Study of Modified Absorber Plate with Aluminium Foam of Solar Water Heating System

Abstract

Solar water heating system (SWHS) is water heating equipment that utilizes solar energy for domestic and industrial needs. An absorber plate is the main part of the SWHS that functions to absorb solar energy. Porous materials are efficient in increasing heat transfer, energy efficiency, energy storage, and reducing reflectance losses. Efforts have been made to add aluminium foam as a porous material on the lower and upper surfaces of the absorber plate. Porous materials function absorb heat and store radiant heat energy before being transferred to the fluid. Experimental tests were carried out by testing three models of absorber plates on a solar thermal energy unit with similar conditions. The first model is a standard flat plate (SFP) without aluminium foam. The second model combines standard flat plate and aluminium foam (SFP-TAF), placed on top of the SFP. The third model combines standard flat plate and aluminium foam (SFP-BAF), placed under the SFP. The results showed that the SFP-BAF model has a higher thermal efficiency than the other models. The SFP-BAF model has an efficiency increase of 2.71 % at a flow rate of 10 L/h and 5.39 % flow rate of 12 L/h compared with the standard model (SFP). The position of the aluminium foam at the bottom surface is substantial enough to help absorb and store radiant heat for transfer to circulating water.