Performance comparison of built-in-storage type solar water heaters

Abstract

Three identical built-in storage type solar water heaters (BSWH) were tested under same conditions simultaneously in IUT campus, Bangladesh. All of the heaters having corrugated plates as absorbers, they differ as one has two reflectors and the other two has one reflector each. Tests were carried out during the months of May and June and again during August and September in the year of 2014. For each of the tanks, the temperature of the water, the ambient temperature and the solar insulation, ‘I’ were recorded at an hourly basis from 08:00 am to 05:00 pm on days with adequate solar radiation. The energy absorbed by the water, and so the efficiency of the absorber were also calculated on a daily basis from the data obtained. The BSWH using water and single reflector is recorded to heat 138 liters of water to a maximum temperature of 51.6 0 C, which is in the month of May. The BSWH using Nanoparticles with water and single reflector is recorded to heat 138 liters of water to a maximum temperature of 58.5 0 C, which is also in the month of May. The BSWH using water and double reflector is recorded to heat 138 liters of water to a maximum temperature of 55.10 C, which is also in the month of May. The efficiency, from the recorded and calculated data reveals that the efficiency of the BSWH using water and nanoparticles is higher than that of the BSWH with two reflector, and both of them have efficiency higher than the BSWH with water and single reflector.