Qualification of a Small-Scale Parabolic Trough Collector with Direct Steam Generation for Process Heat and Solar Cooling Applications
Abstract
A small-scale parabolic trough collector was further developed for use in process heat and solar cooling applications with an operating temperature between 140 and 200°C. Measurements of both the optical characteristics of the reflector and the thermal behavior of the collector operated in direct steam generation mode were carried out. Both tests show good results. The optical measurements of the collector geometric accuracy show that around 99% (depending on the angle of incidence) of the reflected rays actually hit the receiver. The thermal measurements were carried out with 10 collectors connected in parallel. Because of the direct steam generation mode the flow rate in the collector circuit is very small. Therefore, small pipe diameters and pumps can be used. The response time to heat the flow temperature from ambient temperature to 200°C operating temperature is very short (2 min). The flow temperature is kept constant thanks to the self regulating valve inside the collectors.