Y. T. Chen's research while affiliated with University of Science and Technology of China and other places

... To date, various technologies have been developed to harness solar energy for applications including electricity generation, solar water heater, daylighting, food processing etc [1][2][3][4][5]. The demand for solar photovoltaic (PV) systems has increased dramatically for the last several decades as a source of renewable energy to reduce the use of fossil fuel [6]. ...

... A similar model was also applied to heliostats control in Refs. [20,21], in these two papers, the master-slave heliostats is set to achieve a better concentrating effect of the sunlight under the rotation-elevation mode. This paper will apply the principle of the leaderfollower control strategy to scientifically block the heliostat field, and set one or more leader heliostats in each heliostat group. ...

... A new method of reflectance measurement was presented in 2003, which employs a fast rotating reference mirror and a geometry configuration to alternatively deliver the light via a sample mirror or by passing it to a photo detector [91]. The instrument incorporates four optical components (see Figure 32): a sample mirror, a reference mirror, a flat- surfaced photo detector and a laser source. ...

... Suppose the solar incidence angle during the central time of the power generation period meets the DNI conditions by setting the reference angle of the optical module. In that case, the variation range of solar incidence angles during the power generation period is within |α| < 15 • [25,26]. Therefore, based on the analysis and experimental results, it is suggested that the module proposed in this study, with a concentration efficiency variation within |α| < 15 • of daily solar incidence angle variation, within 15%, may not require tracking means for this purpose. ...

... Thus, it lowers the maximum spread and increases the uniformity of the reflected image from each heliostat [65,66]. A conventional heliostat tracking system has excellent focus at a particular time of the day and it is poor at other times but the uniform performance of target aligned may be advantageous. ...

... Buck and Teufel 13 compared various canting methods and tracking types, and showed that targetaligned heliostats are superior to azimuth-elevation heliostats with regards to spillage (or annual incident-powerweighted intercept), with improvement up to 7% for certain heliostat locations. Various other methods to reduce astigmatic effects have been proposed for fixed-facet target-aligned systems, for example, use of elliptic shape stretched membrane heliostats 12 , use of customised mirror shape 15 , and a smoothing procedure to optimise the incidence angle used for off-axis canting 6 . However, the magnitude of the optical improvement allowing for dynamic canting is far higher than possible with fixed facets. ...

... The concentrated solar systems which make solar tracking in two dimensions are the central receiver and high-temperature solar furnaces. Using the two-stage systems having a large-scale solar furnace for different applications can produce the high thermal power up to 1000 kW at temperature of 3000-3800 • C. Melting a tungsten wire on the focal point at approximately 3500 • C is achieved by using a parabolic dish at 60 cm diameter and the heliostat at 4 m 2 [1]. In the other solar furnace (double stage), the solar beams are reflected to the parabolic dish using a heliostat tracking the sun. ...

... Consequently, the angle-of-incidence effects mentioned above cannot be resolved, so the (nearly flat) mirror is generally given the optical figure of a sphere as the best option. Alternatively, the mirror can be given a third axis of rotation (about its center) and rotated continuously to retain the correct orientation with respect to the sun-mirror-receiver plane (Chen et al., 2001;Zaibel, Dagan, Karni, & Ries, 1995). A tracker with the first axis pointing toward the receiver, or a spinning-elevation tracking system accomplishes this also (Zaibel et al., 1995). ...