There is provided an AI-based air damper control system and method for industrial boilers. An AI-based optimal air damper control method according to an embodiment calculates energy efficiency under a given control condition and an environment by extracting energy efficiency-related data from industrial boiler operational data and analyzing a correlation between corresponding data, trains an AI-based optimal air volume-for-load prediction model by using the extracted data and the calculated energy efficiency as training data, and derives an air volume condition that results in peak energy efficiency under a given load, based on the trained optimal air volume-for-load prediction model, and automatically controls the air damper according to the corresponding air volume condition.

The disclosure concerns a waste heat recovery unit comprising a main heat exchanger configured to exchange heat between an exhaust fluid from a heat source and a working fluid of a waste heat recovery system, wherein the waste heat recovery unit comprises an additional heat exchanger configured to exchange heat between the exhaust fluid and alternatively a cooling fluid or a portion or the whole of said working fluid during transitory states.

A back-up boiler system for a solar thermal power plant (201) for transferring solar energy into electricity, said back-up boiler system comprising a combustion chamber (70) and a convection section (80) in fluid connection with said combustion chamber (70), wherein in the convection section (80) at least a first heat exchanger (92) is provided for heating a molten salts mixture of the solar thermal power plant and a second heat exchanger (90) for pre-heating boiler feed water of the solar thermal power plant, wherein the back-up boiler system (25) is configured to allow selection between only providing heat to the first heat exchanger (92), only providing heat to the second heat exchanger (90) and providing heat to both heat exchangers (90, 92), preferably dependent on availability of solar radiation and/or dependent on demand of power generation. The invention also relates to a solar thermal power plant (201) for transferring solar energy into electricity and a method for operating a solar thermal power plant.

A non-oxygen-consuming energy storage system includes: an interconnecting pipe, connecting a heat recovery boiler or a flue gas header to a chimney or its flue gas duct; a gas inducing equipment along the interconnecting pipe, inducing gas inside the heat recovery boiler to enter the interconnecting pipe through the chimney and then enter the heat recovery boiler; and a heater along the interconnecting pipe and heating up the gas in the interconnecting pipe, and using electricity or other non-oxygen-consuming heating devices as a heat source. Thereby, the gas in the heat recovery boiler is circulated and heated up by the system, and pipelines and components of each unit are kept in a hot standby condition, thus under an emergency power demand on the power grid, the combined cycle unit can rapidly ramp up its load to meet the demand, and can also reduce energy consumption during start-up stage.