Compound parabolic collectors concentrating

The photoreactivity experiments were carried out by using compound parabolic collectors (CPC), installed at the Plataforma Solar de Almeria (PSA, Spain). CPCs are static collectors with a reflective surface formed by two connected parabolic mirrors with an absorber tube in the focus. They have no tracking system and their design allows the solar rays to be reflected onto the absorber tube, attaining a low concentration factor, defined as the ratio of the collector aperture to the absorber perimeter (it is usually 1-1.5 depending on the application). 

Compound parabolic collectors (CPCs) belong to the most promising photocatalytic solar reactors which combine the advantages of parabolic trough concentrator and non-concentrating system [178]. CPCs are low-concentration static collectors with reflective surface and can be designed for any given reactor shape (see Fig. 7.3a) [182]. The CPC reflectors are usually made from polished aluminum... 

The aim of the solar thermal collector development is to improve and optimize them for the temperature level from 80 °C to 250 °C. There are different approaches like double-glazed flat plate collectors with anti-reflection coated glazing, stationary compound parabolic concentrator (CPC) collectors, evacuated tube collectors, vacuum flat plate collectors, small parabolic trough collectors, linear concentrating Fresnel collectors and a concentrating collector with a stationary reflector. 

From the application point of view, a large attention is always given to desulfurization processes. Recent reports include exploiting the UV-B region of the solar spectrum, concentrated by using a parabolic collector. This was shown to be an effective method for the pre-treatment of sulfur water wells with H2O2/O3. In 15 min the sulfur compounds were transformed into sulfates that were later removed by reverse osmosis. ... 

Compound parabolic concentrator Name given generi-cally to a class of nonimaging collectors with reflecting walls (not necessarily parabolic) that concentrate flux by the theoretical limit. 

Dielectric compound parabolic concentrator Nonimaging collector that operates by total internal reflection. 

Compound parabolic concentrators permit the use of low to moderate levels of concentration for solar thermal collectors without the requirement of diurnal tracking. When used in conjunction with an evacuated absorber with selective surfaces, a fully stationary CPC (designs with concentrations of l.l-1.4x are now commercially available) has a typical efficiency of about 40% at 150°C (270°F) above ambient with available conventional materials. An experimental 5x CPC requiring approximately 12 tilt adjustments annually, when used with a similar available evacuated absorber, has a measured efficiency of 60% at 220°C above ambient and is capable of efficiencies near 50% at 300°C. With such thermally efficient absorbers, higher concentrations are not necessary or desirable. 

Rabl, A., O Gallagher, J., and Winston, R. (1980). Design and test of non-evacuated solar collectors with compound parabolic concentrators, Solar Energy 25,335. 

Compound parabolic concentrator (CPC, also called Winston collector or Winston cone) [95-97] is a reflective nonimaging light concentrator intended to collect incident light from a spatial angle larger than that of imaging concentrators and to... 

Vidal et al. presented the first pilot-plant study about solar photocatalysis for bacterial inactivation. Researchers constructed a new low-cost compound parabolic concentrator (CPC) prototype containing solar collector (Pyrex photoreactor tubes, aluminum reflective surface), flowmeter, pump, sensors (pH, O, T, UV radiation), pipes, fittings, and tanks (PVC). This solar photoreactor has an area of 4.5 m and it was tilted at local latitude to maximize the available solar irradiation. It was observed 5-log reduction for E. coli and Enterococcus faecalis (initial concentration lO -lO" CFU/cm ) after 30 min of solar irradiation (solar UV value 25 W/m )... 

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