J. Pernpeintner German Aerospace Center (DLR), Cologne, Germany
The receiver is a key element of the parabolic trough collector. Quality control of the receiver is realized by destructive or nondestructive methods. Spectroscopic measurements of absorptance, emittance, and transmittance are performed on small samples of the absorber and glass envelope. Samples are either taken during the manufacturing process or cut from receivers. Nondestructive quality control of parabolic trough receivers includes measurement of heat loss, calorimetric measurement of optical efficiency in solar simulators, and nondestructive spectroscopic measurement of absorptance and transmittance.