After a period of research and commercial development of the parabolic trough
collectors in the 80
0
s a number of companies entered the field producing this type of
collector, for the temperature range between 50 and 300
C, all of them with one-axis tracking. The solar collectors produced by the Industrial Solar Technology
(IST) Corporation are considered here. IST erected several process-heat installations
in the United States with up to 2700 m
2
of collector aperture area[16]. This type of
collector has been considered in this study. The characteristics of the IST collector
system are shown in Table 9.