Page 233 - Design of Solar Thermal Power Plants

216 3. GENERAL DESIGN OF A SOLAR THERMAL POWER PLANT

3.8.2 Principles of Selecting Thermal Storage Capacity
Thermal charging and discharging power of thermal storage shall be
equivalent to the output power of collector field and input power of a
steam turbine. Output power of collector field at the design point is
equivalent to the sum of rated input thermal power of a steam turbine and
the transient thermal storage power. However, input power of thermal
storage still has been designed according to the maximum thermal
charging power, and the thermal discharging power has been designed
according to the maximum load requirement of a steam turbine.
When calculating thermal storage capacity solar multiple acts as an
important concept, which comes from concentration field. In case of
considering the concentration field while supplying power to the steam
turbine and thermal storage, area of concentration field at the design point
must be considered to be large enough. Relationship between thermal
storage and receiver has been given in Sections 3.7.1 and 3.7.4. While in
Section 3.7.4, the more precise value of thermal storage can be obtained by
applying TRNSYS, and also, the thermal storage unit can be designed and
the respective working status can be understood. In addition, during
design of thermal storage, self-consumed energy of thermal storage unit
must be considered as well, including fossil fuel backup and synthetic oil
or molten-salt anti-coagulation measures.

3.9 MAIN POINTS FOR POWER PLANT SITE PLAN

The overall planning can be conducted based on the location of urban
areas, meteorological conditions, access route connection, HV outlet,
water source, road, land coverage of concentration field and other
external conditions as well as features of the plant area by integrating with
specific concentrating power generation process, in which the following
points shall be specified: power plant capacity, concentration field layout,
steam generating area, thermal storage area, conventional generating
area, location and transportation of the power plant, HVoutlet orientation
and passageway, water source of power plant, fuel transportation,
drainage of power plant, power plant general layout and general elevation
planning factors.
1. Power plant capacity. Current scale and reserved scale for site
expansion shall be determined, especially for the concentration
field; when the site is arranged, long-distance transmission losses
of high temperature fluid and wind direction shall be considered.
For a power tower plant, necessary site conditions for receiver
tower installation and receiver maintenance service shall be
considered.