Ключевые слова: alternative, alternative energy, big, building, cell, double, double roof, eco friendly, ecofriendly, ecology, electricity, energy, home, house, industrial, installation, joint, large, light, modern, olar, panel, photovoltaic, power, private, ray, renewable, residence, residential, roof, rooftop, saving, series, sky, solar, solar panel, sun, sunlight, supply, system, technology, tile, top, two, window,