Estudo numérico e experimental de um aquecedor de parede assistido pelo princípio de funcionamento de termossifões

Abstract

The present work comprises a numerical-experimental analysis of a wall-mounted heater assisted by the operating principle of thermosyphons. Experimental tests were conducted in a controlled environment on a prototype using the operating principle of thermosyphons, and another one, designated as conventional, which uses oil as the working fluid. The heaters were made of stainless steel with identical geometry and an internal volume of approximately 4.45L, powered by an electrical resistor with a power dissipation of 900W. For the experimental analysis, fill ratios ranging from 60 to 100% were used, with working fluid volumes between 356 and 594mL. Thermocouples were employed to measure internal and surface temperatures, while a system was implemented to measure current, voltage, and power consumption, as well as environmental parameters such as ambient temperature and relative humidity. Additionally, the internal pressure was obtained through a pressure transducer. Statistical analysis of the results allowed for an evaluation of thermal performance, demonstrating behavior consistent with literature expectations. The results highlight the superiority of the prototype with an 80% filling ratio, reducing heating time by approximately 52% compared to the conventional device, while offering greater thermal stability and energy efficiency. The prototype’s energy consumption was approximately 21% lower than that of the conventional heater, demonstrating its economic viability. The numerical analysis was based on the best configuration of the experimental data, corresponding to the 80% filling ratio. Numerical simulations using the VOF and Mixture Models showed good agreement with the experimental data, validating the heat transfer phenomenon and emphasizing the VOF Model’s ability to represent the vapor fraction. This work contributes to the development of more efficient and sustainable heating technologies, with potential for reducing energy consumption and environmental impacts, as well as enabling advancements in the development of nationally viable technology, suitable for patent filing, stemming from these investigations.