Performance evaluation of nanofluid on parabolic trough solar collector

In the present work, the performance of aluminum oxide and deionized water nanofluid used as heat transfer fluid on a parabolic trough solar collector system with hot water generation tank is evaluated. The parabolic trough solar collector is developed using easily and locally accessible materials. Five different concentrations of aluminum oxide and deionized water based nanofluid from 0.5-2.5% is prepared by the magnetic stirrer initially and then the mixture is subjected to ultrasonication process to break aggregates with the absence of surfactant. The prepared nanofluids are allowed to flow through the absorber which is located at a focal point of the solar collector. The performance of nanofluid is compared with pure deionized water. The test is conducted from 8.00 a. m. to 16.00 p. m. daily in the whole length of the test span. The heat transfer fluid is allowed to flow at a mass-flow rate of 0.020 kg/s and 0.09246 m/s velocities. The maximum solar radiation is 821 W/m2, and maximum efficiency is observed at noon time 60.41% for deionized water and 60.49% for 2.5% volumetric fraction of alumina nanofluid. The efficiency enhancement was 3.90% than deionized water. The influence of the critical parameter on the performance is also examined. nema