Effect of Colored Absorbers on the Performance of a Built-In-Storage Type Solar Water Heater

Abstract

Four built-in-storage solar water heaters (BSWH) of equal volume, equal projected area are tested simultaneously under identical working conditions for their performance comparison in terms of efficiency and heat energy absorb ability. Three of the heaters of BSWH are painted with three different colors (black, blue and red brown) and one is left colorless. The BSWH with different colors are used to heat 138 liters of water.  Maximum temperature of water is achieved while the heater is painted black. In the month of March, temperature of water is achieved 54_­⁰C for black absorber absorbing 542 W/m², 50⁰C for blue absorber absorbing 448 W/m², 43⁰C for red brown absorber absorbing 341 W/m² and 41_­⁰C for colorless absorber absorbing 336 W/m². Monthly average efficiency of BSWH with black absorber is 57% in February and 56.5% in March, with blue absorber is 53% in February and 50% in March, with red brown absorber is 41% in February and 40% in March and with colorless absorber is 35% in February and 35% in March respectively.