The paper describes the system and experimental evaluation of an evacuated tube heat pipe collectorarray augmented with a novel design internal concentrator having a direct flow absorber and tested inthe north–south and east–west align configurations under real outdoor conditions. External and internalconcentrators have the potential to supply higher generator inlet temperatures needed for solar drivencooling systems. However, internal concentrator augmented solar collectors can further reduce heatlosses and increase output temperatures. It is shown that collector outlet temperatures of 110 C or moreis possible and can be efficiently used to drive solar cooling systems with higher coefficient of performance(COP). The evacuated tube collector array augmented with a novely designed internal concentratorhaving a direct flow absorber in the north–south alignment was found to be more energy efficientwith larger temperature lift and outlet and inlet temperature differential and substantial improvementin thermal performance compared to its east–west align configuration due to shorter connection pipingconnecting the internal concentrator augmented CPC to the evacuated tube heat pipe collector array.
Nchelatebe Nkwetta, D., & Smyth, M. (2012). Comparative field performance study of concentrator augmented array with two system configurations. Applied Energy, 92, 800-808. https://doi.org/10.1016/j.apenergy.2011.08.030