Effectiveness of reflective surfaces on thermal performance of heat pipe solar collector in Malaysia.

Four solar hot water heater systems were tested side by side to determine their performances simultaneously. Each system consisted of an evacuated glass tube heat pipe solar collector connected to an insulated storage tank. Three of the systems were fitted with three different types of reflective surfaces to improve their performance. The reflectors had various shapes. The first reflector consisted of a plane reflecting surface. The second had the sides of a plane reflector bent upwards to form a “trapezoidal wing”. The third reflector was bent into a compound parabolic concentrator shape. The results of the three systems with the reflectors were compared with the fourth system which did not have any reflector underneath. The comparative results showed that the most cost effective solution in terms of storage tank temperature generated was obtained by just placing a plane reflective surface under the collector. From an economic stand point of view, the plane reflector is recommended.