Experimental Study of Polyethylene Fusion by Scheffler Solar Concentrator

Aims: The present work is the use of Scheffler technology to melt plastic waste to produce composite materials using an oven type receiver. The composite material in this study contains polyethylene as a matrix and sand as reinforcement. Study Design: The fusion temperature of polyethylene is about 200°C and is obtained by solar concentration. The experimental plastic melting unit in Saaba (latitude 12.38° N; longitude -1.43° E), Burkina Faso, uses two 8 m² Scheffler concentrators sharing a cubic receiver. Three types of mirrors with a reflectivity of at least 90% are used as reflecting facets to equip the Scheffler dishes at the site. Methodology: The thermal behavior of the receiver is analyzed experimentally. Temperatures are measured on the inner and outer walls as well as the internal air temperature with 5 K-type thermocouples. When the fusion temperature is reached on the inside, we introduce the plastic waste which has been previously washed, crushed, dried and weighed. Results: The installed model obtained an average energy of 1.80 kW at the receiver and an average internal temperature of 251.15°C for an average irradiance of 623 W/m² during the no-load test. During the load test, an average energy of 1.34 kW and an internal temperature of 206.4°C were reached for an average irradiance of 473 W/m² and an optical efficiency of 56%. This test led to the production of two pavers of the composite material matrix with 2.2 kg of plastic waste. Conclusion: These results show that the profiles of the primary reflector, tracking system, and tilt axis are accurate and the maximum concentrated solar flux converges on the absorbing surfaces of the receiver. The tempered panes of the absorbing surfaces is more transparent and less emissive. Thus our device contributes to the valorization of plastic waste by using a non-polluting energy source.