Determination of the Performance Characteristics of a Modified Solar Water Heating System

Abstract

Heated water is very essential for domestic, agricultural, commercial as well as industrial operations. Obtaining hot water usually comes with a cost. Though conventional water heating systems exist, however, the operational cost and environmental impact of this method is contributing seriously to the already worsened energy situation in Nigeria. Solar water heating system (SWHS) is a practical application to replace the conventional electrical water heater. The low efficiency of solar water heaters has been the main reason why many people still prefer the conventional methods. To improve on the performance characteristics of the existing solar water heater, a modified version was developed by re-shaping the solar collector and making it adjustable so that it could attract maximum solar radiation. The pipe was replaced with another pipe of smaller diameter to allow for more heating surface area using the same collector frame. The tank and the sides of the collector frame were lagged with a special polysterine material to reduce heat loss due to radiation and a unidirectional control valve was introduced to the tank so that the already heated water that can be preserved in the tank. Tests were carried out on the existing as well as the modified heaters. The results obtained show a significant improvement on the performance of the SWHS. The inlet average temperature increased form 24.64 oC to 35.14oC while the outlet temperature increased from 51.53oC to 60.73oC which corresponds to an improvement in the performance of the system’s inlet water temperature of 15.65% and outlet water temperature of 15.14%.