Solar steam generator having a standby heat supply system

This patent application claims the benefit of U.S. Provisional Patent Application No. 61/045,361, filed Apr. 16, 2008, and U.S. Provisional Patent Application No. 61/057,460, filed May 30, 2008; and which are incorporated herein in their entirety.

The present disclosure relates generally to a solar steam generator, and more particularly, to a solar steam generator having a standby heat supply system.

It is known to use solar energy to heat working fluids which function to provide thermal energy to industrial processes or to generate electric power. In power generation applications, radiant energy from the sun is focused onto a solar receiver to heat a working fluid whereby the heat is used to generate steam to power a turbine which rotates a generator to provide electricity. During the daylight period, the radiant energy is available to heat the working fluid. However during the nocturnal period, the heat transfer fluid cools down, resulting in energy loss and increased recovery time to heat the transfer fluid come the daylight period. When daylight returns, the solar energy once again heats up the working fluid, which can take a significant period of time before the power generation is functioning at optimal levels. Furthermore, the repetitive thermal cycling of the components in the solar receiver increases the stresses on these components which may result in cracking, reduced component life, or component failure.

Accordingly, a need exists to reduce the effect of the thermal cycling of the components of the solar receiver resulting from the repetitive cooling and heating. Furthermore, a need exists to reduce the startup time of the solar generator once daylight arrives.

The present invention provides a standby heat supply system to overcome these problems associated with the cooling of the heat transfer fluid during the nocturnal period.

According to the aspects illustrated herein, there is provided a solar steam generator that includes a solar panel that heats fluid passing therethrough. A steam drum separates steam and fluid received from the solar panel; and then provides the fluid to the solar panel. A standby heat supply system heats the fluid in the steam drum during periods of low solar energy provided to the solar panel.

According to the other aspects illustrated herein, there is a method of maintaining a fluid within a solar steam generator at a desired temperature during a nocturnal period. The method includes heating a fluid flowing through a solar panel with standby heat, circulating the heated fluid to a steam drum that separates the steam and fluid received from the solar panel; and circulating the fluid from the steam drum back to the solar panel. The method further includes circulating the flow of the fluid to a standby heater when the temperature of the fluid drops below a desired temperature; and circulating the heated fluid flow from the standby heater back to the steam drum.

The above described and other features are exemplified by the following figures and detailed description.