I am conducting an experiment on the parabolic trough that concentrates the solar light and heats up water. I am using different metal sheets (zinc, aluminium, copper, tin...) for the parabolic trough to see the differences in temperature change. I researched on a few things and I understand that it's the microwaves from the sun that's responsible for the water heating up. Then I came across with plasmon that is responsible for reflecting microwaves at the metal surface. Correct me if I'm wrong... And now, I was thinking, how about thermal conductivity? I found out about phonon; is there any relationship between phonon and plasmon? and ultimately, is there relationship between the thermal conductivity and the temperature change in the water (in my experiment)?