Glass Separation Process for Recycling of Solar Photovoltaic Panels by Microwave Heating

Abstract

Installations of solar photovoltaic (PV) and collector modules have been increasing significantly in the past ten years and continued to do so in many countries, especially in Southeast Asia. For example, in Thailand, the Electricity Generating Authority of Thailand plans to install more than 2.72 GW of hydro-floating solar hybrid projects, encouraged by the country Power Development Plan (PDP2018). The project will be the most significant floating PV source in southeast Asia, having more than 1 million PV modules assembled. The approximate lifetime of a PV panel is about 25-30 years. Therefore, these solar PV wastes will be enormous at the end of life and may cause a big problem. Previous research showed many methods to delaminate solar panels. Still, some recommended that thermal practice such as radiofrequency heating is simple and has a low environmental impact and low operating costs. Unfortunately, it has a high installation cost and is hard to develop into commercialization. Therefore, in this work, a dielectric heating method using a microwave was deployed. After a crystalline-silicon cell PV was prepared, the microwave was launched at various times and power. Surface and spot temperatures and ethylene-vinyl acetate layer temperatures were measured and collected by a thermal imaging camera and digital thermometer with type K thermocouples. The force required to remove a glass pane was investigated by a force gauge using the experience standard. After heating the PV panel with a microwave, the results showed that removing the glass pane could be conveniently conducted easier than a non-heated panel by about 50-60% of the force. In summary, the microwave frequency appeared to be an attractive option for delaminating expired or damaged PV panels. In the future, the second life of PV panels after heating and delamination by microwave frequency should be further investigated to see if benefits may be obtained here.