Energy Performance and Economic Feasibility Comparison of Evacuated Tube and Flat Plate Solar Collectors for Domestic Water Heating

The study provides performance analysis and economic feasibility examination of Solar Domestic Water Heating (SDWH) Systems employing two different types of solar collectors, Flat Plate Collector (FPC) and Evacuated Tube Collector (ETC). The work studies the system performance, solar system fraction, collector and storage tank outlet temperatures, collected energy, and the system efficiency. The performance analysis of the two solar water heating systems was carried out considering the annual weather conditions of Beirut city by using T*SOL® and TRNSYS Simulation tools. Results showed that the annual efficiency of SDWH using ETC (44%) was 4 points more than the annual efficiency of SDWH employing FPC (40%). The annual solar fraction of SDWH with ETC (89%) is found to be 9 points more than that of FPC (80%). This makes the system with ETC more effective in terms of energy performance, leading to more economic benefits over its life of the operation. This has been proved by evaluating both systems' economic feasibilities over their operation life (20 years). The economic feasibility results showed that the total savings of SDWH using ETC is $ 47,615, and the saving-to-investment ratio is 7.7. The total savings of the system using FPC is $ 42,840, and saving-to-investment ratio is 7. Keywords: Solar domestic water heating, solar collectors, Flat plat collector, Evacuated tube collector, Performance analysis, Economic feasibility.