Page 116 - Design of Solar Thermal Power Plants

2.8 VARIOUS SPECIAL CLIMATE CONDITIONS 103

simply estimated on the basis of a 10-m height according to the land
wind shear exponent, land wind forces corresponding to heights of 50
and 70 m above ground can be measured.
Areas with stronger wind are mainly distributed on the southeast coast
and neighboring islands, Inner Mongolia, Xinjiang, and the Hexi Corridor
of Gansu, as well as North China and partial areas in the QinghaieTibet
Plateau. Furthermore, partial areas in Central China also have strong
winds.
Wind in China is significantly influenced by region and season;
northern areas have stronger wind than southern areas; winter and spring
are under the influences of Siberian high pressure and exhibit wind forces
that are stronger than those of summer and autumn.

1. Wind direction variations for various months can be produced to
facilitate concentrator load design by filling out Table 2.20.
From Table 2.20, a wind direction diagram can be drawn.
2. Maximum wind speed and wind direction data from neighboring
meteorological stations by year, as well as maximum wind speed,
mean wind speed, and annual dominant wind direction on a 10-m
height basis for a period of 50 years, are recorded.

2.8.3 Precipitation Parameters

1. Annual mean precipitation is the mean height of liquid or solid
(after melting) water per square meter every year falling from the
sky to the ground, which can be obtained from the local
meteorological station.
Precipitation within unit time is referred to as the precipitation
intensity. Normally the unit time is 10 min, 1 h, or 1 day.
2. Annual mean evaporation is the amount of water that spreads into
the air through evaporation within a year, which is normally scaled
by evaporated water layer thickness (mm).

2.8.4 Disastrous Weather Phenomena and Respective
Parameters
1. Hail. Annual mean hailing days, diameter of hailstone, maximum
diameter, and maximum annual hailing days.
2. Sandstorm. Annual mean frequency of sandstorm, which can be
measured by days and used as a reference for solar shade
calculation and concentrator design. Furthermore, the travel rate of
sandstorms shall also be provided.