In-door experimental analysis of concentrated and non-concentrated evacuated tube heat pipe collectors for medium temperature applications

▸ Concentrated heat pipe showed an improvement of 30% in overall average outlet and inlet fluid temperature differential. ▸ An improvement of 25.42% in total daily energy collection was recorded by the concentrated heat pipe system. ▸ Lack of concentration resulted to 46.22% higher heat losses from the non-concentrated heat pipe. ▸ Better temperature response with higher average efficiency and energy collection made the concentrated heat pipe preferable.