Investigation of Temperature and Flow Distribution in a Serially Connected Thermosyphon Solar Water Heating Collector System in Minna, Niger State,Nigeria

Abstract

Natural circulation solar water heating systems are designed and fabricated with varying collector geometries, materials, storage tank capacities and specifications of individual components. Despite the availability of theoretical and experimental studies including the test procedures, to estimate the performances of these systems, there are few experimental studies showing the temperature profiles of a particular collector geometries and materials with water temperature and flow rates in the units. This paper presents detailed experimental observations of temperature and flow distribution with solar radiations in a thermosyphon solar water heating system with four flat plate collectors, connected in series and using locally available materials, under a wide range of weather conditions of Minna for a whole year, to determine its suitability in meeting the hot water requirement for bathing in residential apartments. Results showed that the system is capable of meeting 70 – 100% hot water requirements and an average of 65.5⁰C water temperatures is obtained daily with high temperatures reaching 90^oC on excessive hot days of March to May annually. Water temperatures in the hot water tank are of the range 45^oC to 78^oC and a mass flow rate averaging 55kg/hr was achieved for the system. Detailed temperature distributions, solar radiations variations and mass flow rate of the system were determined and presented. The experimental results were compared to the results found in the literatures and they showed good agreement.

Keywords: Flow measurement; Mean absorber plate temperature; Mean fluid temperature; Radiation measurement; Solar thermal collector system; Solar water heating system; Temperature measurement; Thermosyphon.