Estudo experimental de uma bomba de calor solar a propano para aquecimento de água dotada de tubo capilar duplo

• Ano de defesa: 2021
• Autor(a) principal: André Gonçalves de Oliveira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ENG - DEPARTAMENTO DE ENGENHARIA MECÂNICA; Programa de Pós-Graduação em Engenharia Mecanica; UFMG
• Palavras-chave em Português: Bomba de calor assistida por energia solar; Capilar simples; Capilar duplo; Dimensionamento; Radiação solar; Engenharia mecânica; Bomba de calor
• Link de acesso: http://hdl.handle.net/1843/41825

The present work aims to carry out a comparative study between a propane heat pump assisted by solar energy working with a single capillary and the same heat pump working with a double capillary. The heat pump's single capillary consists of a single capillary 5.60 m long and 0.064’’ in diameter. The double capillary consists of a set of two capillary tubes, one 4.00 m long and 0.064’’ in diameter, and the other 1.85 m long and 0.050’’ in diameter. The single capillary is designed to meet both high and low solar radiation conditions. The double capillary, on the other hand, is designed to work with a capillary to operate in low solar radiation and another for high solar radiation. The capillary tubes were dimensioned by mathematical modeling, using the EES (Engineering Equation Solve) program. In this modeling, the chosen geometry for the tubes was the helical one, as it presents a more compact shape. The coefficient of performance (COP) found for the single and double capillary operating in a high solar radiation environment was 2.79 ± 0.33 and 2.92 ± 0.31, respectively. As for environments with low solar radiation, the COP found for single and double capillaries was 2.55 ± 0.36 and 2.64 ± 0.37, respectively. Based on the results of the degree of superheat, the values presented allowed us to conclude that it is not safe to operate the heat pump with just a single capillary, as the degree of superheat becomes negative at low solar radiation and when exposed to high radiation solar energy, reaches a value of 22 °C. Therefore, it is concluded that a single capillary cannot cover the variation in solar radiation over the course of a day. The results presented using two capillaries are satisfactory because the superheat remains positive at low solar radiation and does not exceed 20 °C when exposed to high solar radiation. Therefore, analyzing the configuration of the double capillary heat pump, it is concluded that it is safe to operate it over a day, with variation in solar radiation.