÞ.
(3)
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3. Results and discussion By applying the above procedure and the data at the 30 stations listed in Table 1, the CDFs are calculated for daily global solar radiation and for each selected month over the whole selected period of years, as well as over each specific year in the selected period. Then, for each month, the FS statistic is estimated for every year, and the typical solar radiation year was formed consisting of the selected months with the smallest values of FS.
Global solar radiation (MJ/m2 day)
30 Typical year Average year Worst year
25
20
15
10
5 Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month Fig. 1. Annual variation of monthly mean daily values of long-term global solar radiation for the whole period, for the selected typical solar radiation year and for the worst year.
30
ITRY (MJ/m2 day)
25 20 15 10 5 0 0
5
10
15
20
25
30
Long-term measured global solar radiation (MJ/m2 day) Fig. 2. Comparison of monthly average daily values of long-term global solar radiation data and ITRY for 30 stations of China.
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Table 2 The typical solar radiation years with minimum (min) FS and monthly mean of daily global solar radiation (ITRY) for China Station
Month
Year
Min FS
ITRY (MJ/m2day)
1
Beijing
January February March April May June July August September October November December
1977 1979 1966 1990 1984 1961 1978 1961 1973 1975 1965 1984
0.027 0.035 0.029 0.018 0.034 0.025 0.030 0.029 0.028 0.035 0.024 0.033
8.56 12.09 15.07 18.47 21.00 21.10 17.85 16.52 15.96 12.83 8.97 7.28
2
Changchun
January February March April May June July August September October November December
1998 1993 1995 1999 1972 1972 1960 1995 2000 1978 1964 1994
0.021 0.027 0.027 0.026 0.027 0.029 0.032 0.030 0.025 0.023 0.026 0.030
7.35 11.22 14.29 17.18 19.99 20.25 17.35 16.21 15.30 11.60 7.57 5.93
3
Changsha
January February March April May June July August September October November December
1994 1991 1996 1996 1998 1994 1991 1994 1994 1988 1987 1988
0.035 0.039 0.028 0.036 0.032 0.021 0.040 0.055 0.032 0.041 0.040 0.041
5.49 6.12 7.23 11.39 14.24 14.75 17.44 16.85 12.59 10.85 7.32 7.21
4
Chengdu
January February March April May June July August September October November December
1981 1976 1978 1977 1990 1975 1969 1962 1990 1968 1976 1999
0.019 0.024 0.030 0.024 0.023 0.023 0.028 0.021 0.031 0.024 0.029 0.025
5.20 6.39 9.65 12.20 13.55 13.83 14.65 14.08 9.11 7.03 5.51 4.52
#
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Table 2 (continued ) Station
Month
Year
Min FS
ITRY (MJ/m2day)
5
Chongqing
January February March April May June July August September October November December
1994 1999 1996 1994 1988 1994 1997 1989 1993 1992 1991 1993
0.034 0.023 0.031 0.037 0.023 0.021 0.022 0.040 0.028 0.035 0.031 0.028
3.57 4.46 6.83 9.70 12.02 12.30 15.63 15.34 10.18 5.81 4.12 3.01
6
Fuzhou
January February March April May June July August September October November December
1993 1981 1982 1972 1970 1981 1985 1970 1994 1983 1998 1993
0.028 0.038 0.033 0.025 0.022 0.029 0.020 0.028 0.037 0.020 0.026 0.045
8.11 7.43 9.09 11.97 13.17 14.14 18.87 17.80 13.68 11.70 9.17 8.78
7
Guangzhou
January February March April May June July August September October November December
1978 1978 1996 1961 1984 1979 1971 1972 1996 1986 1978 1983
0.035 0.025 0.029 0.037 0.023 0.028 0.023 0.031 0.032 0.030 0.022 0.025
8.64 7.60 7.99 10.12 12.29 13.10 15.67 14.65 14.26 13.35 12.25 10.72
8
Guiyang
January February March April May June July August September October November December
1981 1996 1977 1999 1985 1990 1979 1984 1990 1961 1989 1978
0.031 0.042 0.028 0.022 0.018 0.025 0.034 0.023 0.025 0.024 0.036 0.029
4.88 7.01 9.42 11.63 12.67 12.15 14.06 14.67 12.02 7.90 6.08 5.67
9
Haerbin
January February
1982 1988
0.026 0.024
6.23 9.50
#
ARTICLE IN PRESS J. Zhou et al. / Renewable Energy 31 (2006) 1972–1985
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Station
Month
Year
Min FS
ITRY (MJ/m2day)
March April May June July August September October November December
1972 1984 1980 1976 1986 1999 1967 1979 2000 1967
0.025 0.030 0.026 0.030 0.024 0.032 0.028 0.035 0.024 0.036
14.11 16.33 19.28 20.40 18.15 16.52 13.96 10.40 6.87 4.56
10
Haikou
January February March April May June July August September October November December
1962 1972 1995 1977 1976 1972 1987 1990 1994 1980 1989 1993
0.033 0.034 0.042 0.029 0.029 0.035 0.035 0.023 0.024 0.029 0.034 0.028
8.36 8.74 11.43 15.31 17.82 17.88 19.60 17.83 15.04 13.08 10.89 9.38
11
Hangzhou
January February March April May June July August September October November December
1970 1997 1969 1972 1983 1984 1975 1996 1983 1990 1990 1990
0.024 0.034 0.026 0.033 0.026 0.036 0.031 0.027 0.028 0.024 0.034 0.030
6.87 8.56 9.87 13.00 14.14 12.84 18.17 17.07 12.65 10.63 8.30 7.55
12
Hefei
January February March April May June July August September October November December
1979 1991 1979 1977 1971 1998 1975 1984 2000 1995 1990 1970
0.028 0.029 0.021 0.035 0.024 0.031 0.033 0.028 0.027 0.018 0.036 0.017
7.34 8.73 10.73 12.85 15.70 16.12 16.38 16.60 12.45 10.71 8.54 7.38
13
Huhehaote
January February March April
1965 1965 1966 1966
0.046 0.060 0.064 0.045
9.91 13.86 16.13 19.87
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Table 2 (continued ) #
Station
Month
Year
Min FS
ITRY (MJ/m2day)
May June July August September October November December
1960 1964 1962 1965 1961 1965 1963 1965
0.033 0.026 0.027 0.063 0.031 0.052 0.027 0.059
22.42 25.86 22.57 22.44 17.00 14.48 10.04 8.16
14
Jinan
January February March April May June July August September October November December
1993 1974 1973 1966 1970 1986 1961 1979 1977 1977 1972 1990
0.035 0.035 0.024 0.029 0.027 0.037 0.023 0.035 0.032 0.029 0.031 0.031
7.86 10.20 13.94 16.55 20.09 19.78 16.22 16.03 14.75 11.23 8.33 7.07
15
Kunming
January February March April May June July August September October November December
1997 1996 2000 1998 1966 1996 1969 1977 1982 1961 1982 1993
0.035 0.042 0.045 0.028 0.039 0.022 0.026 0.027 0.025 0.024 0.036 0.027
14.07 16.47 17.76 19.91 17.84 15.06 14.50 13.88 13.71 11.62 11.38 11.96
16
Lanzhou
January February March April May June July August September October November December
1988 1967 1972 1963 1990 1991 1976 1984 1989 1990 1971 1971
0.025 0.031 0.030 0.032 0.024 0.029 0.027 0.032 0.021 0.035 0.017 0.029
7.90 11.71 14.47 18.17 20.91 21.34 19.83 19.17 14.68 11.32 8.85 7.00
17
Lasa
January February March April May June
1995 1998 1986 1976 1971 1976
0.033 0.034 0.023 0.034 0.016 0.031
15.96 18.26 20.36 22.33 25.49 26.31
ARTICLE IN PRESS J. Zhou et al. / Renewable Energy 31 (2006) 1972–1985
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Station
Month
Year
Min FS
ITRY (MJ/m2day)
July August September October November December
1985 1976 1979 1996 1977 1977
0.041 0.026 0.021 0.041 0.035 0.047
23.84 22.06 20.91 19.27 16.63 14.57
18
Nanchang
January February March April May June July August September October November December
1995 1997 2000 1978 1972 1997 1985 1972 1995 1994 1970 1976
0.033 0.031 0.025 0.028 0.025 0.028 0.027 0.025 0.027 0.035 0.033 0.021
6.86 8.12 8.60 11.99 14.17 15.01 19.80 19.20 15.77 12.37 9.40 8.02
19
Nanjing
January February March April May June July August September October November December
1975 1991 1961 1997 1978 1966 1963 1983 2000 1982 1985 1961
0.027 0.029 0.027 0.027 0.034 0.030 0.024 0.034 0.026 0.035 0.032 0.027
8.00 9.65 11.77 14.41 16.02 15.91 16.94 17.17 12.73 10.97 9.39 7.73
20
Nanning
January February March April May June July August September October November December
1992 1979 1968 1966 1976 1971 1963 1978 1962 1968 1993 1990
0.027 0.035 0.026 0.022 0.024 0.033 0.029 0.032 0.032 0.029 0.035 0.041
7.27 7.88 7.72 11.16 14.83 16.33 17.82 16.41 16.79 14.11 11.17 9.84
21
Shanghai
January February March April May June July August
1997 1995 1997 1993 1996 2000 1997 2000
0.031 0.030 0.043 0.024 0.033 0.031 0.057 0.024
7.16 10.37 10.84 14.54 17.27 15.39 15.80 16.04
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Table 2 (continued ) #
Station
Month
Year
Min FS
ITRY (MJ/m2day)
September October November December
1995 1993 1994 1992
0.034 0.025 0.045 0.032
14.97 11.81 8.36 7.43
22
Shenyang
January February March April May June July August September October November December
1992 1964 1978 1978 1998 1973 1990 1984 2000 1993 1998 1997
0.019 0.028 0.028 0.032 0.018 0.023 0.015 0.027 0.024 0.024 0.022 0.025
6.95 10.60 14.18 17.71 19.50 19.11 16.91 15.76 15.28 11.31 7.39 6.00
23
Taiyuan
January February March April May June July August September October November December
1975 1964 1964 1977 1975 1971 1985 1964 1983 1989 1974 1977
0.032 0.036 0.028 0.029 0.033 0.024 0.026 0.038 0.036 0.027 0.037 0.032
9.35 11.39 14.63 18.04 20.78 20.91 19.17 18.05 14.19 12.28 8.49 7.56
24
Tianjin
January February March April May June July August September October November December
1977 2000 1987 1974 1993 1982 1981 1989 1992 1976 1996 1988
0.021 0.036 0.022 0.026 0.033 0.029 0.022 0.029 0.035 0.030 0.032 0.033
7.98 11.20 14.72 18.61 21.14 20.86 17.73 16.60 15.34 11.43 8.49 6.76
25
Wuhan
January February March April May June July August September October
1979 1975 1977 1979 1964 2000 1963 1998 1977 1977
0.027 0.027 0.032 0.035 0.033 0.028 0.031 0.038 0.025 0.040
7.30 8.17 10.45 13.35 14.75 16.58 17.97 17.21 13.90 11.06
ARTICLE IN PRESS J. Zhou et al. / Renewable Energy 31 (2006) 1972–1985
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Station
ITRY (MJ/m2day)
Month
Year
Min FS
November December
1990 1976
0.042 0.026
8.41 7.53
26
Wulumuqi
January February March April May June July August September October November December
1986 1986 1981 1966 2000 1982 1961 1971 1974 1968 1981 1986
0.039 0.038 0.035 0.030 0.027 0.030 0.024 0.028 0.027 0.024 0.033 0.035
5.56 8.00 12.10 17.24 21.96 22.77 22.72 20.36 16.78 11.67 6.58 4.44
27
Xian
January February March April May June July August September October November December
1994 1987 1975 1998 1967 1991 1962 1961 1967 1986 1968 1972
0.026 0.030 0.036 0.023 0.032 0.032 0.027 0.045 0.035 0.027 0.022 0.043
7.35 8.93 11.66 14.44 16.84 17.80 17.94 16.79 11.61 9.37 7.65 6.96
28
Xining
January February March April May June July August September October November December
1979 1974 2000 1982 1973 1974 1972 1988 1979 1962 1978 1979
0.042 0.030 0.037 0.024 0.021 0.034 0.035 0.037 0.022 0.020 0.036 0.051
10.42 12.97 16.43 19.57 21.31 22.35 20.73 20.05 15.20 13.14 10.86 9.27
29
Yinchuan
January February March April May June July August September October November December
1997 1995 1987 1977 1983 1977 1965 1990 1988 1996 1974 1985
0.026 0.026 0.028 0.028 0.027 0.029 0.037 0.031 0.032 0.030 0.039 0.043
10.02 13.38 16.71 20.21 22.49 24.26 23.40 19.16 17.01 13.72 10.42 9.01
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Table 2 (continued ) #
Station
Month
Year
Min FS
ITRY (MJ/m2day)
30
Zhengzhou
January February March April May June July August September October November December
1994 1981 1988 1986 1999 1982 1993 1985 1971 1971 1966 1990
0.028 0.024 0.027 0.029 0.034 0.036 0.029 0.027 0.032 0.029 0.031 0.030
8.58 10.61 12.99 16.34 18.87 20.29 17.35 15.87 13.23 11.29 9.23 7.56
40 Beijing Chengdu Haerbin
35
ITRY (MJ/m2 day)
30
Haikou Lasa Wulumuqi
25 20 15 10 5 0 Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month Fig. 3. Comparison of ITRY with six stations in Table 1 as example.
In Fig. 1, with Beijing as example, the mean monthly values of daily global solar radiation are given for the typical solar radiation year, for the long-term measurements and for the most unfavorable values of FS for each month in the period. As can be seen from Fig. 1, the difference between ITRY and the long-term measurements for each month is small, whereas difference between ITRY and the value for the most unfavorable values of FS for each month is high. This can also be found for other stations, and the comparison between ITRY and the long-term measurements for all the 30 stations was shown in Fig. 2. The typical solar radiation year with minimum FS for monthly mean global solar radiation for the 30 stations listed in Table 1 are given in Table 2. These data would be useful for the utilization of the solar energy in China. As listed in Table 1, the minimum and maximum values of monthly mean of daily global solar radiation on a horizontal surface (ITRY) of the 30 stations are, respectively, 3.01 MJ/m2 in December in Chongqing, and 26.31 MJ/m2 in June in Lasa, with an annual average value of 13.30 MJ/m2.
ARTICLE IN PRESS J. Zhou et al. / Renewable Energy 31 (2006) 1972–1985
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Annual average of ITRY (MJ/m2 )
25
20
15
10
5
0 2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Station number Fig. 4. Comparison of annual average value of ITRY for the 30 stations.
Fig. 3 shows monthly mean of daily global solar radiation data (ITRY) of the typical solar radiation year for six stations selected from Table 1. As shown in Fig. 3, the difference of ITRY for each month varies substantially between stations. The annual average value of ITRY was shown in Fig. 4. It can be seen from Fig. 4 that there is a remarkable difference between the solar energy resources of different stations. This difference is brought by different cloud formation and sunshine duration in the 30 stations. By using Fig. 4 and the geographical information of 30 stations in Table 1, it can be concluded that there was relatively abundant solar energy resource in northern and western China, and relatively low in inner and southeastern China. This agrees with our former study [12]. 4. Conclusion Solar radiation data, especially the typical solar radiation data, is very important for calculations concerning many applications in the field of thermal engineering. Based on data at 30 meteorological stations in China, typical solar radiation year for daily global solar radiation for these 30 stations are produced using at least 10 years’ measured data. It is found that there is good agreement between long-term data and typical data on a monthly basis. Finally, the geographical difference of solar energy resource of the 30 stations was analyzed. It is found that the solar energy resource in northern and western China is abundant, whereas it is relatively low in inner and southeastern China. Because a complete and detailed typical solar radiation data are not available for China, the work in this paper will fill this gap and will be useful to the designers of solar energy conversion and utilization devices. References [1] Xiao C, Luo H, Tang R, et al. Solar thermal utilization in China. Renew Energy 2004;29(9):1549–56.
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