Optical and thermal testing of a new 1.12X CPC solar collector

✍ Scribed by M.J. Carvalho; M. Collares-Pereira; J. Correia de Oliveira; J. Farinha Mendes; A. Haberle; V. Wittwer

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 964 KB
• Volume: 37
• Category: Article
• ISSN: 0927-0248
• DOI: 10.1016/0927-0248(94)00205-3

✦ Synopsis

A new CPC collector is described and tested, both optically and thermally, in different configurations. This CPC has a receiver shaped as an inverted "V", which was conceived to accommodate a large gap between itself and the reflector, without optical losses, a novelty which distinguishes this device from others previously proposed. Its acceptance angle was chosen to be large (56.4") before truncation, and 76" after truncation) in order to allow for both fully stationary E.W. and N.S. possible orientations for the collector to be used. Collector height was chosen to allow for the inclusion of convection suppression mechanisms, to enhance the thermal performance of the collector at high temperature. Measurements of instantaneous efficiency are presented, for the collector in E.W. and N.S. orientation. Measurements are also presented for the instantaneous efficiency when a double cover configuration achieved with a Teflon film and a transparent insulation material of the honeycomb type are included. It is shown that the collector's low heat losses are reduced by roughly 30% trough the addition of such convection suppression devices.

Based on these results, the average yearly performance is calculated and compared with the energy delivered by other collector types (flat pates, evacuated tubular collectors). It is shown that, up to 100" C, the present collector outperforms the others, and has a cost which is comparable, if not potentially lower than conventional flat plates.