**2.4.3 Compound parabolic collecting reactor (CPCR)**

The compound parabolic collecting reactor (CPCR) is a through reactor without any solar concentrating properties. The major difference between the PTR and CPCR is the shape of their reflecting mirrors. The reflector of a PTR has a parabolic profile and the pipe is

Fig. 3. Schematic view of the reflector of a CPCR

positioned along the focal line. Subsequently only parallel light which enters the parabolic through can be concentrated on the pipe. The reflector of a CPCR generally made up of two half circle profiles side by side. The focal line is situated just above the connections of the two circles. Thus light entering from almost any angle can be reflected to the focal line of the CPCR. Fig. 3 shows the schematic view of the reflector of a CPCR.
