In consideration of the increasing significance of Domestic Hot Water (DHW) in the energy consumption of residential buildings, the alignment with the United Nations' agenda for Sustainable Development 2030 underscores the importance of integrating renewable energy sources within this particular sector. Therefore, the integration of Solar Water Heater (SWH) with Thermal Energy Storage (TES) technology has become an essential approach to simultaneously reduce building energy consumption and effectively harness solar irradiation during peak periods to fulfill future needs. This investigation presents an inventive SWH, which integrates an encapsulated Phase Change Material (PCM) storage tank, intending to reduce the need for electrical heating in meeting the demands of DHW. The system being proposed facilitates efficient thermal energy storage of excess solar energy, which can be utilized to fulfill the energy requirements of a building during nighttime periods. The present study proposes the development of a transient daily analysis model utilizing the TRNSYS software. This model aims to accurately simulate the dynamic response of a solar-assisted water heating system, taking into account the fluctuations in weather conditions and hot water demands, within the confines of a residential apartment over 30 hours. In addition, a novel MATLAB component has been developed to enable a comprehensive simulation of the enclosed PCM storage tank. The accuracy of the model is validated and compared with experimental data to ascertain its reliability. Thermal analysis encompassing the consideration of phase change phenomenon, along with latent and sensible heat energy storage, is undertaken to comprehensively evaluate the efficiency of the system. The research findings indicate that the incorporation of the PCM storage tank effectively stores 18 MJ (17060 Btuh) thermal energy approximately. This storage system is instrumental in reducing the energy requirements of the DHW system as it functions as the primary heat source when solar energy is unavailable. In addition, the transient analysis provides insights into the system's capacity to sustain a desired temperature range for hot water supply throughout the entire day, including nighttime. This is achieved with minimal dependence on electrical energy, even when faced with low levels of solar radiation. The aforementioned discoveries highlight the significant potential for achieving considerable energy conservation and improved thermal efficiency within residential hot water systems, ultimately facilitating the promotion of energy efficiency and mitigation of greenhouse gas emissions in buildings.