# Preliminary Ray Tracing and Experimental Study on the Effect of Mirror Coating on the Optical Efficiency of a Solid Dielectric Compound Parabolic Concentrator

^{1}

^{2}

^{3}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Experimental Study

_{1}is the area of the CPC front aperture, S

_{2}is the area of the CPC base, and n is the refractive index.

_{sc}at different times on a sunny day. A PV cell of same size without solar concentration was also used in the entire experiment for comparison.

## 3. Rays Tracing Analysis

**Figure 4.**Schematic diagram of ray tracing results for the experimental solid CPC. (

**a**), (

**b**) and (

**c**): for the incidence angles of 15°, 35°, 40° respectively and no coating; (

**d**), (

**e**) and (

**f**): for the incidence angle of 15°, 35°, 40° respectively and with mirror coating.

## 4. Results and Discussions

_{sc}of the solid dielectric CPC PV without coating was the highest, followed by the solid dielectric CPC PV with coating, and the lowest is the flat PV. The open circuit voltages of the three PV modules were quite close.

_{max}and voltage V

_{max}corresponding the maximum power output were obtained from the I-V curve. Subsequently, the maximum power P

_{m}and the fill-factor FF were calculated as follows [19]:

_{1}is the solid dielectric CPC PV, and P

_{in}is the incident irradiance.

Parameters | Solid dielectric CPC PV without coating | Solid dielectric CPC PV with coating | Non-concentration flat PV |
---|---|---|---|

I_{sc} (mA) | 120 | 108 | 70 |

P_{m} (mW) | 44.80 | 39.45 | 25.86 |

FF | 0.69 | 0.68 | 0.70 |

η(%) | 7.98 | 7.03 | 11.52 |

_{sc}of the solid CPC without coating is higher than that with coating. The ratio of short circuit current of the solid CPC PV modules to the flat PV may indicate the optical concentration ratio of the solid CPCs. The optical concentration ratio of the solid CPC without coating is approximately 1.7~1.8. The optical concentration ratio of the solid dielectric CPC with coating is about 1.5~1.6. The short circuit current or the optical concentration ratio of the solid CPC without coating is higher by approximately 14% than that of the coated solid CPC. This is satisfactorily in consistence with the results gained from the indoor testing.

**Figure 10.**Optical efficiency of the truncated solid dielectric CPC with and without mirror coating at different incidence angles.

**Figure 12.**Comparison of optical efficiencies of the truncated solid CPC without mirror coating, with full or partial coating, respectively.

## 5. Conclusions

## Acknowledgments

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**MDPI and ACS Style**

Pei, G.; Li, G.; Su, Y.; Ji, J.; Riffat, S.; Zheng, H.
Preliminary Ray Tracing and Experimental Study on the Effect of Mirror Coating on the Optical Efficiency of a Solid Dielectric Compound Parabolic Concentrator. *Energies* **2012**, *5*, 3627-3639.
https://doi.org/10.3390/en5093627

**AMA Style**

Pei G, Li G, Su Y, Ji J, Riffat S, Zheng H.
Preliminary Ray Tracing and Experimental Study on the Effect of Mirror Coating on the Optical Efficiency of a Solid Dielectric Compound Parabolic Concentrator. *Energies*. 2012; 5(9):3627-3639.
https://doi.org/10.3390/en5093627

**Chicago/Turabian Style**

Pei, Gang, Guiqiang Li, Yuehong Su, Jie Ji, Saffa Riffat, and Hongfei Zheng.
2012. "Preliminary Ray Tracing and Experimental Study on the Effect of Mirror Coating on the Optical Efficiency of a Solid Dielectric Compound Parabolic Concentrator" *Energies* 5, no. 9: 3627-3639.
https://doi.org/10.3390/en5093627