The Chinese 100-kW project laid the foundation for the 3- iun mirror module development to date. However, there is a significant difference between the market requirements for China versus the United States. China’s interior does not have the transmission line infrastructure already installed in the United States. So China’s solar need is for village electric power. For China, then, our modules can be used on horizontal beam trackers in fields.
Meanwhile, we believe the U. S. market will be for PV integrated into commercial buildings with our target initial market in the sunny southwest. Horizontal beam trackers or post-mounted trackers are not suitable for this building-integrated market. So, JXC has designed, fabricated, and deployed a carousel tracker for use on commercial building flat rooftops [8]. This carousel tracker has been described in Chapter 9.
The photograph in Figure 12.15 (left) shows a JXC carousel with 180- W 3-sun modules installed on a building flat rooftop at ORNL. This unit has been
 |
|||
|
|
||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
 |
|||
500
450
400
g-350
300
250
200
>
150
100
50
0
Figure 12.14. Typical string currents, system voltage, and array power for a 100-kW (PTC) 3- sun system (see text for more details). Idc = DC current, Vpv = PV array DC voltage; dcc = Direct current.
|
Figure 12.15. Four CPV 3-sun modules on a carousel at ORNL (left) and UNLV (right). |
successfully operating under test since September of 2007. Another carousel of this type has also been installed on a rooftop at the UNLV (Fig. 12.15, right).
While 3-sun modules have been in successful operation in China, solar flux data has generally not been available for correlation with performance. The ORNL site is the first test site with good solar flux instrumentation. Data are available for the direct normal flux, diffuse, and global horizontal solar irradiance. Similar data are also available at the UNLV site.
Figure 12.16 shows exemplary data collected for these two carousels over the last 18 months. These data are consistent with a 155 ± 5 W PTC 3-sun module power rating.
