1) Flat Plate collector:
A Flat Plate collector consists of an absorber plate, covered on the top by a flat glass pane and insulated at the bottom and at the sides by insulation material.
2) Evacuated Tube collector:
An Evacuated Tube collector consists of several vacuum tubes installed
together in a rack. In each tube, an absorber strip has been inserted into the glass tube and insulated by a
surrounding vacuum.