AN IRIS MECHANISM DRIVEN TEMPERATURE CONTROL OF SOLAR THERMAL REACTORS

In spite of their attraction for clean production of fuels and commodities; solar thermal reactors are challenged by the transient nature of solar energy. Control of reactor temperature during transient periods is the key factor to maintain solar reactor performance. Currently, there are few techniques that are being used to accommodate the fluctuations of incoming solar radiation. One of the commonly practiced methods is to adjust the mass flow rate of the feedstock which is very simple to implement. Another method is focusing and defocusing of the heliostats which requires careful control of the heliostat field. Although these techniques are very convenient and widely being practiced successfully, there are several drawbacks associated with each of them. For example, although the temperature inside a solar reactor can be easily controlled by varying the mass flow rate of the feedstock, it disturbs the flow dynamics inside reactor. This is a major problem for cases where the flow pattern must be maintained constant. Therefore, an alternative temperature control inside the reactor should be developed. This paper presents a promising approach where an iris mechanism is driven by a closed loop control system to adjust the area where solar energy enters the reactor.